Celestron CGX Reviews and Testing

[glend]

I am starting this thread for the reviews and testing results of the new Celestron CGX mount. Looking for input from Australian or other southern hemisphere CGX buyers concerning assembly and setup, alignments, operations, imaging experiences; along with any things to watch out for, and problems/solutions. This will include reviews of the anticipated PWI software due for release early February.
My CGX is currently set up on its tripod in my observatory awaiting a clear night to fire it up and get stuck into polar alignment.
More to come.:welcome:

[toc]

Thanks - I will contribute what I can. I am not up to the skill level of most here, but I have a nice selection of scopes to use - 90mm refractor, 7inch MAK Newt, and a 12 inch SCT, which should be getting near the payload limit.

[Camelopardalis]

Pics! Pics! :lol:

[traveller]

Astro PORN :lol:

[toc]

Spent most of the night with the CGX and my 190mm Mak-Newt. Enjoyed the mount - had no issues with the home switches (and I used it a lot) balancing, gotos where very accurate with starsense.

My horror show with PHD guiding continues though :D even though I was well polar aligned (used the Celestron ASPA, and then sharpcap) and was shooting 80 second unguided images of M42, guiding was a waste of time.

In truth I have NEVER been able to get PHD to work on any of my other mounts (HEQ5,CGEM) either with my Orion short tube 80, or various finder guiders, so this result was not unexpected. :lol:

Next step will be to replace the finder guider, cables, and perhaps switch to an OAG.

Was very disappointed and frustrated with guiding, but was happy with the mount.

[glend]

Tim, try Metaguide first. I had all sorts of problems with PHD2 but when i switched to Metaguide it worked first time on default settings. Metaguide is free.

[Merlin66]

Tim,
Posting your PHD data on the PHD forum may give some answers.
I'm no expert, but when you do have the mount connected there are lots of Dec (south) corrections - this usually indicates a PA issue.

[glend]

Ok Dunk, I have a few for you. I have disassembled my old NEQ6 pier cage and installed the CGX on it's tripod in the observatory for preliminary testing. A few of my observations on the setup:
- It's heavy, but a bit easier to manage than the NEQ6 thanks to the two handles.
- The tripod is ok, the tops section is really good but the lower leg extensions seem like they could be made stronger. The graduations on the lower leg are useful for setup on level surfaces, or as a reference.
- Like most mounts the provided bubble level is useless, it did not agree at all with my caravan bubble x/y level.
- Adjustment of Alt and Az is a breeze compared to the NEQ6. Good elevation control.
- Love the screw on locking nut for the power cable, something less to worry about.
- I checked the play in both RA and DEC and there is no slop and move very smoothly.
- What I don't like - there are no setting circles on either axis. Perhaps this is just that I am used to them on the NEQ6, and used them alot. I like having a visual reference for home positon, and it is useful when balancing.
I have attached a few pics.

First light might be tonight, and I will start out with my 115mm refractor, and do a PA using Sharpcap, then star alignment with Nextstar. Probably won't do any serious imaging until I have the new top plate and adaptor for my pier, the observatory floor is strong and I can do some test images but I would need to stay out and run everything from the house via Teamviewer. Besides that tripod takes up alot of room.
Please so far.

[toc]

Ok, here is the strange thing - I polar aligned with the All star routine, and then used Sharpcap 2.9's polar alignment routine. When I run PHD2's guiding assistant, it told me my polar alignment was WAY off. Given I was able to do 1 minute unguided exposures tells me it was wrong.

[Camelopardalis]

Love it :thumbsup:

Looks like someone up here must have bought one (wasn't me LOL) as it's cloudy all week...

[toc]

I am looking at it now. Looks like a busy interface, but if it works, then I dont care :) Clouds are starting to come in now, but fingers crossed I can be victorious tonight :lol:

[Merlin66]

I found the write-up by Bruce Waddington helpful.

[toc]

Well I was reviewing my setup, and can see some major issues with the finder. might explain the strange results.

[Merlin66]

Tim,
I found a loooong thread on the UK SGL site by Ian L. which I've edited and prepared in a PDF.
Well worth reading.
I'll post a new thread.....

[toc]

Hi y'all - I took the plastic covers off the drives in the CGX, and I can see that in the DEC axis there is a slight wobble in the gear on the motor - it doesn't seem to translate into any wobbling on the gear on the worm because of the belt I guess. My feeling is that this is really just cosmetic. I don't really see how this could cause issues, but do you think it is worth maybe taking the belt off and fixing it? RA is not perfect either, but much less obvious.

Kind of nickpicking I guess.

[glend]

Tim if you watch the Celestron video posted online on the website and on CN, you may see the same apparent wobble on the drive sprocket. At the time i first saw it i assumed it was the flat spot on the shaft that is used to lock the sprocket on the shaft with a grub screw, and as it rotates under power it gives the illusion of a wobble.
I would not touch the belt drive if i were you, as you could potentially create warranty issues, if in doubt ring Bintel and report it, or raise a ticket with Celestron Support. I have not taken the plastic cover off the belt drive area so i have not seen it, not sure i want to as my mount is working fine.

[toc]

Mine is working fine as well - Another clearish night in Melbourne, so hopefully I can sort my guiding. I will use the short tube 80, and I will give metaguide a go.

[toc]

Had much much better results tonight with the short tube 80 :) Only thing that mucked be up a bit was that I couldn't get the sharpcap polar alignment routine working with the shorttube 80 - presumably there is too much focal length. I am finding the ASPA combined with the freakishly good goto's of starsense is getting me about 4-5 arc minutes close to PA, which seemed good enough. Had a try of metaguide - not bad. I dont like the fact that you have to center the star to do calibration. That was pretty annoying.

[glend]

With Sharpcap PA you need a 2 degree field of view. I have no problem running it using my imaging camera on my 115mm f5.5 refractor. It does need about 15 stars to solve.
I have got mine pretty close tonight (PA that is), at a little less than 1' off the SCP, before the cloud stopped me again. The benefits of having an observatory, its all sitting there when i get back to it
Re Metaguide, geez if centering a guide star annoys you use PHD.

[glend]

IMHO the guide port and PC port really should be on the other side (the east side), or the rear. The rear mounted controller and power connections are ok location wise but too close together and the hand controller cable has no stress relief on that little RJ (and the locking plastic tab is on the bottom - it should be on the top in that placement to stop rotation away from the contacts) and requires an immeadiate 90 degree bend to get down to the controller holder and the coiled cable exerts a pull, and the power cable falls over it. That RJ seems like an eventual failure point and the cable itself cannot be changed separately (as it can on the NEQ6) as it goes inside the controller.

[glend]

Mod 1: Creating RA and DEC index marks on the mount. This is just a quick fix until i get the mount head onto the pier - hopefully by the end of next week when the adaptor arrives from Canada.
- I worked on the RA first, using a right angle level on the counterweight bar I determined the position where the bar was vertical, checked the housing on the rear and found the centre of the rear housing.
- Marked the spots on the RA and rear housing with small arrows of masking tape.
- Moving the level to the scope clamp, with it extending out the back, rotated the DEC to level the scope.
- Marked the index spot on the side of the DEC housing and axis cover.

These will be replaced with something more permanent once it is on the pier and PA completed.

Photos are attached.

[Camelopardalis]

I thought it was supposed to be auto-homing?

[toc]

the home switches work well - actually you can home anytime you want (aligned or not) via the hand control - just go to 'Telescope'->Goto Home Switch. Its very very useful feature.

[glend]

Thanks Tim, i have not had a chance to explore it yet. I have modified or deleted posts below. I will auto home it then check my marks.

[toc]

Sharpcap polar alignment didnt work with the shorttube 80 and QHY5L-ii - at least not in my suburban location. :) had mostly hot pixels. (it was hot in Melbourne last night, so that didnt help)

I think the frustration with Metaguide was also related to my tube rings and screws - it makes fine adjustment tricky. When I was trying to find guide stars for various targets I had to crank the exposure up to 4 or 5 seconds and that made adjustment a very tedious process. Since I seemed to have PHD2 working better, and I didnt bust a gut on it.

[toc]

Actually I will add some marks on mine as it would be nice to be able to line it up without power.

[glend]

I just powered it up and went through the initial steps. Once i set to the switch position and it moved alittle, it was spot on my RA marks and maybe a half a mm out on the DEC. I adjusted the Dec mark and now they are sync'd with the system.
Set up my observatory location info.
One question Tim, re the time, we are zone 10 i think in the eastern states, which i assume is their short hand for GMT +10?

[traveller]

Glen or Tim,
Great review so far, very informative. Will either of you use EQDIR cable to bypass the handset?
Thanks
Bo

[glend]

Bo, software is provided with the mount, well a download is, which includes driver/comms/planetarium software that allows the mount and a laptop to connect. You do not need EQDIR but a simple USB cable to provide the connection,
There is another way as well, Sky Safari Pro can wifi connect through the Aux2 port using a Nexus-S or Celestrons Wifi box.
Coming soon is the Plane Wave imaging software for the CGX, due for release on 1 February. This is an integrated control program, like SGP.

[traveller]

Sounds like a well thought through integrated package (except the non-Skywatcher connector locations).

[glend]

Bo, the USB connector on the mount is not for ASCOM or other third party software
, it is for use with the supplied Starry Nights 7, Celestron Special edition, or for upgrading the control firmware of the mount. The mount usb is a B-type on the mount, like a printer usb cable, to an A-type on the pc end.
To control via ASCOM you need to connect through the mini-usb port on the bottom of the Nexstar+ hand controller. So the ASCOM connection uses a mini-usb to standard usb to your computer.

I have had a play with Starry Nights 7 and it is certainly a useful goto planetarium package.

[traveller]

Got it :thumbsup:
Waiting for the next episode of report :D

[toc]

Yes that is it - we are +10 DST.

[glend]

Finally some clear sky! I managed to do a fair amount of setup on the CGX last night: Using Sharpcap I managed to get the PA down to 11", which given that it is on the tripod which is sitting on the suspended Ply flooring of my observatory, is about as good as I can get it, until I move it onto the pier. Small PA adjustments are just so easy with the CGX (compared to the NEQ6).
Followed up with alignment, initially two star, then one star, and then quick align, returning to Home and powering down between them, just to see the differences that they would make. I don't really like that the software defaults to the western sky stars (where I have some tall trees), and reverting to the menu to switch to an eastern star is a pain. I expect that once I have the mount on the pier, I will nail the PA, and then just use Quick-Align all the time, if any alignment is then required. I was only using the hand controller for these steps and I guess I am spoilt in having a Sky Safari Pro display to actually see where my scope is pointing at all times. I must order the Celetron SkyPortal Wifi dongle today; as alas the Nexus-S will apparently not work with Celestron (according to Serge at Astro Devices).
I did not try Starry Night 7 control as I ran out of time, maybe tonight.

So moving to guiding, I sat the scope on Sirius and launched Metaguide and the ZWO 130mm guide camera. Without changing any of my former mount settings, I did a full calibation and started guiding. It worked, in fact it worked very well, and stayed exactly on the cross hairs for ten minutes. The guide error plot was very smooth.

Moving to Eta Carinae, I started SGP and ran a series of 12 Ha test subs (120s). I had setup Teamviewer so I could run this from inside the house and not risk distrubing the tripod by movement in the observatory. The guide error plot looked excellent, staying below 1, even with my NEQ6 agression settings. So apples to apples, using the same settings, the guide graph was showing less than half the plot variance for the duration of the test. On the NEQ6 it would struggle with the same gear and target, to stay under 1.5-2 with more swings and chasing, especially DEC. Sure I guess this can be expected with a mount with more capacity but the NEQ6 was on a pier and the CGX was on a tripod on a raised floor, with the ocassional puff of breeze. I am impressed.

The plan for tonight, sky permitting, is to seek out a faint narrowband target and run some 5 minute subs initially.

I have processed the test subs from last night and put the resulting image up on Astrobin here:

http://www.astrobin.com/full/279244/0/

Tumbnail is attached below.

[mountainjoo]

Glen, when you say guide errors were staying below 1, are the units in pixels or arc seconds?

[glend]

Metaguide uses Arc Seconds in the Error Plot.

[Wombat]

Hello Everyone,
Just finished setting up my cgx mount.
Tried to do a rough alignment to see if eveything is working ok, put in all the details, location and time, then selected a 2 star alignment. Selected first star in list, pressed enter, ra started moving and dec started moving.
The dec moved somwhere between 25 to 30 degrees to the west and the hand control comes up with a limit switch warning and stops while the ra keeps going.
I tried alignment a couple of times using different stars but this keeps happening.
Long. and Lat. are correct and eq south is selected.
Has anyone had this problem?
Cheers,

[glend]

Wayne, perhaps the stars you are selecting are not above the horizon or they are below the range of the mount and the limit switches stop it.
Did you set the mount to home switch position? When you first power up it should ask you that. I would recheck the time and position details are entered correctly, and the GMT zone (+10).

[Wombat]

The mount home switch is set, time and location is correct and time zone set to +10.
Did a quick align and scope goes to objects on eastern side, checked this with sotware, but when an object is selected on western side the limit switch warning comes up.
Beginning to think it is a software problem.

[glend]

Are you sure the mount head clamp, on the dec axis, is turned around the right way? As packed in the box it is turned backwards and you have to rotate it so that the arrow in the clamp area points towards the south celestrial pole.

[Wombat]

Hello Glen,
The dec axis arrow is pointing to the south celestial pole.
I will have another look at it tomorrow and will pay special attention to where the alignment stars are located.
Very cloudy with some rain here tonight.
Thanks for your input.
Cheers,

[glend]

Continuing my testing of the CGX, I picked the Running Chicken nebula in the early hours of this morning. CGX was setup slightly east heavy, much less so than I would apply to my old NEQ6, and I ran a full calibration routine in Metaguide before starting. I have found that for some reason Metaguide needs full calibration with the CGX, whereas it would be fine with a Quick-Calc with the NEQ6.

This is a test image, consisting of just 10x300S Ha subs, of the Running Chicken Nebula near the SCP. Taken with an ASI1600MM-C camera, through a 115mm TS Photolline APO, running a f5.5 reducer. Guided with Metaguide, and error plot performance was very good, the best achieved so far; there were times it was pretty much flat lining . There is still a slight hint of field curvature on the sides of the image and I need to look at my reducer/corrector spacing.

Obviously I am not really challenging the CGX, as the combined weight of the scope/camera/reducer/ filter wheel, etc is probably less than half the rated capacity of the CGX. However, it is still sitting on a ply floor in my observatory (and I had to discard two subs due to my movement in the obs during the test). I have to remember to start the run from Teamviewer in the house, at least until I get the CGX on the pier.

Astrobin image details here:
http://www.astrobin.com/279589/

Full screen here:
http://www.astrobin.com/full/279589/0/

[dylan_odonnell]

Looks great Glen!

I too haven't fully challenged it yet and am still tweaking and adjusting and looking forward to a properly clear night.

However I can say that my decent guiding results after a single 2-star align + 4 and ASPA still hold true even with my new 11" RASA + other gear. I've got 50 pounds (22 kilos) of counterweight on there now almost all the way across to balance so I'm approaching the high end of the payload capacity and all is well!

d

[toc]

I posted this on CN, but thought I would add it here as well. This is probably my best image from the CGX so far:
Eta Carinae (http://astrob.in/full/279451/C/)

Nothing really that challenging - 8x80 seconds at 1000mm. Anything past 3 minutes is really hit and miss at the moment - I did 10 or so images of M42 at 4 minutes and only one is really borderline useable so still a bit of work to do. My fantasies of 15-30 minute guided exposures are a distant far off dream at the moment :lol:

[Camelopardalis]

Nice one Tim :thumbsup:

Don't bother with longer exposures with the Canon...anything more than 5 minutes can get a bit hairy. Just vary your ISO to get the histogram where you want it within that timescale.

[toc]

Thanks :) I guess I need my expectations set :D what sort of guided performance should I expect to be able to achieve with a mount of this class, assuming that things like wind are not an issue? (At say 1000mm)

I also have a 12 inch Meade SCT that I would like to do some AP with, but want to get an OAG before I really bother.

[glend]

I had initially expected to be able to use my Astro Devices Nexus-S to wifi connect to the CGX, as it was working great with the NEQ6 Pro. Of course it is naive to expect that there would be a standard for mounts communicating via wifi, and sure enough the Nexus-S cannot support the signal levels of the Celestron mounts, so it's not just a cable change.

The solution was to sell the Nexus-S and get a Celestron Skyportal Wifi dongle (which arrived today). As Celestron claim compatiblity, and Sky Safari confirm that it will work with Sky Safari Pro as well as the Celestron Sky Portal software (a cut down version of Sky Safari by the same folks), i thought that everything would have been sorted out.

On connecting the wifi dongle to the CGX is apparent that the design team did not consider the implications, or had no other choice. As you can see in the photo below the wifi dongle sticks up in the air like a dogs tail, ready to snag any slewing heater cable, or break off if bumped. The RJ end cannot be rotated, nor was there an extension cable provided. As I have noted before I think the Aux ports are turned around the wrong way with the locking tab at the bottom - but it is what it is. So I am off to source an extension cable now so that I can relocate the wifi dongle down to a less exposed position.
I checked the line of site on the clamp base, fearing that long scopes might strike the raised tail of the dongle, but it appears on the dovetail to clear, however, on a refractor with a diagonal and EP which had been rotated for viewing ease, returning to home position this might not be the case, or something like a smaller RC or SCT where gear might be hanging down in that area. Extending it seems prudent for all using it. Live trials of it soon.

[toc]

Yeah I also have the skyportal, and agree the mounting is not ideal. I added a small USB hub on the top of my CGX (would be nice if they could find room for a USB hub somewhere) and when all the cameras and controllers are connected it's a bit of spaghetti mess :) luckily the CGX design helps to reduce the chance of cable snags.

[Wombat]

Hello Everyone,
Finally back online after a large tree branch took out power and phone lines, took a lot of cleaning up and just under the price of a cgx mount to get power back on.
Still having problems with the mount and I have sent a video to celestron to see if they can determine what the problem is. The dec axis still goes to a limit switch warning when it spins to the west to find a star.
Just out of curiosity, my hand control is version GEM 5.29.6225 does this match everyone else's version?
Regards,
Wayne

[glend]

My Pier adaptor blocks arrived from TPI Astro (Canada) this morning. Photos are attached. I asked Dave to make these for me as a "budget" adaptor model, he has a full disc adaptor as well. These are cheaper to ship as well. If you have some bar stock aluminium you could probably make them yourself. Tapped for the Celestron mount bolts (M10x1.5) on the ends, they bolt directly to my pier top plate. An accurate template was also provided for drilling the bolt holes in the plate and it matches the drawing I made based on my mount base measurements.

I hope to get this finished once it cools off a bit, at 42C it is just too hot.

[Camelopardalis]

Nice one Glen :thumbsup:

It's "only" a balmy 32 up here...

[Wombat]

Celestron does not know what is wrong with my mount and may have to be sent back to the US.
Not happy, good thing the weather is no good.

[glend]

The Cloudy Nights thread reports that Celestron engineers found at least one instance of a limit switch connector was not properly seated in the factory. How that got past QA testing is the question. So that is one out of over 300 now delivered. I would suggest that Bintel should, as the local agent who has some tech ability, be abke to remove coverings to check limit switch connector seating. Shipping an entire mount head back to Celestron seems un-necessary. If it was me, and Bintel could not or would not do it, i would ask Celestron to talk me through checking it and give me approval to do so.

If the above cannot happen then i would ask Bintel for a refund and return shipiping at Celestrons expense. Apparently there is a time limit on refund requests, check with Bintel on their policy in this matter. You should be keeping Bintel across everything. As agent they are responsible.

[Wombat]

Hi Glen
Got in touch with Bintel and have been told to ring monday because that is when their tech "Don" gets back from holidays. So I will ring first thing monday.
Wayne

[glend]

Today I managed to get the CGX onto the pier. Photos attached.
A couple of issues with the Celestron 10mm bolts used to lock the mount to the tripod (or pier adaptor) and the ones used to lock down the AZ rotation to the base. The issue is that some of the bolts (2) were binding in the holes. I noticed this when I was testing on the tripod but let it go until I was putting it on the pier. On examination what I found was that the anodising/or paint on the bolt threads was applied pretty thick and this was causing them to bind. The fix for this was to run each of the bolts through a 10x1.5 die to clean out the threads, I also ran a 10x1.5 tap through the receiving hole to clean out the threads. While retapping these holes I found that the factory had not run the tap all the way through the hole thus the one that was binding was bottoming out as well.
I decided to go ahead and retap all the seven holes and put all the bolts through the die. This fixed all the issues, but left a fair amount of metal dust to clean up. I put some anti-seize paste on the bolts and now everything is nice and smooth and all lock downs are clamping as they are suppose to.
In fairness to Celestron, the factory most likely does not assemble the mount head onto the tripod for testing prior to shipment, but the AZ lock bolts should have been picked up as three were tight enough but the fourth was bound before grabbing. They have some QA issues to address. I suggest all CGX owners check these seven lock bolts (the 3 around the tripod flange), and (the four on the base which lock the AZ rotation). Your looking for freedom of rotation, non-binding in the hole, and enough depth to seat against the base and lock it in place.

[glend]

Since the middle of last year, Celestron has been touting the Planewave developed CGX control software, which will be available to CGX owners. This carrot has little factual information. The Celestron website is still saying that the Planewave software will be released "BY the 1st of February 2017". With only a few days left in the window to get this software out BY the 1st of Feb, the silence is deathening. If anyone runs across news of this release please post it here. Thanks.:shrug:

[glend]

I am having problems getting Sky Safari Pro/Sky Portal wifi working reliably on the CGX.
The wifi connection through AUX2 is failing to connect at times and generally poor. I am connecting a tablet to the Skyportal device (using the Direct connection method) but it drops out when it connects at all.. The nearby laptop ( which runs SGP) and manages the imaging gear, is connected to the house wifi and running a Teamviewer session back to the house PC for remote monitoring. This same setup (two independent wifi sessions) worked perfectly with the NEQ6 and Nexus. Has anyone got Sky Safari Pro working through the Skyportal wifi device attached to a CGX? If so how did you set it up?
Another very strange issue is that when it does connect, it assumes NCP orientation despite my Obs longitude and latitude, GMT offset, time etc being clearly Southern Hemisphere. I cannot find a setting that changes this to SCP. How did you manage this, it its running?

[ChrisV]

Probably not relevant but I always used access point mode with my skyq on the adv gt mount. Direct mode had no range at all and dropped out all the time.

[glend]

The CGX software is now available for download. Go to the Celestron CGX web page and scroll down to the very bottom, its called Celestron PWI software now. Comes with a quick start guide that should be read. Only works on CGX and CGX-L.
I have installed it on my laptop and will be trying it on the mount tonight, i hope.

Initial impressions are that it is pretty basic. Provides PA provided you are roughly aligned. Uses PointXP modelling. Can find thing by M & NGC number but Skyview has no zoom in capability. Certainly no threat to Stellarium or Sky Safari in the GUI area. I have to actually play with it before any further thoughts.

[toc]

I downloaded it and had a look. Don't see much value in it for me at the moment...

[toc]

Well the last few nights out have been pretty frustrating and unsuccessful. Not really sure where I am going wrong - could be balance I guess, but getting reliable guiding is very difficult. Seems to be acceptable (but still not amazing) when imaging closer to the SCP, but in other locations I am getting jumps on RA (up to 3" or 4" that are ruining subs.

I mentioned this in CN, but PHD2 tells me that I have significant backlash in DEC, which I was not really expecting. Could this simply be a balance issue? Could this somehow affect my RA guiding?

I did have an issue with an unnoticed slipped counter weight that I thought might have done some damage, but I think that is a red herring.

[glend]

Tim did you check the antibacklash settings? Have a read through that section in the manual, on page 20, it gives you a routine for checking and adjusting it. I have not had a problem with mine so have not checked my settings yet. Importantly it says that for guided imaging the settings might need to be higher than for visual use.

My guide plot is pretty much a flat wiggling line, no jumps at all.

Re balancing, i find the CGX is not as touchy about that as my old NEQ6, but i still balance east heavy usually but not near as much as with the old mount.

I did have a problem with the Az lock bolts that are worth checking. Two of the four bolt holes were not tapped right though, so the bolt was bottoming out and binding, feeling like it was locked down tight when in fact it had not pulled the two plates together. I discussed it with Eric from Celestron and he asked fir a report and photos, which i supplied. Check your Az bolt washers, if you can turn them with a finger the plates are not properly locked and this could cause some movement of the scope or inaccurate alignment.

I have given up on those various CN threads, i think i will stick with this one.
Good luck.

[peter_4059]

I thought the CGX had spring loaded worms. Isn't that meant to eliminate backlash?

[glend]

Yes it has spring loaded worms, but there are still anti-backlash software settings. There are two factors (vertical and horizontal) involved in drive meshing: The spring loaded worm keeps the worm engaged with the ring teeth by applying a constant pressure (about 5lbs), but one with the ability to adapt (compress or extend) in response to very small irregularities in the worm itself - thus it is non-binding. The CGX worm drive belt is also held under tension, eliminating the meshing issues sometimes found in gear driven worms. Some older systems used grub screws to press a pad that pushed the worm onto the ring; the problem with this system is that it was subject to binding if tightened too much as it was non-forgiving of irregularities in the worm or its bearings.
The anti-backlash adjustment is a separate thing, as it deals with the potential gaps between the worm spiral and ring teeth. All gear driven systems have some slack in the grooves/teeth alignment. Anti-backlash settings ensure that when a movement is completed the worm motor drive assumes a position that will allow the next move to happen without a jump at the beginning or the end of the move (in other words it is preparing its position at the meshing interface). In the case of the CGX, the controller buttons are used to adjust the backlash compensation. This means that guiding commands are executed without a jump. The anti-backlash compensation adjustment process is described on page 20 of the manual. It suggests that settings would be different for visual observing and imaging; with visual settings at a value between 20-50, and a higher value needed for imaging guiding.

This represents my understanding of how it works at this time.

[toc]

Thanks very much Glen :) Lots of great info.

[toc]

Didn't have much luck solving my DEC backlash, so for now I am just ensuring that I balance the scope with the weight on the mirror side. That said, I am seeing the same level of performance as others wth the CGX, which is good.

[glend]

So how are people coming along with their CGXs? I realise the heat has shutdown many of us, myself included. Who has what problems? Any new mounts purchased in the last few weeks? Any "L's" on order?

[toc]

I am a bit frustrated - i can't get rid of my DEC backlash problems, so I might just not guide in DEC from now on. I tried last night to use the backlash compensation on the handset, but this caused PHD2 to go nuts during the calibration phase. Since the backlash seems dependant on what part of the sky I am imaging I am not sure how that would help anyway. I think I can mange it with balancing, but it is a big pain to have to redo the alignment to re-balance every time I want to image something on the other side of the sky. Btw I can tell the backlash issues are real because I can see phd sending many corrections in DEC before the mount moves. I have adjusted the backlash on the mount itself, but I haven't not been able to reduce it significantly.

Despite this I can occasionally get good results, almost always around the area of ETA carinae or the turancula nebula.

[glend]

Tim, out of curiosity, what is your tracking like without guiding? A correctly aligned CGX should be able to hold a target for a long time unguided. Are you running on the factory default settings or have you changed from them? I'd suggest going back to Nextstar default settings if you have moved off them, and testing again. Have you tried a target on the celestial equator, like the Horsehead, there should be very little DEC movement required there. Is your wedge altitude set correctly, have you checked that? I use Metaguide so I don't know much about PHD2. Do you have a place to specifiy the Declination of the target in the setup (Metaguide does)? Also do you have an aggressiveness setting for DEC? I'd ask why is PHD2 sending so many small DEC commands to the mount, or why the mount is ignoring them - sounds like a setting sensitivity issue. I know you asked about this topic on CN as well but there are no Southern Hemisphere CGX owners on CN other than us, but maybe that does not matter.
BTW I don't have your problem. Why not send a PM to Dylan and see if he can offer some advice, he has not been around here in awhile. Alternatively, get onto Celestron's forum and ask there.
If there is some setting you would like to compare with mine just let me know and I will check (but obviously not being a PHD2 user I can only advise on CGX settings).

[toc]

- Generally I can do unguided exposures of about 1 minute - not perfectly round, but roundish. This is at about 1000mm FL.
- Have not touched the factory defaults for guiding.
- Horsehead is not bad for tracking, but the longest I have done the Horse head and M42 is about 3 minutes guided. I start to get some missed subs anytime longer than that. DEC seems ok for these targets, but RA is quite a lot worse.
- Does not appear to be a setting for 'wedge altitude' in PHD2, or any location to specify the declination of the target. I think it just relies on you doing another calibration :)
- PHD2 does have an Aggressiveness setting - I am using the defaults mostly here - I have played around a bit with it, but didnt see an improvement. I guess the issue is that the backlash is bad enough that PHD2 is sending a correction, and the mount is not moving. I could try to ramp that up I guess.

I think you have the same scope as me - a Skywatcher 190MN. How are you balancing the scope? do you bias it one way or the other, or leave it perfectly balanced?

Thanks for the help! If I get a chance tonight, I will forgo any imaging, and just fiddle. :)

[glend]

Yes i have an MN190, and i am actually in the middle of imaging NGC3324 (Gabriel Mistral Neb). Waiting for the moon to get out of the way so i can shoot Oiii. I balance it east heavy on RA, and rear heavy on DEC - just a little bit. It does not need as much heaviness as the old EQ6. I get nice flat guide plots for eastern targets. I am shooting 5 min narrowband subs. My PA is sitting on 9 arc secs off the SCP.

Dave (Syscore) on CN has just finished testing his CGX, worth a read in his new thread. He is very happy and has put up some 60" unguided subs as examples.

[Wombat]

Mount now on it's way to US to be repaired at Celestron's expense, apparently no one in Australia knows how to do repairs on these mounts as they are pretty well straight out of factory.

[glend]

Gee that's ashame Wayne. I assume the techs at Celestron California will be looking at it and that is where any US returns go. Who is covering the shipping cost, hope its not by boat. I hopevthey only sent the head unit.

[Wombat]

Hi Glen,
The mount head only goes to US tripod stays. Celestron is picking up the shipping cost, and I do believe it is air freight as it went through Celestron's DHL account.

[glend]

Full page back cover advert for the CGX in the Australian Sky & Telescope (issue 100) which arrived in the post this morning.

[toc]

You are probably sick of seeing my annoying posts, but I have a minor update to my DEC saga :)

I think I have the culprit... (but I am waiting for some comment from Celestron)
I took the cover off the DEC housing and looked at the belt and gears when moving. There is a noticeable wobble on the gear that is connected to the motor. I thought that perhaps it was not seated correctly, but it looks like to me that the hole in the gear has been drilled on an angle. When I reversed the direction I could see that at times the slack on the belt (presumably because of the uneven pressure) meant that it there was a bit of a delay in driving the gear. This might not necessarily be a huge drama, but thought I would feed this back just in case others see similar issues.

Part of me wants to return the mount for repair, but I am loathed to have to return the mount to the US, and be without a mount for 3 months because of one 50 cent gear. What would be awesome is if they could send me a replacement - it would be a very simple job to swap the part over. I will let you know what mr C says :)

[glend]

Tim have you communicated directly with Erik the Celestron product engineer? I have his email address if you want it, i can PM it to you. He asked me to send him some photos of the problem i had with the base Az holes not being tapped all the way through. He certainly takes an interest. If you post your comments about the DEC gear on CN he will probably see it. Put some photos up or a video on utube of the wobble

Edit. Tim i have sent you the email address via PM..

[toc]

Thanks :)

[glend]

Perhaps contact Dylan as well, he is suppose to be a Team Celestron rep, whatever that means, and was quick to spuik the mount on launch but has pretty much disappeared since then. I would like to hear from him in this thread.

[dylan_odonnell]

Hi guys!

I haven't read through this thread yet sorry, I've been out of action because my beloved CGX also had to be sent away like Wayne's for repair.

Glen suggested that I may shoulder some responsibility for problems others may have had with the 5 that were sold early from Bintel because I spilled the beans they were in the country before their official release. If that is the case, I do apologise. I did preface my original thread by saying something like "(Disclaimer, I'm on "Team Celestron" so am an ambassador of sorts for them, and I work as a third party with Bintel. However neither of these companies pay me for comment and I pay for my own gear like anyone, though I do get discounts and heads up on new stuff from time to time.)" (that's a copy and paste from what I said on Cloudy Nights)

I shared my results to everyone who asked for them with graphs and logs etc as nobody else was doing so at the time. They were good results, and ironically my faulty CGX worked great. It just had an intermittent shudder (which I also described on cloudy nights) that was fixed by slowing the default slew speed down.

But a new mount is a new mount, and like you guys, I paid for a new mount and went back to Bintel and Celestron did the right thing and took it back at their cost. Which is the same for Wayne I believe.

I don't have any more info than you guys, and I don't work for Celestron. I'm not a social media influencer as I don't get paid for comment. I said it before "If it sucks - I'll tell you!".

Anyway .. I'm BACK thank god. My wife was getting jack of me playing heavy metal again while I missed a few good imaging weekends with no mount. The CGX is back in the obs and I've summoned the clouds forthwith.

I'm on "Team Celestron" simply as a user. A fan perhaps, but also a big user of their gear. I write for their website and I'll be speaking for them (unpaid) at the world science festival in Brisbane with Dr Alan Duffy, Dr Lisa Harvey-Smith and Dr Duane Hamacher on March 25th for a free star gazing evening. You should all come :)

I've also put together the Star Stuff event, which is now sponsored by Celestron and Bintel and ESA (among others), with zero funding or support from government or academia. In fact, I'm paying for it all out of my own wallet because that's how much of a space nerd/fan I am. You should come to that too! ( https://www.starstuff.com.au )

I hope that clears it up and sorry to hear about any issues other may had. I believe this first batch was literally 5/50 that came straight off the factory floor and were shipped internationally. I only know of 2 returns so far and apparently all of the UK stock was fine with no returns. But I'm not Celestron, if you have an issue - discuss it with your Authorised dealer (Bintel) first as they have more weight with Celestron than we do. That's what I did.

I reckon those first few did have factory-first / early-adopter / manufacturing issues that Celestron has resolved. Still the best mount I've ever had.

d

[glend]

Thanks for clearing that up Dylan.:thumbsup:

[glend]

After Tim's (toc) description of his DEC wobble, I thought I had better have a look at mine, and RA at the same time. Here is what I found, and photos are attached:

I removed the covers of both DEC and RA belt drives, and I will say I was surprised by the belt alignment as delivered. I had not removed the covers before. The mount I had before this CGX was a Rowan Belt Mod NEQ6 Pro, and it was a well engineered bit of gear, which I installed, so I know something about belt systems and alignment.

First I did a slew to M42 and watched the belts in action, they were doing their job and did not exhibit any bulging or wobbling action that Tim described. However, it did seem like they were out of sprocket alignment and on RA hanging over the end of the sprocket. The motor drive sprocket does not have an edge flange so it is free to move across the sprocket seeking to centre itself. The Worm sprocket does have an edge flange. What I noticed about the motor sprocket is that if was positioned fairly far out on the axle, like they were trying to get it far enough out but the motor shaft is too short, it is just on far enough to engage the lock screw on the shaft but it looks to me that it is too short for that arrangement. I can see how the motor sprocket could develop a wobble as the belt will move outward and put more force on the outside of the sprocket which may cause the sprocket to move against the flat of the shaft. The worm sprocket cannot be moved inboard any further due to the casting so the motor sprocket has to be out as far as possible to make it work, and the narrow sprocket cannot be made larger because of the confines of the plastic cover and the risk of rubbing on it. Both DEC and RA belt drive designs were similiar, and frankly a disappointment, this is bad design and they have tried to fix it by positioning of the sprockets.. I expected better, certainly as good as a Rowan Belt mod. Perhaps Rowan can come up with something to make this work better, a thinner belt and worm sprocket might allow a straight alignment. The constraint to a solution is going to be the plastic covers.
Now some will say "it doesn't matter what it does when its slewing, it's the tracking or guiding performance that counts", and this is true; but it bugs the heck out of me none the less.
Photos attached of DEC and RA.

I wonder what they have done with the CGX-L, there is potentially more room there as bigger rings are used, and the drive areas look larger in general.

[dylan_odonnell]

Well I don't know enough about engineering to say Glend.. I'm more of a computer guy than a gear and cogs one :)

I can say it's good to be back online in the obs tonight and I'm getting great results again fully loaded with the 11" RASA, guide scope, finders scope, camera and filters.. about 19-20 kgs. CGX is rated to 25kgs.

2 x ASPA routine with the hand controller after 2 star align + 4 cal stars.

Guiding graph attached. Also how amazing are these 60 second Ha subs with the RASA (!!)

d

[toc]

Thanks Dylan - out of interest, did Bintel replace or repair? How long did it take? I guess my issue is that the mount is not really malfunctioning, its just not performing as I would like/hope.

[dylan_odonnell]

The head was sent back to Celestron to investigate and after 3 weeks I received a new head, at least I think it is.

They changed CEO and have had a lot of internal changes recently which I believe added to the delay but I think they're back on track now.

There was no need to ship the tripod / weights etc of course. Work with Bintel to determine if the mount is performing as it should or if it is indeed faulty. There are an embarrassing few posts on CN where a guy swore blind a returned Celestron mount wasn't performing but it turned out it was perfect so it must've been him.

But these things do happen for us early adopters so after you nail polar alignment and star alignment 101% you should be able to demonstrate whether its performing to spec or not. I've used the CGX for fairly long unguided subs too which might be a good start. That way your guiding setup is out of the equation.

d

[toc]

Here is a video of my wobbly DEC gear :)

https://www.youtube.com/watch?v=MYska4wQTZ0

It looks bad to me, but perhaps I am just too picky? Either way, I am still struggling large DEC backlash, so that is a bummer.

[dylan_odonnell]

Looks a bit skew-if doesn't it? Would that have an effect on backlash though? In theory its the gaps between the "teeth" that would increase backlash and having it skewed would mean a tooth edge is likely to close the gap quicker wouldn't it? I don't know anything about anything though.

I can say I loaded the CGX up to about 24kgs and it didn't handle it. It physically would not slew back against gravity, which is not ideal. They should probably pull back it's rated payload.

d

[casstony]

Definitely looks wobbly - the gear looks wobbly too :)

If the shaft was straight and the only issue is a bad cog it sure would have been a lot easier for them to send a new part, even if they sent it to Bintel.

[glend]

It does not look that much different to mine, the main issue i see is the belt is hanging over the side of the motor sprocket and it appears to walk back and forth slightly, perhaps due to the bad fit on the shaft of the sprocket; or the belt is being guided by the worm sprocket edge flange. An over hanging belt puts alot of force on the outside of the sprocket. I believe both RA and DEC motor sprockets need to be replaced by a longer sprocket in these mounts. Walking belts, or belts hanging off of drive sprockets, is not good design. I am comparing it to my old NEQ6 with the Rowan Belt Mod, where both sprockets had edge flanges and lined up perfectly. I am wondering if Rowan Engineering could produce a replacement motor sprocket set for these mounts. Ideally Celestron should fix this on all CGXs.
Now the big question is, does visual wobble in high speed slew have any affect on very low speed guide or tracking movements? Perhaps not. However, it could be affecting worm gear end play at various places in the rotation of the worm as the belt tooth might catch on the worm sprocket edge flange when running at that angle.

I hope Celestron is on this, and not just focused on the CGX-L launch. Tim did you file a report with them?

[toc]

Yes I did - both through support, and team celestron.

[Camelopardalis]

Glad to hear you guys are shakin' the mounts down for the rest of us ;)

Hope Celestron get on the case with this, the lack of belt stop on the top cog looks a bit of an obvious oversight, but I'm far from a mechanical expert!

I'd be keen to get one of these once the teething issues are over.

[Shiraz]

the cgx-l looks to have the same mechanism, but the belt is running straight
in the demo video at https://www.youtube.com/watch?v=3Nzf-Ava6OM

agree yours and Tim's look significantly out of whack - that is definitely not how a precision belt drive should look. Hopefully these are teething problems and they will be fixed by the company - the basic design concept looks exciting.

[glend]

Thanks Ray i had a look at that video. The L is using the same belt as the CGX, a T5x165 P07, designated with the TLnis branding. They cut away the video of the belt drive before the mount rotated around enough to see if the belt was skewed on the sprockets, but the inside gap is the same so i think it was probably hanging over the drive sprocket as well. Surely they have to be aware of the problem. The sprockets look to be the same as well. The belt is only about 10mm wide. The motor shaft dia is 5mm. I am trying to track down a wider motor drive sprocket with the same teeth and diametre, but would surely void the warranty if i pulled that assembly apart to change the sprocket. I doubt Bintel would want to tackle disassembling the drives, so what is left, a return to Celestron?

Dylan can you have a look at your 'new' mount and see if they fixed the misaligned belt?

[toc]

Perhaps we could engage the services of a talented iceinspacer with a CNC machine or lathe, and get some new ones made up :)

[glend]

I have opened a ticket with Celestron Tech Support re the belt alignment issue. Tim i assume you have a ticket open re the DEC wobble? I have also inserted my photos in the CN thread i started on CGX Belt Misalignment. To quote Mal, from Serenity, "I aim to misbehave". I want some answers.

[toc]

I do have a ticket open - they asked for a link to my video of the wobble, and I sent that off a few days ago. No response so far.

I also have a thread in the Team Celestron site, but that is more around the backlash issue.

I imagine we will see an silent update to the design in a year or so :)

[Shiraz]

just a thought Glen. The belt will run off if the two shafts are not parallel. The worm is held both ends, so it is OK, but it looks like the only things holding the motor in place are the two adjusting screws pulling the motor end plate up against the worm block. If this is the case, any tension on the belt may be sufficient to flex the motor plate and pull the whole motor assembly out of alignment. Maybe back off the belt tension and see if you can tighten the belt by putting finger pressure on the far end of the motor. If you can, it could possibly be worth shimming the front of the motor where it attaches to the end plate or using a zip tie? to stop the far end of the motor from lifting when the belt is tensioned - obviously keeping away from anything that looks delicate.

It sort of looks like maybe they used their spring loaded worm block design ideas from the CGEpro and put it in this mount - however, the original was designed for gears, not a belt under tension???

then again, the above might be rubbish..

[glend]

Ray, I need to have a close up look at the assembly to see how the motor and worm shafts are held in alignment. They are both attached to a cast frame, so hopefully there are some adjustment screws and it maybe a simple process to line them up - and then maybe the existing spocket arrangment would be ok ( although i still think it needs and end flange).
This sprocket, with the right pitch dia etc might be the ideal way to offset the belt slighly, and not have to mess with the alignment if the shafts.

http://www.ebay.com.au/itm/2pcs-2GT-20T-5mm-8mm-Bore-Aluminum-Pulley-Gear-Wheel-for-3D-Printer-Timing-Belt-/182386266482?var=&hash=item2a77119172:m:m8IMzs5qm_Ytz maNWdeyWfw

[glend]

I have just had a closer look at both belt drives and have some new photos to share (first 4 photos are RA and the last 3 are DEC). I have marked the DEC photos with red arrows to indicate the adjustment points. It seems the drive casting, while supporting the Worm at both ends by bearings as expected, does not support the motor at both ends. The motor is only supported at the sprocket (transmission?) end by a separate casting. It appears that when they tension the belt they push up the motor casting by set screws, (via the small wedge adjusted to push against the bottom casting) and when the lock screws are tightened motor is tilted (and thus the sprocket as well), in relation to the worm sprocket, and this leads to the belt walking over to the end of the motor sprocket. I tried an experiment, pushing the belt into alignment on the motor sprocket (on both DEC and RA) and then running a slew to a target. By the time the belt had rotated a few times it was hanging off the end of the sprocket again. A flanged sprocket might stop it but at what cost, as the motor assembly is still skewed.
Perhaps simply putting more turns on the wedge set screw (before locking it down) might actually level it up. Opinions?

[traveller]

Interesting arrangement of sprockets.
So the worm sprocket has flanges but the motor sprocket does not?
Have you measured the distance between the middle of the motor sprocket and end of the motor spindle where it attaches to the sprocket and compare that measurement against the distance on the worm spindle? (like the Rowan belt alignment routine)
If there is a bit of room for adjustment in the alignment, is it possible to shim a couple of thin but slightly oversized washers to the motor sprocket to act as a flange?
Just a thought.
Bo

[bojan]

maybe just add a shim to tilt a motor in the right direction.....

[glend]

Might be a good idea. I have just spent an hour trying to adjust out the problem, just on the RA drive. Tightening the lock bolts tilts the motor back, the wedge is mainly serving as a belt tensioned and was backed right off on my drive. With the motor tilting, the sprocket tilts. So shimming the motor carrier might work. I did manage to move the sprocket further out on the shaft slightly, which decreased the overhang of the belt when slewing, what can j hse as shim material, it has to be pretty thin?

[bojan]

Try thin (cigarette?) paper.
Or Aluminium foil

[Shiraz]

coke can makes good shim. of course, if you tilt the motor back, you will first need to back the belt tension right off and then carefully adjust it up with the shim in place.

[glend]

Thanks guys. I am making some progress. Working on just the RA for now, I cut and tried a variety of shim material, including aluminium flashing material, and some thin galvanised steel strapping used in building. Backed off everything, and inserted the thin gal steel strip in between the motor carrier and the main drive casting. Once adjusted and locked down, effectively pushing the motor drive outward, it improved the situation a fair bit, with the belt now staying on the motor sprocket with no overhang. It will need some more refinement in coming days, to tune the angles and belt tension abit more, but i have had enough for now. At least its on a pier and easy to work on.:thumbsup:

Edit: I am considering inserting a support block under the motor in the area indicated in orange, as the entire weight of the cantelivered engine and transmission is supported by the arm and secured with the lock down screws. Small movements in the shim area affect the angle of the rear of the motor (in red) and thus the running angle of the sprocket.

[Shiraz]

sounds good. in future when someone asks what sort of mount you use, you can say "home made" :lol:

[toc]

Interesting! This won't fix my issue - I need a replacement sprocket, but I might have a play. :)

[traveller]

Is there enough room for a cable tie or a hose clamp?

[glend]

In more tuning today, the RA drive is now performing pretty well. The belt is staying on the motor sprocket, through all sorts of slews. The final shims are aluminium flashing material. I made a template out of plastic so that I could do a production run of shims, 8 in all, 4 for the RA and 4 for the DEC. I would still like to get a hold of a couple of new motor sprockets with edge flanges, with some offset build in (I might be able to ditch the shims then). The sprockets I need, have 14 teeth, a 22mm outside dia from edge of tooth to edge of tooth, 5mm axle shaft, tooth width seems to be about 2mm at the base, and to work with the T5x165 belt. Something like this.

http://thumbs1.ebaystatic.com/d/l225/m/mrjQZzuc9sEhuuG0HdM8HGg.jpg

[Boozlefoot]

Naismith Engineering, Seven Hills.

[glend]

I have finished off the belt tuning, thinking that it is the best I can do without a new motor pulley. I gave up on the thin aluminium flashing shims, and just went with a piece of 1mm plate under each motor carrier. Can't push it up too far as the belt starts to rub on the motor carrier. I also extended the motor pulley on the shaft as far as I could (this provided about 1mm of extension as well). Photos are attached of DEC and RA. Did a bunch of slewing to check on how the belt was behaving and it looks good, no wobbling and tension is about right. The photos are post the slewing. If yours needs tuning, be aware that the adjustments are very touchy, and you don't want belt tension to get too stiff or loose - the belt is not spring loaded, that's for the worm only.
Of course Celestron should have paid more attention to this aspect of QA, IMHO.

[traveller]

Glad you got the solution sorted Glen. This sort of engineering oversight is not what you should expect for a new mount. Let's hope it will be addressed in Mk 2.
Bo

[casstony]

Although there often are bugs with newly designed mounts. The CGEM had its issues at first which were fixed later with firmware upgrades.

[billdan]

Celestron should pay you for solving their problem.

A friend of mine in Brisbane solved a graphics card issue with the Apple II when it was first released. He got a free trip to the USA and a cheque for $50,000.

[glend]

While I was working on my belt alignment I had a look at the spring loading on the worms. The CGX is supposed to have spring loaded worms right? I couldn't find any evidence at all, I could not get the worm carrier to move, I thought I was doing it wrong. So I returned to it today to work out why there was no movement possible in the worms. I tried the recommended pull back technique (put your index fingers on either side of the worm carrier below the bearings and pull back away from the ring, and you should see and feel some movement - not a lot, just enough). In my case, both worms were screwed down tight against the ring gear, no movement. If you check page 25 of the CGX Manual, it sets out the method to check the recoil and adjust the spring loading tension. I have backed off the Distance Adjustment screw so that there is now a small amount of recoil. You don't want the recoil to exceed 1mm and can use the Range Limit screw to control that. I have mine set at about 0.25 - 0.50mm at the moment, just enough to feel it move back. Obviously you need to pay attention to any backlash on the axis your working on, and I still can't detect any.
I am looking forward to some imaging weather to test the new settings and see if there is any change to the PE. Sadly, we cannot assume that they are setup correctly by the factory.

[Shiraz]

it might be a good idea to lock them down for transport. If that is what they do, it might also be a good idea to let users know.

[glend]

I have finally received a response from Celestron Tech Support concerning the drive belt misalignment problem which I reported early last week, this is from Christopher in Customer Support:

"I am sorry to hear about the experience that you are having with your mount. I am working with our product development team to get some instructions on how to make the adjustments to the belt send out to our distributor. I am going to be working with our distributor in Australia to get the issue resolved with your mount. I apologize for the delay and want to thank you for your patience in this matter. I will have an update tomorrow with more information."

So my take on that is that Bintel will be expected to adjust the drives to correct the problem. I await the instructions (assuming I am allowed to see them). I don't know how Bintel will be able to solve the problem without a hardware solution such as a shim and/or a sprocket change. We'll see.
I don't want to send the mount head back to Bintel until I know what the procedure involves, and am convinced that they are equipped to solve the problem permanently.

Tim, did you ever hear back from Tech Support on your wobbly drive sprocket?

[toc]

Not yet...I will remind them tomorrow.

[toc]

I have finally heard back from Celestron. They don't see any issues with the movement. They basically are saying that the gear is fine, It's just that the belt is moving back and forth across the gear. I have already seen th wobbling occur without a belt attached, so that will be the next expose :lol:

[toc]

Just a small follow up - here are two videos of the DEC axis with the Belt removed, and also the sprocket removed.

https://www.youtube.com/watch?v=NN3Cf4txQco

https://www.youtube.com/watch?v=B0CWDVk5Ong

[casstony]

It may or may not create any issues but it's definitely not square. So Celestron, do the wobbly CGX's qualify for a manufacturer discount compared to the straight drive models? Might have to check the mount in the shop before paying.

[glend]

Tim i believe you could probably get that sprocket to turn perfectly. A bit of adjustment of the screws, maybe a piece of shim material inserted in the outside edge might do the trick.
Other options are a new sprocket, flanged if you can find one.
I doubt its worth returning the mount and being without it for who knows how long. Maybe John Cross can score a handful of sprockets for us.

[Wombat]

I finally got my cgx mount back from the US on Wed, set it up on tripod in lounge room and everthing worked ok. Before being sent the US the limit switch warning message appears on hand control and stops the dec. movement.
The Celestron techs replaced the Dec board and then tested got-to, tracking, all functions, reset slew limit and mechanical testing.
I would thought that Celestron would have put in the box a form or paperwork that tells you what was replaced and what tests were done and certifying that the mount is in good working order after the tests were done.
A form detailing what was done, in my view, should be sent back with the mount as a record for the owner and a buyer in the future would want to know the history of the mount.
I only know about the above items from a Celestron support e-mail that was sent before the mount was shipped back to me.
I also found damage to the box where something put a hole on either side of the box, but it did not penetrate the foam packaging so there was no damage to the mount
Now have the mount set up in observatory and waiting for a clear moonless night to see how the guiding runs while doing astrophotography.
Regards,

[glend]

That is good news Wayne, they seem to have had the mount for awhile. Good luck with testing, and a clear night.

[glend]

Just a 'heads up' on possible rust developing on parts of the CGX. The long Alt and Az adjustment bolts are mild steel not stainless. I had the beginnings of rust on mine near the handles on non-threaded section where the knob shaft sticks out from the mount. This is probably due to condensation cycles. My mount is on a pier in my observatory, so is always somewhat exposed to humidity variations, unlike one kept inside in a box until setup on a tripod. It would have been nice for Celestron to use Stainless Steel for these parts, especially since they advertise it as an observatory mount, i suppose they saved a couple of bucks by using mild steel.
So how do you prevent the rust if pier mounted? The best way is probably to shield it by painting the shafts with a rust preventative epoxy enamel. Burnish off any rust with emery paper and put on a couple of coats of satin black, which matches the mount.
I have added this to my CGX Mods, Fixes, and Adjustment thread on Cloudy Nights, photos are there as well.
This applies to CGX Ls as well.

[dylan_odonnell]

Living next to the ocean rust is a serious issue in my obs. Most of my gear rusts up quick and I bring anything electronic inside each night instead of leaving it in the pod. Thanks for the tip!

Haven't had too much of a chance to image recently but have been playing around with the CGX software and PC control generally. I don't have a solution for plate solving yet as Astro tortilla and the celestron ASCOM driver don't seem to talk to each other well enough to share a "sync" :/ Hasn't been a big deal though because the Goto's are so good my targets are always in frame fairly close to center anyway.

Anyone know of any plate solving solution that will work with the CGX driver?

d

[glend]

Dylan i believe i saw a thread on the SGP forum about it. SGP can plate solve.

[Camelopardalis]

If SGP is doing something other software can't, then it's not ASCOM compliant...

[glend]

I have been told by a Celestron engineer that any CGX owners with rust on the Alt lock knobs or the Az lock knobs, can have them replaced under warranty. You will need to go through Tech Support, but i believe they will be sent to you. I don't know if the replacement will be a higher quality Stainless steel. So Dylan, there is an option for you. I am happy with mine now that they are de-rusted and painted black.

It appears Celestron is now moving to address concerns raised by owners on the forums.
I have another update on the belt alignment issue coming soon.

[sharpiel]

You really have to wonder why it needs user feedback to change corporate marketing and production. We all know stainless steel works best in conditions where water (read condensation) exists. Why aren't all external fixtures in all mounts stainless steel or aluminium? Lewis replaces all fixtures with stainless steel and so do I because everything ferris corrodes.

Come on manufacturers...care about more than just selling a product. Actually care about what the purchasers think and do it right first time even if you have to pass the cost to us.

I'd rather have a quality product than have to feel disappointed spending more to get it right.

[glend]

I have had a ticket running with Celestron Tech Support, to try to get them to provide some belt alignment instructions to owners, as they do in the Manual (page 25) for worm carrier spring adjustment. Celestron are now advising potential buyers, when asked, that the early belt alignment issues were due to poor factory setup on a limited number of early CGXs and this has been resolved ( I am paraphrasing here). That is great news, but does not do much for you if your the owner of one of the early models.

For affected owners,

Note: your mount in under warranty, if you have any serious concerns or issues with belt alignment then please contact Celestron Tech Support, or your local retailer for advice. I understand that some servicing of the CGX and CGX/L can be undetaken in Australia now.


Edit: in the space below i had written detailed instructions on how to align the belt drive pulleys, but now believe such instructions may do more harm than good for many owners. And so i recommend contacting your retailer or Tech Support if you have any concerns. I know several mounts have been returned to Celestron for setup remediation.

[toc]

Just to update my situation, Celestron organised for my mount to be returned to Bintel for adjustment at the start of the week. Hopefully it wont be too long.

[toc]

Came across this video on using PHD2 guiding with the CGX
https://www.youtube.com/watch?v=acXxHusl3O0

[glend]

Update. This information on worm period was recently confirmed by a CGX owner in the US and verified by Celestron:

One of the things we discussed was the tooth count and worm cycle time for the two CGX models.
From the horses mouth (Celestron)...
CGX 180 teeth and 478.6794 seconds (7.9781 min)
CGX-L 288 teeth and 299.18809 seconds (4.9863 min)