Red Dot Finder vs Telrad

[WestAusChris]

Hi All

Just another question to get the little friendly equipment arguments started :)

The cheapest Telrad i can find is around $79 and the cheapest Red Dot is from Andrews for $59 (4 target).

I have the 6" Dob and are on a tight budget now and wondered which you would recommend to a beginner trying to find the stars.

Maybe some pro's and con's of each?

Thankyou again for putting up with question after question from me

[astro744]

Andrews also has a $29 red dot finder (single dot). It does the job and is small.

The advantage of the Telrad is that it has 4deg, 2deg & 0.5deg circles and runs on 2 x AA batteries which last a very, very, very long time. It is well built and holds alignment well.

The single red dot finder does the job too but runs on a single large button cell but I don't know how long before you have to replace the battery. You can slide the single red dot finder into a standard Skywatcher foot whereas the Telrad has its own base which can be screwed or simply double-sided taped to the tube assembly.

The Telrad is very nice but if you're on a budget the $29 single red dot finder will do just fine. It's far better and safer than a laser and doesn't annoy fellow astronomers at a star party.

[Brundah1]

Standard single RDF limitations soon become apparent.

Telrad is the traditional visual observers tool, because it integrates well with star charts with Telrad guide circles.

However I chose the unique Stellarvue F2 Deep Sky finder (unfortunately had a recent price hike to USD78 - was USD58). (See Stellarvue website).

The SV F2DS has significant advantages over both the single red dot finder and the original Advanced Multi-reticule Finder (AMRF) - sometimes referred to as the "Williams Optics MRF".

Note the original version of the AMRF was actually designed as a rifle sight with multi-coated lens for day & night use and later adopted for astronomy. Surprisingly the lens coating causes annoying reflections and cannot be dimmed enough under dark skies.

The SV F2 features:
- larger clear lens with a thin frame.
- lower intensity red illuminator, still with 6 levels, intensities which are much
better suited to astronomy use. Not so good in daylight.
- easy to use collimation adjustments.
- four selectable reticule targets patterns. I find the SV F2 center circle
with external crosshairs the preferred pattern.
- Very long battery life, just remember to turn it off = 0!
- Design is otherwise almost identical to the AMRF and build quality is
excellent.

Both the "WO MRF" and SV F2 DS compensate for some paralax error, but you soon learn to get the best accuracy by keeping the target pattern centered in the lens.

My personal preference is to mount the SV F2 part way up a refractor OTA, not at the back as you would a standard finderscope. Rear Cell on SCTs.

Stellarvue has a huge range of stalks and mounting adaptors to suit any telescope. (See Hands On Optics listing).

Kendrick produce a dedicated dew heater which fits both multi reticule finders - SV F2 requires minor trimming of the heater plastic frame. (Available from Bintel).

For medium power visual observing with a CPC8, I prefer to use both the SV F2 DS and a SV F60M (10x60 RACI). The SV F60M (USD 189) and SV F50M2 (USD139) are perhaps the best finderscopes ever produced.

These comments are based on extended use of the "WO MRF", SV F2 DS, Single Red Dot Finder, Takahashi 6x30, and various generic finderscopes.

David

[that_guy]

i would just like to say... TELRAD FOREVA!!!!!! GO TELRAD!!!!

[astro744]

Remove the words 'tight budget' and many possibilities open up, even the Tele Vue Starbeam. The $20 difference between the Telrad and 4 target finder is not worth thinking about and I'd recommend the Telrad anytime. However the $50 difference between a Telrad and a single red dot finder is significant and I was merely pointing out that the $59 red dot finder is NOT the cheapest.

[WestAusChris]

Wow thankyou everyone for your comments and replys, so many choices now :)

I have only used my 6" for 3 days and already have a stiff neck from bending down and twisting to look through the OEM finder on the dob.

Still so many choices though, i guess it comes down to what suits the individual in the end :)

Small town here so no star parties that i know of and for medical reasons i cant travel so thankyou again for all your advice will take it all in and make a choice :)

[WestAusChris]

Would a laser finder be easier or harder than all the above mentioned?

For the price of a telrad i could get a green laser finder shipped from the US.

Or would warrenty issues etc just be not worth it.

[mithrandir]

You'll have problems importing it. Any laser worth importing will be over the power limit so will need customs preapproval and probably a police permit.

The telrad would be much less stressful.

[Jeeps]

I bought the $59 red dot laser from Andrews last week and i've been waiting for a few days for some good weather. It slid into my SW's standard viewfinder dovetail easily. Hopefully i will be able to test it out tonight. I'm a bit skeptical, maybe because i reckon my SW's factory viewfinder is an awesome bit of kit so i'm not that hard to please LOL ;)

cheers

[WestAusChris]

Thanks for the tip andrew.

Sam i hope you get some clear skys soon to try it out, let me know how it goes :)

[Suzy]

Hi Chris,
I quickly got fed up with that finder as well as it was so hard to look through, so off it came. I replaced it with a red dot finder which cost me around $80. It has different patterns (cross, dot, etc) that you can choose, but most useful is that I can reduce the intensity of the light on it. When I bought it, Ron at Sirrius Optics told me that particular feature was a good one to have, and he was right. Regarding the batteries, they are cheap enough and easily obtainable from such stores as Jaycar. Make sure you buy a few each time and keep them with your eyepieces. You never want these batteries to run out without backup. They last for ages, providing you remember to turn it OFF when finished observing. I lost a few batteries in the beginning because of this.
I can't comment on the comparison to the Telrad as I don't know enough about the Telrads.

[bojan]

Red laser will not be visible at all (red light is not scattered in the atmosphere.. that is why green lasers are used).


As far as red dot finders (or red dot sights, of holographic sight - BTW this is totally wrong description) are concerned, they are OK (sometimes they suffer from parallax, especially physically shorter model), and they are cheap. Telrad is good, but quite big and cumbersome... and expensive.

Have a look at couple of ebay listings:
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=360315853170&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=310235792387&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=180581420184&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com.au/New-1-x-40-Red-Dot-Sight-Rifle-Gun-Scope-Great-Accuracy-/190463579298?pt=AU_Hunting&hash=item2c588394a2
http://cgi.ebay.com.au/BSA-1x30-MOA-Red-Green-Dot-Sight-Scope-f-Pistol-Handgun-/330493390782?pt=AU_Hunting&hash=item4cf2f0efbe

[Jeeps]

Ok i had a chance to test it out last night. The weather was terrible again last night, not a cloud in the sky but lots of dewy foggy haze. I could only make out bright stars, I couldn't even see orion's belt with naked eyes or barely with binoculars for most of the night but there was the occasional clearer patch. I still managed to see a lunar eclipse on Jupitor ;)

I had already fitted it to the scope's dovetail on friday. I took the scope outside and started to 'line up' the red dot finder. This is the $59 red dot finder with 4 selectable laser patterns from Andrews. The service from them as usual is excellent and the build quality of this unit looks very good with an all metal body. I started to line up the horizontal alignment with the supplied allen key and this worked fine. I then stated on the vertical alignment and this didn't work at all. No matter how many times i turned the allen key left or right it did nothing. A few more turns and "POP" out came a retaining piece from the finder. It hit the strut on the scope and bounced back onto the ground where i found it. I'm glad it didn't pop into the scope and land on the primary!

Off to the shed i went to use a clamp to hold it steady while i re-fitted the retainer. Still, no vertical adjustment. At this time i remembered that there was a smaller allen key supplied but not mentioned in the manual. I looked closely and found a small hole directly behind the horizontal adjustment screw. I stuck the small allen key in there and loosened the bolt and the rear of the finder sprung up. It appears that this it a 'major' vertical adjustment - just not mentioned in the manual. Within a few minutes i had the red dot finder back on the scope and using my thumb and finger i squeezed the rear of the red dot finder until it was lined up and then tightened the small allen key. Still not ideal as there was no 'fine adjustment' but at least i could get the dot into the 'vicinity'.

It was very easy to line up jupitor and any other star which i could make out in the poor conditions. It was easier than using the viewfinder. The glass viewer stops the laser from penetrating but it's also easy and clear to see through and the laser is very visible on the glass. It has 4 selectable patterns but i found the easiest was the smallest dot. It also comes with a cleaning cloth and a rubber dust cover for the glass. Here is a picture. Notice the vertical allen key adjustment on top of the finder which was ineffective:


http://i421.photobucket.com/albums/pp300/jeeps_photo/Astronomy/reddotfinder01.jpg


I have called andrews and asked them if this is a known problem and/or if they have any solutions to the vertical adjustment issue. I spoke with Luke who said that they've sold hundreds without any issue and none coming back and he wanted me to send it to him straight away (i'm in QLD) and he'll express post another out immediately.

cheers

[bojan]

Sam,

You are talking about laser, but this is NOT a laser - it is LED, placed in a focus of curved mirror (glass lens).
What you are seeing is the image of the dot (or pattern) projected on the sky.

Telrad works in the similar way - the difference is, instead of one one concave semitransparent mirror, it has a lens and flat semitransparent mirror.

[mental4astro]

I like the Telrad for the graduated 'circles' that help with charts. But too big and cumbersome for me.

I like the dinkie little RSF. I have TWO. One sits on my 8" f/4 dob. The other on top of my BIG 3" finder of my 17.5" dob. The 8" is a rich field scope, so the accuracy of the single dot RSF is just fine.

Hickny has a Telrad & a 3" finder together on his 13.1"!

Hickny & I find that a red dot/Telrad are great as "gross" finders, yet the light gathering of an optical finder is a great help with fine tuning, or when the target is just not easily locatable.

If your scope already has an optical finder, I suggest just a single dot finder is a fine addition. Most times the RSF is sufficient. Yet, the optical finder gives me a little more 'guts'.

As an example, from my home, to find the Tarantula nebula last night, with my light poluted skies just using just the Telrad on Hickny's scope or the RSF on mine would have been a very, very difficult task. The optical finder had enough "beef" to actually show the Tarantula, and make locating it in the scope a piece of cake. The optical finder doesn't need to be like my overkill 3"er. A 30mm would have done just a good a job. Even if I can't see the object, the finder will show sufficent surrounding stars to assist with star hopping to the target.

The pics below show the RSF & 3" finder arrangement (I still need to take a photo of my completed 17.5" scope fully decked out with all its bells & whistles).

[mswhin63]

Is there any around with right angle viewing, I would consider this better on DOB's and straight view ones on Refractors or large DOB's

[mental4astro]

These pics below were my solution to the 8" f/4 dob- extend the standard stalk:

[Jeeps]

Cheers thanks for correcting me ;) It's not listed on the andrews website or the manual. The battery, switch setup etc is identical to my laser collimator. If it is an LED then the battery should last longer!

It's definitely small and light. I might see if i can place it next to my current viewfinder when i get another sent out (if it works ;) )



cheers

[bojan]

No worries mate :thumbsup:

Battery lasts but you should still switch the unit off after use, as Suzy suggested. I have the same battery for a year already..

You may also consider changing the resistors that limits the current through the LED - battery will last longer, and what is more important, the brightness will be reduced further (those units are designed for rifles and pistols, not for astronomy).
The resistors are placed on a small pcb below the battery, it is not that hard to dismantle the whole thing.
I used the values up to 15 kohms to sufficiently reduce the glare of the dot.

[astro744]

Tele Vue Starbeam. A very nice red dot finder indeed with flip mirror for right angle viewing should you desire.

[bojan]

Our Price: $199.00
List Price: $285.00:eyepop:
You Save: $86.00 (30%)

[Suzy]

Chris, as I said earlier, I don't know anything about the Telrad to comment on them, but after reading this thread, I'm gathering they have some weight to them. A bit of a warning here...
The 6" dobs get very top heavy easily. Even a 2 inch barlow lens is enough to affect the balance (even worse is putting a big wide angle premium ep with barlow). Be careful, sometimes those tubes can hit the base pretty hard because of it, which is why from the start I put a square piece of adhesive foam on the inside of the base. There is a fairly easy solution to this problem of balancing the tube. I used a Velcro strap passed thru a camera case (you know the ones that have got the strap so your whole hand can hold it?) and filled it with weights. Placed I guess about 10-15cm up from the bottom of the tube in line with the eyepieces. I have also heard people use magnets (bought from Jaycar I think). I had the balance set pretty well with my weights so never had to add or remove weights. A good all rounder weight I found to be a good option, instead of struggling in the dark even more.

[astro744]

Only 262 grams including batteries but not the base which is also quite light as it is also made of plastic.

[WestAusChris]

Thankyou again everyone for links and write up's i certainly have some good ideas from you all and once i have decided what to buy i will take some pics and put them on the forum. :)

Really appreciate everyone taking the time to write.

[turbo_pascale]

Telrad and Red Dot finders aren't going to fix your stiff neck issue.

Get a right angle finder instead.
https://www.bintelshop.com.au/Product.aspx?ID=6877

Won't help your budget any, as it is more expensive than the Telrad!

I have one, and love it, although I literally used mine again for the first time for 2 years, and there is a little rubber o-ring that disintegrated in it, which is making it wobble around. Outside of that (which should be easy enough to fix) it was the easiest finder I used, especially with an SCT, where finding the pole means the finder is upside down "under" the scope in the polar home position.

I also have the bintel multi-red-dot finder, but anything more than the first light setting is too bright (even that is annoying).

When I had everything setup on my SCT, I had a green laser, the RDF and the right angle finders, all aligned with my main scope and the guide scope. It is quite good to get rough position with the laser, then step up to the RDF, then the right angle finder, then the guide scope, then the main scope. It was like having 5 levels of zoom!

Turbo

[mswhin63]

I must admit stiff neck issue was a big problem for me too, I also bought a right angle finder and would consider laser as a way of quick targeting. I wouldn't use laser though for serious deep sky observing but for general DSO it should be fine. Important to consider other people in the location. I think the laser is good enough to get enough bearing to then use the right angle view finder. I dont have a laser so I only use the finder ATM. My original scope DOB had a straight finder and was one of the first things to change.

[WestAusChris]

Im very tempted to get a friend from the US to just post a laser and say its electronic parts and hope it gets through.

Only be used on the back verandah with only one niebour who is 4 house blocks away, live on a new estate in a small country town so there is no street lights and can get very dark night skies.

[mswhin63]

You can buy them in Aus, I am also applying for a licence to manufacture as well.

[Jeeps]

Just an update - i received the new red dot finder during the week. I fitted it up and waited for the sky to clear...

I did notice immediately though that this one's displayed patterns were crispy sharp. The previous one's patterns weren't so clear and sharp.

Anyway went out on Thursday afternoon as the clouds had cleared a little bit. Setup the scope early and pointed the dob at Jupitor and started to align the red dot finder. I decided to use my intuition this time rather than rely on the sparsely explained manual that came with it. I first loosened the right rear 'locking bolt' of the right side of the finder with the large supplied allen key and also the left rear side 'locking bolt' with the small supplied allen key. These 'locking bolts' are shown in the diagram if you study it hard enough, but no mention of them or their appropriate use is otherwise explained in the manual.

Once these locking bolts were loosened i started to turn both the allen bolt on the left side for horizontal adjustment and also the allen bolt on the top for the vertical adjustment. It worked this time! At first i didn't think it was working because it takes many more turns to get the vertical adjustment to move than does the horizontal adjustment.

When the dot was lined up i tightened the 'locking bolts' and checked the alignment. It was now out a bit so i then had to loosen them and readjust the alignment a little bit. Tightening the 'locking bolts' misaligns the dot a little bit - similar to tightening the locking bolts on the primary mirror of the dob after collimating ;)

The clouds then rolled in so i didn't get to do any viewing :( so i packed up the scope and also put the supplied dust cover on the red dot finder. I was interested to see if putting on the dust cover misaligned the finder as little bit of wriggling is required to get it on.

Come last night (saturday) after getting home around midnight there were finally stars! So out came the scope and i turned on the red dot finder to see if it was still aligned. Pointed it at the Orion Nebula, put a 30mm GSO Superview eyepiece in and there it was in the centre! I put a 20mm GSO Superview and then a 12mm in and it was still in view. It was towards the edge with my 9mm TMB and right at the edge with my 6mm TMB. Not bad! It seems it does hold alignment quite well!

I pointed it at a few items, Pleiades, around orion a bit etc then started to do a star collimation and guess what? The clouds rolled in... :mad2: :P

Andrews service was great as usual and the replaced finder does as advertised. After playing briefly with it i would say that the red dot finder is much easier than the straight through finder to use. The red dot finder is best on the 'smallest dot' pattern and the lowest brightness setting. Any brighter and the stars in the background get washed out and it's harder to point at things.

All i need now is some clear weather ;) :D :rofl:

cheers

(i'll post up a pic this afternoon)