My portable backyard tent observatory

[naskies]

After spending more time setting up / tearing down equipment than actually imaging in recent months, I decided to set up a temporary tent observatory in my back yard.

The main tent is a Black Wolf Mojave SG6 which is split into a front screen room and rear bedroom. The screen room acts as my warm room and storage area, and is high enough for me to stand up in. The tent is extremely well designed with a *lot* of vents - it doesn't get muggy at all, even with the fly in full waterproof mode.

I leave the mount + scope uncovered during imaging, but during the day / cloudy nights it's covered by a towel (helps dry off any dew), a Telegizmos cover, a doonah, and a heavy duty tarp - all inside an OzTent CR2 cubicle. This is a bit overkill, but it gives me peace of mind that it's well-protected from both rain and sun.

Both tents do get a little warm during the day with direct sunshine, but I discovered an unexpected benefit - the heat discourages and/or kills any insects that try to move in. No wanted guests so far!

For power, I've just run a 30 m extension cord into the tent to top up the deep cycle battery when needed. The tent is too far from the house for wifi, so I've run a Cat6 patch cable out to an Airport Express wifi base station.

I'm imaging with an adaptive optics unit using an OAG with 0.1 sec exposures, which means that Maxim DL loses the guide star and starts alarming immediately when clouds pass through. Whether I'm sleeping in the tent, or home in bed, I just have Remote Desktop connected to the laptop with the volume turned up to wake me up - this has already worked quite well.

To compensate for not being able to just look up at the sky or see where the telescope is pointing (while building a pointing model), I've used an SBIG ST-i guide camera with 6 mm C-mount lens to give me a 60x45 degree FOV. It's wide enough that I can see about 2-3 constellations (like a Telrad finder). My main imaging camera's field of view represents 5x5 pixels, which is enough to land a target on there by hand. With looping 1 sec exposures, I can see the horizon, passing clouds, planes, satellites, etc.

I've had this set up for about 2-3 weeks now - so far so good. It's weathered through both hot days and rainy days (about 100-150 mm of rain so far - still bone dry) without a problem. We haven't had any gale force winds yet, but I'm confident it'll be fine as the spot is protected from strong winds on all sides.

The best part of this set up though is that I can pack it all up, drive out to my usual dark site, and have the identical system up and running within a couple of hours. In theory, anyway... first test will be this weekend. The power extension cord just goes into the generator instead of power point, and substitute 3G data for wifi.

I'm currently building my own all-sky camera to improve horizon visibility, and also saving up for a motorised focuser and camera rotator for better automation.

[naskies]

The very best part of all - waking up in the morning to a huge amount of data! In the past two nights, I've imaged ~12 hours across two panels on the Running Chicken, and 12.5 hours from late last week on the Cat's Paw. Here's a quick stretch and peek at the data in DSS.

Fingers crossed for lots of clear nights this winter!

[Draco]

nice ;)

[Dennis]

Clearly a man with a passion for astrophotography! Excellent write up and photos.

Cheers

Dennis

[alistairsam]

Hi Dave,

That looks great.

But cant you cut a hole in the roof of the tent so you can just zip up in the morning?

I've been thinking of a tent as well.
would be good if the tent is modified to just cover the ota and mount when its horizontally parked. that way, it'll clear the opening during normal use.
there was a qld company selling this tent for $300 I think.

what do you use for your sequenced capture? i'm currently evaluating SGP,

below is what I do or am testing, may or may not be of any use.

with SGP, it looks like you can set a whole night's run on it as it slews, centres, auto starts guiding with phd and aborts if the guide star is lost.
same with the meridian flip. all automated.

I then set an auto park with eqascom to park after 10 hours, and then with maxim, run the skyflats plugin to capture sky flats at dawn with a target ADU.

I also use a $5 timer that powers everything, to switch off at 6am. that way the CCD doesn't need to keep its cooling running till I wake up in the morning, and I have a laptop in the box under the mount that's set to hibernate when on battery after 15 mins.

so objective is to power down everything at 6am automatically, and lappy hibernates at 6:15.
scope should face south, so no risk of direct heat on the scopes optics and ccd.

I also use eqascom to save and load alignment points on startup, so if there are a few clear nights, I don't have to redo all the alignment.

currently looking at adding a series of bright stars to an SGP sequence with 30second exposures.

That way, SGP can slew to a star, plate solve, centre, then sync mount, adding a sync point and continue for however many bright stars i add.
something like maxpoint or Tpoint. So I'd end up with atleast 10 sync points.

I'm yet to test this.

I'm however using an eqascom script to do the ccd polar alignment slew. that works great. i have one for 30s, 1m, 2m, 4m.
by the end of the 4m run, my PA is very very close.

Hope its of some help.

Cheers
Alistair

[leon]

Excellent Dave, what a great idea.

Leon

[peter_4059]

Alistair,

You shouldn't need to bother with sync stars if you are using SGP with plate solving. The plate solving will keep iterating until it centres your target based on the reference image/target coordinates. I've been using it for about 18 months and don't even bother with an initial alignment star anymore - just do a blind solve first, slew to the target and let the plate solving centre the target automatically. Same after a meridian flip.

Peter

[naskies]

Thanks Niv!



Thanks Dennis!



Yes, ideally I would like to house the telescope inside a "proper" enclosed tent with a bucket floor and insect proof mesh. During heavy rains, the Oztent becomes very humid inside - but my Black Wolf stays very dry and well ventilated.

I chose to have a separate observatory/sleeping tent to help improve comfort (high ceilings, spacious, well ventilated, holds up to adverse weather, etc) - especially during dark sky trips. Having the observatory room "inside" the tent is great for being able to tweak the imaging run without having the go outside into the cold/wet.

I looked at Sirius Optics' tent but wasn't impressed by the size, price, materials, etc. It's not designed to be rain proof, so you'll end up having to throw a tarp over it - which then risks becoming a sail during strong winds (and thus lots of pegging down).

The OzTent is very quick to peg down (four corners at the base, plus four guy ropes), and the large entry door is great for ventilation on warm sunny days. I've been considering a small gazebo tent (like the one below) that I can collapse down around the scope/mount during imaging:

http://oztrail.com.au/WebPage.gtl?Product=MPG-GUTI-B?currentgroup=ZZZ009?currentsubgro up=ENSUITES

The Kendrick Stargate would be the holy grail of observatory tents. Aside from being sold out (possible new production run coming, though) it's extremely expensive at ~ $800. My main concerns with it are the lack of vertical supports over the mount area (water can pool during heavy rain), and lack of sufficient ventilation for Aussie conditions. I may consider putting my name down for one though...

http://www.kendrickastro.com/astro/observatory.html



My iPhone's alarm clock set at ungodly hours of the night :rofl:

I've looked into CCDAutoPilot and it seems perfect for my needs. However, the Maxim DL implementation of Adaptive Optics is a bit finicky so I have my doubts about whether it would work well. My EQ6 benefits from being east-heavy which makes automated tracking of a target on both sides of the meridian a bit tricky.

So far, I've just picked a target that starts/ends at the meridian and let it run its course. Wake up in the morning, park the scope, etc.



I'm playing around with the MaxPoint trial at the moment. The auto mapping feature works great - takes about 30-40 mins to get me 100 sync points, all automated.

I've found the EQMOD N-point mapping feature works really well. Being able to do the 100 point mapping automatically with be brilliant. Maybe with Elbrus/Astrotortilla or some other equivalent free astrometry package?



Great! AlignMaster works pretty well for me. I've noticed that MaxPoint has a polar alignment routine too, with the error calculated from the full model rather than just one star pair. I haven't had a chance to see how accurate it is yet.



Thanks Leon!

[RobF]

Thanks for sharing Dave, but fun to read along when you're saw addicted by the need for more data :D :thumbsup:

The reality of many of us in surburbia can be questionable horizons and difficult sites for observatories, not to meniton very average skies in terms of light pollution. To that extent the better the set up you can muster for reliable performance at a dark sky site becomes important, and you look like you'll be travelling in luxury there.

An unexpected benefit of collecting "mega-data" from home is you can often overwhelm the light pollution even for LRGB galaxy work, at least on the brighter objects. Be interested to hear more on your exploits!

[naskies]

Thanks Rob! Luckily, I live on an acreage so the horizons and space are good. Yes, I've been very impressed by what various people have been able to shoot from light polluted areas - so I'm looking forward to plenty more clear skies :)

[h0ughy]

listen - a word or warning from me - cover your mount with a tarp - even in that toilet tent. it rains that tent leaks like a sieve, it ponds water on the top and it drips onto the mount. astrofest experience. i love your outlook and setup - good luck

[naskies]

Thanks David! Yes, I discovered the leaky sieve like nature of the shower tent at the onset of a big rainstorm (40 mm in an hour) :rolleyes:

Ironically, once the tent was completely soaked through it no longer leaked - there was even a pool of ~ 10 litres of water trapped on the roof/fly the next morning.

I keep the scope/mount under a Telegizmos cover and a heavy duty tarp within the shower tent, which keeps me confident that the electronics + scope will stay dry.

[naskies]

A clear night in SE QLD for a change, all the cameras snapping away, and I can keep an eye on everything from the warm comfort of my bedroom... it's nice when things eventually work!

[RobF]

Glad to see Dave. Good season to be indoors!

Looks like high cloud might spoil our party around midnight though?

[DavidTrap]

You need a bigger monitor!

DT

[naskies]

If only there were some way to safely cover up the scope from the comfort of home... :question: :lol:

What a miserable year it's been! Are you and David out at Peter's place?



The car's already a bit too full for dark sky trips... :D

[jwoody]

Nooooooooooooo:mad2: This year has been a bit rubbish so far imaging wise.

A nice setup naskies. I have that tent also and it is a beauty.
Clear skies
Jeremy

[RobF]

I'm set up at home Dave - trying to shoot some Ha.
Grrr - kids back out of bed again