Budget Astrophotography: Polarie, Astrotrac, Advanced VX

[amber-leung]

I can now say I have tried both the Vixen Polarie and the Astrotrac.

After the fact, I'm shocked that I could get such good alignment on the Polarie quickly, right out of the box, allowing me to easily achieve 1 minute exposures at 420mm (Canon Rebel T4i with 300mm F4 + 1.4x extender) without star trails. Sitting on a heavy tripod and a Manfrotto 410 geared head, this was terribly unbalanced, however, and the weight of the camera and lens threw off alignment just enough that 1 minute was the absolute limit.

Right out of the box, the Astrotrac is not the least bit close. It is my understanding that it is capable of better accuracy than the Polarie, but only after much tinkering.

Polarie Manual, polar scope illustrated on pg 23

http://www.vixenoptics.com/PDF/POLARIE%20Manual.pdf

Astrotrac Manual

http://www.optcorp.com/pdf/AstroTrac/AstroTrac%20TT320X%20Instruction%20Manual%20v1.0%20-%20Web.pdf

Long story short, once you learn how to adjust it, the Polarie scope is very quick and easy, just adjust for the date and time, line it up with Polaris only, and you're set! The astrotrac scope is illuminated (that's nice) but needs to be modified, collimated (explained here: http://www.fredmiranda.com/Buzz/Collimating%20The%20AstroTrac%20Polar%20Scope.pdf), and then aligned with three stars. After all that, what I don't like is the three-star alignment. Even in less than perfect sky conditions, alignment with just Polaris was still very quick and easy.

The alternative is modifying the arm on the Astrotrac to hold the Polarie scope.

Or possibly just buy the Celestron Advanced VX mount, though I can't spring for the 8in SCT at this particular time, however. What do owners of the AVX mount say?

EDIT: I realize I have been very spoiled by the ease of Polarie scope. I'm leaning toward modifying my Astrotrac to accept it. As a working mom, time and budget tend to be my limiting factors.

[amber-leung]

Don't even get me started on the flashing green light on the Astrotrac

That'll certainly need to be extinguished. ಠ_ಠ

[buster-wilson]

Hi Amber. I find it interesting to see how different mounts go about getting polar alignment. Like you wrote that the Polarie is simple to adjust. Yes it looks like the Astrotrac may need extra work to be able to get it to the point so that it is easily set up also. Once the extra work for alignment is done and it should make the next time setup much easier and quicker then maybe your tracking will show the improvements. You may be surprised how much tinkering is needed on many of the higher end price mounts need too with computers or not. Have you looked at any Advanced VX mounts in person and seen their set up needs also ? Any chance you will have your newest mount at GB Park tonight to show us how it works ? Hope so ! Tonight looks to be the best until again next week *BW*

[amber-leung]

Buster,

It has dawned on me the degree of tinkering needed no matter the mount

I believe I have a plan to modify the Polarie scope to fit the Astrotrac, perhaps it will be ready to go in a few days.

I'd love to see some better mounts (and their more knowledgeable owners) in action. I'll try and make it out to the park tonight to play with the Astrotrac with its current polar scope.

-Amber

[steve-fung]

Hi Amber, I'm sorry to see your frustration with the AstroTrac. Like I mentioned earlier, I was thinking about purchasing the AstroTrac over the Vixen Polarie Star Tracker and iOptron SkyTracker for wide-field AP during my travels, but now I'm having second thoughts seeing your difficulties. Also, the green light you mentioned looks like a design flaw. Can it be covered? Still, I'll be glad to hear your opinions once you get more experience working with your equipment. Next time, I'll bring both my CG5 and AVX mounts for you to try out. Both of these mounts have All-Star polar alignment capability, which if properly set up should be more accurate than using the polar scope alone.

[amber-leung]

Well, I'm still working on improving the collimation of the Astrotrac polar scope and experimenting with mounting the Polarie scope on it. Just a matter of ordering a few parts I need. I think I can get the accuracy I want, just takes some fiddling. Even with those issues, I like it and see a lot of promise in it. Pretty sure I can cover up that light. It's all in the fiddling.


Sent from my iPhone using Tapatalk

[steve-fung]

Nice picture of the setup. The image is dark, but after enhancement, looks like you modified your AstroTrac quite well with the Polarie polar scope. The polar scope looks fairly wide; I'm assuming this is pipe insulation to hold it in place? BTW, have you seen this website where the author modified his AstroTrac exactly the way you did because he thought the AstroTrac polar scope was crap (http://www.laszlopusztai.net/2014/02/27/building-an-astrophotography-rig/). To attach the Polarie polar scope to the AstroTrac, he machined a custom adapter to hold the polar scope in place. In your opinion, do you think a counterweight bar and weight would be helpful?

[steve-fung]

I'm reviving this post to ask if anyone in HAS has experience with the Sky-Watcher Star Adventurer mount (http://skywatcherusa.com/mounts/star-adventurer-astro-package.html). I was looking for a light-weight portable tracking solution that can be easily mounted on an existing heavy-duty camera tripod for wide-field astrophotography (14-200 mm focal length), which I'm planning to do on my trip to the Canadian Rockies this summer. After months of paralysis by analysis, I was ready to buy the AstroTrac and modify it with a Polarie polar scope per Amber's solution when I came across the Star Adventurer equatorial mount. The build looks heavy duty, weighs 2.2 lb (1 kg), and stated load capacity is 11 lb (5 kg). Review seems good, but what do people here really think?

https://www.skywatcher.com/downloads/Star%20Adventurer-SA-F-100326V1-EN.pdf

http://www.cloudynights.com/topic/469185-sky-watcher-star-adventurer-first-light/

https://www.youtube.com/watch?v=sFzQiVwL1NU

[edward-fraini]

ALL-
The thought of being able to mount a DLSR on a tracker and do some wide field astrophotography appealed to me. I liked what I saw on the WEB for the Sky-Watcher Adventurer. So I purchased one along with the EQ hardware. I spent several nights working with it mounted on a very very heavy duty tripod. Never could get decent stars even at very short exposures. I knew that I was having a hard time getting a Polaris alignment and the results proved it. I packed it all up and it sets on the shelf. It is evident that some people had great success with this tracker but I would not personally recommend it. It will be interesting to see the outcome of all the contributors to this thread as I still have an interest in wide field photography, like to see what works for folks.

Ed

[edward-fraini]

PS-

Happy to loan this Sky-Watcher Adventurer out to someone to work out the bugs