Of late all the focus and attention of those who like their imaging gear small (relatively) inexpensive and highly portable has been (deservedly) on the Vixen Polarie.
I have one and love it.
However, I have been having great fun with my Astrotrac which I find is really capable and ticks all the boxes (as far as I am concerned in terms of simplicity, lack of hassle and portability)
I have teamed the Astrotrac with a Borg 45ED (with a 0.8 focal reducer) and a Canon 450D. Occasionally, Ill just use the canon kit lens
I have two ED telescopes, two mounts a CG5 meant be the portable mount and an EQ6), two cooled QHY CCDs and for the past year have not touched any of these, so clearly I must like the Astrotrac. (and Polarie which I use when I cant use the Astrotrac for any reason )
I plan to image the Messier catalogue with the astrotrac, which given how infrequently I get out is a long term project.
Usually 90 second subs and about an hour or so in total. Once the astro trac runs out of track and needs to be reset I find it impossible to reframe the target exactly, so am limited by that in terms of total exposure.
Yep, I love mine.
So did the previous owner (well known IIS member)
So does another IIS member that has borrowed it a few times now (and he has already reserved it for another outback adventure in July )
They are great bits of kit even with the two-hour limit before having to rewind.
The whole kit(pier+wedge+head+counterweights etc etc) is kinda expensive but well worth it in my opinion.
Yep, I love mine.
So did the previous owner (well known IIS member)
So does another IIS member that has borrowed it a few times now (and he has already reserved it for another outback adventure in July )
They are great bits of kit even with the two-hour limit before having to rewind.
The whole kit(pier+wedge+head+counterweights etc etc) is kinda expensive but well worth it in my opinion.
I don't have the pier and head/counterweight but I have seen it in operation most notably at November's eclipse.
It's a nice bit of kit ..and as far as I am concerned has stopped me from sliding down the slippery slope of ever more expensive mounts and telescopes and CCDs.
Great pics! Good to see such high quality longer focal length shots from an AstroTrac. I also love mine.
Quote:
Originally Posted by seeker372011
Hi Houghy
Usually 90 second subs and about an hour or so in total. Once the astro trac runs out of track and needs to be reset I find it impossible to reframe the target exactly, so am limited by that in terms of total exposure.
I am drift aligning
How long do you spend on the drift alignment?
Regarding re-framing. I find it easy because I have a ball joint between AT and camera which has two separate adjustments for rotation vs other directions. As such I can rewind the AT then unlock the rotation of the ball joint and rotate it back the appropriate amount (30 degrees if it's the full 2 hours but I usually base it on a star's position in one far corner of the FOV). Just a tip in case you haven't tried that. It's not perfect but it's easy to get very close and there's only variation in the RA because I won't have adjusted it in other directions.
Thanks Roger and Dave. It was both your wonderful images with an Astrotrac that convinced me of this mounts abilities.
Roger, drift aligning the astrotrac does take some time. Since I don't have an eyepiece in my set up and I am not using PHD to autoguide, the drift alignment consists of getting close using an altimeter and compass, then pointing at a star at the meridian as you would for normal drift alignment; taking initially 30 sec image, making an adjustment in azimuth till the star is round at 30 sec (guess a direction and see if it is getting better or worse); then going up to a minute and repeating. Usually try to get at least 3 minutes with no noticeable drift, though have gone as long as 7 minutes.
then repeating with a star on the western horizon for altitude correction-usually this doesn't need a huge change as I am back at the same dark site.
Find I sometimes need to tweak again in azimuth after getting the altitude right.
It is not as bad as it sounds but it is not a 5 minute job. And I have the astrotrac wedge
Regarding re-framing. I find it easy because I have a ball joint between AT and camera which has two separate adjustments for rotation vs other directions. As such I can rewind the AT then unlock the rotation of the ball joint and rotate it back the appropriate amount (30 degrees if it's the full 2 hours but I usually base it on a star's position in one far corner of the FOV). Just a tip in case you haven't tried that. It's not perfect but it's easy to get very close and there's only variation in the RA because I won't have adjusted it in other directions.
The Borg sits on a heavy duty Benro ball head, which sits on an Astrotrac wedge, which in turn sits on a heavy duty Benro tripod.
Always hang a weight off the tripods hook to lower centre of gravity and add a bit of stability
Narayan
Hi Narayan,
I also have a heavy duty Benro tripod, but use a Manfrotto 410 geared head (which i love) and 486rc2 ball head (which i hate!).
Another question, when you drift align are you running the astrotrac in test mode and following the ccd drift alignment (i.e. run it fordward 1min then backward 1 min etc..) or are you simply just imaging for 30seconds while the astrotrac is tracking normally?
I tried that running one minute forward and then back but I could never really get it to work
I just start the Astrotrac tracking normally and take as I said first 30 sec then longer images and try to get rid of trailing
The only glitch I have found is sometimes I get to talking with people and forget which way I adjusted in azimuth and invariably guess wrong undoing any progress I was making .. But that's just operator stupidity not a process fault
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They are excellent images 
Looks like drift alignment has paid off.
