Quote:
Originally Posted by JohnH
Hello IISers - I need some advice - I have acquired a small EQ mount with RA motor (stepper) drive for use as a portable widefield AP mount mostly just for my Canon 20d with 50 or 135mm lenses and if I am lucky with .8 FR and WO66 SD.
I have hit what I think is a snag. Polar alignment is tricky, the setup has a PAS but I am not sure how accurate that will get me, here is what happened.
I aligned as best as I could with the PAS, focused and got tracking going then tried a series of shots at the Antares region. I got 60s shots with the 135mm lens without too much trailing (a few frames were rejected with trails but that is ok - the mount was only $200 and the lens less than $50 I am not expecting perfection!).
What I did notice though is that over the run antares gradually drifted down the frames so that after 3 hrs it was about 1/3 of the way down the frame. I guess this means my alignment was off in AZ quite badly but with this setup I will not be able to do a drift alignment readily (no scope!) so I am wondering what the best way forward would be.
I am also concrened my RA drive may be running slow, is there any easy way to check that - I guess it will depend on knowing the gear and worm ratios - of course I do not have those as the kit was bought s/h. I have timed the roataion at the worm spindle and it is 1 rev/8 mis approx.
All thoughts/advice welcome.
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Hi there!!
good polar aligment will allow you to have exposures up to around 2 mins, well i have found that from my experience. i drift align, but i doubt you could do that with this setup
maybe someone else will chime in.
