On Sat, Aug 1, 2020 at 05:51 AM, Andrea Lucchetti wrote:

Hello,
I need to polar align my Mach 2 very quickly to save time on field.
I thought Polemaster would have been a good choice but I cant get a good alignment with it (I am ways off)
The procedure goes very well, till the end, including the precise alignment step, but I have drift in my images.
running the Polemaster twice results in a small change.


I am not using the refraction calculation , as I leave at 42 deg latitude: can this be one of the reason?

my aim is to shoot 10 min subs unguided (@790mm focal and 1,6 arcsec/pixel resolution).

I still don't have my OTA ready so it is difficult for me to check with the drift method for the time being ( I can borrow a dslr and C8)

Would the RAPAS be a better solution for my needs? 
I understand it can be mounted on the MACH2 using a dovetail, with repeatable accuracy.
Is the accuracy enough for imaging and how it compares to Polemaster?

Thank you,
Andrea

Andrea,

Your original post message is a little confusing.

First you said:

"The procedure goes very well, till the end, including the precise alignment step, but I have drift in my images."

then you said:

"my aim is to shoot 10 min subs unguided (@790mm focal and 1,6 arcsec/pixel resolution).

I still don't have my OTA ready so it is difficult for me to check with the drift method for the time being ( I can borrow a dslr and C8)"

You don't have OTA ready but still get drift in your images? How can you get images if you don't have OTA ready?

What scope were you using that's giving you drift and are you trying to image unguided? Also you said you are aiming for unguided imaging at 790mm focal length which can be very hard to do assuming you are not using pointing model with APCC-Pro. Are you using pointing model yet? If not, I would not expect absolute encoder alone to get pinpoint stars without the help of pointing model even with perfect polar alignment due to many external variables like refraction in the sky, flexure, etc.

So, if you polar align using PoleMaster and its software and use guiding, then I would expect excellent images. Like others said, I would prefer Sharp Cap Pro as well as it's not only accurate but super easy to use. If you already have PoleMaster, then you may not need RAPAS because PoleMaster with Sharp Cap Pro is really good and quick.

Can you clarify your original message a bit more?

Peter