Re: large alignment error with polemaster & mach2

Christopher Erickson

SharpCap Pro is a critical tool for me. I use it for controlling my QHY174M-GPS cameras when doing occultations. The price is dirt-cheap and I would still pay for it at four times the price. It is the only camera control program that is capable of collecting the GPS timing and location data from the cam and putting it into the FITS headers while collecting up to 450 frames a second. If course most of the time I am collecting frames at about 4 frames per second.

It's an amazing program for the price. And for many people, the free version is sufficient.

-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738

On Sat, Aug 1, 2020, 5:29 AM Cheng-Yang Tan via <> wrote:
Hi Rolando,
   I think my "Unfortunately, SC polar alignment costs $", is more of a lament that the software that comes with PM does not seem to be as accurate and the op has to spend money to get it to work better.

  To be clear, I don't begrudge people making money from doing software work.


On Saturday, August 1, 2020, 10:02:50 AM CDT, uncarollo2 <chris1011@...> wrote:

Unfortunately, SC polar alignment costs $
Everything should not be zero cost. Writing software takes time and expertise and should be rewarded. If everything is zero cost we will all be forced to become subsistence farmers scraping a living from the soil.


-----Original Message-----
From: Cheng-Yang Tan via <>
Sent: Sat, Aug 1, 2020 8:18 am
Subject: Re: [ap-gto] large alignment error with polemaster & mach2

I’d suggest trying Sharpcap with the Polemaster camera. I’ve always found Sharpcap gives a better PA than the Polemaster software. An advantage of SC is that it gives an alignment error when you are adjusting alt and az which is absent in PM software.

Unfortunately, SC polar alignment costs $ and is an annual subscription, but it’s cheap.

As usual YMMV


Sent from Yahoo Mail for iPad

On Saturday, August 1, 2020, 7:51 AM, Andrea Lucchetti <andlucchett@...> wrote:
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,

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