PA with QHY

Using SharpCap's Polar Alignment feature
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brada
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Joined: Thu Oct 19, 2023 1:47 am

PA with QHY

#1

Post by brada »

I had lots of issues last night trying to PA with a Polemaster and Sharpcap.
Has successfully used the combo several times previously, but last night;
The biggest issue was after I started Sharpcap, select the Polemaster camera, a couple of frames and the black sky with some stars.
It had trouble plate solving and when it did, went to the next step, then rotate the axis, and would give me the numbers and everything would stop.
No more frames counting in the lower left and the numbers would never change as I adjusted the mount. Over a 5+ time period, maybe 50 frames total.
One time, sharpcap and the computer stopped responding and required a hard reboot.
I tried plugging in the polemaster directly into the computer bypassing the Pegasus, no change.
As the night went on and I tried different methods to connect and it finally stopped plate solving all together.
All the plate solving attempts were with Sharpcap.
This is actually not the first time with USB challenges, but the last couple of times, no issues at all with the Pegasus.

I plugged a QHY5III462m and lots of frames in the lower left during live view.
The challenge, I have not used the camera yet with my AskarV Guide Scope and it is not focussed properly.
Could/should I use this instead of the Polemaster?
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admin
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Re: PA with QHY

#2

Post by admin »

Hi,

sorry to hear you had trouble with the polemaster camera - the only thing I can think of to suggest beyond what you have already tried for that camera is to adjust (increase) the USB traffic control (if the camera has one) as that can stabilize things.

As far as I can see, the QHY462 camera connected to the guide scope should work fine - I am asuming the guide scope is a short focal length (under 250mm).

cheers,

Robin
brada
Posts: 5
Joined: Thu Oct 19, 2023 1:47 am

Re: PA with QHY

#3

Post by brada »

I tried USB traffic a couple of times within your software, this has seems to have worked in the past.
Friday night I was able to PA but it took a good 45 minutes with camera still not working properly.
I would get 10-15 frames then nothing for a period of time, and then a few more frames, etc.
Don't know if it is computer related or camera & USB cable issues.

I will give the QHY a try when I can get something to get that focused on such as the moon in a couple of weeks.
The Askar V guide scope is 32mm aperture, 128mm focus length.

I guess anything over 250mm focal length would be problematic?
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Re: PA with QHY

#4

Post by admin »

Hi,

for the polar alignment, the field of view is the critical thing - it should be bigger than 0.5 degrees in both directions (ideally about 1 degree in the wider direction). So, the exact focal length that will be a problem depends on the sensor size of the camera you are using. You can use one of the 'field of view' calculator websites that exist to work out the field of view for your camera/telescope combination. With standard, small sensor, planetary/guiding cameras then the 200-250mm focal length works well, but anything up to about 350 should be OK.

cheers,

Robin
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