How close is sufficient

Using SharpCap's Polar Alignment feature
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Burly
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How close is sufficient

Post by Burly » Sun Apr 22, 2018 3:22 pm

How close is within reason using Sharpcap PA ,i was setting up my Pier head the other night and wondered how close to PA is within acceptable limits for imaging .

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admin
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Re: How close is sufficient

Post by admin » Sun Apr 22, 2018 8:06 pm

Hi,

I've seen sources that say that within 2 minutes of arc is good enough for most purposes.

If you think about it, being 2 minutes of arc out means that you will be 2 minutes too far up in DEC on one side of the polar and 2 minutes too far down on the other, so your dec would drift 4 minutes over 12 hours or about an average of 20 seconds of arc per hour. That sort of drift would be easily corrected by guiding. It would probably be fine without guiding up to 3-5 minute exposures too.

Feel free to aim for better, but you must turn on refraction correction in the settings (SharpCap 3.1), otherwise atmospheric refraction will be your biggest error.

cheers,

Robin

Burly
Posts: 6
Joined: Thu Apr 13, 2017 7:49 am

Re: How close is sufficient

Post by Burly » Sun Apr 22, 2018 8:32 pm

Thanks Robin

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