Yet another guidescope question

Using SharpCap's Polar Alignment feature
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devonshire
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Joined: Thu Dec 14, 2017 12:37 am

Yet another guidescope question

Post by devonshire » Fri Mar 22, 2019 3:04 pm

Robin,

I'm looking at getting a longer-FL guidescope, but do not want to compromise my Sharpcap PA, which has been working fine.

I'm looking at new guidescopes in the 60/F4/240mm class, and combined with my current Altair camera, Astronomy.tools tells me that the chip will see a FOV of 1.14 x 0.86 degrees.

Is this FOV sufficient for PA?

Thanks!

- Bob

AndyBooth
Posts: 52
Joined: Thu Mar 01, 2018 6:55 pm

Re: Yet another guidescope question

Post by AndyBooth » Fri Mar 22, 2019 3:11 pm

I use a 285mm focal length with the Altair 1280x980 pixel chip,
Which gives only a 1x0.7 degree field I think.
Works fine, but i have to orientate the camera so that when i rotate the Ra axis, it moves horizontally on the longer side of the field, if you get my meaning.
Has never failed yet.

devonshire
Posts: 20
Joined: Thu Dec 14, 2017 12:37 am

Re: Yet another guidescope question

Post by devonshire » Fri Mar 22, 2019 3:53 pm

Andy,

Thanks! So, just to be clear - Portrait/vertical orientation at the start, and then rotate to landscape/horizontal orientation to finish?

- Bob

AndyBooth
Posts: 52
Joined: Thu Mar 01, 2018 6:55 pm

Re: Yet another guidescope question

Post by AndyBooth » Fri Mar 22, 2019 3:59 pm

yep thats about the size of it Bob.
I find that Sharp cap doesn’t need a full 90 of the RA axis rotate to work either,
Just gives a bit of breathing space by setting the camera portrait.

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Re: Yet another guidescope question

Post by admin » Fri Mar 22, 2019 8:14 pm

Hi,

Yes that guide scope should be perfectly fine, It's when the field of view darts to get down towards 0.5° as a maximum dimension that polar alignment tends to have trouble.

Cheers, Robin

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