Skywatcher Evoguide 50ED

Using SharpCap's Polar Alignment feature
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MisterQ
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Joined: Tue Sep 22, 2020 8:58 pm

Skywatcher Evoguide 50ED

Post by MisterQ »

Hi all,

Fresh to the forum and I've searched high and low for a specific yay/nay for my question but with no luck. Please feel free to link me to the answer if you find it I shall not be offended! :-)

I am looking to purchase a guiding/PA scope and I've been trying to plug the details of the Skywatcher Evoguide 50ED along with the ZWO ASI120mm-mini into various FOV calculators with no luck. Does anyone who uses Sharpcap PA have this particular combo or any experience with it either working or not working for them? I'd love to know if this will work so I can get on with experimenting with it and trying to achieve a better PA than my eyesight will allow! :-)

Link to the proposed purchase here: https://www.firstlightoptics.com/guide- ... undle.html

Many thanks in advance all.
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admin
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Re: Skywatcher Evoguide 50ED

Post by admin »

Hi,

yes, that combination should be fine - plenty of peoply use the 120MM with guiders from 200 to 250mm focal length.

Robin
MisterQ
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Joined: Tue Sep 22, 2020 8:58 pm

Re: Skywatcher Evoguide 50ED

Post by MisterQ »

Thanks for coming back to me Robin. I was just having trouble calculating the FOV as the line in the SharpCap PA requirements of "A field of view in the camera of between 1 degree and about 2.5 degrees" made me think this combination would provide too wide a FOV. I can find lots of information on the 120MM in combination with the Evoguide but not so much on the 120MM-mini.

When adding the Evoguide and 120MM-S to the astronomy.tools FOV calculator it comes out with the following:

Focal Ratio: 4.84 Resolution: 3.19"x3.19" per pixel Field of View: 1.13° x 0.85° Dawes Limit: 2.32 arc/secs

Is the the FOV too big, too small or just right for your polar alignment routine? the 0.85 degrees had me thinking it would be too narrow that's all.

All the best,

Adam
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Re: Skywatcher Evoguide 50ED

Post by admin »

Hi Adam,

the early versions of polar alignment did require a field-of-view above 1°, but as the functionality has been improved most people be able to get it working with a field-of-view down towards 0.5° – certainly 1.1 x 0.85 should be no problem.

Cheers, Robin
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