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Crescent Moon with Celestron C90 and QHY5III-178C

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#1 james7ca

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Posted 21 April 2018 - 09:45 AM

Taken on the evening of April 20, 2018 using a Celestron C90 (90mm aperture, f/13) and an uncooled QHY5III-178C camera. Best 20% or 2000 frames, 4-frame mosaic using AutoStakkert!, Registax, and Photoshop CC2017. Image capture using SharpCap.

 

Sorry about the strange orientation, but this is the only way I can post images larger than 1200 pixels since CN wants to limit the height to a maximum of 1200 pixels even though the stated limits are 1600 x 1200 pixels (why not allow a height of 1600 pixels with a width of 1200?). The "final" master on this image was over twice this size (2236 x 3714), so you can view the full-size image on this link to Flickr:

 

  https://flic.kr/p/26jFS5G

Attached Thumbnails

  • Crescent Moon with Celestron C90 and QHY5III-178C (Small).jpg

Edited by james7ca, 21 April 2018 - 10:21 AM.

  • Carol L, jgraham, troyt and 8 others like this

#2 Tom Glenn

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Posted 21 April 2018 - 02:29 PM

Very nice image. It's always impressive the amount of detail that can be obtained with a 90mm aperture.  I especially like Piccolomini and Rupes Altai stretching out towards the terminator.  



#3 jgraham

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Posted 21 April 2018 - 07:18 PM

Wow, gorgeous!



#4 james7ca

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Posted 22 April 2018 - 08:20 AM

Tom and John, thanks for the notice.

 

I located a few small craters near to the rays from the crater Messier and calculated a resolution of about 1.5 arc seconds (2.7km). Dawes limit for a 90mm scope is 1.29 arc seconds, so I suspect that with better seeing I could do even better with the C90 (I would probably rate the seeing conditions when I took this image as no better than average, although for a fairly early crescent moon the elevation of the moon was pretty good -- as happens each year during the spring season).

 

Below is a 1:1 crop from the image, that's a bit more scale than I'd like to do with a one-shot-color camera, but it allows you to detect some of the smaller features in the capture. The "large" image that I liked to on Flickr was a 66% reduction from the original, while the image above that I posted to CN is about a 28% scale.

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  • Messier Crop.jpg

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