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Old 05-09-2018, 04:23 PM
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Paul Haese
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Paul Haese is offline
 
Join Date: Jan 2009
Location: Adelaide
Posts: 9,991
AG12 first light (M55)

Well, lets say first colour image. The scope has taken lots of hours of tinkering so far and I am far from happy with it at present.

Something I have learnt is that a fast Newtonian gets harder to collimate the faster it is below f5. Tilt of the secondary, centring of the secondary and rotation of the secondary are all hyper critical.

To add to the above the way the Wynne is seated and positioned can be extremely difficult to get right. This is the closest I have gotten it so far, which required a feeler gauge, some shimming and a set of digital vernier. There are still some weird stars off to the right of the image, which I hope to fix one night when I can get down to the observatory for final collimation.

The image is of Messier 55, which is a globular cluster in Sagittarius. I thought this would be a good litmus test for this scope. I must have imaged it over 30 hours in the last month. The image is a 100% crop.

The good news is that the star shapes remain the same both sides of the meridian and no matter where in the sky the scope is pointed.

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