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ST80 Imaging Experiment


BlueAstra

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Been think of getting a small refractor for wide field imaging to complement my C8. I have an ST80 originally obtained as a guidescope, but now a little unused since I moved to an OAG. To give me some idea of what FOV I could get with a 'proper' refractor I set my ST80 up with my 1000D via a 1.25" nosepiece on a T mount, with a SW LPF. Attached are two shots, one of M42 and one of M45, both 10 x 90s unguided.

Must admit I was quite pleased at the results, although the camera was a bit skew leading to a focus change across the image, and I haven't got proper flats for this setup. I attribute the focus error to the rather flimsy barrel of the ST80 when racked nearly all the way out, or a fairly loose fit of the camera. I think the FOV is about 3 deg, which compares to about 1 deg with my C8 + FR.

If I can get this with an ST80, I can't wait to get my hands on a high quality refractor! Hmm, now where was that review of 80mm refactors. Over to equip. help for advice on an 80mm!

post-16060-13387742422_thumb.jpg

post-16060-133877424226_thumb.jpg

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Those look nice mate, I was fancying picking up a cheap refractor to see what sort of quality could be expected and tbh, on the cheaper side of life, that looks a great starter imaging scope.

Just one question, whats the rings around the center about? and could these be removed without much problem or damage to the image?

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I think the rings are a combination of my duff processing skills and the fact that the 1.25" drawtube on the ST80 clips the light in the corners when using relatively big CCD (such as in the 1000D). Some flats required! I think the more expensive refractors have 2" tubes which reduce the clipping. But flats or proper processing should get rid of them. Spent a bit more time on M45 and the rings are less noticable.

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If I can get this with an ST80, I can't wait to get my hands on a high quality refractor! Hmm, now where was that review of 80mm refactors. Over to equip. help for advice on an 80mm!

That's how I started, using an ST80, like you I was very encouraged with the results. I upgraded to a William Optics Megrez 80II FD which I obtained second hand. The results were a magnitude better, the colour correction was so good. I've been using it for about 2 years now and the scope hasn't given me a bad image yet, I only get those through sky conditions and my own errors.

I'd definitely recommend a WO 80mm scope.

Good Luck

:)

Chris

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