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lukebl

First Light: M82 with 8" Ritchey-Chrétien

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Posted (edited)

Hi folks,

This Christmas I treated myself to a 203/1624 Omegon Ritchey–Chrétien Telescope.

I've been studying these for a while, and finally decided to get one, despite the horror stories here and elsewhere on the web about the nightmare of collimating them. I've wanted a longer focal length for imaging for a while, to capture smaller DSOs and get greater detail on larger ones, and had considered a Mak-Cass. But I've had them before and didn't get on with them , and I figured that they always need reducers and correctors to get them to a manageable focal length and correct optical errors. So I thought it would be better to get something designed for the job. A 1624mm focal length seems about right to get a reasonable image scale and also to guide adequately on my NEQ6. Another reason for getting it now was that imports might soon (i.e. after March) be getting a lot more expensive or even unobtainable in the UK (unless they fall off a container ship)! It arrived from Germany after only a few days, and I'm very pleased with its solid feel and construction. Here it is mounted on the pier of my Tardis roll-away observatory.

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Needless to say, it's been cloudy since it arrived, but I awoke last night at 2am to see the sky clear. So I dashed out to get some test images on M82, the Cigar Galaxy. Fortunately, it seems that collimation is good on this one. Hopefully it'll stay that way for a while.

This is the result of 40 x 3 minute exposures, Atik 428ex. Colour added from an image I captured 5 years ago. No flats, bias or darks, but I'm pleased with the result for a first hasty capture. I'll probably return to this object and capture some HA for the full starburst effect.

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Here's the image from where the colour was extracted.

It shows supernova SN2014j. Captured with a 250mm f/4.7 Newtonian. The new RC shows distinctly greater detail. I thought that this supernova was only a couple of years ago, and I couldn't believe that this was five years. A lot has happened to my life in that time!

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Edited by lukebl
  • Like 15

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How did you find collimation? It seems to be delivering some great results so I presume it went well?

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Excellent first light. You should not have any problems with field curvature over such small sensor (11mm diagonal) even if collimation is a bit off. Just check defocused star pattern - see if it is concentric, for best sharpness. Judging from the image, you probably don't need to fiddle with primary, only slight touch up on secondary if defocused image star in center of the field is not fully concentric.

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nicely shot! Im currently working on this one was well for  my "second light" with the 8rc. I completed m81 for first light. Im really happy with this scope so far. looking forward to more :)

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Heres an updated image with about 7 hours-worth of HA added.

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Edited by lukebl
  • Like 3

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Thats is one heck of a good result... excellent detail.

 

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