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First light for the Canon 200mm f2.8....

stan26

By stan26
in Imaging - Deep Sky

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stan26

stan26

Posted
Posted

Hi folks,

I got my new DIY widefield rig all sorted for the weekend (just gone) in time for the much needed gap in our somewhat frustrating weather of late......

This was my first opportunity to test out my new canon "L" 200 f2.8 USM II lens that I brought from a good friend of mine. The target I choose NGC2244 is a completely new target to me, my ninth bagged DSO since I started astrophotography last March. I thought the rosette would make a nice widefield object.

The Canon 200 2.8 prime is a fussy little git with focusing, I don't think I would have had much luck with it if it wasn't for the fact I made a little bahtinov mask before hand and was able to use APT to help focus it. That said I think I nailed it......

Subs where kept to 3mins because of bad LP to my south. No filters where used and as per usual I used my un-modded canon 500D, All guided on the EQ3-2, lens set to f4.Total exposure time is approx 4hrs. No flats added, just 20 x darks.

Overall I'm very very happy with the Canon's performance, the flat field right out to the edges is pure bliss and comes as something very new to me, as is the complete lack of CA which was once a real ball ache for me using the ST102. I can't wait to get out with it again.....

How many stars! and to think this has been cropped in to about half the size of the actual FOV :D

Stan:)

post-23582-133877735389_thumb.jpg

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rocketandroll

rocketandroll

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Awesome pic... it is a lovely lens isn't it... I blame Olly for everyone getting these the last year or two :-) Maybe he's on commission from Canon? :-)

@Badgers: they come up second hand fairly regularly, about £400 - £500 as a rough guide. I don't think they are available new any more?

Ben

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stan26

stan26

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Thanks guys, However I can't believe how awful it looks on the forum, and even worse on my work computer. The rosette looks completely washed out lacking in contrast and the stars lack any sparkle :).....not sure why this is, it looks OK on my home PC...?

Hey Olly, yes I'm sure I read somehwhere that you suggest 57mm as a good starting point for the aperture mask..? I will def make one in due course....

Regards

Stan :D

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Psychobilly

Psychobilly

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No probs...

I want the max aperture that gives acceptable star shapes corner to corner.. I might further tune it once I am in the right ball park...

I used mine around f3.2 last weekend on an unguided EQ3-pro

For focusing I either use Remote Manual focusing in combination with the FWHM analysis in BackyardEOS or my DIY version of the TS focusing rings and a Bahtinov...

Olley have you noticed any focus shifts with changing temperature? One night I had forgotten to leave the lens and camera outside so went from the warm house to the cold outside and haf a slight focus shift...

Peter..

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stan26

stan26

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I'm with you on that chris, whilst editing the large superwide version it suddenly became apparent to me that I should appreciate this lens for what it offers and stick to wide views with no, or at least minimal cropping.......

Stan

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