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Author Topic: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!  (Read 12927 times)

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Offline Kieron

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #15 on: 18:45:06, 05 April, 2006 »
Andy,

I might have missed the point, but surely this kind of comparison will only be valid for prime-focus images? I could show you some interesting examples of CA on shots taken through my Takahashi FS-60C with a Nikon CP4500 - but the aberration is introduced by the Scopetronix eyepiece/adapter, not the 'scope.


Regards, Kieron
Orion Optics OMC200 / Vixen Super Polaris : Takahashi FS-60C / EQ3-2
ToUcam Pro : Nikon Coolpix 4500

Offline GordonCopestake

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #16 on: 22:39:03, 05 April, 2006 »
I must have been too loud, the clouds heard me bragging about my clear skies all day. A thick haze covers most things :(
I can just about see a few bright stars and the moon is a thick blur. Oh well, i'll try again tomorrow.

Offline the fordster

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #17 on: 09:23:04, 06 April, 2006 »
Andy,

I might have missed the point, but surely this kind of comparison will only be valid for prime-focus images?

Yup, that's why I've not mentioned reducers and other bits. The idea is to do a basic comparison of different prime focus set-ups.

i.e. someone may say - "I have a 300D and wonder what 'scopes will give me a flat field and no CA" then they could browse this thread to see what is available. If we get enough posts, I'll divide it up by 'scope and camera type, then make it a sticky...

Offline synner

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #18 on: 07:42:03, 07 April, 2006 »
Hmmm... I'll have a trawl at the weekend. I'm not sure how many shots I've got without reducers in!

Must have some though eh! :roll: :lol:
Nick
VC200L - TV76 - SM40/BF10 - SXV-H9 - 300D - SC3
www.synner.co.uk

My ethical unpredictability is by default proof of its hard won vitalty

Offline the fordster

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #19 on: 15:11:37, 07 April, 2006 »
You using a reducer with the 102, Nick?

Offline synner

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #20 on: 16:01:37, 07 April, 2006 »
Not yet, I was going to try the TeleVue one in there, but it's the one for the shorter focal lengths. Can't hurt to try though :D

I'll have a look tonight for a shot through it without a reducer. Most of my shots throuh the TV76 and the VC200 have been with reducers though, so I may have to shoot a couple for them 8-)
Nick
VC200L - TV76 - SM40/BF10 - SXV-H9 - 300D - SC3
www.synner.co.uk

My ethical unpredictability is by default proof of its hard won vitalty

Offline Sam Scoggins

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #21 on: 16:32:40, 07 April, 2006 »
Just found this gallery of 3D Field Curvature Maps for different scopes and cameras:

http://ccdware.infopop.cc/groupee/forums/a/tpc/f/7421008431/m/4901089521

-Sam

http://csc.lamost.org/images/southampton.png

C9.25CF XLT : FLT 110 : ED 100 : Rev 80 : Sphinx SXW
5D : ART285AQ : HX516 : ToUcams : Watec 120N

Offline the fordster

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #22 on: 17:53:03, 07 April, 2006 »
Nice link, Sam! That's exactly the kind of thing I was looking to do (but not as technical and for those with a smaller budget! :lol:)

A great resource there 8-)

Offline synner

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #23 on: 20:44:13, 07 April, 2006 »
Here ya go :D

Starlight Xpress SXV-H9 and a Takahashi FS102 prime focus. Now with added full frame :D

[attachment deleted by admin]
Nick
VC200L - TV76 - SM40/BF10 - SXV-H9 - 300D - SC3
www.synner.co.uk

My ethical unpredictability is by default proof of its hard won vitalty

Offline the fordster

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #24 on: 22:15:56, 07 April, 2006 »
And we're off! Any chance of a full frame too, Nick so we can see the FOV?

I've got a fair few dug out too, all with the 300D - Will be posting them up shortly!

Offline synner

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #25 on: 12:05:14, 08 April, 2006 »
I'll dig it out when I get home... working hard again.









 :lol: :lol: :lol:
Nick
VC200L - TV76 - SM40/BF10 - SXV-H9 - 300D - SC3
www.synner.co.uk

My ethical unpredictability is by default proof of its hard won vitalty

Offline dciobota

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #26 on: 12:15:10, 08 April, 2006 »
 Okey dokey Andy, here's what I got:

 Canon 350D and Celestron ED80 (same as Orion)
 30 sec at iso1600
 Center crop, bottom left crop and full image resized.

 Hope this helps.


[attachment deleted by admin]
PLEASE REMOVE ME

Offline the fordster

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #27 on: 14:03:49, 08 April, 2006 »
And we're off! Thanks, Dan!

Offline gaelicstorm7

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #28 on: 11:51:44, 10 April, 2006 »
Ok, here's my first contribution

Skywatcher ST80 on EQ5 driven mount Canon 350D, 30sec, 1600asa, fringe killer and cls filter heavily light polluted site

ST80.jpg is full frame
ST80C.jpg is centre (ish)
ST80BL.jpg is bottom left

Cheers

Alan

[attachment deleted by admin]
Megrez 80mm SD II Semi Apo on EQ5 driven mount, Celestron G8-N, Meade ETX90, Canon 350D, Meade LPI, Astronomik CLS filter.

Offline Gee

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #29 on: 12:16:02, 10 April, 2006 »
Here's the TMB115 and ST2000XM

10mins Luminance, binned 1X1


image corners are full size and the full frame image is resized to 50% , both with the levels bumped up


Gee

[attachment deleted by admin]
TMB 115, G-11 w/Gemini,
Mod 300D, 300D, Canon EOS 10D, SXVF-M5C

http://www.mackayphotography.co.uk

 

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