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Author Topic: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!  (Read 14159 times)

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Offline gaelicstorm7

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #30 on: 14:46:00, 10 April, 2006 »
My next contribution,

Megrez SD80 II (semi apo ? ! ?), on EQ5 driven mount, 350D (with a 2" nosepiece, don't know if this makes a difference but thought I'd mention it), VH-1 filter 64 seconds, 800asa, from a dark site (hence no CLS filter)

SD80.jpg is full frame
SD80C.jpj is centre (ish)
SD80BL.jpg is bottom left

as with my ST80 frames no messing in photoshop done with any of the frames, just as they came out of the camera, interesting to see how the Megrez seems to have a worse field then the cheap little ST80 !.

Cheers,

Alan

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

Offline Alun

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #31 on: 22:55:51, 10 April, 2006 »
Never question the power of the ST80!

If you want to sell the Megrez... :D

Cheers
Alun 8-)
Skywatcher Startravel 120(f5)mounted on CG-5 Roboscoped for GOTO
Helios Apollo 150 mounted on EQ3-2 soon to be sold
Skywatcher Startravel 80 Tabletop mounted on EQ3-2 or CG5 as needed
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Offline the fordster

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #32 on: 09:35:24, 12 April, 2006 »
Cheers guys, a great start (and an amazing result from the ST80 too :whistling:)

Offline janmclare

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #33 on: 21:44:32, 14 April, 2006 »


I'll try to get some shots in too later...


Jan
  • AP 130 EDF, Televue Bizzaro 85, Borg 60ED

Offline the fordster

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #34 on: 15:37:39, 16 April, 2006 »
Me too! :oops:

Offline Dave_Rose

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #35 on: 20:25:54, 18 April, 2006 »
I've just dug a couple of test shots I made when setting up my system.
Scope - 10" f6.3 Newt.
Camera - Sbig St10
Image taken with and without Televue Parracor coma corrector, crop of each corner and centre.
Reference drawing to show crop areas relative to full frame.
Cheers, Dave

< edit >
Tried a couple of time to upload the image, but 2nd and 3rd files fail to appear correctly.
I must be doing some thing wrong ??

Here they are instead.

http://www.astroccd.freeserve.co.uk/Latest/WithParacorr.jpg
http://www.astroccd.freeserve.co.uk/Latest/WithOutParacorr.jpg
http://www.astroccd.freeserve.co.uk/Latest/CropAreas.jpg



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10" F6.3 Newtonian. ST10 xme. CFW8. Ap1200. Vixen 102ED. TMB 80/600 apo
www.daverose.co.uk

Offline dciobota

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #36 on: 09:14:51, 19 April, 2006 »
Hi guys,

 Just completed a test of the C80ED against the WO ZS66 petzval.  The short of it is the ZS is a bit of a disapointment, so up for sale it will go.  I know I've already posted the results from the C80ED, but these are shots of the same area of the sky (centered on Arcturus) with the same exact conditions and setup (350D on a 2" adapter in both cases, prime focus).  Images were 30sec at iso1600.  As you can see, the ZS66 has much more coma than the 80ED... even though it's supposed to have a totally flat field.  :-(  Maybe they forgot to put in the other two lenses?  :shock:

Here are crops from the ZS66 (bottom left and center) plus the whole image, downsized to 800x600:



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Offline dciobota

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #37 on: 09:17:09, 19 April, 2006 »
 Next is the C80ED, same crops and downsized image:


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Offline AndrewG

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #38 on: 17:55:19, 28 April, 2006 »
Just in case you all missed the review of the Baader MPCC here http://ukastroimaging.co.uk/forums/index.php?topic=17315.0 - here are the resulting pics... With and without the MPCC...

Scope : Skywatcher 250px 10" f4.8 Newt



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AndrewG
10" Newt, 12" Darkbridge (DSC+BlueTooth+PalmTX) :evil: , Vixen ED103SWT, William Optics ZS66, ST102, QHY8, QHY5, EQ6 MK1 + SkyScan

Offline AndrewG

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #39 on: 17:56:07, 28 April, 2006 »
...and Without (yuk)

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AndrewG
10" Newt, 12" Darkbridge (DSC+BlueTooth+PalmTX) :evil: , Vixen ED103SWT, William Optics ZS66, ST102, QHY8, QHY5, EQ6 MK1 + SkyScan

Offline the fordster

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Re: Coma and Chromatic Abberation Comparisons - Could Be A Winner!!!
« Reply #40 on: 19:54:35, 28 April, 2006 »
That is one capable 'scope, Andrew - Beautiful flat field with the MPCC

Offline dciobota

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Hey Fordy,

 I know you're looking for more responses on here, and I did order another little scope to torture myself with.  ;-)  I'll be posting results with that one, hopefully it will be better than the last.

 But in the meantime, I got to try the Mogg reducer last night and was wondering if you might want the results here or maybe in a separate topic?  How about creating a prime + reducer comparo topic on various scopes?  

 Andy's already got one (very nice btw Andy, wish I had that flat a field).




 
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Offline the fordster

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Hey Dan, nah, stick them here! I'll compile a complete listing comr the end of this thread, of all the different combos...

Offline janmclare

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Yay the D1X has finally shown up... :roll:

Will get some shots in the next clear night.


Jan
  • AP 130 EDF, Televue Bizzaro 85, Borg 60ED

Offline dciobota

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Ok, so here it goes.  This series is the C80ED with Mogg 0.67 gen 2 focal reducer for dslr's.  Never tried the original, but I find this one to be a bit of a disappointment still.  The reducer barrel was pretty loose in the focuser actually, so I had to shim it with some makeshift paper "bushings".  Even then, the optics show some weird sort of pattern, like pinched optics or something.  Can anyone take a guess as to what this kind of distortion it is?

 Anyways, I plan to write Steve and send him the results.  Maybe it's just a defective unit, maybe I can exchange it or get a refund.  I sure hope so.

 Here's the corners, center crop and resized full frame... I notice there's quite a bit of vignetting also, unusual for a 2" diameter barrel.



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