M42 cdk17 new version and crops

[gregbradley]

I finally got some colour about a week ago for the luminance I posted a few weeks back.

I reshot the luminance and the cores as the skies were clearer and no thin cloud.

Planewave CDK17, Paramount ME, FLI Proline 16803, Astrodon Gen 11 filters.

LRGB 30 50 50 60


http://upload.pbase.com/gregbradley/...31216181/large regular size

http://upload.pbase.com/gregbradley/...16181/original large image

Greg.

[Troy]

Wow a very nice image Greg.
Love the detail in this shot

[Paul Haese]

Nice Greg, especially given little exposure time. The detail is great.

[Bassnut (Fred)]

WHOA, face smacking gear,eye smacking pics, bang, nice work Greg, a bit harsh but lots of impact

[Screwdriverone (Chris)]

Hi Greg,

I'm not sure about this one.

There is heaps of details and amazing resolution, but I just dont know what it is that's bothering me about this pic.

It seems.....plastic? Is it too sharp or not enough blue channel?

Please dont get me wrong, I love your pictures, just something doesnt look right here.

It almost looks like an oil painting????

Apologies if I cause any offence, none is intended (and I have no experience with this level of work) but I just can't put my finger on why this image seems "strange" to look at, almost artificial.

I'll pull my head in if I am out of line, but it is just my opinion...

Sorry,

Cheers

Chris

[alan meehan (Alan)]

Nice structure and detail Greg well done
Alan

[gregbradley]

Originally Posted by Troy

Wow a very nice image Greg.
Love the detail in this shot

Thanks Troy. The scope did pick up a lot of detail eh.

Originally Posted by Paul Haese

Nice Greg, especially given little exposure time. The detail is great.

Thanks Paul. I imaged this one over several nights but was picky about which to use. Luckily M42 doesn't really require 12 hours of data. I need to be picky with the subs from the CDK17 as any thin cloud, light pollution etc and the vignetting on the 16803 becomes a problem. This scope would be optimum at my dark site but its not powered at this time.

Originally Posted by Bassnut

WHOA, face smacking gear,eye smacking pics, bang, nice work Greg, a bit harsh but lots of impact

Thanks Fred. It definitely is in your face compared to my other versions of it in the past.

Originally Posted by Screwdriverone

Hi Greg,

I'm not sure about this one.

There is heaps of details and amazing resolution, but I just dont know what it is that's bothering me about this pic.

It seems.....plastic? Is it too sharp or not enough blue channel?

Please dont get me wrong, I love your pictures, just something doesnt look right here.

It almost looks like an oil painting????

Apologies if I cause any offence, none is intended (and I have no experience with this level of work) but I just can't put my finger on why this image seems "strange" to look at, almost artificial.

I'll pull my head in if I am out of line, but it is just my opinion...

Sorry,

Cheers

Chris

I know what you mean. It is slightly harsh with its heavy contrasted details. I pondered over this aspect at a point in the processing. I can easily do a version which is less harsh but less detailed. One of those processing decisions. I chose to show the extra detail over the usual gaseous filaments which are smooth. Perhaps I should do a 2nd version. Of course your viewpoint is perfectly valid and well accepted. Thanks Chris.

Originally Posted by alan meehan

Nice structure and detail Greg well done
Alan

Thanks Alan. The big scope gets a lot of detail quickly on bright objects.

[Garyh]

Like Fred said...WHOWA...now thats in your face M42 very contrasty and colorful...Nice detail in the care!

[gregbradley]

Originally Posted by Garyh

Like Fred said...WHOWA...now thats in your face M42 very contrasty and colorful...Nice detail in the care!

Thanks Gary.

I have posted another version that is less punk rocky and some interesting cropped areas.

[gregbradley]

I did another version which is less Punk Rock plus I took some very interesting crops.

I love this Paramount ME and CDK/Proline combo. Crops that are highly magnified still show round stars. Thank you Mr Paramount! Guiding on this image was almost all using an ST402ME. The cooled CCD is better in summer than the uncooled Lodestar. Plus it is more sensitive and easier to get a nice round guide star.

New version of M42:

http://upload.pbase.com/gregbradley/...31678/original large

http://upload.pbase.com/gregbradley/...31231678/large regular

Crops:

http://upload.pbase.com/image/131231889 M42 core

http://upload.pbase.com/gregbradley/...31231905/large waterfall nebula

http://upload.pbase.com/gregbradley/image/131231895 M42 crop


Original Punk Rock version of M42:

http://upload.pbase.com/gregbradley/...31216181/large regular size

http://upload.pbase.com/gregbradley/...16181/original large image


I have more Orion area shots planned. What's better than a CDK17?
A CDK17 with a Tak FSQ106ED with reducer on top!!

I'll be doing some widefield images using that and the MMOAG ST402ME guiding at 3 metres focal length through the CDK17. So the CDK17 is the guidescope for the FSQ hehehe. If that doesn't give round stars nothing will! Plus a newly mounted Robofocus on the FSQ will help keep accurate focus which gets quite critical at F3.4 on that scope.

Greg.

[desler]

Hey Greg,

I was leaning a little towards Chris's point of view. It is definitely in your face and full of color and detail, but just didn't look like what I was expecting!

Just had a look at your repro and crops, boy, what images, absolutely stunning. You really have managed to capture it all and present it beautifully. Well done!

Darren

[gregbradley]

Thanks Darren. I am only occassionally punk rocky so the repro is more "me".

Greg.

[marc4darkskies (Marcus)]

Yes, the repro is muuuuch better Greg and a pleasure to view. Your first version was waaay too contrasty. This one is still a bit contrasty for my tastes but ... who cares . BTW a less "harsh" version should never reduce detail - don't quite understand that (?). What length subs did you do BTW? And what layering did you do?

Cheers, Marcus

[gregbradley]

Originally Posted by marc4darkskies

Yes, the repro is muuuuch better Greg and a pleasure to view. Your first version was waaay too contrasty. This one is still a bit contrasty for my tastes but ... who cares . BTW a less "harsh" version should never reduce detail - don't quite understand that (?). What length subs did you do BTW? And what layering did you do?

Cheers, Marcus

Thanks Marcus. 10 minute subs and 60 seconds RGB core shot and 90 seconds luminance in the core. There's no Ha.
Perhaps reduce detail by being less harsh is not the best way to say it more less high contrast that shows up the various details in the tendrils of the gas filaments.
Various layerings but the main one of course is to blend in the core shot into the long exposure
using gaussian blur and masks.

Greg.

[marc4darkskies (Marcus)]

Originally Posted by gregbradley

Thanks Marcus. 10 minute subs and 60 seconds RGB core shot and 90 seconds luminance in the core. There's no Ha.
Perhaps reduce detail by being less harsh is not the best way to say it more less high contrast that shows up the various details in the tendrils of the gas filaments.
Various layerings but the main one of course is to blend in the core shot into the long exposure
using gaussian blur and masks.

Greg.

I think your short on Lum then - only 3 x 10 min subs. Even with a 17" I'd guess you're sailing close to the wind for S/N in the fainter extremities.

[marc4darkskies (Marcus)]

Originally Posted by gregbradley

Thanks Marcus. 10 minute subs and 60 seconds RGB core shot and 90 seconds luminance in the core. There's no Ha.
Perhaps reduce detail by being less harsh is not the best way to say it more less high contrast that shows up the various details in the tendrils of the gas filaments.
Various layerings but the main one of course is to blend in the core shot into the long exposure
using gaussian blur and masks.

Greg.

Originally Posted by marc4darkskies

I think your short on Lum then - only 3 x 10 min subs. Even with a 17" I'd guess you're sailing close to the wind for S/N in the fainter extremities.

Also, 90 sec Lum subs for the core with a 17" seems too much IMO. I did 30sec LRGB with my TOA and that was still bordering on too much.

[Octane (Humayun)]

Greg,

My initial thoughts last night were also "too harsh". I am so pleased to see your reprocessed images. On my iPhone, they look amazing.

Well done, sir!

H

[gregbradley]

Originally Posted by marc4darkskies

I think your short on Lum then - only 3 x 10 min subs. Even with a 17" I'd guess you're sailing close to the wind for S/N in the fainter extremities.

Yes a bit skinny in luminance although pretty bright.
With the CDK17 it is a compromise on a few things like any scope.
Central Obstruction size, baffling size, F ratio and vignetting. Vignetting is a little high at 20% with a 16803 chip but CO size is smallish at around 40%
so it gives good contrast and detail and good for visual and not just an astrograph.

But the vignetting means you have to have pretty good conditions or you'll have trouble with the processing. Of course flat fielding does most of the work but not all. So if there is any moon, light pollution, thin cloud the subs tend to be wasted as they will not calibrate easily and you'll have vignetting to deal with which can be difficult at times.

Ha images with the moon out are no good on this scope using a 16803 chip. During no moon they are fine. They may be fine with a smaller chip like an 8300 or 6303.
I did about 5 hours of Ha on the Helix and they showed virtually no contrast and you could hardly see the Helix and was a complete waste. Yet a 10 minute luminance during no moon was quite bright and detailed.

RCOS scopes are around 4% vignetting but they are F9 often and also ideally need a corrector. They are also twice the price, don't have a commercial reducer available except the AP 2.7 inch one which limits you to APS sized chips or less. Offaxis focus of stars is a bit better with the CDK design as well compared to most RCs (not all). RCOS RCs have a large central obstruction which means they lose a bit of contrast and are not good for visual or planetary. The CDK can do both. So its a design compromise toss up of pros and cons. No scope is perfect. These are the limitations of the CDK design.

If you were planning to get a CDK and use it for narrowband during the moon weeks and a widefield chip like 11002 or 16803 it may not be good.
If you were planning to use a smaller chip then it might be fine. I am not sure on that last point but will know in a month or so.

So once you know your scope's strengths and weaknesses you can play to its strengths and avoid its weaknesses. Overall this is a great scope, has high quality, easy to adjust (hasn't needed any collimation yet but it is easy to do as the primary is fixed), is very sharp and easy to focus and use.
It should also be good as a visual scope and planetary imager. Reflections from nearby bright stars (may be able to be improved with some careful flocking) and vignetting on large chips are its weaknesses. But at less than half the price of its RC competitors' 16 inch plus an extra inch aperture - its got a lot going for it. It also has a reducer available that makes it F4.5 which is tempting at some point. It does not have a rotator yet (in development) but you can swivel the camera but it involves loosening 3 bolts on the focuser so you'd really have to need to do that!

I know you were considering a 12.5 hence the writeup for your benefit.

Greg.

[gregbradley]

Originally Posted by Octane

Greg,

My initial thoughts last night were also "too harsh". I am so pleased to see your reprocessed images. On my iPhone, they look amazing.

Well done, sir!

H

Thanks Humi. I had a Punk Rock moment last night I think!

I was using a trial version of Topz Labs detail plugin and its pretty harsh.

Topaz Labs have some cool plugins but they seem to be designed for daylight work and are too hard on astro stuff. You have to rein them in a long way and then they are fine. So so much for the Topaz Labs detail plug in.

Greg.

[Screwdriverone (Chris)]

Originally Posted by gregbradley

I did another version which is less Punk Rock plus I took some very interesting crops.

Greg.

Now THAT's what I am TALKIN' BOUT!

Less is more for me. Much more subtle and realistic, this repro sets a nice balance between sharpness and smooth features.

I prefer this rendition, it oozes quality and class, thanks for redoing it.

Love the "Punk Rock" description, sums it up very well. Too Lairy and headbanging before for my delicate palate....

Must be getting old....., anyway, back to my knitting and watching Judge Judy....

Cheers

Chris