Eta pre and post Canon 40D mod

[dugnsuz]

Hello all,

Wanted to post a before and after DSLR mod comparison for those considering taking the plunge, but weren't too sure if it would be worth the hassle/trauma/anguish/effort!!

The mod on my 40D was done by Peter Tan in Hong Kong at a price I thought was the cheapest around. All up for mod, Baader filter, postage/insurance (to $1000AU value both ways) came in at $230AU:eyepop:
http://www.tan14.com/gears.htm

Anyway was it worth it!!??
All in the eye of the beholder!

Both pics:
Canon 70-200mm f4L and EF 1.4x Tele-Extender

Pre mod...70mins, f5.6, iso400
Post mod...120mins, f6.3, iso800

Stacked in ImagesPlus, processed in PS.

First attempts at processing modded pics, so colour may be a bit rough:P

All the best
Doug:thumbsup:

[Hagar]

Hi Doug, I am a little confused as to which image is which. I had really expected a huge diference between the two images. Maybe a processing problem. I would have expected the post image to have much more Ha detail but this may well be embedded into the combined image. I would have a play with the ikage but so small an image with JPEG compression makes it impossible. If you could email me a reasonable compiled image reduced in size in say TIF format I will have a play and see what you have captured.

I was thinking of getting my 40D done but might hang on for a while and see what you think first.

Cheers
Doug

[dugnsuz]

Hi Doug,
As you look at the thumbnails - 1st is unmodded, 2nd is modded.
I didn't think you would have that much trouble identifying each!!;)
2nd pic is significantly "redder" to my eye - with a bit more detail in the fainter nebulosity away from the heart of the pic.
But I think you've gone straight to the heart of the problem.
I too expected a bit more Ha oomph from the pics!

Doug:thumbsup:

[Screwdriverone]

Hi Doug,

I am certainly not an expert on this, but isnt the different exposures, F stop settings and ISO rating for each pic like comparing apples and oranges?

Wouldn't the comparison between the unmodded and modded pics be more effective and subjective if the imaging techniques and settings are exactly the same for both pics?

I would assume that the extra sensitivity of ISO800 and the longer exposure time would bring out more nebulosity anyway?

My suggestion is therefore to match the modded camera image to the original one's exposure settings and then repost? That might give you more of a direct comparison model (apart from the obvious atmospheric variances)

After all that, I think I prefer the second shot to the first as the first is seeming "washed out" compared to the modded one and there is deeper nebulosity further away from the main area. :thumbsup:

Cheers

Chris

[dugnsuz]

Agreed Chris,
I was just trying to Max the effect of the newly modded camera with the higher iso and longer time to hopefully end up with "apples and oranges".
I had hoped that the mod would dramatically increase Ha sensitivity at those settings. But, not so.
Could the smaller aperture of my imaging setup (67mm diam lens) be a factor in the amount of Ha captured!?
Doug

[Robert_T]

Hi Doug, thanks for posting this as I had been wondering myself whether to plug away with the unmodded 40D or mover quickly to the mod. Be interested to see further comparison, but given my novice eye there would be little point in my proceeding to mod at this stage based on what I see here... no doubt reflects my lack of experience in looking at deep sky images.

cheers,

Rob

[AlexN]

I think its immediately obvious which one's which! Some comparisons on different targets might open other peoples eyes a fair bit... ie - horsehead if it was high enough in the sky at the moment...

[allan gould]

Sorry
I cant see an appreciable difference. In fact the nebulosity in the first picture in bottom left is more apparent than in the supposed modded camera with the higher ISO and exposure time.
Doesnt make sense to me

[leon]

Doug, as you say there is not much difference in the detail of either image, other than the fact that the Modded one is a bit redder.

I believe that Eta is not a great object for a comparison shot.

This being that Eta is pretty easy to capture modded or not, for a real test IMHO would be something faint, like the Horse head, Seagull, I know they are not viable at the moment but an object or Mag 8-11, I reckon this would give you a better comparison. :shrug:

I may be quite wrong here, but I'm saying it as I see it, and I too am still learning with this modded stuff, as you know.

You have however captured the Eta very well, with plenty of detail, maybe a bit red, but that is only processing, and I know what that means. :whistle:

Nice work Doug. ;)

Leon :thumbsup:

[dugnsuz]

Ok guys,
Forget the comparison for now.
Let me address this to members with modded dslrs...
Would you expect to capture more Ha detail (than is present) in the modded camera image, given the exposure
time, FL etc?
Thanks for the comments

Cheers
Doug

[monoxide]

mabee it would be better to compare unprocessed subs?
theres not a lot if any difference in the images posted, sure the modded one is a bit deeper but at that focal length i dont think your going to be seeing any fine detail really jumping out.

[dugnsuz]

Thanks leon - great advice as ever:thumbsup:
I thought I'd be swimming in red with Eta!!
Persevere eh!?:rolleyes:

[h0ughy]

most certainly, look at this shot of mine i took (3 min iso 1600) you can see there is heaps more out there( modded 350d-cooled)

[dugnsuz]

So what's gone wrong?
The mod certainly has worked - red histogram shifted to the right, and all camera functions are OK.

Processing was Levels/Curves adjustments, a 5% star minimization action and minor colour balancing.

Shot in RAW mode, AWB mode...would that be a problem? Thought WB didn't matter in RAW mode?

Could it be the shorter FL of 280mm and/or lens aperture - not capturing enough Ha through this system!!???

At a loss!:(

[h0ughy]

the scope was a r200SS f4 8", so there is the f ratio, time and "lens" size, in my case 8"

[skwinty]

Hi Doug
this was taken with a hutech modded 40D.
Prime focus 12" GSO Newtonian.
ISO 400
About 75 seconds total exposure.
10 subs
Full moon
No processing other than gamma scale.
also used AWB as it doesnt affect raw.
I only shoot astro in raw.

http://www.iceinspace.com.au/forum/attachment.php?attachmentid=41028&d=1207657833

[Zuts]

Hi Doug,

I agree with Leon and AlexN. Eta is very rich in Ha so modded or unmodded great pics are possible. The tarantula the same, though you will get a truer redder colour modded. Give the christmas tree neb or horsehead a go and I am sure you will be pleased with the result.

Thats the whole point, if the entire sky was filled with objects like Eta, noone would mod, but its not. So by modding you have increased the viable range of targets you can attempt :)

Also, and I may be wrong. You are shooting widefield so on an object like Eta the extra Ha you are picking up is lost in the widefield. You may see far more detail with a longer FL.

Paul

[dugnsuz]

The first un-modded pic has a very red, noisy background - overprocessed to bring out any faint red in Eta itself. I think that might be what you're viewing as nebulosity. The lower left region of Eta in the modded pic seems to have a bit more structural detail.
Doug:thumbsup:

[dugnsuz]

Steve and Paul,
Thanks for the comments and link.

Apologies for my skewed comparison, but I've been given a link on AstroChat.UK to a helpful page by Terry Lovejoy.

http://www.pbase.com/terrylovejoy/eta_carinae_before_and_after

Cheers
Doug

[dugnsuz]

Best I could do Tj!
Pic #1: Unmodded Combined stack - Subs for unmodded pic have long gone, only have the IP Combined file.
Pic#2: Modded sub
Doug:thumbsup:

[RB]

They both look great Doug, the mod camera looks like it has better response so be patient and try it on other objects.
Eta is like that so not an ideal object to test it on and it does take a little getting use to processing the new 'mod' frames.

Also IMO you need to have identical settings with identical equipment on the same subject to make a fair comparison.

Looking forward to more.

:thumbsup:

EDIT: you posted while I was replying to your original post.

Yes the new post with original subs give a nice indication.

:thumbsup:

[AlexN]

the single modded sub verses the combined stack unmodded really shows what its made of!

[dugnsuz]

Link to higher res modded version...

http://s231.photobucket.com/albums/ee208/dugnsuz2/?action=view&current=ETA-POST-MOD.jpg

Doug

[Tamtarn]

Been offline for a while. Just catching up with Deep Space.

Doug the latest high res is a beauty :thumbsup:

At around $230 to mod !! Well we would be more than happy with that result ;)

[dugnsuz]

Thanks B&D
Been processing and reprocessing all weekend and I think all will be well!!
cheers
Doug:thumbsup:

[Screwdriverone]

Hi Doug,

That Hi Res Eta is an absolute scorcher!

Fabulous, well done, I love the cluster in the top left, my favourite target and it all looks superb.

Keep it up!:thumbsup:

Chris

[dugnsuz]

Cheers Chris - I may try to sort out the brightness around the keyhole before leaving it.
But, happier about the camera mod now
Doug:thumbsup: