Colour added to AG12 Ha Cats Paw - feedback please

[strongmanmike]

I got frustrated waiting for the weather to be kind so bah!! I have added some colour data to the 20min (10X2min) of Ha I got with the AG12 last time out (so long ago I can't remember now..? :rolleyes:).

I used the RGB (30, 30,30min) data I collected on the Cats Paw last year with the Starfire

So the following is an HaRGB image and still illustrates the star size, image depth and detail resolution achieved with the AG12 with just the colour pallet supplied by the Strarfire RGB.

due to miss matched fields and the required cropping, it is now only 1.5deg X 1.5deg field though

Cats Paw (http://www.pbase.com/strongmanmike2002/image/134317836/original)

and a little closer in:

Close up on Cats Paw (http://www.pbase.com/strongmanmike2002/image/134339613/original)

Hopefully it will clear (properly) this week :mad2: :sadeyes:

Mike

[tlgerdes]

Sorry Mike, but I think you should have waited. I personally think you have gone backwards on this blend.

[Paul Haese]

I like the wider field of view. With the close up there is some colour mis-registration; mainly the blue channel.

[gregbradley]

Yeah didn't really work out. I know how that goes. I can tell you're excited and biting at the bit to get an image together.

AG12 colour data no doubt will be superior to your Starfire's.

Greg.

[strongmanmike]

Hmmm?..I didn't think it was that bad :(...I (or you guys? :P) must be getting old eyes :lol: ..I thought for such little data it held up pretty well considering and kinda bodes well for the future me thinks? Anyway, wasn't intended as a masterpiece, done just to fill in time :whistle:, can't expect too much more from 20min worth of Ha in 2min subs..?..can you? :question:

Mike

[avandonk]

For twenty minutes I reckon it is fine. It takes me longer to drink a couple of tinnies. It only gets far better from here.

Bert

[Hagar]

Nice start to your new scope Mike but I think you have maybe suffered the same outcome as I did when using images which required scaling as well as alignment to make them work. I have found this to be the hardest thing to accomplish yet and even just a smidgen out on one of the colours does something to the image which is very dificult to recover from.
I have found that even using Registar to align the images doesn't do a good enough job and taking the images from there into CCDStack and doing a full manual alignment and rotational correction is the only way to go. (even with thyis I still get into trouble).

As an image to frame your new scope and as a first light image it's great. Shows the scope will become your workhorse I'm sure. It resolves the smallest stars beautifully and can only improve in your hands. Don't get to dejected with the comments.

It's great to see someone of your standing copping a bit, it makes the rest of us mere mortals feel human again.

Good luck with it all and lets see a full colour 12" image.

[strongmanmike]

He he Cheers Dougie :thumbsup:

I'm not worried at all ;)...naah, I think it's funny actually, many think an image has to be prefect before posting and then those commenting often feel comments must be solely about pointing out what they think is wrong with an image :rolleyes:...all's good and I agree with your comments..although it's not so much a registration issue as the tiny Ha stars in the AG12 data were hard to match 100% with the corespondingly larger blue stars in the Starfire data so there are some residule blue halos...they don't seem to bother me as much as others :question:, actually someone commented on blue halos in Rich Bowdens latest image and quite frankly I thought they were mad :lol: :thumbsup:

Oh ye I meant to add, Tom Davis told me it would be hard to register wide field frames using the 16803 chip and the AG12 100% evrytime, so I was prepaired :P

Cheers

Mike

[RobF]

Yes, can relate wholeheartedly to what you saying Mike. We're doin' this for fun, so every outing doesn't have to be a masterpiece. Mind you, it could be your fault for always setting the bar so high too sometimes :D
I've never taken the time to image this sucker, so its nice watching it come together.

Something a bit hubble-esque about those brighter stars in the AG12.

[strongmanmike]

He he thanks Robbo :thumbsup:

Ah, we'll just let them have their say, hope they feel better for it and...... ignore'em :lol: kidding kidding :P

The star patterns you refer to seem to only be in the Ha filter :question:..they don't really bother me but it is interesting :question:

Mike

[atalas]

Mike,I think It's a great looking shot and I love the pink! the close up is high impact and the detail speaks for Itself! is It your best?cause not,is It good?hell yeah!

[multiweb]

Little overwhelming Ha but I'm sure you'll get some fine colours when the clouds clear with the big one.

[John Hothersall]

I agree Ha is certainly overwhelming but can't wait for a proper dark site result. Will have to wait for clouds to move, my guidecam is not working so I know the frustration.

John.

[strongmanmike]

Cheers for the feedback guys :thumbsup:

While I recognise this is not my magnum opus :lol:..I am struggling to understand the "overwhelming Ha" bit though..? :question: I am not being concieted I just genuinely want to get a feel for what some of you are seeing here...?

This is normally displayed as a pretty red nebula with little or no colour variation.

Interested in any comments along these lines and would like to see an example of what you think this nebula should look like..?.

Mike
worried about his eyes :lol:

[Paul Haese]

The colouring and blending of the Ha looks fine to me Mike. There appears to be a lot of Ha in the surrounding areas but not as intense as the actual object. This might be what is causing some concern. If anything the background looks a little red to me but that might well be the gas within the region. Star colours look great overall. This looks very similar in colouring to many of your other HaRGB blends in the past.

[strongmanmike]

Cheers Paul

Much more meaningful reply thanks for that Paul :thumbsup:. I have looked at few of the better versions of The Cats Paw on the web and to me there isn't much in it except I have gone for a more meagenta/pink bias and extracted some variation in colour tones compared to most other versions..probably becasue I just liked it that way..? :). It is a well known obscured dusty area so I would expect the surroundings to be week in Ha and thus more uniformly weak given it is a HaRGB blend..?

Cheers

Mike

[multiweb]

The Ha is used to emphasize the deep red parts. There are also blue reflection nebulae (http://www.eso.org/public/images/eso1003a/) within the cat paws that would be levelled by the Ha blend. You should be able to capture those with the bigger aperture of the new scope compared to the starfire.

[strongmanmike]

Perhaps you are onto something, can you show me a good example image Marc, I couldn't find one..? :sadeyes: The ESO shows very little colour variation too :shrug:...it does follow the traditional red look though.

My Previous LHaRGB version (http://www.pbase.com/strongmanmike2002/image/125790920/original)with the starfire, the RGB from which I used for this latest image, does show some slight colour variation in the central areas but this is vey rare from what I can see out there :shrug:.

Of course we cannot expect to get a straight HaRGB blend to cover the full gamut of colours and often such a blend is used to remove this variation for more impact, no?

Mike

[multiweb]

I added the link in the prevous post. You can see tints of blues in the core between the three pads behind all the brown dust. They're supposed to be very young massive stars burried in there. You can also see hints of blues in the trailing dust. Your 12" will show that no problem. I reckon the starfire although sharp as doesn't have the aperture needed to pick this up. That's why I think you should try color with the big one first then blend additional Ha if needed for details but you might not have to in the end.

[strongmanmike]

Sorry I had updated my post (see above) before this reply came through...

Mike

[gregbradley]

How Ha is blended is not a subject where you get 100% agreement.

There are a few methods out there that get similar yet different results.

Ha as luminance by itself tends to wash out RGB I have noticed. A bit of Ha as luminance can be good as it brings out detail and reduces colour saturation a bit in case you have oversaturated the colour.

How Ha is handled is a matter of taste and opinion but in my view these days I feel it is best used as a way of deepening the reds, providing more luminance detail as it often shows billows and ridges etc that luminance does not. I think also the Tony Hallas/Russell Croman approach works best which is to use as a lighten mode layer. Hallas also has it under the luminance layer where it works better. Now you can use curves to increase its effect otherwise it adds very little. So now you have control. You can set Ha layers set to red as screen mode and that is a heavier effect but is less controllable. Lighten also protects the stars. You can also mask the stars to prevent it affecting them if they are still affecting the stars.

So the overwhelm here is the dominance of the Ha details but in a not so nice colour (brightish pink) and also its damaged the stars (almost all blue) and the background is very heavily biased to blue. Also edges of the nebula are too harsh and sharply defined instead of softer edges.

Whereas your Starfire image is your usual very pleasing colour balance, more of a shade of red in the neb, softer edges, nice stars, a more neutral background (although still a touch of blue which I don't mind and is perhaps a bit of a style of yours if any background colour is OK its blue) and overall a nice balance of colours and shades.

As Marc and others have pointed out if you did the whole lot of the image with the AG it would have been a different outcome although a lot of this outcome has come from the processing choices. As I say the above approach to Ha is not the only way and certainly not (the right way" but its a way I personally like and think gets the best results. In my opinion only, I feel most Ha is poorly handled and tends to wreck the images unless its handled way more subtley. This came from a review of my own images not others and this is the conclusion I arrived at. For example I am not a fan of M33 Galaxy images with bright pink blobs for Ha areas as being a good image. That's just me.

Mind you having said the above my Cats Paw images are crap compared to your Starfire one. And your AG12 Ha image is sublime especially for only 20 minutes. So don't in any way think this is a comment about the scope.

Greg.

[strongmanmike]

Now that's what I call a reply Greggles :eyepop: some interesting things you bring up, not sure I agree with them all :question: but I do appreciate your thoughts :love:

The Starfire only shot was an LHaRGB while the AG12/Starfire combo is an HaRGB so you would have to expect some difference.

One thing I did take from the exercise is the density of Ha acheived with AG12 in just 10 X 2min exposures and what I was able to do with that, I can only imagine what a couple of hours would pull down?

Cheers

Mike

[gregbradley]

Yes that's true. HaRGB is its own animal.

The AG12 really got a solid Ha image in no time and you must be thrilled about that.

Bodes well. A bit like the CDK17, you can get the data faster by large aperture or you
can get it by fast Fratio. You've got both.

Greg.

[rally]

Mike,

As Greg has pointed out the philosophical aspect of blending Ha is an issue !
Firstly, how best to do it and secondly, what you are trying to do with it.
For me I prefer to see Ha used to enhance detail in a "natural" looking way without all the colour casts and halos and making allowance for the naturally tighter stars that Ha produces.
To be done well the Ha stars are best enlarged while at the same time retaining a correct profile - not always an easy trick !

I think for your Ha I would have reduced the exposure time and increased the number of exposures. Or better yet done an HDR of short and long.
Your Ha stellar profiles indicate that Ha is saturated (Flat tops) and this then makes it very hard to nicely blend the Ha with any correctly exposed L and R, no matter what type of process you use.
Elliptical stars seem to be present but very hard to determine if they are caused by tracking/guiding, wind/stability, processing/registration, collimation, chromatic aberration etc - doesnt seem to be principally from the Ha image though !

Otherwise good resultant image on a difficult target with your limited data.

Rally

[strongmanmike]

Cheers Rally, some more interesting feedback, appreciated :thumbsup:

To me though the aim of a HaRGB (as opposed to LHaRGB or LRHaRGB etc) blend can be to in fact get the tiny stars to be in final result but as you say and as is evident in this HaRGB result, there can be some residule signs if your combining is not perfect. I did minimise the RGB stars before combining but this still leaves some residule haloing from mostly the blue stars and I did not enlarge the Ha stars so as to retain the pin point star look as, although an illusion, this does serve to accentuate the nebulosity detail.

Thanks again!

Mike

[tornado33]

Great to see the AG is a goer. Ive had a look through all your AG images, looks like a good scope stars nice and sharp.I cant wait to see the first of your ultra deep many hours images you will no doubt produce with it soon :)
Scott

[strongmanmike]

Cheers Scotty, yes it is a relief. I still need to tweek the collimation, it is not perfect yet, I will be ordering CCD Inspector tonight hopefully so I can collimate with the camera in real time - bloody big chips.. they are a curse :lol:



Oooh yeah, you and me both! :thumbsup:

Mike

[allan gould]

Your Starfire was (is) an absolute gem but what you are doing already with such short exposures with the AG12 is to dream about.