Trifid now 22 hours 55 min composite image over 3 years

[gregbradley]

This is a composite of 5 images I have so far of the Trifid Nebula. I had originally posted one of these from the CDK17 and Microline 8300 but it wasn't the best presentation of this object. I thought I would combine the various efforts I have done on this object over 3 years or so from 2 different locations, with 2 different cameras (a 3rd one to come) and 4 different focal lengths - yikes! Thanks to Registar this possible.

This is 12.5 inch RCOS and STL11, TEC180 at F5.25 and F7 and FLI Microline 8300 and Planewave CDK17 at F4.45 and Microline 8300.
A total of 16 hours and 5 minutes.

I have now added some CDK17 and Proline 16803 data I will add to this so the total is now 22 hours and 55 minutes.

I think I still have some data left!


http://upload.pbase.com/gregbradley/image/137366046/original

Greg.

[lhansen]

Greg,

A truly amazing image - thanks for sharing

Lars

[multiweb]

Heaps of sharpening artefacts on this one Greg and something's killed the dynamic range as well I reckon. Due for a repro. Sorry I say it as I see it. Great image scale though.

[jenchris]

you melted it!

[Ross G]

An amazing closeup Greg.

A beautiful photo.


Thanks.

Ross.

[midnight]

Very nice Greg. A lot of red in there and as you have implied, the blue is struggling to come out. But the vibrancy is certainly there!

Darrin...

[atalas]

Very different Greg.

[RB]

Sorry Greg, I'll be honest with you, this one doesn't appeal to me.

:shrug:

[gregbradley]

Fair enough. Looks like it needs a repro. Back to the drawing board.
I think its a bit overprocessed and thats the basic problem.

I did a repro. I think it was the HDR Wavelet in PI that may've caused those
sharpening artifacts as best I can tell.

Anyway a more subtle version with far less processing. Sometimes less is more.
Same links.

Greg.

[strongmanmike]

Yeh the repro is better :thumbsup: the first run was :scared:

This might be a better target for the 16803 actually, unless the seeing is good up this close suffers a bit and you could fit more in too....man you cetainly have choices dude :eyepop: :thumbsup:

Mike

[gregbradley]

The 16803 is more ideal for this setup for sure. The 8300 is really for the refractors but it would most likely do really well on your AG12.

I took this one with practically no exposure time at my dark site with the TEC180 at F5.25 and the ML8300 (a much better match):

http://www.pbase.com/gregbradley/image/134574410

Something to know for those working out what camera to buy. 9 micron pixels are a good compromise for almost any setup but small pixelled cameras are more limited arbitrarily to focal lengths under say 1500mm. The exception seems to be the ST10 with 6.8 micron pixels for some reason. Perhaps the high QE makes up for the oversampling and loss of sensitivity.

Greg.

[gregbradley]

I took in the comments and agree it is best presented widefield with a softer more natural look.

This is now 16 hours and 5 minutes over 3 years, 3 different scopes at 4 different focal lengths, 3 different types of filters and 2 different cameras with a 3rd to come.

Again, this is the advantage of keeping a library of past data.

http://upload.pbase.com/gregbradley/image/137366046/original

Greg.

[strongmanmike]

Other than the very slight harshness (hard edged), overall the TEC 180 shot gets my vote - top shot :thumbsup:

Mike

[multiweb]

I reckon you need to find one night with good seeing and hammer this one with the 17" alone. The details in the core and all the little gas jets will show up. You might even separate the 6 stars in the center. Combining all your data from smaller aperture scopes won't give you the resolution that you are after. And this one's not exactly faint so I don't think you'll get much improvement between 3h or 16h of exposures.

[Lester]

Thanks for the view Greg, nice to know some others are human too and take a few attempts to get the best out of the data. I will take in the info on the pixel size for CCDs too as I may go down that road in the future. All the best.

[Star Catcher]

Hi Greg
Really admire your efforts and the result to get all those different data sources and scales to come together. I have enough trouble dealing with one scale :). Agree it is great exercise with using previous library of data but I think the better results are likely to come from choosing the best scope for the scale you want and just hammering it with that scope and camera.
Ted

[gregbradley]

It is a little harsh isn't it. Didn't notice that at the time it was processed.

Its hard to beat dark skies and APO refractors.



True. The signal increases at the square root of the extra hours so to double the signal to noise ratio you have to quadruple the total exposure time so there is a diminishing returns point.

I suppose some use a guidestick of when the data has little noise and colours are deep and detail is clear and defined. Dark sky sites though
show this one up so well compared to even reasonable skies. It definitely looks best in the dark site data. I have 10 hours now of CDK at home in that. Some of it is a smaller image scale. I think a higher res version of this could be done with the data I have but for now I am happy with the wider field view and the softer natural look with the extensions of the blue neb clearly showing and the bits of background red neb showing somewhat as wel balancing the image for colour and interest.

It won't be the last time I image it thats for sure. Its such a great target.



Cheers Lester. Sometimes you get too into an image and others help you see it in a different way.



That may well be. Its hard though as you know to colllect 22 hours in one go with weather etc.

Cheers

Greg.

[multiweb]

I reckon with your aperture under good seeing you could easily come close to this (http://www.iceinspace.com.au/forum/showpost.php?p=744278&postcount=1). There isn't much integration time but the details in there.

[gregbradley]

Yes I could try that. But the image I want to present really is more widefield. Perhaps I can layer in the fine detail better so it doesn't damage the colour.

Johns detail is finer than what I have seen with the CDK on the Trifid so far. The CDK is not far from it but his is definitely sharper and that little protrusion is a blurry faint line on mine. As you say on a night of really good seeing and perhaps the little ST402 chip it might get that. Then again maybe not!

Greg.