My first Astrofest, and these were captured on the first of my 3 nights there. Had an absolute ball. Learnt so many things.
Still need to work on my post processing skills. Paul [1ponders] was kind enough to spend some time with me showing his processes and I have tried to implement what I learnt.
I think I have come to realise that if I'm going to be pushing, stretching, trying to get the absolute most out of these astroimages I really need Photoshop instead of persisting with GIMP. To date I have not seen the need for it with my terrestrial type photography, because most of the histogram is pretty well spread already and I just do some minor tweaking. But I can see that trying to stretch this data to the max needs more than GIMP's 8 bit handling. You can see the data being dropped in the histogram as you stretch. Anyway...
I also found the MPCC still does leave some eggy stars in corners.
And there seem to be some horizontal scan lines or something in the 100% images, you may just be able to make them out here. Need to get to the bottom of that.
I remember fighting with DSLR images. It's a lot easier processsing CCD images but it's a lot harder solving problems they present in images, if that make sense
They're a beaut pair aren't they.
As for colours, it's the imagers personal interperation of the object. I like to see the Lagoon more subtle, pinkish/red with a bluish tinge to the Hourglass region.
But that's just me.
Thanks guys and gals. Agree with Greg, must admit I had intended to rotate 180 degrees but in my late-night, still-on-Astrofest-time, brain-fried state I forgot...
Very frustrating about the post-processing. I can see there's a little more to tease out, but it's just beyond reach of my software and my abilities at the moment.
Good shot Troy - why not burn the RAWs onto a DVD etc and come around to my place on a Friday night. You can use my PC and Photoshop CS2 and have some fun with it all. Be good to catch up again, plenty of goss I have too. :-)
The horizontal lines may go with darks and bias frames. A dark is simply a shot with the lens cap on for the same duration as the light exposure.
Usually you take at least 6 and median combine them or sigma reject combine to make a master and then you can use it every time you take the same length image. Best done with Images Plus and use what is called adaptive darks as the temperatures the images are taken at will vary and the dark noise is thermal noise and is worse when the chip is hotter. Adaptive darks takes that into consideration.
A bias frame is simply a very very short exposure - say 1 second which shows the noise generated by the reading process of the camera. This may show the horizontal lines (a guess).
Also a flat which is where you take an image with the same setup you took the light exposures with (same focus and orientation of the camera exactly) and at dawn or dusk. About 3 seconds to get a not too bright image which is a picture of your optical system's imperfections and uneveness of brightness. It will also pick up dust particles on the chip of the camera.
Normally you subtract your bias from the flat and then the flat is applied to the light along with the dark. This process is called callibration or callibrating an image. If you don't change your camera's position then that flat is valid until you do.
It is often amazing how much it will improve an image.
In your case 40 minutes is not that long so your stretching is showing up the noise that has not been dealt with above that is normally a bit hidden until pushed.
Nicely done Troy. 8bit processing really does limit your options. See if you can hunt up an early edition of PS (CS1 or 2) on ebay. All the bells and whistles of CS3 and 4 are not necessary. Either that or try for the new pixinsight that h0ughy had. It looks like it has seriously good potential.
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8bit processing really does limit your options. See if you can hunt up an early edition of PS (CS1 or 2) on ebay. All the bells and whistles of CS3 and 4 are not necessary. Either that or try for the new pixinsight that h0ughy had. It looks like it has seriously good potential.
