View Full Version here: : M83
22-05-2012, 09:59 AM
Collected most of this a few months ago. Tried for some more data recently but it's getting too close to the meridian and I tend to get flexure issues at this point in the sky, which probably relates to old tasco refractor which I'm using as a guide scope.
So this is just over 3hrs of data. Not sure about colour...maybe a tad too blue? I tried to bring out some colour in the stars but these are 10 minutes subs @ ISO800 so they appear to be saturated.
Scope: 8" Newt
Camera: unmodded 400d
Exposures: 19x10mins @ ISO800 (total exposure time of 3hrs 10mins)
Hutech Light Pollution Suppression Filter
Lights, darks and flats stacked in DSS and processed in PS.
Image here (http://www.flickr.com/photos/47268787@N05/7245486966/in/photostream)
22-05-2012, 07:34 PM
One thing for sure you have heaps of detail in there, nice work!!
22-05-2012, 10:25 PM
Well done, nice image to look at. The detail you have obtained is excellent. :thumbsup:
22-05-2012, 10:48 PM
Thanks Justin and Daniel. I do like the dust lanes but it still needs a few more hours worth to tame the noise.
22-05-2012, 11:31 PM
Nice result Dan. Good image scale and plenty of detail. The double at 11.00 o'clock is clearly separated and shows good colour contrast. There is colour in the stars but the galaxy disk does look a bit anemic. Maybe try some extra saturation in the bright bits and some selective noise removal in the fainter bits?
22-05-2012, 11:58 PM
That's not bad - it needs reprocessing because the data is good.
What I do is make 2 stacks - one for the background on a median stack
& one for the galaxy with kappa.
I then put the galaxy on a hide all layer mask & paint it through.
It also helps to process the galaxy separately with a luminance layer by converting to black & white gray scale.
Another layer for soft light helps too & don't overdo the sharpening.
23-05-2012, 09:21 AM
Thanks Graeme. Yeah I was having trouble getting the colour balance right in the galaxy. Doing 10 min subs increases the signal but it loses colour.
Alpal: how will stacking using kappa help? Also, call me naive, but how do I do a lumi layer given I'm imaging with a dslr?
I will do a repro as I look to have over stretched the galaxy. Too much noise in the fainter regions. I tried blurring it a bit more it wasn't working for me.
23-05-2012, 10:33 AM
Kool result Dan, great contrast with the dark dust in the arms, sharp in there too !
23-05-2012, 02:02 PM
Kappa - seems to bring out more detail in the brighter areas.
Mean - seems to smooth the high noise background out.
You can make a psuedo luminance layer just by converting to gray scale.
23-05-2012, 02:12 PM
Re psuedo luminance layer: Is there any real advantage to this with dslr images? I didn't come across a lot of this in my reading.
23-05-2012, 07:02 PM
Yes - there is an advantage.
In Photoshop CS5 - you can go to:
image, mode , grayscale then
image, adjustments, HDR toning,
start from :
load preset, neutral (which you've already previously saved)
then use all the HDR features to create a sharpened image.
You then blend that in as a luminosity layer & change the opacity with another layer of the original image.
You can also make another layer as soft light & blend that using opacity.
I sometimes have 5 different layers all with their own opacity.
See - intro to HDR Toning with Ken Crawford - the video for help
if you can't follow what I've written.
Note: make 2 stacks - one with mean & one with Kappa .
process them separately.
Paint in the galaxy at the end of the process.
23-05-2012, 07:12 PM
Cheers for the advice. I will give it a go tonight.
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