M83

[bluescope]

Not great but hey it's my best effort so far on this galaxy !

:thumbsup:

[Robert_T]

Looks great to me Stev I hope to give some galaxies a go down the trk - I'd be well pleased to achieve anything like this!

[bluescope]

Cheers Robert

I'm sure you will get there ! You've got some good equipment by the look of your signature so be patient and don't be afraid to ask for help on IIS ... there's a lot of experience in this group.

:thumbsup:

[mrsnipey]

Steve, what camera settings did you use to capture it.
I've been trying for the past three weeks with no luck.

[bluescope]

Hi mrsnipey

I use my sbig st2000xcm self guided in CCDOPS ... 360sec subs ... I think this was about 8 exposures ... not sure without checking !


:thumbsup:

[mrsnipey]

Thanks Steve,
The best I've got so far is a little smudge. Nothing like your effort.
I'll keep persisting though - nothing like a challenge to keep you interested.
My limit at the moment is about 60 secs. I have to get my alignment perfected before I try for anything longer.

[Ric]

Nice capture Steve, there is some nice detail in this one.

Cheers

[bluescope]

Thanks Ric ... I'm sure there is some more data available in the original of this .... I just have to figure out how to extract it.

:thumbsup:

[jase]

I concur Steve. This would have to be your best of this target. I'm assuming this would be (or close too) a full size crop. A little noisy however...and I'm not certain of the colour tint. Try dropping the R channel curve slightly to bring out the blue starburst regions. Well done.

[bluescope]

How about this version Jase ?

:thumbsup:

[jase]

Steve, I think its you black points. You need to raise them. He's a quick touch up. Probably still a exhibits some tint.

[bluescope]

Thanks Jase .... I messed around with a version stacked from .fits files on this and it has much smoother look but quite a bit darker at this stage. When I have tweaked it better I will post it for a comparison.

:astron:

[[1ponders]]

Nicely done Steve. Here's a little trick I use to set the white and black points (taken from Photoshop Astronomy by Ireland)

1. Select the Eyedropper tool. Press the caps lock to make it a precision picker.

2. Image|adjustments|threshold. Slide the slider to the right until only one star is left showing. Hold down your shift key and click on the star. This will place a colour sampler point on the brightest point of your image (don't worry if it doesn't appear, it's there). Then slide the slider to th left until the darkest part of the image is the only part showing (ignore the edges that may need cropping). Shift +click another colour sampler there. Cancel the Threshold dialog.

3. Open the levels dialog box and double click on the left hand eyedropper at the bottom. In the new dialog box set the RGB in the bottom left of the right hand task bar to R15, G15, B20. Click OK. Do the same with the right hand eyedropper (white point) only set the RGB settings to around 245,245,245. Click ok to close that dialog.

4. Select the black point eyedropper and click on the background colour sampler of your image. Select the white point eyedropper and click on the star colour sampler. Click OK. You have not set your black and white points for all colours. BTW when your precision eyedropper is in the correct position over a colour sampler it will disappear so you know you are in the right spot.

If you look at your info pane now you will see that the two colour sampler points will show their RGB values. Now whenever you adjust your curves you can pop back into the levels box and reset the points when they start to get too out of whack. This is a very rough and ready process but surprisingly effective.

Works best if using adjustment layers as it's non destructive but you can use it on the original and go back through the history if you don't like the results.

If you don't already know this process I hope it helps.

[bluescope]

Thanks for that Paul, I'll give it a go when I next do some processing !

:thumbsup:

[[1ponders]]

As a refinement before you use the precision eyedropper tool and open the threshold, zoom in a bit so you can more accurately select the star. Alternatively you can zoom in afterwards and use shift+click to move the sampler to the center of the star. When you are finished Shift+alt+click on the sampler to remove it. :thumbsup: