Help With First DSO Image

[russellhq]

This is my first attempt at imaging a DSO, M27.

This was unguided, 30s exposure & ISO 1600 on an unmodded Canon 1100D.

I took 10 subs and 1 dark and loaded into DSS but I couldn't get the images to align and was left with squiggles and sumdges

I've attaced a TIF of the raw file if anyone wants a go at it. I found when I loaded them into DSS the images were very dark compared to the JPG copy. Is this a problem with DSS?

l_dumbell_1718.tif

[Freddie]

The dark image in DSS is normal, you can use a slider on the top right of the screen to adjust the brightness you see on screen, does not apply to the actual stacked image though. Can you give some more details of the seetings you have in DSS?

[russellhq]

I think I was just using the default settings (I'll have a look when I get home).

I did change the RAW file settings by changing the brightness from 1 to 10. When it was at 1, DSS would not find a lot of stars.

[NickK]

I was playing with this in PI on the train this morning..

The squiggles are tracking errors.

[russellhq]

NickK, the attacment is a single sub, the stacked image was a lot worse (I haven't attached it).

[NickK]

I tried undoing some of the motion blur but I think the colour saturation from the jpeg is better lol:

[NickK]

I tried undoing some of the motion blur but I think the colour saturation from the jpeg is better lol:

This time with the STF actually applied to the image!

[russellhq]

I had another go at this data today, this time I tried stacking the other subs (8 @ 30s).

I've still got quite bad vignetting and I can't fix the purple cast!

I've attached the unprocessed TIF (M27_Dumbbell_UP.tif) and the processed TIF below if anyone is interested in trying to fix the image.

M27_Dumbbell.tif

M27_Dumbbell_UP.tif

[zakkhogan]

hows this?

[russellhq]

I think that looks better. How did you do it?

[zakkhogan]

do you use any software like gimp/photoshop/photos plus?

[russellhq]

Yeah, photoshop and gimp, but just a beginner.

I tried making a duplicate layer, blurring, darkening then subtracting to get rid of the vignetting but was struggling to keep the detail in the nebula. I also had no idea how to balance the colours to get rid of the purple tinge.

[zakkhogan]

This is just my method..

I copy (not cut) the nebula in to a new layer and then adjust the colour balance of the background and then adjust the layer setting, doge\burn and levels of the nebula to suite

[Shibby]

The easy way to fix the colour balance is to stack using "RGB background calibration"; a setting which I always use.

There's a PS plugin called GradientXTerminator that can help with the vignetting gradient. It's no compensation for a good set of flats, though...

[russellhq]

Flats? I thought it was darks that got rid of it, I've got a lot to learn!

I tried the gradient plug in but was getting better results without it.