Processing the Horse Head Nebula- help required

[el_hop87]

Hi all, 

I have stacked images in DSS (lights and dark) of the Horse Head Nebula, which I am now trying to process in StarTools. So far I can make out the Horse Head but the colours are v pixelated. I am very much learning post processing skills atm, and still a long way to go! - These images were taken when the moon was 60% so it could be that I am having issues with light. 

If anyone is able to help with advice, that would be much appreciated! - I have attached the stacked FITS file in case its easier to look for yourself. 

Thank you very much! 

Elly

Horsehead nebula_00001.fit

[rickwayne]

Thanks for putting up the  data. Would you  mind also posting a screenshot or JPG giving us a  visual clue to  the problem?

[ollypenrice]

2 hours ago, rickwayne said:

Thanks for putting up the  data. Would you  mind also posting a screenshot or JPG giving us a  visual clue to  the problem?

Yes,  277 meg is rather a lot!

Olly

[el_hop87]

Hello both, 

Thank you for your replies- this is a jpeg file of the same stacked image (unprocessed). 

Many thanks again

Elly

[JSeaman]

Just a background extraction and stretch showed this:

 

 

 

[JSeaman]

With a crop, smoothing, green reduction and levels/curves you can clearly make out the horsehead and flame

[el_hop87]

Thank you JSeaman! - I suspected the moonlight was a problem. Do you think there is anyway of rescuing the image or at least making the nebula stand out? 

Thanks again for your help. 

[el_hop87]

Oh wow, thank you, I have just seen your 2nd image - much better. I will keep trying myself to bring out the details. 

[JSeaman]

That was just a quick process so you should be able to get something better out of it. If I were you, I would treat it as a learning exercise by gathering the exact same data on a moonless night and see what difference it makes

[shropshire lad]

Can you tell us what equipment was used and your settings please

[Andy56]

From my limited experience, the "Marks in the optical chain" look just like the dust on the sensor I had a week or two back. A sensor cleaning kit fixed it. They did not show on individual subs but accumulate in stacking.

Cheers

Andy

[el_hop87]

Thank you everyone! 

I'm using a Nikon D5200, AZ GTI, SW Evostar 72ED, IDAS light pollution filter. 25 second subs, for a total of 1 hour 13 mins +10 Darks. 

 

[el_hop87]

This is what I have after another edit- not very happy with the detail, but can't tell if its my post processing skills or the quality of images....

[JSeaman]

I don't think that's a bad job from the data you have. More data is better and lower ISO if you can for noise reduction. And no moon of course!

[jager945]

Hi,

I think your data acquisition efforts and precious time spent under the night skies are let down by not calibrating with flat frames. They are really not optional; they would calibrate out the dust smudges and severe vignetting.

Right now any signal is mired in uneven lighting, making it impossible for people (and algorithms) to discern artifact from faint signal.

Have a look here for some important do's and don'ts when acquiring and preparing your dataset for post-processing.

 

[wimvb]

13 hours ago, el_hop87 said:

 the colours are v pixelated

There’s your problem. What you describe are symptoms of underexposure. Either your sub exposures are too short or you have too few. More data is the best solution. Withe the moon about, you need even more data in order to reduce the noise caused by moon light.

[el_hop87]

Thank you all, thats really helpful! - always feel like I'm learning loads on here. 

[AstroNebulee]

13 hours ago, el_hop87 said:

Thank you everyone! 

I'm using a Nikon D5200, AZ GTI, SW Evostar 72ED, IDAS light pollution filter. 25 second subs, for a total of 1 hour 13 mins +10 Darks. 

 

Great inage with the az gti were you using it in eq or az mode, as I've the az gti and 72ed coming moro hopefully, no wedge yet as my star adventurer probably not arriving until late April at earliest and like to give this a go. Clear skies