Eastern Veil

[gnomus]

I continue on with my 'Oh No, It's Selwyn Froggitt' approach to astrophotography.  This time the Eastern Veil nebula.  It is my first attempt at a colour narrowband image.  I snapped the photos in September 2015 and again in November 2015. Between these two dates I changed my mount (and also had some other issues that meant multiple reconfigurations) and when I set the ED80 back up this week I inadvertently rotated the camera somewhat so that there is a mismatch between the orientation of the September and November images.  This meant I had to crop a fair bit.  The new mount did give me better guiding in November.  Furthermore, by November I was paying more attention to focus - that is I was checking focus every 60 minutes.  So I cannot decide whether I like the 'better-guided-more-attention-to-focus-but-less-exposure-time' image or the 'more-time-but-even worse-data' shot.  I post both.

Image one is the full monty - 8 x 1200 seconds Ha, 4 x 900 seconds Ha (changed exposure time because I was not happy with the 1200 second guiding on the CGEM), 9 x 1200 seconds OIII

Image two is 6 x 1200 seconds Ha, 9 x 1200 seconds OIII.

Baader filters

ED80 scope mounted on a CGEM (September) and Mesu (November).  Guiding ZWOASI120 on a ST80.

Processed in PixInsight and Photoshop

Image 1:

Image 2:

Comments welcome.  I can see some 'redness' in the lower right corner, especially of the wider field of view.  I am not sure if this is genuine nebulosity or if it is a gradient. 

[wxsatuser]

Don't run yourself down as you have some good data there.

Practice makes perfect.

[gnomus]

Don't run yourself down as you have some good data there.

Practice makes perfect.

It's meant semi-humourously.  I'm reasonably pleased with the image but I do want to improve so wish to invite criticism.  I think that 'redness' is a gradient.  I ran the non-linear image through a second iteration of DBE (not sure if that is kosher or not) and got this:

[Mick J]

It's nicer in focus gnomus, are you using a ccd camera or dslr ?   have I missed that info somewhere.  nice work.

[gnomus]

It's nicer in focus gnomus, are you using a ccd camera or dslr ?   have I missed that info somewhere.  nice work.

You didn't miss it, I forgot to say.  It's an Atik 383L.  Here is a second iteration DBE of the more heavily cropped effort:

[laudropb]

very nice images you can be proud of. As they say Rome was not built in a day and you are definitely making very good progress.

[gnomus]

very nice images you can be proud of. As they say Rome was not built in a day and you are definitely making very good progress.

That's very kind of you.  I suppose the question is, how long did it take to build Rome?  

[Barry-Wilson]

Very good Eastern Veil Steve.  You should be justifiably pleased.

I think you've certainly improved focus and you're correct about the gradient and there is nothing wrong with a second iteration of DBE (but not ideal and better to re-try the initial extraction).  The colour balance is good.  I would be tempted to experiment with LHE (don't know if you have?), with low amounts and the background protected with a inverted luminance mask.  Have you tried LRGB combination with the Ha as the luminance layer?  This can be beneficial in NB images; sometimes you need to readjust saturation to avoid the 'salmon-pink' Ha effect.

Regarding focus and refocusing during a sequence, with my Tak, although a different scope and you may have automated your focusing with your Tak (sorry to read about your flat field issues in your other thread), I refocus every 1 deg C change, and find the focus point does change slightly with each degree.  The drift over 1 deg C is within the CFZ, but I prefer to closely track its change.  The focus in your image is good - could it be slightly sharper, what do you think?  Using MLT with bias set to 0.03 or 0.04 for layer 1; 0.2 for layer 2; and 0.01 for layer 3, and an inverted luminance mask to protect the background can sharpen the nebulosity gently.

HTH

Barry

[gnomus]

Very good Eastern Veil Steve.  You should be justifiably pleased.

I think you've certainly improved focus and you're correct about the gradient and there is nothing wrong with a second iteration of DBE (but not ideal and better to re-try the initial extraction).  The colour balance is good.  I would be tempted to experiment with LHE (don't know if you have?), with low amounts and the background protected with a inverted luminance mask.  Have you tried LRGB combination with the Ha as the luminance layer?  This can be beneficial in NB images; sometimes you need to readjust saturation to avoid the 'salmon-pink' Ha effect.

Regarding focus and refocusing during a sequence, with my Tak, although a different scope and you may have automated your focusing with your Tak (sorry to read about your flat field issues in your other thread), I refocus every 1 deg C change, and find the focus point does change slightly with each degree.  The drift over 1 deg C is within the CFZ, but I prefer to closely track its change.  The focus in your image is good - could it be slightly sharper, what do you think?  Using MLT with bias set to 0.03 or 0.04 for layer 1; 0.2 for layer 2; and 0.01 for layer 3, and an inverted luminance mask to protect the background can sharpen the nebulosity gently.

HTH

Barry

Barry

Thanks for taking the time to comment on my image and suggest other things I could try.  I used your Astrobin image as my 'plate solve' in SG Pro!!

I tried the Ha as Lum thing but it seemed to make things worse.  The LHE did bring out some detail though and I have tried a little more sharpening as suggested, using a range mask with a star mask subtracted so that only the nebulosity was affected.

 

[gnomus]

With the 100 extra minutes of Ha the use of Ha in LRGB combination seemed to work better:

[gnomus]

Some final (I hope) tweaks in Photoshop:

[Garethr]

Great image gnomus

Love seeing the image develop during the thread gives us all hope.

Gareth.

[gnomus]

Thank you Gareth.  It is interesting for me to watch it develop too, not least because at one stage I must have been happy with the first versions.  Now I see nothing but flaws.  It is difficult to know where to stop.  Here is the version with 220 minutes of Ha, and with better colours I think:

[sloz1664]

Lovely image Steve. After all the grief you have had, it's nice to see the fruits of your labour.

Steve

[gnomus]

Lovely image Steve. After all the grief you have had, it's nice to see the fruits of your labour.

Steve

Thanks Toxic - this is the ED80 though not the Tak (an issue which is still not resolved).

[strutsinaction]

Very nice Steve. Just shows you how good the ED80 is, in the right hands of course 

Regards

John

[gnomus]

Very nice Steve. Just shows you how good the ED80 is, in the right hands of course 

Regards

John

Thank you John.  The problem is that, according to Takahashi, I am a prize plum.

[Horwig]

Nice to see the image develop, I'm the same, I can't stop tweeking, one thing that still worries me about your image though, where did you find all that clear sky to shoot extra Ha? I've not had a clear night here since the 3rd of this month      

Huw

[gnomus]

I can assure you things haven't been easy here.  For the last set of subs, I was monitoring the imaging in the house on Team Viewer when PHD2 lost the guide star.  I looked out of the window and could only see a clear and star-filled sky.  Only when I went outside did I spot a small cloud above the house and noticed that the rain from it was being blown straight into the observatory, moistening the gear.  Got the roof closed.  Dried everything off.  Heating on.  Went outside - clear skies again with not a cloud in sight.  Retire to the pavilion - alcohol.  Alcohol.   

[Horwig]

Retire to the pavilion - alcohol.  Alcohol.   

I also find it helps.

H

[MarsG76]

I think the second last posting has the best balance of brightness and saturation, at least on my iPad... That said all of your veil images are great.

Did you find having to adjust your focus hour to hour at at when you checked every hour?

[gnomus]

Thank you. I think I agree. The answer to your focus question is: sometimes. I use that Bahtinov Grabber program and this gives an actual 'number'. Assuming you have entered some basic details, it will also tell you if you have moved out of the critical focus zone (CFZ). Using Bahtinov Grabber was recommended to me by Sara Wager (no doubt after she'd seen some of my blurry monstrosities), so who am I to argue?

Sometimes the focus just creeps out of the CFZ and I will adjust. Sometimes it reports that I am still within critical focus though the reported number is worse than I remember it being an hour previously. In these circumstances ..... I still adjust to try to get the number as low as possible (I aim for less than +/- 0.2 but this is a number just plucked from my brainz - I don't know what the top guys aim for). It adds a bit of time (though not too much time). It is early days, but I think it is paying dividends ...... Unlike Royal Bank of Scotland, but that's for a different forum.