Cygnus Loop in NB - First Light with 314L+ & 105mm lens - WIP

[Gina]

A couple of hours of clear sky last night and I managed to set up and take a few Ha subs of the Cygnus Loop with the Atik 314L+ mono CCD camera with Asahi Super Takamar 105mm f2.8 prime lens at f4. The first few subs were too low and in the trees but I managed 3 15m subs before the cloud came in. This is just a very rough start and I need to adjust a few things having just put the widefield imaging rig back on my mount. I would like to change the camera angle for one thing.

The moon was out and shining brightly being not far off full and caused a gradient in the background which I need to sort out in the processing. I'm not sure now much more data I will be able to add with the moon getting nearer full - have to see. This is with an Astrodon 5nm Ha filter. Guiding with ST80, Lodestar and PHD.

So... just 3 15m subs Ha stacked in DSS and processed in PS - just a rough first go.

[michael.h.f.wilkinson]

Very good image given the conditions.

[fwm891]

Hi Gina - your 105/314 combo is ideal for those larger areas. Not sure is the focus slightly soft?

[Coco]

Hi Gina

Looks like a wonderful field of view, I tried the SMC Tak 135mm and found star bloat a problem on long subs, I think its more to do with lens coatings than the focus been out a touch.. Do you use FWHM?

[Gina]

Very good image given the conditions.

Thank you

[Gina]

Hi Gina - your 105/314 combo is ideal for those larger areas. Not sure is the focus slightly soft?

Yes, I think so I did my best with the focus but I think the seeing was poor - I sometimes got down to FWHM of 1.8 but more often it went to 3 or so without changing focus. Even with10s exposure subs for focussing it varied by at least 2:1. I think the later subs may have been affected by thin high cloud. I agree that the definition is poorer than expected.

[Gina]

Hi Gina

Looks like a wonderful field of view, I tried the SMC Tak 135mm and found star bloat a problem on long subs, I think its more to do with lens coatings than the focus been out a touch.. Do you use FWHM?

The 105 seems to be a particularly good lens and I'm very pleased with it Yes, the FOV seem just right for this. When I did calculations from my DSLR images of the Cygnus Loop I though it might be tight but it seems fine Yes I do use FWHM - find it very good

[Coco]

The 105 seems to be a particularly good lens and I'm very pleased with it Yes, the FOV seem just right for this. When I did calculations from my DSLR images of the Cygnus Loop I though it might be tight but it seems fine Yes I do use FWHM - find it very good

There is tilt in there somewhere, the stars in the right are much sharper than the left..

[Gina]

After early cloud it turned clear last night though seemingly not very clear - the transparency was decidedly poor. I could only get an FWHM value of around 3 which is very poor with a 105mm lens - I usually get around 1 and have sometimes had lower with Ha. I think there could have been little bits of cloud about as I had to discard several frames due to poor guiding and a couple due to very light background. Also there was a big bright full moon which lit up any dampness in the atmosphere and caused a background gradient. So not such a good night as it first appeared in fact I was in two minds about posting the final image.

Here we have the result of stacking the 11 best subs out of about 16 15m subs, stacked in DSS and processed in PS - uncropped.

[WaveSoarer]

That's already very impressive. I'm looking forward to viewing this part of the sky again soon - though I'll need to wait until it's cleared the trees.

[davew]

Hi Gina,

The framing is much better now but it looks like the conditions were against you.

Do you ever use a Y mask to double check focus ? I find it works ok at 105mm so long as the star in question is bright.

Dave.

[Gina]

That's already very impressive. I'm looking forward to viewing this part of the sky again soon - though I'll need to wait until it's cleared the trees.

Thank you Yes, I have to wait until it's cleared the trees - and the odd post...

[Gina]

Hi Gina,

The framing is much better now but it looks like the conditions were against you.

Do you ever use a Y mask to double check focus ? I find it works ok at 105mm so long as the star in question is bright.

Dave.

Yes, I took the assembly off the mounting so that I could get at the camera rotation screws and rotated it roughly vertical but it's still a bit out.

I use FWHM to focus. I took severeral goes at the the optimum but the curve was very shallow and difficult to decide on the best. Usuually the movement versus FWHM forms a much sharper V. This time the bottom was several steps wide and I set it at what I thought was mid way. This time it wasn't so much seeing as transparency - there wasn't much variation in focus - just a generally fuzzy image.

Whether it will be any better tonight is anyone's guess - it's partly cloudy today, like it was yesterday.

[Gina]

Clear sky tonight with much better transparency - moon only one day past full though. I adjusted the camera orientation and I think I've got it almost vertical now. I think (and hope) that tonight may be the first proper imaging session on this object this year. I decided to go for a change from Ha and try the OIII 3nm filter in virtually full moonlight - it's looking promising This is also the first imaging run with my new Asus laptop - the first time I've got it to behave Now I'm just hoping it will continue to behave for the next 4 hours and not update, reboot or crash while I leave it unattended and grab some much needed sleep.

Here is the first 15m sub simply histogram stretched using Levels and Curves in PS then turned through 90 degrees so that north is upwards. No other processing. FWHM tonight is between 1.5 and 2.0 - vastly better than last night (so far).

[ollypenrice]

Great to see the whole thing. I like the new framing very much, too.

You should be able to kill that gradient easily enough. DBE would eat it for breakfast and I dare say Gadient Xterminator would wolf it down as well.

Olly

[Gina]

Great to see the whole thing. I like the new framing very much, too.

You should be able to kill that gradient easily enough. DBE would eat it for breakfast and I dare say Gadient Xterminator would wolf it down as well.

Olly

Thanks Olly

I've just downloaded the trial version of Gadient Xterminator and copied it to C:\Program Files\Adobe\Adobe Photoshop CS5 (64 Bit)\Plug-ins\Filters as stated in the ReadMe but I can't see it in PS. If it plays up I may take a look at PI and see if I like that - I gather there's a fully working trial version of it which, unlike some, gives full functionality before just stopping working after the trial period. I can't stand trial versions where saving (or something else essential) is disabled. I'm going to be very careful what I get - I bought AA5 as it looked really good but so far I've just not been able to get my head round it - it seems far too theoretical. I want a tool (or collection of tools) to do a job not a lesson in maths - I'm just too old for heavyweight maths, did that many decades ago.

[Gina]

The new laptop has behaved itself and has been working properly since last night. So the imaging run completed and finished about half hour after dawn exactly as planned I had a couple of spoilt frames due to guiding failure but did manage to collect 14 good frames. Set up the GN panel on top of the lens this morning and took 35 flats - 0.55s each.

Here is the result of 14 x 15m OIII subs plus 35 flats, stacked in PSS and processed in PS CS5. For some reason DSS flips FITS files so I "unflip" in PS and rotate 90 CW to put north at the top. Then applied Curves and Levels to produce this final image. Well I say final - just final for now - I need to sort out gradient removal. The gradient was due to a nearly full moon of course. Have to say, I'm pretty pleased with the Astrodon 3nm OIII filter, used in very nearly full moon conditions If I can get the gradient fixed I'll have a result

[kirkster501]

Very nice that. I really like it Gina.

Steve

[andyo]

Good progress with this Gina the last one is looking very good.Gradient xterminator should show up under filters RC-Astro.

[davew]

Gina. Check when you open CS5 that the 64 bit version opens and not the 32 bit version.

I know that sounds a daft thing to say but it's happened to me !

Dave.

[davew]

Double !

[Gina]

Very nice that. I really like it Gina.

Steve

Thank you Steve

[Gina]

Good progress with this Gina the last one is looking very good.Gradient xterminator should show up under filters RC-Astro.

Thank you Andy Got it! I hadn't restarted PS Now it is there and when I tried running it, it asked for ID and PW which I then entered and it is working

[Gina]

Gina. Check when you open CS5 that the 64 bit version opens and not the 32 bit version.

I know that sounds a daft thing to say but it's happened to me !

Dave.

Thanks Dave Yes, it was opening in 64 bit But needed restarting to show the new part - doh

[Gina]

Well folks - it works! I've just applied it to my latest image followed by more Curves and Levels plus some sharpening and this is the result :-