Battled the dragons of Ara again

[LewisM]

Decided to fiddle with the CCDStack settings some more - this time using Lanczos/sinc 36 instead of my usual Catmull-Rom - and what a difference it made!

Need to tweak it more but probably not much point without extra data. Maybe a bit blue tinged...

http://www.pbase.com/lewism/image/160881975

[codemonkey]

Looking good, Lewis. Doesn't look blue at all to me.

What was the difference you noticed between those algorithms? Do you have an old image with which we can compare?

[LewisM]

Just a SLIGHT difference LOL : http://www.pbase.com/lewism/image/160722053

[multiweb]

Wanna see highres mate. ;) This is postage stamp stuff. :lol:

[LewisM]

Non. Je ne suis pas un sadiste...:)

[LewisM]

Here is a bigger stuff up though... sharpened it in ccdstack too much and did not notice the hollow small stars till too late. This one looks blue...
http://www.pbase.com/lewism/image/160881895

[multiweb]

Not bad. Looks a little out of focus. What scope was that?
Punching the star cores in CCD Stack can be caused by too much deconvolution or out of focus subs to start with. You can make a star mask in PS, select the stars, contract the selection by a pixel or two, feather by one then blur the core. Usually it brings back some color in them. Startools can do that automatically for you. It has some nifty routines to deal with star profiles. Or you can download the carboni actions. Back in the days that's all there was.

[LewisM]

Manually focused FSQ-106ED. Didn't think I needed to refocus as the temp seemed stable. I was wrong.

[multiweb]

Yep. The FSQ is a blessing and a curse. I've struggled with mine. Now I have the temperature compensation working it refocuses automatically while I'm imaging. I can leave the scope out and go to bed. The FWHM varies maybe +/- 0.1 which is within a range I can live with. I sample the temperature every 10s and it adjusts steps in near real time. So the focuser moves while I'm imaging. It works really well. It's set and forget now.

[LewisM]

I have a Sharpsky on order, but Dave ran out of components and went on holidays just when I went to pay! Should be another couple of weeks.

[multiweb]

Good stuff. You'll never look back. Also get a Tak 7:1 micro-focuser for it.

[Slawomir]

+1 for autofocus. I was also surprised how much focus changes with temperature (TS doublet). "By eye" I did not notice any shift in focus, but numbers clearly indicated that it changed. Now I have software set up for automatic refocusing for every 1C change in ambient temperature- and it works very well for me.

Keep fighting the Dragons :)

[LewisM]

New version

[Slawomir]

Last version looks sharper and shows more faint detail, well done Lewis :thumbsup:

[gregbradley]

Overall looks better but the stars have been oversharpened. Its better not to apply sharpening to stars and use curves after the stars are selected to pull them back a little if they are too intrusive. Sharpening is best done with a mask and brush in the areas you want sharpened otherwise it will damage the stars.

Greg.

[LewisM]

Greg,

Thanks, but most of the sharpening errors you see here are in fact JPEG compression artefacts - I uploaded a 755kb file here, which the IIS system shrinks to below 500KB, in the process "worsening" things. I have uploaded this revision to my PBase account:http://www.pbase.com/lewism/image/160889307

Still over-sharpened, but was TRYING to compensate for the focus issue (which it failed to do). Also remember this is really SMALL data - not even 2 hours worth.

[RobC]

Well done . Good one Lewis

:thumbsup:

[LewisM]

Heeded Greg's words, and went and redid it AGAIN.

Below is a 25% image. LINK is to half size: http://www.pbase.com/lewism/image/160890607

Yes, I know it is soft focus, and yes, I know there is some tilt at bottom half (camera is NOT orthogonal - will adjust the grub screws a touch)

[Rex]

Wow Lewis, they are all pretty good mate. Nice saturation and good details in the neb, well done mate!