NGC 1316 Galaxy Deep Field - Sidonio'd he he

[DJT (David)]

Great image Mike, could look at this for hours trying to do the count.

Congrats on the move to your dark site!

[gregbradley]

Originally Posted by strongmanmike

Just reprocessed...only slightly, got rid of the noise and a few other minor cosmetic improvements....

All the same links

Reeeeally looking forward to next New Moon

Mike

Ah bit by bit we are turning you into a noiseophile!

Nice improvement although I did not find the earlier noise objectionable.

Greg.

[strongmanmike (Michael)]

Originally Posted by gregbradley

Ah bit by bit we are turning you into a noiseophile!

Nice improvement although I did not find the earlier noise objectionable.

Greg.

Think you mean Noiseophobe

Well I agree with you I didn't find the original noise level (ie no noise reduction) objectionable either, in the first instance I just wanted to make sure no tiny little galaxy was smoothed over.

Now I wanted to improve the aesthetics a little without wiping any faint fuzzies or stars so I was very careful with the noise reduction when I applied it and under close inspection when blinking between the two versions it seems no tiny faint stars or galaxies have been wiped

Mike

[strongmanmike (Michael)]

Originally Posted by DJT

Great image Mike, could look at this for hours trying to do the count.

Congrats on the move to your dark site!

Cheers Dave, I haven't looked forward to a new moon as much as this next one, for a long time

Mike

[rogerg (Roger)]

Spectacular

F/3.8 .... Mmmmmmmm

... Slight edge distortion creeping in... Can't ask for perfection when such a large FOV at f/3.8

[strongmanmike (Michael)]

Originally Posted by rogerg

Spectacular

F/3.8 .... Mmmmmmmm

... Slight edge distortion creeping in... Can't ask for perfection when such a large FOV at f/3.8

Thanks Roger

Well you can...just costs more money

It is a 2.5 deg diagonal field at 1.57"/pix

I think I could still tweak the corrector spacing and maybe collimation a tad, the rest is image plane tilt and flexure, not sure I can ever eliminate the last two 100% with this OTA design, it is already acceptable to me but once I get her permanently under a dome (soon) and have more time, I will play with that corrector spacing and maybe I can shim something...?

Mike

[rogerg (Roger)]

Originally Posted by strongmanmike

Thanks Roger

Well you can...just costs more money

It is a 2.5 deg diagonal field at 1.57"/pix

I think I could still tweak the corrector spacing and maybe collimation a tad, the rest is image plane tilt and flexure, not sure I can ever eliminate the last two 100% with this OTA design, it is already acceptable to me but once I get her permanently under a dome (soon) and have more time, I will play with that corrector spacing and maybe I can shim something...?

Mike

2.5 degree, yes the enormity of the task is not lost on me I would be happy with your current situation, considering all, unless it can be tweaked of course . No comparison to my mass produced 12" struggling with its little ST8 at f/10

[David Fitz-Henr]

Originally Posted by strongmanmike

Thanks Roger

Well you can...just costs more money

It is a 2.5 deg diagonal field at 1.57"/pix

I think I could still tweak the corrector spacing and maybe collimation a tad, the rest is image plane tilt and flexure, not sure I can ever eliminate the last two 100% with this OTA design, it is already acceptable to me but once I get her permanently under a dome (soon) and have more time, I will play with that corrector spacing and maybe I can shim something...?

Mike

Yes, the corrector / chip spacing is quite sensitive, and the technical specs by some of the manufacturers leave a lot to be desired. I've found that collimation can be a bit tricky as well as you can't just rely on laser collimators to get it right; that's why the classic star test is recommended, but even then the standard visual star test at the centre of the field won't guarantee pin-point stars to the corners of a large field. I am still tweaking this for my own scope; I have used the laser collimation tests to get close, and then I have fine collimated based on the appearance of stars in the corners of test images that I then take. I then use the laser collimator again to see where the centre of the paraboloid is to simplify future collimation. When I spoke with Mark Suchting he commented that the centre of the paraboloid moves around the geometric centre of the mirror by about 3mm or so during final figuring (correct me if I've misquoted you, Mark) which makes sense and accounts for the fact that a simple laser collimation using a centre mark doesn't guarantee perfect collimation. The other thing that I've realised out of this is that having defined the centre of the paraboloid and collimated the primary accordingly, that the secondary also needs to be recollimated on the same spot or some image tilt may be noticeable (I'm still doing some testing on this but the clouds aren't co-operating at the moment). Finally, with these mid/large newtonians I wouldn't necessarily assume that any "flex" is all in the way the camera is supported; the optics themselves can't be superglued in place (well, unless you want severe astigmatism!) and may have some slight play (for me probably a limiting factor in using an external guidescope for longer than 15-20 min exposures). Eg. if the silicone supporting the secondary mirror is too thick it may tilt slightly under the weight of these larger secondary mirrors. ... anyway, food for thought ...

[strongmanmike (Michael)]

Cheers Dave, I'm with ya.

Some things there I need to do, just been reluctant given I have to set up and put away each session ...haven't wanted to waste too much sky time. This is just quick Catseye collimation and I am away...it'll do for now

Mike

[stevous67 (Steve M)]

Very enjoyable to look at Mike!

Cheers,

Steve

[Fabiomax (Fabiomassimo)]

Absolutely fantastic, Mike! Wich corrector you use with the Newton?
Bravissimo!
Fabiomax

[gregbradley]

[QUOTE=strongmanmike;910048]Think you mean Noiseophobe

Yes indeed! That's funny. I wrote that without looking up the definition!

That's great noise reduction when you can remove noise without affecting faint signal areas. Very expert.

Greg.

[strongmanmike (Michael)]

Originally Posted by Fabiomax

Absolutely fantastic, Mike! Wich corrector you use with the Newton?
Bravissimo!
Fabiomax

Hi Fabiomax

It is an Orion Optics AG12, made in the UK with their own corrector design based on the Wynn corrector see (scroll to bottom to see the corrector) HERE

Glad you like it

Mike

[strongmanmike (Michael)]

[QUOTE=gregbradley;910668]

Originally Posted by strongmanmike

Think you mean Noiseophobe

Yes indeed! That's funny. I wrote that without looking up the definition!

That's great noise reduction when you can remove noise without affecting faint signal areas. Very expert.

Greg.

As you know I am indeed not scared of noise. To me it is rare that noise reduction isn't obvious. Many great galaxy images, even by some big names, show the blended noise reduction quite clearly and you particularly see this most plainly in many DSLR images taken in summer. I often leave a bit of noise in to save detail too..but in this case after being initially happy with the slight noise I worked on it in the end and was careful not to impart too much, it helps when the signal is good in the first place and even on such a faint field 260min Lum with 12" at F3.8 under a dark sky helps.

Mike