Centaurus A now with colour repro and added time

[gregbradley]

I got quite a bit of colour and some Ha for the luminance I posted.
32 x 5 minutes gain 53, -10C blue
23 x 5 mins red, 22 x 5mins green, 12 x 5 minutes Ha

The camera is very sensitive and very low noise.

I got more exposure time last night. I added this to the image plus reprocessed it from scratch using flats as well.

It looks a little yellowish but I believe that is the correct colour as the data wants to go that way and also elliptical galaxies are often yellowish.
The image is also starting to show a hint of the shell structure and some odd shaped extended star halos at both ends.

Same links:


https://pbase.com/image/170640292/large regular size

https://pbase.com/image/170640292/original very large size

I think this makes the Honders a galaxy imaging machine.

Greg.

[Camelopardalis]

:thumbsup:

What's not to love about high QE, lots of tiny pixels and fast f-ratio?!?

[gregbradley]

Yes its a pretty ideal combo. Focusing though seems to be a lot harder. Less so now that it should close to focused when I turn everything on.

Greg.

[topheart]

Well done Greg!!
What's the critical focus zone for the setup with the Honders?
Cheers,
Tim

[gregbradley]

Thanks Tim.
With an Atlas focuser and a 9 micron pixel camera usually I get it to within .2% of the travel of the focuser which is 10mm.
Not sure what it is with the smaller pixels, perhaps nearly 1/4 of that.

Greg.

[Placidus]

Superb!

[Atmos]

My RH200 has a CFZ around 30 microns under my usual seeing being an 8" F/3.

Your Honders is a 12" F/3.8?
That should have a CFZ around 75 microns under 2" seeing.

You have captured some pretty nice detail too btw :)

[gregbradley]

Thanks M and T.




Thanks Colin. The CFZ is pretty tight. I used @focus 2 (in the Sky X) tonight and it
worked quite well.

Greg.

[Atmos]

I’ve heard @focus3 is a significant improvement, I haven’t used it myself though. I find FocusMax to be really good once calibrated.

[gregbradley]

Thanks Colin. I'll see if I can get @focus3 otherwise I'll try FocusMax again.

Greg.

[multiweb]

That looks excellent Greg. Nice image scale with that combo. :thumbsup::thumbsup::thumbsup:

[gregbradley]

Thanks Marc. Still learning how to get the best out of this camera.

Good imaging weather this week eh?

Greg.

[Phil Hart]

Impressive scale and detail for sure Greg - you would be happy with that setup. I reckon this online version has ended up a little black-clipped. You might be able share a bit more detail with us than what's in that version?

Phil

[gregbradley]

Yes I see what you are referring to. I'll do a repro on this one.

I might use flats on this as well as whilst there was no appreciable vignetting there was a slight reddish gradient that I tried to remove and probably black clipped a little there. Thanks for the suggestion.

Greg.

[Retrograde]

Looks great already Greg. Will be interested to see the reprocess.

[gregbradley]

I think I will use some flats and see what they look like. Perhaps some background Pixinsight magic.

Greg

[gregbradley]

I added some extra exposures I took last night and reprocessed it from scratch and used flats.

https://pbase.com/image/170640292/large

Greg.

[peter_4059]

The galaxy details are amazing but there is something about the large stars that doesn't look quite right to me - perhaps it's my monitor or failing eyesight :screwy:

[codemonkey]

Lovely colour and contrast, Greg! Well done.

I do agree with Peter though, the stars look a bit funky. Looks a bit like something I see on stars when I use too much decon?

[gregbradley]

Thanks. I think I have corrected the halo effect around brighter stars. I was so concentrated on the centre details I didn't really check the brighter stars. Thanks.



No a bit of an artefact entered in. Corrected now.

If I get another clear night tomorrow I might add even more exposure or start combining with earlier data.

Greg.