ETA widefield RGB

multiweb (Marc) · #1 12-04-2011, 08:01 PM

Here's my second shot from last Saturday. 6x10min in RGB with QHY8. Very little to no processing. Just data rejection, stacking and color balance.

Bigger picture here [2.6MB - 1800px wide].
Nothing special. Just another Eta until the main object was getting higher in the sky.

alan meehan (Alan) · #2 12-04-2011, 08:12 PM

nice widefield Marc,well done
AL

h0ughy (David) · #3 12-04-2011, 10:21 PM

sniff sniff

wished mine looked normal

multiweb (Marc) · #4 13-04-2011, 08:26 AM

Quote:

Originally Posted by alan meehan

nice widefield Marc,well done
AL

Thanks Alan.

Quote:

Originally Posted by h0ughy

sniff sniff

wished mine looked normal

Don't despair David. This one's not too much to look at. Check Ross's latest.

atalas · #5 13-04-2011, 05:06 PM

Marc,I think It's real nice....good contrast too,well done.

Ross G · #6 13-04-2011, 09:30 PM

Hi Marc,

A beautiful photo. It has such a smooth and natural look.

Ross.

multiweb (Marc) · #7 13-04-2011, 10:16 PM

Quote:

Originally Posted by atalas

Marc,I think It's real nice....good contrast too,well done.

Thanks Louie.

It's sharp alright. Might redo the colors though. A bit more blue.

Quote:

Originally Posted by Ross G

Hi Marc,
A beautiful photo. It has such a smooth and natural look.
Ross.

Thanks Ross. Not nearly as good as yours.

gregbradley · #8 13-04-2011, 11:11 PM

When you say RGB isn't the QHY8 one shot colour? I suppose that means its RGB and no luminance or did you split the channels and recombine them in processing?

Overall quite nice. Be nice to do a couple of hours on it. I know the problem, you're main target is later and you want a fill in object while you are waiting.

Some Ha would bring it up. Didn't you do some nice Ha with your C11 and Hyperstar? You could register it with Registar and add it in for some zing.

Greg.

multiweb (Marc) · #9 14-04-2011, 08:27 AM

Quote:

Originally Posted by gregbradley

When you say RGB isn't the QHY8 one shot colour? I suppose that means its RGB and no luminance or did you split the channels and recombine them in processing?

Overall quite nice. Be nice to do a couple of hours on it. I know the problem, you're main target is later and you want a fill in object while you are waiting.

Some Ha would bring it up. Didn't you do some nice Ha with your C11 and Hyperstar? You could register it with Registar and add it in for some zing.

Greg.

Thanks Greg. Yeah a lot more data would make it shine. I've shot Eta in every possible bandwidth and I have heaps of data on it. I'm still to get a decent pure RGB version with no blending. By RGB I mean shot with the QHY8 (OSC) then recombined yes. In the future I want to get a mono with a smaller sensor and smaller pixels, maybe a QHY9, to do luminance and NB only. Keep the QHY8 for color.

TrevorW · #10 16-04-2011, 01:36 PM

Marc not just another ETA

Cheers

Trevor

multiweb (Marc) · #11 16-04-2011, 06:05 PM

Thanks Trev.

Lester · #12 16-04-2011, 07:36 PM

Very nice image Marc, showing the outer regions well too. Thanks for the view.

multiweb (Marc) · #13 17-04-2011, 09:28 AM

Quote:

Originally Posted by Lester

Very nice image Marc, showing the outer regions well too. Thanks for the view.

Thanks for looking Lester.

RickC (Richard) · #14 17-04-2011, 02:31 PM

Marc, you have got some great images again, Ilford must have been good to you. I on the other hand am in a ccd black hole learning curve!!
Richard

gregbradley · #15 17-04-2011, 08:57 PM

Quote:

Originally Posted by multiweb

Thanks Greg. Yeah a lot more data would make it shine. I've shot Eta in every possible bandwidth and I have heaps of data on it. I'm still to get a decent pure RGB version with no blending. By RGB I mean shot with the QHY8 (OSC) then recombined yes. In the future I want to get a mono with a smaller sensor and smaller pixels, maybe a QHY9, to do luminance and NB only. Keep the QHY8 for color.

Depending on what focal length you are going to shoot at those seem like conflicting goals - narrowband and small pixels and long focal length don't really go together.

I recently got my FLI Microline 8300 back from repairs and I have shot 2 objects now I had also shot with my Proline 16803 on the CDK17.

I expected the Microline to give finer resolution and larger image scale. Well it gives larger image scale but it gives less resolution and less sensitivity. Both cameras are 60% QE. The 8300 has 5.4 micron pixels and the 16803 9 microns. With 2959mm focal length the Proline gives .63 arcseconds/pixel (close to the ideal .66) and the Microline .38.

What that seems to mean is I am oversampling by nearly twice. And that works out empirically as one shot with the ML8300 had twice the exposure of the 16803 and they seemed about the same (Proline a tad better).

What that means to me is you aim for .66 arcseconds/pixel (assumes average seeing of 3 arc seconds) and the larger pixels for longer focal length. Smaller pixels then suit faster optical systems. Larger for longer focal lengths and slower systems. Smaller pixels generally are less sensitive and more noisy (although not in the case of the 8300 chip).

Greg.

multiweb (Marc) · #16 17-04-2011, 09:31 PM

I hear you but I'm nowhere imaging at 3M FL. My usual FL is under a 1M. The QHY9 would give me a smaller sensor so less problems with the field illumination and aberrations. Smaller pixels too and mono so no loss of resolution when debayering. My image scale varies between 2.5 to 3asp with a pixel size of 7.8um for the QHY8. If I can get down to 5.2um I should get some good lum details with the same gear.