Horsehead in colour

[petershah (Peter Shah)]

love the colour in this

[Robert_T]

Originally Posted by gregbradley

Hehe, yes I am happy with it for a first light. It can only get better from here.



Mode 2 Gain 26 offset 10.

I think these are the default settings for Mode 2. Mode 1 for narrowband and Mode 3 for fast large optics for the extended full well. This mode might be more appropriate for the Honders at 305mm aperture and F3.8.

AP130GTX with the quad compressor might be good with mode 3 as well or stick to Mode 2 for broadband imaging.

I am not sure how much offset affects things. I experimented with my QHY294M and 2 quite different offsets. I checked the images in CCDstack - they looked almost identical. The histogram peaks shifted slightly.

Perhaps a higher offset can remove some of the background banding along with higher gain.

These Sony sensors have a dual gain amplifier so read noise drops significantly at some point. I am sure that point is in the graphs on the QHY site. I looked it up, its Gain 26. Read noise drops considerably.

Greg.

Hi Greg, I think this has the same sensor characteristics as my QHY268c ? It has that same sweet spot in Photographic mode at gain 26... I've never got any clarity of offset. For what its worth I've played around with all three modes and found High Gain mode the most useful... mostly at gain 60 which has very low read noise yet still respectable dynamic range, but even when I want deeper wells the High Gain mode at zero gain is very deep (similar to photographic mode at 0 gain and not that much less than Full Well but with much lower read noise) . upshot is they are the only two setting is use now.... high gain mode with either 60 or 0 gain. Cheers robert

[gregbradley]

Originally Posted by DavidTrap

Thanks Greg,

I’d hoped to get a feel for this camera over the summer, but alas no.

DT

Originally Posted by petershah

love the colour in this

Hi Peter, Yes I was surprised at the saturation of the colour as well. Initially the 30 minutes worth each of rgb seemed pretty noisy but surprisingly it cleaned up well. I think though 1 hour each of rgb really should be the minimum.

Originally Posted by Robert_T

Hi Greg, I think this has the same sensor characteristics as my QHY268c ? It has that same sweet spot in Photographic mode at gain 26... I've never got any clarity of offset. For what its worth I've played around with all three modes and found High Gain mode the most useful... mostly at gain 60 which has very low read noise yet still respectable dynamic range, but even when I want deeper wells the High Gain mode at zero gain is very deep (similar to photographic mode at 0 gain and not that much less than Full Well but with much lower read noise) . upshot is they are the only two setting is use now.... high gain mode with either 60 or 0 gain. Cheers robert

Thanks Robert. Yes the 2 sensors have the same architecture so I would not be surprised if the settings translate across the 2 models.

Are you sure the well depth is still high in high gain mode? It usually butchers the well depth.

As to gain and offset there seems to be little difference in the images so I would not fuss over it too much. I tried last night Gain 26 versus Gain 56, images looked almost identical and the histogram was simply a bit higher with the higher gain.

Greg.

[Andy01 (Andy)]

Looking very promising Greg!
I agree with Peter W though, Altinak is very distracting when presented like this.
I'll be fascinated to see what happens as you fine tune the new camera settings

[gregbradley]

Originally Posted by Andy01

Looking very promising Greg!
I agree with Peter W though, Altinak is very distracting when presented like this.
I'll be fascinated to see what happens as you fine tune the new camera settings

Yeah I did a bit of experimenting last night until the clouds rolled in. The full well mode does tame Alnitak quite a bit.

Greg.

[Placidus (Mike and Trish)]

Gorgeously rich colour. Very appealing.

Alnitak is fine. It's a part of the fun.

[multiweb (Marc)]

Looks great Greg. Your ha was already super tight and you've blended the colors really well. Alnitak is the way it should be. Makes the picture real. Some will say there's probably an AI plugin for that.

[rustigsmed (Russell)]

nice classic looking HH Greg!

[JA]

Very Cool Greg. I especially like the detail in the red curtain and hills & peaks behind the Horsehead. Flame rocks too

Best
JA

[gregbradley]

Originally Posted by JA

Very Cool Greg. I especially like the detail in the red curtain and hills & peaks behind the Horsehead. Flame rocks too

Best
JA

Thanks JA. I am happy with the camera's performance at this early stage.

Greg.

[Robert_T]

Originally Posted by gregbradley

Thanks Robert. Yes the 2 sensors have the same architecture so I would not be surprised if the settings translate across the 2 models.

Are you sure the well depth is still high in high gain mode? It usually butchers the well depth.

As to gain and offset there seems to be little difference in the images so I would not fuss over it too much. I tried last night Gain 26 versus Gain 56, images looked almost identical and the histogram was simply a bit higher with the higher gain.

Greg.

Hi Greg image attached shows the well depth and read noise for the various modes... dark blue is high gain. At zero gain well depth is a pretty respectable 60k and read noise low. That said I note they've added an Extended Full Well mode now (yellow) that has a lower read noise so closes the gap a bit on this and may be worthwhile for high dynamic range subjects where expsoures are long enough to swamp the read noise.

[gregbradley]

The QHY600M graph is similar but I think the dual gain kicks in a tad earlier at Gain 26.

Thanks for that.

Greg.