One Shot Colour Cameras

[TrevorW]

I recently imaged NGC3293 cluster in Carina using my QHY268c on a 10"F/8 GSO RC, captured the stars nicely in 2hrs30min, the data frames varied from 3min to 5min but I couldn't for the life of me process any of the background nebula into the image. Is this a matter of integration time or an inherent problem with OSC cameras capturing faint nebula. Bortle 5/6 suburban skies

[AdamJL]

Hi Trevor. I've got two almost identical cameras to that.. the mono version and the ZWO colour version. Both are extremely capable of picking up faint nebula. But of course, capable doesn't mean they will always do it.

You're right in that integration time matters. The more time you give the sensors, the more they will pick up. Also, if you're fighting both light pollution AND moon-filled skies, it will be harder to pick up those fainter details.

What other settings did you use on the camera?

That said, care to share an image so we can see what you're up against?

[TrevorW]

gain 6 offset 23 QHY different to ZWO


Exposures 3 and 5 min


see image


Thanks

[ChrisV (Chris)]

That is a very slow scope and a small fov. So you might not see much of the H in the nebula around it. I think it's quite feint.

But you should also try stretching it more with less black cut off. Or might be better to move to the nearby ngc3324 cluster which has the brighter Gabriela Mistral nebula behind it.

Either way. It's a nice shot of the cluster!

[AdamJL]

Originally Posted by TrevorW

gain 6 offset 23 QHY different to ZWO


Exposures 3 and 5 min


see image


Thanks

What capture software? I use Gain 56 offset 25 on my QHY268M in NINA. I think it's the High Gain Mode as well.

[TrevorW]

EZcap Qt


would an optolong L pro filter be any good



thanks

[AdamJL]

Originally Posted by TrevorW

EZcap Qt


would an optolong L pro filter be any good



thanks

Not totally. I mean it will help cut out light pollution, but it won't make lots of details magically appear. I don't think the Ha is being swamped by light pollution here. Play with your gain settings and make sure to choose the correct gain (and very importantly, gain mode because QHY cameras offer different read out modes) in your capture software. I don't know how it works in EZCap.

Also, I've never shot this area before so I'm not sure whether the Ha region is just really low mag and you'll simply need more integration to bring it out. Are you getting the same issues on other nebulae, or just this one?

[Nikolas (Nik)]

Dual band narrowband filters will bring out much detail Heaps even just look at the results with the Lultimate and Lextreme filters

[Startrek (Martin)]

This open cluster called “The Gem” cluster is adjacent to Gabriela Mistral Nebula ( a huge arm of the Carina Nebula ) and has dense nebulosity clouds surrounding it.
If using OSC camera you need your Gain set for a higher dynamic range with lowest read noise ( ZWO 2600MC is Gain 100 ) at least 13 stops

You definitely need a OSC Dualband filter like L Enhance , L Extreme , L ultimate or Antlia ALPT to adequately expose the Ha. (L Ultimate and Antlia ALPT are the best )

If using a f5 scope 3 minute subs are satisfactory and require just an hour or 2 to expose the nebulosity ( see my image attached with 2 hours or so of data with the L Extreme captured in 2021 )
Sorry for the crappy resolution I use my iPhone to downsize it but you can see the nebulosity, also my Star colours are crap as I used a Star mask to try and fix the colour but didn’t work ( no orange Star ) should have imaged RGB for stars only.

If using an f10 scope I’d reckon you need 4 to 6 hours with 3 to 5 min subs using the OSC Dualband filter

Also my image was under Bortle 7/8 Sydney skies ( heavy LP ) so yes you have to remove the gradient as best you can which doesn’t restrict your image Stretch but more signal or more hours on the target will greatly improve the result.

I looked at the specs and performance charts on the 268C and for narrowband imaging ( using Filter ) and Mode #1 is most suited ( Gain 55 and above ) however I’ve never used this camera , only going by recommendation
Cooling the camera down to -5C to -10C should be more than satisfactory for mitigating dark current

Hope the above helps

Martin

[TrevorW]

Thanks Martin