Spongey

There has been a couple of updates since then, I apologise I had a typo in my post above and have now corrected it. Download and install the one I have linked and try that

Did you download and install the All-In-One pack v21.02.20? Located here. There is an issue with the USB drivers of previously released packs with this camera and the 294Pro, as these cameras were manufactured with a new USB controller chip. The manufacturer updated the design without announcing it and it has some issues with the old libraries. The new libraries are now included as part of this pack. QHY also recommend only using a max 3m length USB 3.0 cable, or using a powered repeater cable for stable connection.

Are you running through ASCOM or the native driver? What version of the QHY drivers are you using? Did you also update the USB driver package?

Fantastic image! I hope you don't mind but I ran the JPEG through PixInsight's image solver and annotator, which has shown that yes, you caught a fair few PGC galaxies too! 😅 The way to do this is to solve the image in PixInsight using the ImageSolver script, and then run the AnnotateImage script with whatever objects you wish to highlight. Cheers

Ouch! Metal can shear like it appears to have done for you; I have the same SkyGuider and never questioned that this part wasn't metal. There is a fancy Williams Optics replacement for the base part that has glowing reviews and is supposed to be much superior, but is a little expensive. Otherwise a replacement from iOptron can be purchased too. Cheers

Had another go at the data from scratch, but this time in a different palette. A little less star reduction in this one too. Cheers

Glad to hear it A value approx. 40-50% of the max ADU is a good place to aim, so 24000 is fine.

Looks good, and yes it is normal for darks to have a long tail as you say, this is due to hot pixels / dark current etc. Your chip looks similar to mine, in that offset 10 should be fine. I'd double check a fair few frames though to make sure none of your pixels are clipping at zero.

I'm afraid I'm away from my pc for a few days but I can tell you that the histogram is just off the left side. The best way to check if you're clipping values is to use a tool that will tell you the minimum pixel value of a bias / dark frame. PixInsight has a tool that will do this called 'statistics' if you use it. The minimum value will vary by a few tens of ADU per frame based on noise, so as long as you don't clip any pixels in ~50 different frames you're safe. I think the minimum I saw in all my darks and bias frames was 27 ADU. This is cutting it a little close but fine for my chip. If you're concerned and just want to set and forget then choose an offset value of ~20 and forget about it. It's worth noting that if you're taking narrowband subs then you may need to add a pedestal of ~200 ADU (or just over the average of a bias/dark frame at your offset) to your frames during calibration to avoid clipping when subtracting the dark / bias frame from your light. This shouldn't be an issue with LRGB as your noise floor will be much higher.

Fantastic! What bortle scale are you in?

Yes, the gain and offset are independent of the read mode. Further info on each of the read modes is here. In short, High gain mode (#1) provides the best combination of dynamic range, FWC and read noise for most users (gear and conditions). If you're shooting with really large aperture and / or in heavy LP, then you might benefit from extended full well mode, but as long as you're not clipping too many star cores and swamping the read noise, then mode #1 is fine. For mode 1, there is an argument to only ever shoot at gain 56, but with LRGB in moderate light pollution you'll swamp the read noise at gain 0 within a couple of minutes anyway. Shorter exposures at gain 56 have benefits such as tracking errors etc., but will also take up ~3x the disk space as an equivalent SNR stack from gain 0. This is why when asked for a 'set and forget' mode, I suggest Mode #1, gain 56 and offset 10(ish). If you want to get into the details and really pull the best from your skies, gear and other limitations then reading more into the different modes might help you.

The read mode settings are those shown on QHYs website. For the vast majority of situations you will be best off using High gain mode, aka mode #1. Offset 10 works for my chip but if you find that you have any clipped (0 value) pixels in your bias or dark frames then you will need to increase it.

No worries. I'd be interested to hear if you have any issues. I've been getting some QHY SDK crashes with Nina but it doesn't seem that anyone else is haha. Have done some debug work with the Nina devs and the issue is being reported back to QHY so will hopefully be resolved for me shortly. I hope you don't have any of the issues I do!

You want the latest beta SDK located here, version 21.02.01. What capture software will you be using?

Backfocus of 12.5mm is without the M54 4mm adapter plate. With the M48 5mm adapter you have in your hand the backfocus will be 17.5mm. Interesting that yours came with the M54 adapter already bolted on, mine was blank. Regardless, it's a simple case of unscrewing the M54 adapter and replacing with the M48.

UPDATE: Unfortunately flipping my Antlia 3nm PRO Ha filter has not changed the halo situation. I'll probably be looking to exchange it with another, as it doesn't seem that anyone else is having this issue. I will send the details on to Antlia and get in touch with the vendor tomorrow. Good news is that I have no halos with Sii; I did a test sub on Alntiak for 300s and no halo was visible 👍

Great news Please do update the thread with your findings! I'd be interested to see how the Optolong filters perform. What scope will you be using the camera on primarily?

Ah okay I expect drivers to be the issue then. I had multiple issues my first night out before NINA was updated to support the latest SDK, let alone other issues with guiding (first time using multistar on PHD2dev3), focuser issues (sesto senso slipping when pointing near zenith), and filter halo issues. I have now hopefully fixed the former three of these and hope to get some good data tonight. I've flipped my Ha filter so hopefully that fixes my halos, the LRGB have gone back so waiting on a new set of those, and I need to do some proper tests with Sii as well. A busy night awaits! Cheers

That is strange... Are you using the latest drivers (SDK v21.02.01)? On the plate below the mounting face of the camera there is a large flathead bolt. This is where the dessicant tube screws in. How were the images?

I am using the QHYCFW3M-US, which is 17mm thick. This is for 36mm filters

Using a QHY600 short bfl version or 268M with the corresponding filter wheel gets you to 34mm / 29.5mm respectively, which leaves you enough room for a 10mm lens adapter. I plan on using my 268M with my Samyang 135 in this way!

My first attempt, configured as SHO. Great to have quality data to work with again

Thanks, and thank you for your input. I'm afraid I've pretty much ruled out reaching ambient temperature, as, for example, my scope had been outside for 4-5 hours by the time these subs were taken.

I have the Sii but no Oiii yet, waiting for that one to come in still. No halos so far on Sii but haven't had a chance to do a proper test with it yet. In mode 1 (high gain mode) you are best off using gain 0 or 56. If you have somewhat decent skies and a good computer for stacking then mode 1 gain 56 is pretty much set and forget. Offset you just want high enough to prevent clipping of the low end in bias / dark frames. For me an offset of 10 is sufficient, but it will depend on your specific chip.

That's curious, I also had some strange ringing in my flats that wasn't present in my lights so ended up not using them for my first light. I've now flipped the filter but not tried taking flats again so I'll give that a go next time I get the chance. Perhaps that will solve both the halos and the strange flats! one can hope haha. Are you using 36mm unmounted filters with the QHYCFW?