That's a great Orion, especially for a 'quick stack'!!
Interesting that you mentioned the lack of histogram zoom in Neb compared to Maxim. I like and use Neb, however I wish it would allow me to zoom the histogram. Perhaps a quick email to Craig...
Cheers,
Rob
While you're at it. A stopwatch feature would be handy too.
But yeah if he could do something similar to what Maxim does that would be pretty cool. Unless they have the rights to that kinda feature?
The idea and method Craig used was for the MINIMUM value to be around 1000 and not the maximum. This gives a bit of a buffer where at no point the black point will go to zero and thus loose data.
I always ran my settings in Nebulosity2 at a gain of 1 or 2 and an offset of 65. Black point clipping is the main concern as data that is clipped is lost forever. The black point can be adjusted during processing and some processing tasks such as contrast enhancement and shadows and highlights requires a bit of space in the black end.
Hope this helps a bit.
Quote:
Originally Posted by leinad
A quick question of gain/offset
In Nebulosity I found that
Gain 0 Offset 50 I get a Max value just on 1000. I believe thats right from what Craig Stark mentioned.
At bias 0.001 secs, this puts the histogram right to the left. Pity you cant zoom to view the histogram like MaximDL does.
Above was a quick stack (flat/bias calibrated and stretched) with a couple of 2min, 5min (Gain 0 Offset 55) and 1 10min (Gain 5 Offset 55).
I seemed to get similar results as well at Gain 1 Offset 110 compared against the Gain 5 Offset 55, though this wasnt good with the bias test shots.
If I understand this all correctly, I should find the right Offset with Bias frames then use that, and just boost the Gain with lights to get the best results with exp time.
Managed to purge the TVDE QHY8 drivers from my system/laptop and load the straight drivers from QHY. The reason that I did this was in Nebulosity you could only get 1x1 or 2x2 binning. I wanted to use the 4x4 binning mode but the TVDE drivers caused Nebulosity to crash. Now have all 3 binning modes for the QHY8 and am a happy chappy. Really loving this camera
Hi Allan, please tell me how you managed to get rid of the Tom Van den Eade drivers please. They seem very resistent to myt attempts - sdame reason as yours.
Peter
Hi Allan, please tell me how you managed to get rid of the Tom Van den Eade drivers please. They seem very resistent to myt attempts - sdame reason as yours.
Peter
It's a while since I switched, but as I recall it, download the uninstaller from Tom's page http://www.astrosoft.be/ (near the top of the page).
Download the latest QHY8 drivers http://qhyccd.com/files/QHY8-0906.rar unpack them, plug the camera in, and point the new hardware wizard at the directory.
The only reason I have ever used the TVDE QHY8 drivers was the noise wihile downloading the pictures from the camera via USB to the laptop. But that was a long long time ago. Has this been addressed and are the stock QHY8 drivers sorted out now? I'm asking coz I'm considering going back to the main stream drivers now. Neb2 seems to chuck a fit in the very latest versions with the old drivers .
The only reason I have ever used the TVDE QHY8 drivers was the noise wihile downloading the pictures from the camera via USB to the laptop. But that was a long long time ago. Has this been addressed and are the stock QHY8 drivers sorted out now? I'm asking coz I'm considering going back to the main stream drivers now. Neb2 seems to chuck a fit in the very latest versions with the old drivers .
A while ago I purged the tom drivers and added the new qhy8 drivers, but with the latest Nebulosity I had noisy downloads, so I uninstalled again and loaded the drivers as above to get 1x1, 2x2 & 4x4 binning with no noise in the down loads. I just wish all these sites with all the different versions of these damned drivers would purge them all or at least give good and clear directions for which should be loaded and under which circumstances. It confuses people like me.
Have a question to ask of you fellow QHY8 users. Just recently I had a go at imaging the HorseHead nebula with the qhy8. I was using the UV?IR filter in the camera and taking 1x1, 5min subs. I was disappointed as the image which resulted was not worth the effort. My modded 20D gave far better shots in 5 min than the QHY8. Do I need to change to the clear filter for this type of shot - I wouldn't have thought so looking at the spectrum of the IR filter which comes with the QHY8.
Nothing wrong with your photo but were you using the UV?IR filter and how many subs total to give your image. The attached photo was with a 20d modded at 4x5min subs. With the QHY8 I got nowhere near this.
The filter is embedded in the nosepiece, so yes.
In the raw data I see 8x300, 6x600 and 6x180seconds but I don't know how many made it into the processing, it's a while ago now I think more rather that less subs is always better.
Allan, I'd be interested to see what your rejects looked like. The deterioration of my own QHY8 first became apparent to me imaging the same subject and, like you, I dumped a night's work because the results were so unusable. Got any of your subs left that we can have a look at?
Peter
Just for interest, here is a single sub from mine which we then swapped out for peter's faulty camera and a single sub from his. Both 300sec with a simple ddp stretch.
That's almost empty? Do you have maxim allan? What do your bias shots look like in maxim? Anything like this? The numbers are important rather than the image.
That's almost empty? Do you have maxim allan? What do your bias shots look like in maxim? Anything like this? The numbers are important rather than the image.
Stick with zero percent gain to start with so the question is what's the offset and it's really camera dependant but when I was checking peters camera, maxim came up with a different offset than he got from nebulosity?