Any Experience with QHY IMG0H in 14bit RAW mode?

[jazzysam]

Hi All,

Does anyone have experience of using the IMG0H CCD in 14 bit raw mode?

I've experienced weird results in EZPlanetry, when I switch to 14 bit raw. Specifically, a perfectly/well focused Jupiter, becomes fuzzy and refuses to focus. I've also tried imaging using Maxim DL (via the QHY ASCOM driver), and experience the same problem.

Am I missing something here?

FYI: Gain was set to 13 in Maxim, for 600ms exposures. Gain was 27 in EZPlanetary, 100ms exposures - both AVI and FITS. Nothing in QHY website/blogsphere. Focusing using a moonlite Focuser.

Any guidance would be appreciated...

Thanks in advance!

[riklaunim]

100 ms on Jupiter? Thats like 5 times to much.

[jazzysam]

Prior to first use, I tested the CCD thoroughly to identify the ideal gain settings - came in at 13 gain to produce the maximum data spread as per histogram - anything much higher created substantial blooming.

In both Maxim DL and EZPlanetary, any exposure setting lower than 75ms produced an image that was barely visible - i.e. low data spread (and very few green bars in the EZPlanetary histogram). I also checked the histogram on test exposures prior to running the imaging session, and the data spread looked ok - no blooming, and no max values on any pixels.

I think I've done what the manuals suggest; if I haven't, could I trouble you to elaborate?

The big issue I have is that switching to 14-bit from 8-bit colour seems to do something funny and makes the image fuzzy - even after using FWHM assisted focusing first.

Any suggestions?

[riklaunim]

ICX618 sensor in normal planetary cameras should give you nicely exposed Jupiter on exposure times around 20 ms. The 14-bits mode in QHY probably lowers gain values to much lower. So you should try 8-bit mode, and focusing by looking on the preview image. For planets it's the best focus option.

[jazzysam]

Thanks for your advice, much appreciated.

I can confirm that the ICX618 sensor works well in 8-bit colour mode [i have the OSC version], and produces ok images using EZPlanetary and Registax - running at approx 20-25 fps - just as you suggested.

Background to the question was that I was trying to up the data feed to 14-bit, in order to maximise data capture. I suspect there is a software problem with the QHY driver that is causing the effect in EZPlanetary and Maxim DL. I'm also wondering if the Bayer matrix implementation QHY have stuck on the ICX618 is in some way screwing up the feed. I know this doesn't make much sense, but I can't work out if the CCD is malfunctioning and should be returned, or if the problem is purely in the driver implementation.

[riklaunim]

Those cams are rarely used so it's hard to debug those problems. There is one color IMG0H user in Poland and as far as I know he managed it to work correctly in ezPlanetary (playing with finetune settings etc.).

14 bit will be slower than 8 bit as more data must be sent.