SharpCap Forums

Having encountered the same problem, I had to test how to crop the images. I attach a small sequence of images that explains the process in PixInsight. Finally, I cropped from the bottom left corner -22 in X and -34 in Y, but there are still 6 pixels too many on the right. So you have to crop another 6 pixels from the right. So, it seems to me that it works. Is it camera dependent? I don't know.

Hi,

thanks for the report - somewhere I have notes on when I worked out the equivalent cropping for the 294PROC - I will have to find my notes and see if the values are the same or not.

cheers,

Robin

Hello,

With my QHY-268 camera:
- Live mode: 6280x4210
- Still mode: 6252x4176

One similar hot pixel is at the following coordinates:
- Live mode: 114;157
- Still mode: 92;123

Which windowing parameter are necessary for producing the smaller still image from the large one ?
114 - 92 + 1 = 23, 157 - 123 + 1 = 35
6280 - 6258 + 6252 = 6274, and in Y direction ... the final height is achieved 4210 - 35 + 1 = 4176

So the windowing of the Live mode (from the 6280x4210 image) is as follow:
X1 = 23, X2 = 6274, Y1 = 35 and Y2 = 4210.

Regards,
Jean-Francois

Hi,

thanks Jean-Francois - looks like the same figures as @Psynergie, which is encouraging.

Measurements from other models of QHY cameras very welcome!

cheers,

Robin

Hello Robin,

For the QHY-600 ... I have a look in old images (I have my camera not with me ... I'm this time in Newbury for the work).

With my QHY-600 camera:
- Live mode: 9600x6422
- Still mode: 9576x6388

One similar hot pixel is at the following coordinates:
- Live mode: 147;122
- Still mode: 123;88

Which windowing parameter are necessary for producing the smaller still image from the large one ?
147 - 123 + 1 = 25, 122 - 88 + 1 = 35
9600 - 9576 + 9576 = 9600, and in Y direction ... the final height is achieved 6422 - 35 + 1 = 6388

So the windowing of the Live mode (from the 9600x6422 image) is as follow:
X1 = 25, X2 = 9600, Y1 = 35 and Y2 = 6422.

It is not the same as the 268 camera ... with the 600, it has no column at the right side (6 with the 268 camera).

Regards,
Jean-Francois

Hi Jean Francois,

I just tested with the QHY294PROC

With the 294, the switch from live mode to still mode crops 16 pixels from the left of the image and 28 from the bottom. Nothing from the top or right.

I'm not seeing a pattern here

All the other camera manufacturers have, to their credit, hidden this from the software developer/end user. QHY sadly have made it hard for us

cheers,

Robin

Hello Robin,

The "black" zones on the detector can be used for monitoring some parameter during imaging.
But, I guess that no amateur will use it. For more "scientific" use of the detector, it make sense to have the possibility to save it.

But with the QHY camera ... a different choice would be better ... the user select to have the black zone on the live view or the still mode.
So that both modes can switch on or off the black zones saving.

Regards,
Jean-Francois

Hello Robin,

The QHY-183 camera seems to have 2 pixels shift (horizontal) between the LiveView and Still Mode.

The capture area is the same for both images. I check with 2 images, they have the same dimension (5544x3684).

The LiveView image has 2 black columns on the left (with noise values) and 2 white columns on the rigth (with constant 2048 value).
The Still Mode image has 4 black columns on the left (with noise values) and no white column on the rigth.
Regards,
Jean-Francois

Hi Jean-Francois,

thanks for reporting that - it's unfortunately then as we feared... There seems to be no real pattern to the offsets or size changes and they vary from model to model

I do wish QHY could have hidden this anomaly from programs using the SDK under normal use (maybe an extended mode to make this sort of thing available). Every other camera manufacturer seems to have managed to hide this sort of anomaly behind their SDK so that end users (and developers like me) don't have to worry about it...

cheers,

Robin