Return Features from 2019 versions

Would you please return the equipment profile name to the sequence header.

With the removal of the ZWO driver, we can no longer modify the gain/offset per filter in the event box. Can this be fixed.

The color frame and mosaic images are a nice touch, but take too long to load when opening the sequence file. Downgrade images or go back to black and white.

Having the equipment profile name in the title was incorrect from the start. It really only identified the name of the profile when the sequence was created and made for some incorrect assumptions that the Equipment Profile continued to control the sequence. Once a sequence is created the link between the two is severed. We removed the profile name to make that more apparent.

The native driver is still there, just unsupported. Gain exists for the ascom driver but offset does not. We cannot add that in the ASCOM driver. That would be a decision that the ASCOM team would have to make.

You can do this in the “Other” menu in the Framing and Mosaic Wizard:

image

Thank you,
Jared

Thank you very much for that clarification. I tried running the new version again Saturday night and it is still failing on autofocus. Just an fyi. Others in my club are having the same issue. Using a moonlite focuser. My other telescope that has not been updated since the fall works well.

Please create a support ticket for the auto focus issue. We’ll minimally need logs to look into it:

You can re-create the issue in SGP and then use the Help menu to create a ticket using the “Report a Problem” link.

Thank you,
Jared

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I submitted a request to the AscomTalk forum about adding CMOS camera Offset to the ASCOM camera standard. This has prompted a lively discussion, but the ASCOM developers are reluctant to add a new camera parameter. The standard was developed for CCD cameras, and they have not considered IF the offset is important, or it is the start of a potential cascade of requests for new parameters that would convenience the camera makers.

My position is that it should be added to the standard, since CMOS sensors are different than CCDs, and that the Offset must be known as a function of gain for lights, darks and bias frames.

Please weigh in on AscomTalk to advocate for the change.

Mark W

Offset is not important as long as it’s high enough to not create values below 0.
CCD cameras also have offset, but it’s just not adjustable in most drivers.
The best would be to let the driver automatically handle offset like for CCD and remove it from the camera drivers.

The offset setting is really just creating confusion :frowning:

Thanks for doing this. I have been asking people to do this for years and AFAIK you are the first person to do so. Some said they would but didn’t.

One thing that I’m not sure that many users appreciate is that every time you change something that affects the data the camera generates you need a matching set of calibration data, bias and darks at least. This applies to gain, offset and the multitude of other processing options that some colour cameras seem to have.

Chris,

Thanks.

The only parameters I see important for at least my ZWO ASI1600 are Gain, Offset, Exposure time, Binning and Cooler Temperature setpoint. Everything except for offset are available in SGP. I have reverted to using the “unsupported” ZWO native driver to be able to set offset.

Mark W

Hi Mark.

Would you please explain, what optimizing criterias for the offset you are using?

Kind regards,
Horia

Horia,

For the ZWO ASI 1600MM Pro I tabulated the data values from the camera specification curves (offset vs. gain). I then fitted a curve in Excel. For the two gains I use now, the offsets are 76/15 and 139/21 (gain/offset)

Mark

Mark,

what happens if you use offset = 21 for both gains?

Kind regards,
Horia

Since the sensor has only 12 bits and targets are at the low end of the intensity scale, you loose a little bit of range at the low end. Probably does not mean much in loss. As gain increases, the offset needs to as well to avoid dead pixels. At 300 gain, the offset may be around 50.

Mark

Let’s go with 50 for all gains.

That will set the black level in the raw image at 50ADU and the white level at 4095ADU - limited by the 12 bit of the camera, i.e. (2^12 -1). After calibration (the bias substraction part) the black level will be shifted to 0, where it belongs, and the white level will be shifted to 4045ADU.

So, there is absolutely no loss at the low level - where the interesting signal for us is - and there is a loss at the high level, reducing the saturation from 4095 to 4045ADU. I would suggest that this reduction is completely irelevant for the quality of the image.

You may even try an experiment: take 20 exposures at a gain of your choice and the corresponding optimized offset and then 20 exposures at the same parameters (gain, exposure time, temperature) and an offset of 50 (or 200 to go crazy). Then take the corresponding calibration frames (some 25 darks for each case would be sufficient for this), calibrate everything and integrate the two stacks. Then compare the two images.

Kind regards,
Horia

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