With the new beta release of SGP we are informed that the native ZWO driver will no longer be supported. I’m OK with using the ASCOM driver, but it appears that I can no longer set the Offset value on a per sequence basis, only the Gain. Is there a way to do this, or am I stuck?
There is no way to do this. ASCOM does not expose offset as the ASCOM confederation does not believe it should be exposed to clients or users (and should be handled dynamically by the manufacturer on the camera or in the driver). If ASCOM decides to implement it, we will follow.
To the OP and Ken, I too have the ASI 1600 using the ASCOM driver (Camera 2). There is a toggle radio button labeled Advanced. After clicking that toggle you can set the Gain and Offset
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Yes, you can enter the values there, but that applies to all Events. With the ZWO driver you could set a Gain/Offset for each Event. That capability is now lost - you can only set the Gain.
Correct, ASCOM does not support Offset. Sam from ZWO sent us a message about discontinuing our native support. They are in support of it as well since they update their ASCOM driver more frequently than we can update their native driver.
I wonder how critical Offset really is? I’m sure to a point it is important but for the most part you really just need enough to get non-zero values. Even if the gain is scaling after the offset is applied (which I don’t believe should be the case) then you’d really have to push the gain to clip on the high (over exposed) end.
Thank you,
Jared
I will be taking some test exposures later this week to see if the Offset really matters as much as some think. Of course, right at this moment I’m taking advantage of the rare super clear skies to get IC443 in NB. I’ll reply once I try the test with the ASCOM driver.
I think everyone using a camera that has an offset option is interested in this discussion.
If Offset doesn’t matter (or shouldn’t be user adjustable), why was it ever an option to adjust? Funny that the native driver gave the option but ASCOM doesn’t and now ZWO supports not having it???
If there’s a perfect Offset for a given Gain, the driver should automatically set that value. On the other hand, if there’s some way for a user to discover what the best Offset if for a given Gain setting on their camera, we should have a defined process for figuring that out and setting it.
I’m not an expert but this topic has puzzled me for some time now.
JT
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This forum is not the right place to discuss grievances with offset. ASCOM has a yahoo group and this discussion would be more meaningful there. ZWO might also have thoughts on this… We have no control over it and are not in a position to provide support for native drivers.
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Sorry, Ken. That wasn’t a dig on you guys at all but I suppose it came across that way. More on the developers and the issue as a whole. I’m sure you’re getting tired of hearing about it here and have tried to steer the discussion elsewhere before.
My apologies. It was a spurious comment that really had nothing to do with SGP.
JT
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Nor did I interpret it as such… was just noting where this conversation would be most effective.
Just curious, why has been native driver support discontinued?
Martin
Because there is an adequate ASCOM driver available. We created the native implementation when the ASCOM driver had issues (frequent crashes and hangs) but now that the ASCOM driver is more stable we’re moving to that. Also ZWO recommends their ASCOM driver as well rather than native support. Native drivers are something we try to avoid because they:
- require us to keep on top of manufacture updates
- add complexities of device level support which takes away time from feature development
- require us to have specific hardware to support the testing and integration of those devices (often multiple types per manufacturer)
- creates a situation where the device manufacturers are not responsible for the implementation of their control protocol (basically allows them to do whatever they want without any repercussions besides the clients complaining that their driver is awful)
- expose idiosyncrasies that the client should not really care about (a good example of this is RBI flash.)
So why do we prefer ASCOM:
- Makes the device creator responsible for how their devices acts regardless of the client.
- Creates a generic manner in which we can communicate with the device (all cameras “look” the same to us)
- Allows the device creator to update their device drivers and create new devices faster (they don’t rely on us to integrate with their new APIs…this allow them to get hardware to market faster)
- Creates a better overall experience for the end user.
- Doesn’t require that we own every device a manufacturer makes for testing.
- Removes additional testing burden from us.
Hope that helps,
Jared
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Only the nativ driver was OK for my autoguiding with ASI 120 MM-S…
The ASCOM driver give me a message « After 30sec the 2 sec image was not downloaded… »
And SGP stops because no more guiding…
Unfortunately I use the ASI1600MM-Pro and ASI1600-MC Pro cameras in my imaging and also trying to use SGP Pro to automate my setup. I recently have run into a situation with my dark calibration frames not being compatible with my light frames because of the offset. If I set the offset using the ASCOM interface, does it always use these values? Or are they ignored in the end when the subframe is captured?
If the lack of offset control is my problem with darks, then I won’t be able to use SGP Pro going forward. I use unity gain most of the time and that is what I have set the ASCOM interface to.
Not sure where to take this next.
Dale
Yes, ASCOM drivers will force use of the same offset for all images (as specified in the ASCOM interface). SGPro has no ability to control the camera’s offset.
I contacted the ASCOM folks and madde the request for adding Offset to the camera driver standard. They told me that they may consider it. It was not included before since cameras were CCD and offset was not needed. Now that there are more and more CMOS cameras, Offset may be a needed parameter.
You may want to visit the ASCOM site and make a request for adding Offset. More requests may convince them to make the change.
Mark W
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