SX camera problem, super dangerous loop


I am recovering from a hard disk crash and re-setup of software, and at the same time I am using my old sxvf-h9 ccd. In the past I have connected to this camera directly with other software, but in this case I am using the ascom driver because I don’t see another way to connect with SGP. I am doing a number of short, 1s exposures with MetaGuide dithering in between - and after about 20 frames the camera freezes during download in a bad way and I have to close sgp and disconnect the camera - then reconnect. In the past the camera has been reliable - but I’m not sure if the issue here is related to sgp or the ascom driver.

So my questions are - can I connect to the camera directly with its drivers, or do I need to use the ascom interface? My other question is - is there a workaround for this issue. A long log is attached. I am using on a win 8.1 laptop. The log indicates something about a super dangerous loop.

Franksg_logfile_20150612183246.txt (803.3 KB)

You cannot, for SX, we only support ASCOM.

There is not, SGPro and SX cameras (only) appear to be completely broken when working together. This is the message from your log… your camera thinks it is in an exposure state when SGPro tries to start a new one.

[6/12/2015 7:18:14 PM] [DEBUG] [Camera Thread] ASCOM Camera : StartExposure called while in state cameraExposing (System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Runtime.InteropServices.COMException: StartExposure called while in state cameraExposing

This is the same issue as here (everyone with SX cameras is suddenly experiencing issues):

Thanks - I didn’t realize it was a recent issue and it affects all sx cameras. My timing is bad because I don’t think I have used this camera in years - and I picked a bad time to start using it.

One odd thing is that I had it in frame/focus mode with very short exposures and binned - and it was working just fine basically providing near realtime video for a long time - and there were no hangs or glitches. But as soon as I went to 1s exposures captured to disk and binned 1x1, it failed after about 20 exposures repeatedly.

I am also using the latest/greatest driver installation package from sx for the camera - since I am rebuilding this laptop. Previously I had used the strange manual process to install the drivers with io.dll and so forth. So this is different in using the latest drivers - and in using ascom. But I had never previously used the camera with sgp.


Just to add another data point here, I have a Trius SX694M and for me what happens is my first exposure (of frame and focus) takes a long time to download, 60-90sec but then after that the images download in the usual timeframe.


I have not imaged for 6 weeks and all was working then , should I leave my software as is , I presume this is a SGP problem
nothing has changed with the SX driver ???


I have written drivers for the SX in the past and am very familiar with workings of the SX cameras.

This must be something with the ACOM driver. The camera doesn’t have an “exposing” mode. With SX cameras you just read the pixels whenever you want and a “start exposure” is just a “wipe pixels”. There is a timed exposure mode where a timer is started and a read occurs when the timer reaches zero, but most drivers do their own timing and don’t use this mode.

If the driver is reporting “Camera in expose mode” that is something internal to the ASCOM driver. Do you have the driver? The SX hardware driver should be

Has anyone notified Starlight Express and/or the driver author? He may not be aware that there is a problem.

From what I can see the current SX ASCOM driver was released over two years ago so it’s difficult to see how this could be responsible for a recent change.


It is an H9 and according to Bret’s site it has not been tested with the H9. The H9 isn’t that old but you never know.

Have you let him know that you have a problem?


We have been in contact with both SX and the ascom developer.


I agree, but it also stands apart as the only ASCOM camera that has issues with the current build of SGPro. Not to say we aren’t doing something wrong… just a data point. It is also true that these issues have been present in SGPro for a long time… even in early builds of 2.3. With the notification system, we revamped a lot of the error handling. The primary difference is that a lot of things were allowed to fail silently prior to 2.4.

Also… @bretm has asked us if any users would be willing to provide SX Camera debug logs (in addition to SGPro logs for correlation). Please let us know and we can provide data to help out…

Bret also pointed to this as a possible issue:

There has been some discussion of a possible issue with the lower level (usb) driver (see Yahoo | Mail, Weather, Search, Politics, News, Finance, Sports & Videos)

That link described SX native driver issues, not ASCOM. Does SX ASCOM driver use SX native driver?

I had issues with Lodestar and Superstar using SX latest native driver with PHD2. Sometimes there would be a lockup and stops capturing and downloading images. I reverted back to previous SX native driver and no more problems.

I think this thread is about SX ASCOM driver since SGP would only communicate with SX cameras via SX ASCOM driver.


The ASCOM driver will use the low level SX drivers so if there’s been a change to these it may affect how the ASCOM driver behaves.

It’s one of the challenges of being a driver author is that the easy approach is to blame the driver - and put the driver author to a lot of trouble diagnosing someone else’s problem.

From a quick look at the driver Brett has put a lot of logging in it so driver logs, with the corresponding SGP logs, should provide a lot of help.


In that case, previous version SX driver is still available from SX web site.


Any volunteers to help out with this issue?

Yes, absolutely Ken. Any special instructions? I’ve had nothing but clouds and rain for weeks now, so haven’t had an opportunity to test under normal conditions. I guess I could just run some frame and focus loops and see what happens.

Thanks Joel. No special instructions really. Just turn ASCOM camera logging on, reproduce the issue and send both the SX ASCOM logs and the SGPro logs. Seems easy enough to reproduce (just stop FF during download).


I’ll do the same. Of course the forecast here is clouds and rain at least until the moon comes back. :smile:

I’ll chip in here. Should be able to do this with the aperture covered.