Re: Dark Library Data Lost When Switching Between Camera Profiles

[Bruce Waddington]

I'm not able to sort through all this.  When you have made your best effort on this without encountering connection or driver-related problems, collect your PHD2 log files and upload them to our server:

https://openphdguiding.org/getting-help/

The sanity checking logic in PHD2 is pretty straightforward: it expects the physical geometry of the reported sensor size to be the same as those same properties when the dark library was built.  When you do your testing to prepare logs for us to look at, it would help if you could use the Dark Library menu and capture a couple of extra dark frames.  You don't have to throw away what you have, just choose an exposure time you haven't included before and let it capture a few frames at that new exposure time.  This will put extra data in the debug log file that will tell us the geometric properties of the dark frame.  All of that said, the most common reason for the problem you're having is that you aren't getting PHD2 connected to the right camera.

Bruce

On Wednesday, August 12, 2026 at 2:07:21 PM UTC-7 BigDan wrote:

Correction on the prior post:  The native driver is what I was running subsequent to Bruce's comment.

On Wednesday, August 12, 2026 at 2:20:58 PM UTC-4 BigDan wrote:

I belong to an astronomy club that has the ZWO ASI 2600 MC Duo (guide chip on the imaging camera face), and I have a ZWO ASI 174MM guide camera for my rig at home.

I ran the profile wizard in PHD2, and set up a different profile for each guide camera.

I set up a dark library for each camera.  Before ZWO came out with their new driver package recently, because a MS update gave them problems, I would switch back and forth between profiles when I switched cameras.  However, I consistently would get an error message that "You have switched cameras, and you do not have a compatible dark library."  PHD2 would allow me to run the camera, but the Dark Library icon at lower right was red.

I had some erratic operation of the guide chip on the Duo, and in a prior posting on this forum, Bruce told me that for the guide chip on that camera, I should select the native ZWO driver:  ZWO ASI Camera, and not the ASCOM driver.  The ASCOM driver is what I have been running.

I had downloading problems with the imaging chip on the Duo, and I very recently installed the new ZWO driver package.  In PHD2, I selected the ZWO ASI Camera native driver, as that is what I had been using.  That doesn't appear to work anymore after the new driver package installation.  I get a message that there is no compatible dark library, and it won't let me take any exposures.....  not even to build a new dark library.

I switched drivers as specified in PHD2 to ASCOM ASI Camera ( 1 ), and everything seems to work fine at the moment.  I went ahead and built a new dark library.

I suspect I need to loop both camera chips at the same time..... guiding and imaging, to make certain there is no conflicting problem, because I'm wondering if the ASCOM ASI Camera ( 1 ) driver is actually for imagers.  I think my imaging driver is ASCOM ASI Camera ( 2 ).  

I have the ASI 2600 MC Duo, and my PC, in my possession.  When I get down to my house this weekend, I will try to switch back and forth between the ASI 174MM, and the 2600 MC Duo, and see if I get the "No compatible dark library" messages still.

My ASCOM platform version is 7.1.3.4851.

Any words of wisdom will be appreciated.

Regards,

Dan