SharpCap Forums

Dears colleagues (message sent to SharpCap, Pegasus and Skywatcher representative),

I use an HP PC running Windows 11. I have a Skywatcher AZEQ6 mount that I control in ALTAZ with the Ascom SynScan driver (via the USB cable). In order to correct the rotation, I bought a Pegagus Falcon V2 that I control with its ASCOM driver. I collect my images with SharpCap 4.1.

When I start all the devices from SharpCap, the system often crashed. So I stopped starting everything from SharpCap. So, my startup sequence goes through 1) launching SynScan and goto to the sun. Then, 2) I start Sharpcap and my focuser. Once the images are stable (thanks in part to the solar tracking of the SynScan driver called from SharpCap), 3) I launch the Rotator Falcon V2. I position the active regions I want to image and I turn manually with the rotator until I am correctly positioned. Then, 4) I ask the Pegasus Falcon V2 driver to connect with the SynScan driver and then I activate the Derotating. It works... Until, randomly, the Falcon driver displays the message “Failed to create driver for device” (see my PDF file joined)... This message is repeated multiple times... And sometimes it manages it alone and reconnect. But sometimes it doesn't reconnect. Sometimes, all that is needed is to stop and restart the application. Sometimes stopping and restarting is not enough. The driver cannot find the Falcon. I then have to disconnect the USB-C and physically reconnect it to the Falcon. Then, when I restart the Falcon driver, the system restarts normally.
Regularly, when I have to stop and restart the Falcon application, I activate the “Goto right” arrow and the rotator turns correctly (I can see it on the camera). But when I press the “Goto left” arrow, the app crashes and I have to restart everything.
Finally, sometimes the message “Error on invoking method [CalculateDerotatingSpeed]” appears and the system crashes (see attached PDF file).

It is difficult to know where the bug comes from (Rotator vs Mount). What is clear is that if I activate the two ASCOM drivers in SharpCap (Pegasus + SynScan), request Derotating and use SharpCap's “Feature Tracking”, the system crashes.

Thank you in advance for your help.
Best regards
Christian Voirol

Hi Christian,

unfortunately your attachment isn't there on the message above - perhaps you forgot to add it at the end or perhaps the system has somehow lost it. Probably worth trying again or sending it via email (use the 'contact us' link at the bottom of the page).

It's difficult to give an exact answer to your problem from the description, but there are plenty of things you can try, including:

* Make sure you have the latest Pegasus Unity platform, ASCOM platform and version of SharpCap installed - you sometimes need to reselect the rotator in the ASCOM driver setup after updating Unity

* Try accessing the ASCOM driver for your mount via the ASCOM device hub (set up SharpCap and Pegasus to talk to the Mount Hub, then set that up to talk to the Synscan driver). Using the hub helps isolate the applications to some extent from the driver and can help

* Try one of the alternative ASCOM drivers for your skywatcher mount - Green Swamp Server (GSS) or EQMOD. I used to use EQMOD but now use GSS - I have seen reports of reliability issues before with the official SynScan software, so maybe that is what you are seeing and an alternative driver would help.

cheers,

Robin

Dear Robin,

Thank you for your answer. I didn't see it until last week-end. Sorry for the delay. In fact, the answer of Pegasus was "a cable problem or a power problem". I changed my USB hub, my cables... But the problem was still present. Then, I take three days to explore the differents situations. I desactivated the SharpCap hardware control. But the problem remain. I just sent a long message to Pegasus and SkyWatcher:

----------------------------------------

"Dear colleagues,

A few weeks ago, I wrote to you to inform you of difficulties with my Pégasus Flacon V2 Rotator.
It would regularly disconnect after a period of derotation and crash when I used the forward or backward arrows after a period of derotation.

You told me that it was probably a cable and/or power issue.
So I bought a hub delivering 3A per port and changed the cables. But the problem was still there.
I therefore decided to record all my interactions with the driver of my Pegasus Falcon 2 Rotator (Falcon) when it was working with the SkyWatcher SynScan driver on AZ-EQ& in ALT-AZ mode.

Here are my initial findings:
• I was using the Falcon with a SharpCap startup. I removed this link and the problem is still there. So it's not coming from SharpCap.
• When I don't connect the Falcon to SynScan and control it manually (see the latest screenshots in the “250611” file), there is no problem. No unexpected disconnections, no power or cable problems... it works. So the problem is not with my cables or the available power.
• When I use the “Derotating” function and connect the Skywatcher SynScan driver, the problem occurs with or without derotating. Sometimes it works for several hours without any problems (see files “250609”, ‘250610’ and “250611”)... But the derotating is not correct. The image slides as if the field rotation was not compensated.
• Sometimes the software freezes... The angular positions are no longer updated. But the software does not seem to have stopped. This could explain why, after a manual shutdown (or a crash), the angular position when restarting does not correspond to the one that was displayed before the shutdown or crash. I saw this because I was on the “Configuration” page and the Falcon page crashed and disconnected... But the software was still running on the Configuration page.
• When the software freezes and no longer updates the angular positions, it is sometimes possible to set “derotating” to OFF, select “Disconnect” then ‘Reconnect’ then “derotating” ON and sometimes it starts again. If it does not start again, you have to stop it manually and restart it.
• When the software freezes and no longer updates the angular positions, any attempt to manually change the angular position with the left and right arrows crashes the program. Sometimes it restarts on its own, sometimes it doesn't. Sometimes the program restarts but can no longer find the Falcon. In this case, you have to physically disconnect the USB cable... Then restarting the program works.
• One last thing concerns the work site and therefore probably only the SkyWatcher SynScan driver. I use a DIYMall G-Mouse GPS. It works perfectly with the EQMOD driver. However, with SynScan, it does not record the altitude. It always shows 0 (see under “250611,” pages 4 and 5).

That's it. I tracked all the runs over three days. You will find the log files on :
https://www.dropbox.com/scl/fo/wi68v6ha ... 0yccr&dl=0

I would appreciate it if you didn't just dismiss my request or respond with a reply saying that it's a cable or power issue. Clearly, the Falcon is an excellent product. It is robust and stable. But the goal is for it to be able to catch up with the field rotation. If it can't do that, it's not very useful. In this case, the SkyWatcher SynScan driver and the Falcon driver are not working together correctly. I would appreciate it if you would seriously look into this issue.

Thank you for your attention and cooperation.
Best regards

------------------------------
So, my conclusion is the problem is not with Sharpcap. I thank you again to took the time to respond.
Best regards

Christian Voirol

Hi,

thanks for sharing your further findings - I hope that you get a response from Pegasus that helps solve the problem.

Since it sounds like you can spot the failures due to the falcon stopping responding, you could test on a different PC, using the ASCOM simulated mount and the Falcon just sitting on a desk. If you can, use different USB and power cables and a different 12V PSU. That way, you have changed everything apart from the Falcon/Unity software, so if the problem persists you can be confident that it is a problem with the hardware or the Unity software. On the other hand, if everything now works then you can slowly change things back to match your normal setup (change one thing at a time) until you find the thing that makes a difference between working and not working.

cheers,

Robin

Hi,
I sent another message: "
Dear Sirs,

I spent my Sunday taking pictures of the sun with the new driver for the Falcon 2 (the one with the ‘Solar’ option).
Unfortunately, it's not working as expected yet. I've uploaded a new file called ‘250622 - Rotator’ to Dropbox. Please take a look at the last part of the log file... I have noticed that the derotating is not working correctly... When I do it manually, it works perfectly. But in automatic mode, the driver still does not work. This morning, I thought it was working. But as soon as the derotating ratio increased, I had to admit that it was not working correctly.
Thank you for your work and your help
Best regards
Christian Voirol
"
The answer was:
"Hello Christian,

have you seen the previous reply from me and Evans?
Copying here again "
Then I Answered:
"Hello Illas,

Thank you for your message. And no, I didn’t see it before today, 23th of June 25.

Repeated freezes and crashes are problematic. Could it be a power glitch that is causing the USB port to crash? If so, a cable allowing external power supply to the motor would be useful.

Concerning the derotating function, if derotating does not work with the sun (I think this information should appear in the product specifications... A $600 derotator that doesn't derotate the sun is still a serious obstacle...), could you provide functions accessible from Python, for example (e.g. using SharpCap programming interface)? Or simply a field that would allow me to set the number of degrees of correction and the frequency of realignment? This function alone would solve most of the derotating problem...Obviously, we would need to be able to manually modify the angular position without the program crashing.

Thank you for your help.
Best regards

Christian Voirol
"

So, my conclusion is "It's a shame to have a $650 derotator that doesn't compensate for the sun's rotation in ALT/AZ.... I'm waiting to see what happens next. Would it be possible to control the Falcon 2 using Python code from SharpCap?"

Hi,

odd that solar derotation is not supported... I would have thought that the derotation rate is just a function of altitude and azimuth (and lat/long/time) - you calculate the 'up' direction now relative to the RA/Dec frame, calculate it again for 30s in the future, divide the difference by 30s and have an apparent rotation rate for the camera that needs to be corrected - it doesn't matter whether you are pointing at the sun, the moon, the stars or next door's chimney stack, the calculations are just the same...

You can control the rotator to some degree via SharpCap scripting -
The ASCOM interface doesn't seem to provide a way to set the rotation rate in terms of degrees per second, but you can ask it to move the rotator by an angle (see https://ascom-standards.org/Help/Develo ... atorV3.htm). So, you could write a script that makes a 1 degree rotation at calculated intervals to keep the orientation the same to within a small margin.

cheers,

Robin