Planetary with ALT/AZ Evolution mount control

[wdh]

Hi All- I'm a planetary imager currently capturing with FireCapture on a MacBook. I would like to give SharpCap a go, based on the enthusiastic reports by Mike Owen. My mount is a Celestron Evolution, with a C8 OTA in straight ALT/AZ mode. Planetary stabilization with mount control would be a big plus- I have controlled the mount in the past via ASIAIR and USB to the HC before moving to FireCapture.

Has anyone had specific success with SC controlling the Evolution mount for planetary captures? I also use a ZWO EAF, although I think Mike has specifically noted that the EAF is well supported in SC via ASCOM.

I'm planning to use an older Windows laptop, under Windows 10. FC seems to run fine, but I haven't tried to connect anything via ASCOM yet. The mount is my biggest concern, since I typically do frequent small manual tweaks to keep the planet centered in ROI. It would be great to have that taken care of automatically.

Any advice would be most appreciated.

[admin]

Hi,

as a relatively new Celestron mount, the control software to use is probably CPWI, I think gives a virtual handset and an ASCOM driver (my only Celestron mount is a 12+ year old Nexstar, so works with an older software version, not CPWI). There have been some versions of CPWI that have come out with fairly substantial bugs in them, but I haven't heard anything like that for a while, so it is probably resolved. You should aim to connect to the mount itself using a wired connection (serial/usb/etc) not wireless if at all possible - the chance of random errors due to dropped connections/timeout is substantially higher with wireless connections.

ZWO EAF should be fine - I use one myself.

There are a couple of options for tracking the planet - one is to use the 'Feature Tracking' function in SharpCap at the same time as planetary stacking - Mike does this. Feature tracking requires a calibration procedure which can take a bit of tweaking of mount movement speeds to get it working nicely, but once calibrated will recenter the planet if it drifts off center. A simpler option if you are using ROI on a larger sensor camera is to let SharpCap live planetary stacking move the camera ROI automatically to keep the planet in view, although that will run out of ROI adjustment in the end if there is sustained drift.

The planetary stacking can use a fair bit of CPU power, but that usually not such a big issue at planetary resolutions (say 800x800 or similar). It's when you try to use it for solar/lunar with a much bigger capture area that you need a high power CPU

cheers,

Robin

[wdh]

Thanks Robin! With my current workflow I do a single object solar system align from the hand controller (sometimes with ASIAIR connected via USB to the HC), and I use FireCapture's center and COG functions to keep the planet and ROI on the sensor until drift requires HC manual slew tweaks. I've never used CPWI, although I believe I've installed separate ASCOM drivers on my Windows laptop candidate. Is your suggestion to use CPWI in conjunction with SharpCap based upon bypassing the HC based alignment? If I elect to align with the HC instead, and connect to the HC via USB via SharpCap for auto-centering, would CPWI still be required? I'm sorry to be asking such basic questions here- I can certainly install CPWI and give it a shot if necessary.

[admin]

Hi,

if it works anything like my older Celestron mount, you keep the hand controller... I have the remote control cable from the PC plugged into the hand controller and I would align using the hand controller and then once that is done you can run the commands from the PC. I have discovered from experience that trying to use it from the PC without hand controller aligning doesn't work well - the mount moves to the wrong places and so on. Mind you the newer hand controller versions may work differently from my older one.

SharpCap needs some way to send commands to the computer to do the tracking - that has to be via an ASCOM driver for the mount, and I think CPWI is the currently supported option for that with Celestron mounts. Certainly the first thing to try...

cheers,

Robin

[wdh]

Thanks Robin! So if I understand correctly, I don't need to run CPWI- I just need to install it to get the ASCOM drivers on the PC. Is that correct?

Bill

[admin]

Hi,

I think you *do* need to run CPWI - again not 100% sure as I do not have a CPWI based system...

From what I understand, the communication goes like this

SharpCap => ASCOM Driver => CPWI => Mount

cheers,

Robin

[kaymann]

Thanks Robin! So if I understand correctly, I don't need to run CPWI- I just need to install it to get the ASCOM drivers on the PC. Is that correct?

Bill

I have CPWI and this is to confirm what Robin said, it does need to be running in order to for SC or any other program (PHD2) to run the drive. This is why I use the Celestron Telescope driver which does not require additional software, other than ASCOM.

CPWI Needs: ASCOM + CPWI Driver + CPWI + SharpCap
Celestron Telescope Driver Needs: ASCOM + Celestron Telescope Driver + SharpCap

[wdh]

Hi Kaymann- sorry about the late reply to your answer. Can you tell me what ASCOM driver you are referring to?

[kaymann]

No worries, I have been unavailable forever myself. I am talking about the ASCOM "Celestron Telescope Driver" You can find more with this page:

https://www.cloudynights.com/topic/8699 ... elestron/