SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

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Wind_58
Posts: 6
Joined: Thu Dec 09, 2021 4:30 pm

SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

#1

Post by Wind_58 »

Hello SharpCap team

I’m using SharpCap Pro since last year when I bought an Altair 294C Pro TEC camera. The way I’m currently following is using the Live Stacking feature of SharpCap for DeepSky objects. After a few trial runs I realized issues with my Celestron Nextstar Evolution mount (non auto-guided so far) in loosing the target object with my current set-up after typ.. 30-40min from the “screen”, resulting in alignment errors messages by SharpCap.by subsequently throwing all the frames away.
After having installed SharpCap4.0 recently, I’m currently try to use the guiding feature to solve the non-alignment problems.
Consequently I installed the ASCOM Device Hub V 6.5.1.0, the ASCOM Celestron Telescope and Focuser Driver V 6.0.6824.26827, as well as the PHD2 Guiding application V 2.6.10 on my Windows7 (64bit) laptop. In this configuration with PHD-Server setting enabled, I’m able to manually control the mount in all directions within SharpCap’s Scope Control window by related buttons. Info “Connected” is available.
Although the “Monitor Guiding Application” setting has been enabled during my Live Stacking sessions, the mount again lost the target object with no recognizable guiding activity. The alignment of the frames has been performed in this example unless the problem occurred by 6-8 stars.
In fact the Guiding Status within SharpCap was shown as “Stopped” all the time and up to now I couldn’t find within the User Manual an explanation/hint what this status info exactly means and what is missing to reach active guiding.
I’m a beginner with respect to the ASCOM-PHD2-SharpCap connection and still struggling with the question which settings have to be set-up on these 3 platforms to make it happen or how to reach the status info “Guiding” instead of “Stopped”.
Any useful tip would be really appreciated !

Best regards
Horst
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Re: SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

#2

Post by admin »

Hi,

the 'stopped/guiding/...' status comes from the status of the PHD2 guiding application - once you have the PHD2 server enabled and SharpCap is set to connect to it, SharpCap monitors PHD2 for any changes in the guiding status.

In order to get the 'guiding' status, you need to work through the startup steps in PHD - ie

* Connect hardware
* Start looping
* Select a start
* Start guiding (which will probably run calibration first)

Once you have done this, the status in PHD2 should show 'Guiding' in the bottom left of the PHD2 window, and SharpCap should too. If something stops PHD2 guiding (guide star lost due to cloud, etc), SharpCap will spot that change and go back to 'stopped'.

hope this helps,

Robin
Wind_58
Posts: 6
Joined: Thu Dec 09, 2021 4:30 pm

Re: SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

#3

Post by Wind_58 »

Hi Robin
thanks a lot for your quick reply and the hints given!
I like SharpCap Pro very much and will try to verify the steps described as soon clear nights will appear again in southern Germany. :shock:

Best regards
Horst
Wind_58
Posts: 6
Joined: Thu Dec 09, 2021 4:30 pm

Re: SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

#4

Post by Wind_58 »

Hi Robin
Last week we had clear skies and I performed my next trial run, unfortunately without success.

The topic was that PHD2 was indicating ALERT messages concerning the camera during it’s calibration process. I selected within SharpCap 16 seconds as exposure time for the live stacking, whereas within PHD2 a selected 1 s “exposure” for the guiding.
Within the log-file of PHD2 I found the following entry:
„Alert: Camera has not stopped after 21.0 s a 1.0 s exposure, consequently she has been disconnected, to prevent from add. problems. If you believe, that the hardware is working well you may increase the time for disconnect non-responding camera...' within the brain on the camera tab.”
Consequently PHD2 tried to reconnect the camera several times without finalizing the calibration and not reaching the guiding state.

Originally during this trial the time limit for disconnectiong the camera was set to 15s
which is probably wrong when trying to have 16s exposure performed by SharpCap ?


Finally my problem is to understand how the interaction between SharpCap and PHD2 works, using one common camera.
Can the exposure time and gain set independent between the two software packages ?
Which software is the master deciding when to take a 16s picture by SharpCap or using a 1s exposure for the guiding ?
Will PHD2 perform a 1s exposure after each 16s picture in order to secure a proper guiding ?

When performing live stacking an exact guiding is probably not necessary, the algorithm should simply keep the target within the screen in order to secure a proper alignment as part of the live-stacking, right ?
Is the mentioned setting the key point to prevent from conflicts between the two softwares ?

I’m looking forward to involve myself deeper into this interesting approach of guided live-stacking, hoping you may give some more hints.

Thanks Horst
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Re: SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

#5

Post by admin »

Hi,

OK, now it is starting to make sense...

The simple thing is that it is not possible for SharpCap and PHD to share the same camera - you need two cameras to get both working properly. PHD needs to take images at a fairly high rate (every second or so) in order to keep on top of any errors in tracking. SharpCap needs to take longer exposures than that for EAA to give you fine details. Both pieces of software assume that they are in total command of the camera and horrible things (as you have experienced) will happen if you open the same camera in both.

To be honest, it would be best if the second piece of software failed to open the camera with an 'already in use' message, but camera manufacturers often don't have this check in their camera control software, which means that SharpCap/PHD cannot know that this situation is happening.

As you say, with live stacking and short(ish) exposures of maybe 15s or so, guiding is probably not necessary. When you do decide that you need to guide to cope with longer exposures, you will need a separate guide camera and either a guide scope or off axis guider.

cheers,

Robin
Wind_58
Posts: 6
Joined: Thu Dec 09, 2021 4:30 pm

Re: SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

#6

Post by Wind_58 »

Hi Robin

Oh, I got it. I was taking the wrong road..
My understanding was being able to prevent the loss of the target while live-stacking for a longer period of time (e.g. 15s exposure for some hours)
My hope was to get rid of extra guiding equipment and weight on the mount by having some kind of feature tracking available for deep sky applications.
So I thought the star detection and alignment routines of the live-stacking within SharpCap would be benificial to operate the mount over PHD2, to prevent target loss by sending "correction" demands towards PHD2 without the necessity to promote active guiding on PHD2 side. (no camera connected to PHD2)

I really appreciate your quick reply and given support !

Best regards
Horst
Wind_58
Posts: 6
Joined: Thu Dec 09, 2021 4:30 pm

Re: SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

#7

Post by Wind_58 »

Hi Robin
do you think it might be possible as part of a future revision of SharpCap to implement such a feature. A direct control of the mount over ASCOM is already possible by mean of the feature tracking option (without PHD2). The key idea of livestacking I guess is to get rid of the necessity for auto guiding. But this is finally limited by the accuracy of the mount.
In my case with an aperture of 6,3 (8'' Celestron with reducer) and a mid range gain of the Altair Hypercam 294 ProTek by taking 20sec exposures, the max. total exposure time is limited to app. 45-50 minutes. Which is not enough to get a convenient representation in the histogram.

What do you feel about that idea, I could imagine that such a feature would be interesting for some other users as well.

Best regards
Horst
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Re: SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

#8

Post by admin »

Hi,

I do have a feature noted down in the plan to use plate solving for this - basically when I get around to implementing it you will be able to set an option and then live stacking will plate solve the image coming from the camera every few frames and adjust the position to keep the drift from getting too large. The interval (number of frames between adjustments) will be configurable.

cheers,

Robin
Wind_58
Posts: 6
Joined: Thu Dec 09, 2021 4:30 pm

Re: SharpCap 4.0 prompts the guiding status as ”Stopped” while Live Stacking

#9

Post by Wind_58 »

Hi Robin
thanks for your prompt reply !

That sounds really fine. So I will wait for this feature to come, hoping to prevent myself from an auto-guiding equipment.

Cheers
Horst
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