I am a bit confused about how Sharpcap Pro interacts with a mount. I have a Celestron AVX mount and have a guide scope along with my main optical tube. I set the Sharpcap hardware configuration for CPWI (the Celestron program CPWI is also running and I have the ASCOM suite installed). Sharpcap very nicely positions the mount to any object I select from the Sharpcap database. I run a second instance of Sharpcap to store images from a second camera on main optical tube. Everything works pretty well but I get a fair amount of drift. Is Sharpcap correcting using the guide scope or am I really just relying on the equatorial mount? I see a configuration option under Guide for PHD2. Is it necessary to use PHD2 along with Sharpcap for guiding to work?
Sample capture from the setup:
Can Sharpcap pro control a mount using a guide scope
Can Sharpcap pro control a mount using a guide scope
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Re: Can Sharpcap pro control a mount using a guide scope
You need a separate tool for guiding. I use PHD2 with my AVX for this task.
I also connect with the celestron software as you do.
I also connect with the celestron software as you do.
Re: Can Sharpcap pro control a mount using a guide scope
You need a separate tool for guiding. I use PHD2 with my AVX for this task.
I also connect with the celestron software as you do.
I also connect with the celestron software as you do.
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Re: Can Sharpcap pro control a mount using a guide scope
Hi,
SharpCap is good at getting targets into view (using plate solving to correct any inaccuracy if necessary), but does not then try to keep them in view using guiding. You need to run a separate guiding application like PHD2 to do that (that will keep capturing images from the guide camera and send commands to nudge the mount as needed).
SharpCap can *monitor* PHD2 to make sure it is working and pause capture if PHD2 has problems - that's the purpose of the PHD2 related stuff you find in the SharpCap settings and in live stacking in SharpCap.
cheers,
Robin
SharpCap is good at getting targets into view (using plate solving to correct any inaccuracy if necessary), but does not then try to keep them in view using guiding. You need to run a separate guiding application like PHD2 to do that (that will keep capturing images from the guide camera and send commands to nudge the mount as needed).
SharpCap can *monitor* PHD2 to make sure it is working and pause capture if PHD2 has problems - that's the purpose of the PHD2 related stuff you find in the SharpCap settings and in live stacking in SharpCap.
cheers,
Robin
Re: Can Sharpcap pro control a mount using a guide scope
Just now trying to use CPWI, Sharpcap and PHD2 together. Very confusing. PHD2 seems to want control of the images from the Guide camera. Is this a conflict with Sharpcap which I used to "GoTo" a target? Does PHD2 talk directly to the mount - it seems to. It had configuration stuff that appears to connect to both the guide camera and the mount. There is an entry in Sharpcap with localhost and a port - I really can't tell if this is doing anything. I have a separate Sharpcap instance capturing images on my main optical tube and have a cursor on a star to see how good the tracking is. It does not seem better than the equatorial tracking so I am not sure if the guiding is really working.
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Jean-Francois
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Re: Can Sharpcap pro control a mount using a guide scope
Hello pmg,
it exist only one, I repeat only one camera brand that allows to connect 2 software with one camera (at least what I know).
That is the QHY but only with a broadcast driver (that need first to be installed).
If you have other brand, then no chance to have a stable connection between 2 software and a camera.
If you have 2 cameras. One for guiding and one for imaging, then you can perform the guiding with PDH2 only if PHD2 is alone connected to the camera. For the imaging, then you can use SharpCap.
You can connect the guiding camera individually with PHD2 and SharpCap one after the other (and only one software at one time).
It is not convenient but possible, at least at the start during the alignment of the telescope (I do it sometimes).
So you could use SharpCap with the guiding camera (if the field is large enough) for the polar alignment. And then close SharpCap and connect the guiding camera with PHD2 for guiding. The GOTO and centring will be then performed with the imaging camera.
It is now different with the mount driver. Most of the actual drivers are today a "server" that allows several software connections.
So you can have a planetarium software, SharpCap and PHD2 connected to the same mount without a problem.
The only point is to avoid to send a GOTO command from a second software before the completion of a first GOTO from a different software.
I have a 10" Newton carbon tube (FD=2.9 with reducer) with a Williams Optics 50/200 mm guider telescope. The guiding with PHD2 says a RMS below 0.7", but if I observe the image sift during a live stack, then I have several pixels shift (up to 10). The difference comes from the bending or kipping of one optical component during the capture duration. That is normal with a parallel guiding telescope.
Regards,
Jean-Francois
it exist only one, I repeat only one camera brand that allows to connect 2 software with one camera (at least what I know).
That is the QHY but only with a broadcast driver (that need first to be installed).
If you have other brand, then no chance to have a stable connection between 2 software and a camera.
If you have 2 cameras. One for guiding and one for imaging, then you can perform the guiding with PDH2 only if PHD2 is alone connected to the camera. For the imaging, then you can use SharpCap.
You can connect the guiding camera individually with PHD2 and SharpCap one after the other (and only one software at one time).
It is not convenient but possible, at least at the start during the alignment of the telescope (I do it sometimes).
So you could use SharpCap with the guiding camera (if the field is large enough) for the polar alignment. And then close SharpCap and connect the guiding camera with PHD2 for guiding. The GOTO and centring will be then performed with the imaging camera.
It is now different with the mount driver. Most of the actual drivers are today a "server" that allows several software connections.
So you can have a planetarium software, SharpCap and PHD2 connected to the same mount without a problem.
The only point is to avoid to send a GOTO command from a second software before the completion of a first GOTO from a different software.
I have a 10" Newton carbon tube (FD=2.9 with reducer) with a Williams Optics 50/200 mm guider telescope. The guiding with PHD2 says a RMS below 0.7", but if I observe the image sift during a live stack, then I have several pixels shift (up to 10). The difference comes from the bending or kipping of one optical component during the capture duration. That is normal with a parallel guiding telescope.
Regards,
Jean-Francois
Re: Can Sharpcap pro control a mount using a guide scope
I finished my first session trying to use PDH2 with Sharpcap. In the end the only thing that worked cleanly for me was:
1) Use Sharpcap for polar alignment using the guide scope (the main optical tube field of view is too small)
2) Use Sharpcap with ASCOM/CPWI to "GoTo" a desired object in the Sharpcap database
3) Have Sharpcap close the guide scope camera connection (so it does not compete with PHD2 - there was a problem if I did not do this)
4) Start PHD2 and connect to the guide scope camera and the Celestron AVX mount
5) Use a second instance of Sharpcap to capture images from the main optical tube
Sharpcap was great for polar align and "GoTo". PHD2 was great for stabilizing the mount.
I am attaching the results all taken with the same setup: ExploreScientific AR152 1000mm f6 w/IRUV filt, SVBony165 120mm f4 guide, ZWO ASI678 guide camera, ZWO ASI533MC main camera, Celestron AVX mount
Photo 1: Stacked 20 minutes of 10sec subs without registration and WITHOUT PHD2, just using AVX equatorial guiding
Photo 2: Stacked 40 minutes of 10sec subs without registration and WITH PHD2 guiding
Photo 3: All 60 minutes registered and stacked (both guided and unguided)
1) Use Sharpcap for polar alignment using the guide scope (the main optical tube field of view is too small)
2) Use Sharpcap with ASCOM/CPWI to "GoTo" a desired object in the Sharpcap database
3) Have Sharpcap close the guide scope camera connection (so it does not compete with PHD2 - there was a problem if I did not do this)
4) Start PHD2 and connect to the guide scope camera and the Celestron AVX mount
5) Use a second instance of Sharpcap to capture images from the main optical tube
Sharpcap was great for polar align and "GoTo". PHD2 was great for stabilizing the mount.
I am attaching the results all taken with the same setup: ExploreScientific AR152 1000mm f6 w/IRUV filt, SVBony165 120mm f4 guide, ZWO ASI678 guide camera, ZWO ASI533MC main camera, Celestron AVX mount
Photo 1: Stacked 20 minutes of 10sec subs without registration and WITHOUT PHD2, just using AVX equatorial guiding
Photo 2: Stacked 40 minutes of 10sec subs without registration and WITH PHD2 guiding
Photo 3: All 60 minutes registered and stacked (both guided and unguided)
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Jean-Francois
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Re: Can Sharpcap pro control a mount using a guide scope
Hello,
It is nice to see an improvement like that
I guess that the small shift in your second image is coming from differential bending (during 60 minutes) between the main and the guiding scopes.
In addition with a potential vibration of the telescope during the capture.
10 sec subs ? really with FD6 ?
Now you have PHD2 doing the guiding, you can have a longer exposure ... 30 sec or more.
Regards,
Jean-Francois
It is nice to see an improvement like that
I guess that the small shift in your second image is coming from differential bending (during 60 minutes) between the main and the guiding scopes.
In addition with a potential vibration of the telescope during the capture.
10 sec subs ? really with FD6 ?
Now you have PHD2 doing the guiding, you can have a longer exposure ... 30 sec or more.
Regards,
Jean-Francois
Re: Can Sharpcap pro control a mount using a guide scope
The AR152 is a refractor and has a 152mm diameter lens with a focal length of 1000mm and is thus about f/6.5.
I base my exposures on Sharpcap "brain", with a setting lower limit of 10 sec so I do not get too many subs for my hard disk. I set the gain to 103 (unity for my ZWO ASI533MC) or higher (in this case about 250) - just enough to see some stars so I can tell if the mount is drifting. I like the short exposures because I don't need to worry as much about the stability problems of my mounts (I have a Celestron AVX and an ExploreScientific iEXOS-100) neither of which is super stable, especially since my optical setups (I have the AR152 and an SV48P) are on the heavy side for these mounts. I was very impressed by Robin's presentation (there is a YouTube of him explaining the theory behind exposure calculation) and trust his "brain" suggestions. I also started routinely using an IRUV filter as suggested on one of the forums I was on - works quite well to reduce the terrible star bloating I was getting.
I still need to work out my understanding of PHD2. It worked great for the images I posted - but last night after a while PHD2 gave me an error message about calibration and something about the relation to the equator. Apparently I still don't know how to use PHD2 correctly - I will need to give it more study.
I base my exposures on Sharpcap "brain", with a setting lower limit of 10 sec so I do not get too many subs for my hard disk. I set the gain to 103 (unity for my ZWO ASI533MC) or higher (in this case about 250) - just enough to see some stars so I can tell if the mount is drifting. I like the short exposures because I don't need to worry as much about the stability problems of my mounts (I have a Celestron AVX and an ExploreScientific iEXOS-100) neither of which is super stable, especially since my optical setups (I have the AR152 and an SV48P) are on the heavy side for these mounts. I was very impressed by Robin's presentation (there is a YouTube of him explaining the theory behind exposure calculation) and trust his "brain" suggestions. I also started routinely using an IRUV filter as suggested on one of the forums I was on - works quite well to reduce the terrible star bloating I was getting.
I still need to work out my understanding of PHD2. It worked great for the images I posted - but last night after a while PHD2 gave me an error message about calibration and something about the relation to the equator. Apparently I still don't know how to use PHD2 correctly - I will need to give it more study.
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Re: Can Sharpcap pro control a mount using a guide scope
Hi,
glad to hear that everything is coming together and that you are getting some good images now.
As you have noticed, trying to get two applications talking to the same camera at the same time typically doesn't work, so is best avoided. Looking at the details of your setup, you seem to have a field of view of about 0.65x0.65 on your main telescope with the 533 camera, so why not use that camera for polar alignment and GOTO/plate solving in SharpCap (as well as capture), leaving the guide camera purely for PHD2 and guiding? The field of view should be enough for both polar alignment and plate solving to work well.
cheers,
Robin
glad to hear that everything is coming together and that you are getting some good images now.
As you have noticed, trying to get two applications talking to the same camera at the same time typically doesn't work, so is best avoided. Looking at the details of your setup, you seem to have a field of view of about 0.65x0.65 on your main telescope with the 533 camera, so why not use that camera for polar alignment and GOTO/plate solving in SharpCap (as well as capture), leaving the guide camera purely for PHD2 and guiding? The field of view should be enough for both polar alignment and plate solving to work well.
cheers,
Robin