Is there anybody out there who can help me to solve the communication problem? between MetaGuide (MG) and the ASCOM-Pulsar Driver (V5.0.7). See the e-mail correspondence I had with the developer of Metaguide below. I use Pulsar Commander V2.19, and Pulsar Controller Firmware V2.69aR.

Thanks in advance, Ruud



Dear Frank,

Recently I tried autoguiding with my Orion Optics OMC300 (F18 when 2x Televue Powermate is used) scope on a Gemini42 mount with Pulsar (together with SPC900 Philips webcam). There seems to be a problem when MG is calibrating the mount. I successfully installed an ASCOM-Pulsar driver and use ASCOM version 5.0 (not V5.5 because the driver seems to work with V5.0 only). MG is indeed communicating with the mount when I use the Manual N/W/S/E Control buttons. Also the declination is set automatically and correct. So far so good.

Here are some settings. The guide rate (RA and dec) is set to the value of 2 within Pulsar itself (according to the Pulsar manual value 9 corresponds to sidereal, but I am not sure whether 2 means 2/9 sidereal, although it is certainly slower than sidereal. When using 9 the guidestar leaves the field). Aggression is set to default 0.5, although I experimented with other settings, e.g., 0.9. Whatever I choose within Pulsar for guiderates MG sticks with the default values 0.5 sidereal for RA and dec. Is this OK, because the manual tells a different story (driver rates should override MG rates). More important the calibration process begins with a slew to the east. It then stops, and the calibration process to the west, north and south is not done. The laptop sometimes seems very busy after this initial slew, but even when I wait 5 minutes nothing happens and I have to close MG for the next attempt. I always get the message that MG is no longer responding when the calibration process has come to a stop. Could it be a laptop problem, because my RAM is only 700MB (however other functions work well, e.g., FWHM is appr. 1.5 arcseconds, plots seem also OK)? Other option, could there be a problem with the driver (written by Paul Kitching, UK)?


Thanks in advance,

Ruud Zaalberg
The Netherlands

Hi-

Thanks for the detailed report. Which version of MG are you using - the latest beta? Please let me know.

The driver stuff sounds odd in terms of the guide rate. Do you get any warning or error messages from MG? What happens is, the user sets the desired guide rate in MG, and MG then asks the driver for that rate (typically around 0.5x, or half sidereal). Then MG asks the driver what the real rate is - and that is the value shown in Setup. If MG did not complain and it shows the value 0.5, then that is good. If MG complained and just set it to 0.5, then that is bad and MG doesn't know the real rate.

Calibration in RA should be fairly fast. If it ever pauses, it may be due to a guide rate that is very fast and inducing backlash.

Please let me know which version of MG you are using, and send a copy of the Setup after calibration - i.e. Setup.mg. I don't know this driver, and it's immediately concerning if it doesn't work with the latest ASCOM.

Thanks,
Frank

Hello Frank, thanks for your quick reply. I use MG version 4.1.2; August 2009 (http://www.astrogeeks.com/Bliss/MetaGuide/). Because of the calibration problem I uninstalled MG and then reinstalled it. However, nothing changed.

When I press FullCalibrate, no warning is given. MG simply starts with the calibration process. Setup always shows 0.5 without complaining. If I choose guiderate 9 (which is sidereal) within Pulsar I can see that the calibration process is fast, but the star leaves the field within a few seconds. Therefore I use guiderate 2 (for RA and dec) within Pulsar. The calibration process is much slower, but it also ends as described earlier. In both cases (and also with other guiderates) setup always shows 0.5.

Enclosed you will find the Setup.mg I use. Declination is default, but as soon as MG communicates with the mount dec is set to the correct value. In my case I used Arcturus as the guidestar. Guideperiod was set to 1.0. NFrames to 20 and FrameRate to 30 (although I used other settings too).

Thanks, Ruud

Hi-

OK - I wasn't sure if you were using a recent beta version I put on the astrogeeks web site. It has changes to calibration that haven't been tested much, but your version has been tested a lot.

Something is odd because you say that when you set the guiderate in pulsar, the calibration is faster - but if MG is working right, it's the value shown in Setup that should determine the guiderate. If you set the value to 9 in pulsar, then start MG and ask for 0.5, you should get 0.5. If this isn't happening, then the driver isn't telling MG the correct guide rate.

As long as the actual guide rate matches what MG says it is, things should work ok - but ideally the dec. rate value from the driver should be accurate. It's good that the declination value is correct- that shows there is communication.

I suggest you join the astrogeeks group and try the current and future beta releases. The calibration is faster and that may help you. But right now I am concerned that your driver isn't stating the correct guide rate - but I'm not sure.

Frank

OK, I am not an expert in software. But do I understand correctly that MG (i.e., the user) tells the pulsar driver the guiderate the user wants and when this is not (exactly) possible the nearest value is chosen by the driver and this is then shown within MG (again, this last step certainly does not happen)? If that is true, there indeed might be a problem with the driver. This is because the driver overrides guide rates from other software as is stated in the manual I enclose (see point 7). When MG and the driver want to override each other this may result in a 'software' conflict? In other words the driver is now dominant (which explains the different observed guiderates in the first calibration slew when I alter the quiderates within Pulsar), AND it is not communicating with MG.

Do you agree that I ask Paul Kitching's opinion on this matter? (and send him our e-mail correspondence?)

Thanks again, Ruud

Hi Rudd

As stated in the Pulsar ASCOM readme the driver was written for my own use and has not been developed for the use with all pieces of software that is available on the market I just do not have the time or resources to do that. I will need to know what commands are been sent to the ASCOM driver because not all commands are available to it. With this information I will try and help if I can.

Kind Regards
Paul Kitching

Hello Paul, I understand that your time is limited. Just let me know how I can help? I can ask the MG developer for commands? Are there any specific commands you are interested in? Below you will find some developer details, from the MG manual. Maybe this is helpful. The complete manual, and the MG freeware can be downloaded from

http://www.astrogeeks.com/Bliss/MetaGuide/

Best wishes, Ruud



MetaGuide is entirely written in C++ with STL. The GUI components rely on MFC, but there is no use of .NET since MetaGuide is multi-threaded and delivered with most components statically linked – which I believe is disallowed by .NET. ASCOM is incorporated using the early binding mechanisms in C++. One detail is that ASCOM is encapsulated by a separate thread using a GIT, or Global Interface Table. This allows the emulation of an “infinite, interruptable pulseguide” by looping 1 second pulses in a separate thread. This gives greater control over the calibration process, and allows all calibration and guiding motions to be done using only PulseGuide calls. The only ASCOM command that MetaGuide uses to move the mount is PulseGuide.
The video component of MetaGuide relies on the DirectShow environment. MetaGuide uses an in-place transform filter, GuideFilter.ax, to handle the core image processing routines in its own thread.

Hi Ruud

I have no problem with connecting to ASCOM 5.5 with that driver. If you are using the POTH hub then make sure that you have quiet scope selected or try and connect directly to the Pulsar. I do have code in the PulseGuide driver section which is simply the required direction N/E/S/W and the duration of the pulse and then a stop command. I have used the ScopeSetup in MetaGuide and I can see that the correct commands are been received and sent. You cannot set a GuideRate with the Pulsar you must pick the required number you need in the controller itself. The driver will check to see if the controller is set at the correct guide option. I do not have a webcam to be able to do a live star test so I'm stuck with this one, sorry.

Kind Regards
Paul Kitching

Hello Paul, I will try the ASCOM 5.5 again and see if I can use the driver this time. Last time I tried I could not unzip the driver file. A message told me that ASCOM 5 was required. So I did (and with success). I then upgraded to ASCOM 5.5 but I could not use the driver anymore, even though the driver was already unzipped! I then downgraded to ASCOM 5, and it worked.

Within MG setup (and under the chooser button) I do not choose POTH hub, because the MG manual says this may be problematic (page 6; point . Instead I choose the Pulsar Telescope, because this option became available after I installed the driver. I then select properties. The general driver screen is then visible and the correct COM can be choosen. MG is then connected to the G42, because the N/W/S/E Manual Control buttons within MG setup work properly. You can hear the mount respond to the 1s slew commands, and you can see the coordinates change when looking at the handcontroller display. The problem arises when I press the FullCalibrate button within MG. Only one slew is made and then nothing happens!

Next time I will try to connect to the mount via POTH hub, and see what happens. An alternatively is to connect via Generic hub, and then select the driver. This is also explained in the MG manual, although I do not understand why this would solve the problem, because normally you use a hub when several applications must be connected to the G42 independently, if I understand the MG manual correctly. In my case the MG application is the only application I use in this set-up (I don't use the Pulsar Commander simultaneously), although I do use the handcontroller! Next time I will also disconnect the handcontroller to see whether this solves the calibration problem.

I will let the Forum know the outcome asap.

Best wishes, Ruud

Hi Rudd

For some more background information I can say that the driver does not allow simultaneous pulse guide commands. The driver can only process one command at a time and it has to wait for the last pulse guide to finish before it will except another. I have always used a AO unit for my guiding so I never use these commands to guide my mount.

Regards
Paul Kitching

Hello Paul,

I successfully connected MG to the G42 via Generic hub. The calibration process runs smoothly now. Thanks for your advice, although I still do not understand why the connection must be made via a hub, instead of a direct connection.

For those who are interested in using MetaGuide (MG). One of the features is that it helps you to collimate your scope using a stacked view of an in-focus star. When adjusting the collimation screws the autoguide function of MG automatically brings the star to the center of the field again. This helps you to concentrate on your collimation efforts.

MG can also be used for guided deepsky photography. It is freeware!

Thanks again, Ruud Zaalberg