74 replies to this topic

[Tom Gwilym]

I'm working on trying to track satellites using a 17 inch Planewave on an Alt/Az setup.  I have had success using the PW4 software and pasting in the TLE number from spacecraft.  I see that the SkyTrack is nicely updated from what is used to be years ago. Glad to see it's back in 'production' so to speak. 

I see on a video - https://www.youtube....h?v=CHIbOAKltoQ

That they simply click the satellite and it tracks it.  I'm trying the software and it tells me that it will only work in the 'leap frog' mode.  I do have the PW4 set in Ascom for the interface, so I must have a setting wrong in Ascom that isn't allowing the continuous tracking.  Anyone know where I find that setting to get out of the leap frog mode?

Here's a sample ISS from the other night using PW4, but hoping to get the easier SkyTrack working.

 

Tom

Attached Thumbnails

• 

[Bob Denny]

Have you checked with Planewave? Maybe there's a setting somewhere that SkyTrack isn't seeing. For example an ASCOM mount needs to report CanMoveAxis = True if it expects apps to use its non-equatorial motions (mechanical shaft rotations etc.). Maybe SkyTrack is looking for this to be true coming from PWI but it's seeing false and reverting to the leapfrog mode where it's feeding RA/Dec slews to jump along with the earth-orbiter. 

Edited by Bob Denny, 18 May 2023 - 07:56 AM.

[bosh60]

Hi Tom,

 

I would like to work with you to resolve this. SkyTrack uses the ASCOM MoveAxis method to track satellites continuously in a smooth manner otherwise it is a series of "gotos" what I have called leapfrog tracking.  If it says only leapfrog tracking is available then it must be the manner in which the Planewave driver is presenting the axisrates which can be used with MoveAxis.  For example, my AP mount responds to ASCOM queries stating there is one axisrate collection with a minimum of 0 deg/sec to a maximum of 5 deg/sec.  That tells me I can use any value from 0-5 deg/sec for the MoveAxis method. Some mounts present a series of axisrate collections where the min value = the max value, so only a collection of preset values with nothing in between - continuous satellite tracking is not possible then as the satellite rate of movement is constantly changing.  

 

If you connect to your mount and send me the file skytrack_log.txt, it will tell us if this is case.  Use the email contact from the SkyTrack website or PM me.  When we verify that, PlaneWave may be able to update the driver as other manufacturers have around this issue, or there may be another workaround once I see the log file.

 

Thanks.

Edited by bosh60, 17 May 2023 - 04:46 PM.

[ButterFly]

It is so nice that the mount manufacturers are responding.

[RedLionNJ]

I believe many mounts may respond with "CanMoveAxis = False" when working in altaz mode. This would be right in line with Bob & Brent's comments, above.

[ButterFly]

My ServoCAT is on an alt/az dob. Hillios' servocat driver implements moveaxis just fine. The standard references the mount axis to be moved, rather than the sky axis to be moved along. There is room in the standard for a third axis. Use alt/alt/az if you want to remove a dob hole. I would not recommend relying on a third motion axis being present.

[Tom Gwilym]

Have you checked with Planewave? Maybe there's a setting somewhere that SkyTrack isn't seeing. For example an ASCOM mount needs to report CanMoveAxis = True if it expects apps to use its non-equatorial motions to be available to an app. Maybe SkyTrack is looking for this to be true coming from PWI but it's seeing false and reverting to the leapfrog mode where it's feeding RA/Dec slews to jump along with the earth-orbiter. 

I haven't checked with them yet.  It does work with PW4 in continuous movement and I found where I can make small movements to the centering, so it is working.  The  SkyTrack looks good since you can quickly move around between spacecraft.  I figure it's something with ASCOM looking for something from PW4.  I'll check out the CanMoveAxis and see if I can find info on that.   Thanks for the idea!

Tom
 

[Tom Gwilym]

Thanks!  I'll send the log file to you directly.  I did just pull it off the observatory computer and it has the log from my quick attempts before going directly to the PW4 method (ISS was making a good pass and time was short to test things out).

I'm not sure if it's an ASCOM thing in there that needs a checkbox or whatever.  When I tried the SatTracker the calibration routine popped up also and didn't work right.

 

Tom

Hi Tom,

 

I would like to work with you to resolve this. SkyTrack uses the ASCOM MoveAxis method to track satellites continuously in a smooth manner otherwise it is a series of "gotos" what I have called leapfrog tracking.  If it says only leapfrog tracking is available then it must be the manner in which the Planewave driver is presenting the axisrates which can be used with MoveAxis.  For example, my AP mount responds to ASCOM queries stating there is one axisrate collection with a minimum of 0 deg/sec to a maximum of 5 deg/sec.  That tells me I can use any value from 0-5 deg/sec for the MoveAxis method. Some mounts present a series of axisrate collections where the min value = the max value, so only a collection of preset values with nothing in between - continuous satellite tracking is not possible then as the satellite rate of movement is constantly changing.  

 

If you connect to your mount and send me the file skytrack_log.txt, it will tell us if this is case.  Use the email contact from the SkyTrack website or PM me.  When we verify that, PlaneWave may be able to update the driver as other manufacturers have around this issue, or there may be another workaround once I see the log file.

 

Thanks.

 

[bosh60]

Thanks for the log file.  It does seem to be a issue with  the PW ASCOM driver not supporting the MoveAxis method.  When SkyTrack asks for axisrates info it returns an empty collection.  We will need to discuss with Planewave.

Edited by bosh60, 17 May 2023 - 08:36 PM.

[ButterFly]

Something else to add to the conformance checker!

[dghent]

MoveAxis is an optional feature. NOT implementing it in a driver is not a conformance issue.

 

Also, technically, one should query the CanMoveAxis property of a driver to know if it's available. Being that it's a boolean, it's far less likely for a driver author to mess up implementing. Running the AxisRates method to look for a list or exception might get you things you won't expect, and might lead you astray, based on my experience.

[bosh60]

 

Also, technically, one should query the CanMoveAxis property of a driver to know if it's available. 

I query both, but you're right if CanMoveAxis is false then no need to check axisrates.  Interestingly, the driver supports RightAscensionRate and DeclinationRate but not MoveAxis. 

[Bob Denny]

Something else to add to the conformance checker!

Maybe it's there. But good idea. Post to the ASCOM Driver and Application Development Support Forum and you'll probably get a first hand answer one way or the other. Conform is a living document which is why it gets updated apart from the Platform.

[ButterFly]

MoveAxis is an optional feature. NOT implementing it in a driver is not a conformance issue.

 

Also, technically, one should query the CanMoveAxis property of a driver to know if it's available. Being that it's a boolean, it's far less likely for a driver author to mess up implementing. Running the AxisRates method to look for a list or exception might get you things you won't expect, and might lead you astray, based on my experience.

I was under the impression that CanMoveAxis returned true with this driver.  It does not.  I tried PWI4 latest and beta, as well as PWI2.  All return false for CanMoveAxis.

 

So the rates returning a null set is indeed conforming.

 

Yes on checking CanMoveAxis first.

[Bob Denny]

Don't hesitate to let PlaneWave know that you'd like to be able to access their mount's full potential for earth-orbiting objects from apps other than PWI by supporting MoveAxis(). 

[Tom Gwilym]

I'll give that a try and see what they come up with.

Wow...a lot of replies to my question.  I'll read through them and play around with things and share on the ASCOM side too.   This is a great group, thanks for all the ideas! 

 

Maybe it's there. But good idea. Post to the ASCOM Driver and Application Development Support Forum and you'll probably get a first hand answer one way or the other. Conform is a living document which is why it gets updated apart from the Platform.

 

[Tom Gwilym]

From what I understand from talking to them a while back, it seems they are working on combining the PW3 and PW4 software into one program.  It's been working extremely well, and we have been extremely happy with the scope.  There is just confusion about the camera rotator, but that's a topic for another posting.

 

Don't hesitate to let PlaneWave know that you'd like to be able to access their mount's full potential for earth-orbiting objects from apps other than PWI by supporting MoveAxis(). 

 

[bosh60]

Don't hesitate to let PlaneWave know that you'd like to be able to access their mount's full potential for earth-orbiting objects from apps other than PWI by supporting MoveAxis(). 

Email already sent - we will see what happens. I have always been curious of Planewave mounts maximum slew rate as I recall Roland Christen once stating that they are limited by Federal law to a maximum controlled tracking rate of 999x sidereal.

[dghent]

Email already sent - we will see what happens. I have always been curious of Planewave mounts maximum slew rate as I recall Roland Christen once stating that they are limited by Federal law to a maximum controlled tracking rate of 999x sidereal.

He referred to the US's ITAR

 

I'm not 100% sure, but the only relevant description that I can find on the list of covered munitions (yes, any high quality mount produced in the US, is considered to be a munition) is in part 121.1, Category XV "Spacecraft and Related Articles", Paragraph (e)(16):

 

Space-qualified star tracker or star sensor with angular accuracy less than or equal to 1 arcsec (1-Sigma) per star coordinate, and a tracking rate equal to or greater than 3.0 deg/sec, and specially designed parts and components therefor (MT);

[bosh60]

He referred to the US's ITAR

 

I'm not 100% sure, but the only relevant description that I can find on the list of covered munitions (yes, any high quality mount produced in the US, is considered to be a munition) is in part 121.1, Category XV "Spacecraft and Related Articles", Paragraph (e)(16):

Interesting, thanks for the reference, Dale.   I have not seen less than 1 arcsec satellite tracking with amateur mounts yet but definitely less than 1 arcmin.

[daw316]

"Space-qualified star tracker or star sensor with angular accuracy less than or equal to 1 arcsec (1-Sigma) per star coordinate, and a tracking rate equal to or greater than 3.0 deg/sec, and specially designed parts and components therefor (MT);"

 

I'm thinking "space-qualified" refers to "going" into space, not just "looking" into space.  I would guess any gear we could afford would not fall under this provision.

[ButterFly]

The "T" means trafficking, not owning or using, per se.  "US Persons" are free to own and use "munitions", such as my night vision intensifier.  "Trafficking", as defined, limits those with whom I can use the device, as well as to whom I can dispose to, and where I can export to.

 

If an individual were to build a star tracker in her garage, with angular accuracy less than or equal to 1 arcsec (1-Sigma) per star coordinate, and a tracking rate equal to or greater than 3.0 deg/sec, and it were "space-qualified", she couldn't pack it into her luggage for an overseas trip, without being a felon.  In order for it to be "space-qualified", she could, among other things, actually test its operability above 100km.  See the note in the definition for another such star tracker she built, without having tested it.  See the other note for an artistic coffee table she built, that also just happens to be a star tracker with angular accuracy less than or equal to 1 arcsec (1-Sigma) per star coordinate, and a tracking rate equal to or greater than 3.0 deg/sec.

 

I don't know whether Roland has sent any particular mounts above 100km.  Ask him!

[dghent]

ITAR does change over time as technology and sensitivities around the tech evolves. It's possible that there used to be broader verbiage in ITAR that intersected with the capabilities of our familiar telescope mounts, but has since changed to be more specific and perhaps not as applicable. In the end, it's a question that Astro-Physics should pose to a relevant lawyer

[ButterFly]

And its users, if they intend to "export" anything.  A hint of a whiff of "I designed it to work in space" is a problem.

 

Space related ITAR's relaxation is what led to the proliferation of private companies in space over the last decade.  The Artemis program wouldn't really be possible without that either.  Whether that's a "good" thing, or leads to Earth having rings for a little while, remains to be seen. 

[shakafell]

Has there been any update on SkyTrack compatibility with Planewave mounts? With PWI 4.1.6 and SkyTrack 1.9.2 it still reports that Continuous Tracking is NOT available. (at least with the PW Simulated Mount).

 

While PWI4 has built in sat tracking you have to manually add one satellite at a time. SkyTrack is nice because you can switch between multiple sats instantly.

 

I'm curious if anyone knows what tracking software is being used in this video? It doesn't look like SkyTrack or PWI.

https://www.youtube....h?v=CHIbOAKltoQ