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27 Feb 2017
INDI development team is happy to announce the release of INDI Library v1.4.0. This new exciting release builds on the maturity of INDI Library and comes with many new supported devices and fixes for existing drivers. Several improvements and enhancements are included in this release including native support for Cygwin and MacOS platforms in addition to Linux, BSD, and Windows (Client only).
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TOPIC: Dome Sync Gateway not producing timely GOTO commands

Dome Sync Gateway not producing timely GOTO commands 1 month 4 weeks ago #14784

Hi all,

I am using Cloudmakers software, including INDI Server (IS), INDI Control Panel (ICP), and AstroTelescope (AT) with my CGEM DX and home motorized 8' dome. I have been using the Dome Sync Gateway (DSG) in ICP to produce GOTO python commands which drive my dome. The problem is that when DSG is slaved to my dome, only the first (or rarely the first few) dome move commands (all of which are GOTO's) are actually given by the INDI driver.

0) I can reliably get AT to convince ICP to throw a GOTO.py by turning off the DSG, then turning off the INDI link to the telescope, then turning DSG back on, and finally turning the link to the telescope back on. However, this is a very clumsy way to track an object all night!

1) I have tried a range of tolerances from 0.02 degrees to 10 degrees. All result in the same infrequent calling of GOTO's. All other dome measurements are entered in ICP normally.

2) My dome has a tolerance of 0.1 degrees. Meaning, if a goto asks for 165°, the dome might stop anywhere from 164.9° to 165.1°. However, once stopped, it tells INDI via a DSG Status command that it is at 165°, either way. So I don't think it is a tolerance error, or an issue with INDI thinking the dome is still moving (I think - there could still be rounding differences, and possibly output formatting differences that make INDI think the dome is close, but not entirely there).

Does anyone know what might be happening?

Peter Polakovic suggested contacting Jasem - with this post, I am attempting to do just that, as well as crowd-source your wisdom!

Sincerely,

Scott

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Dome Sync Gateway not producing timely GOTO commands 1 month 4 weeks ago #14797

Hi Scott, I just investigated the code and I believe there is a way to remedy this, I'll email Peter about it.
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Dome Sync Gateway not producing timely GOTO commands 1 month 4 weeks ago #14815

Thanks Jasem!

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Dome Sync Gateway not producing timely GOTO commands 1 month 4 weeks ago #14876

Hello Jasem and INDI guru's,

Peter Polakovic got a new version of the INDI Server to me tonight, and indeed, the dome now frequently rotates! Solved - thank you!

However, telescope pointing is off everywhere but the South East quadrant. I suspect something may be wrong with the units in the Dome Parameters. My carefully measured values are here:

Inches Meters
Radius 45 1.14
Width 25 0.64
N -2.75 -0.07
E -0.75 -0.02
Up - 3.75 -0.10
OTA 15 0.38

Edit: Sorry for the weird formatting - it doesn't match what I have entered, and I don't know how to show it properly. The first number is a measurement in inches, and the second a conversion to meters.

To test the parameters, I set the scope to pointing due north, and rotated it so the GEM weight bar was flat, with the weights in the East, then later in the West. I set the meridian appropriately for each case. With the scope in the East, the scope optical axis was aligned with the east-side dome slot edge, partially occluding it's view (it looked like my 11" scope could move at least 7" to the West to get it closer to centered). With the scope in the West, the scope top was aligned with the west edge, enabling a view, but was still very close to the dome slot (it looked like it should move 3" towards the East).

This suggested to me that OTA offset was too small (even though it was carefully and easily measured from the intersection of RA and DEC to the optical axis), as well as there being an E-W offset, in the W direction, of about 4". I increased the OTA offset to 0.5m, which resulted in the western side scope being nearly centered in the dome slot, and the eastern side scope position being just inside the east edge of the dome. I don't understand how this could be the case though, as the size of the offset is clearly smaller than 0.5m.

Next I tried offsetting the E-W dome parameters 4" to the east (-0.13m total). The dome didn't move at all with this change. I then tried -0.5m. This led to a small positional change, but not enough to center the scope in the slot. Finally, I tried a -1m change. The dome moved noticeably, but still not far enough. This doesn't make much sense, as a 1m move of the pier in a small 8' dome is huge!

Is it possible that the units are not all in meters? For example, these observations make sense if the Radius and width are in meters, but the N, E, and Up are in centimeters. I don't yet understand the OTA offset value, unless it is from the DEC-RA intersection to the far side/top of the scope. 0.38 to 0.5 made a noticeable difference in dome position, in the right direction, and I think adding a little more would help. It is almost like it needs to be 1.5X to 2X the distance between the RA-DEC intersection and the optical axis.

Does any of this sound like a known issue?

As always, big thanks,

Scott

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Last Edit: by Riprock99.

Dome Sync Gateway not producing timely GOTO commands 1 month 3 weeks ago #14879

A few more comments:

1) The dome seems centered on the scope when it is vertical and pointing north. So I don't think I have a rotational error exceeding 1 degree or so.

2) I understand that in theory, this calculation is usually unit-less. I am creating hypotheses for the results I am seeing. Looking at the code for the calculation, it looks reasonable, but I can't be sure without working a detailed example.

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Dome Sync Gateway not producing timely GOTO commands 1 month 3 weeks ago #14913

Hi Scott,

All measures must be in meters. But I suppose if you use the same units in all the measures I must work

I expect to have time this weekend to take a look at your problem.

Regards,
Ferran
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Dome Sync Gateway not producing timely GOTO commands 1 month 3 weeks ago #14916

Hi Ferran,

Thanks for taking a look. In my previous experiments, all measures were in meters, yet that didn't end up working very well. I am working on redoing the test I described with debugging turned on, so I can send you a more detailed log.

Sincerely,

Scott

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Dome Sync Gateway not producing timely GOTO commands 1 month 3 weeks ago #14922

Hello Ferran and Scott

Jasem informed me about your issue. I quickly wrote a Python script which calls RTS2's slitazimuth.c,
my original implementation of Toshimi Taki's solution. It is available at

github.com/RTS2/rts2/blob/master/scripts/dome_target_az.py

In order to use it you must clone RTS2 and compile it (installation is not required)
and in do

cd ~/rts2/lib/rts2
gcc -c -Werror -fpic slitazimuth.c -I../../include/ && gcc -shared -o libslitazimuth.so slitazimuth.o -lnova

ciao, wildi


wildi@dc11:~/rts2/scripts$ ./dome_target_az.py
AZ coordinate systen: S=0, W=90 deg
xd: -0.0684 m, zd: -0.1934 m, rdec: 0.338 m, rdome: 1.265 m
telescope alt: 0.000, az: 0.000, dome az: 15.688 deg
telescope alt: 10.000, az: 0.000, dome az: 15.505 deg
telescope alt: 20.000, az: 0.000, dome az: 15.859 deg
telescope alt: 30.000, az: 0.000, dome az: 16.852 deg
telescope alt: 40.000, az: 0.000, dome az: 18.724 deg
telescope alt: 50.000, az: 0.000, dome az: 21.986 deg
telescope alt: 60.000, az: 0.000, dome az: 27.781 deg
telescope alt: 70.000, az: 0.000, dome az: 38.917 deg
telescope alt: 80.000, az: 0.000, dome az: 62.186 deg
telescope alt: 0.000, az: 90.000, dome az: 108.680 deg
telescope alt: 10.000, az: 90.000, dome az: 108.213 deg
telescope alt: 20.000, az: 90.000, dome az: 108.252 deg
telescope alt: 30.000, az: 90.000, dome az: 108.814 deg
telescope alt: 40.000, az: 90.000, dome az: 109.964 deg
telescope alt: 50.000, az: 90.000, dome az: 111.790 deg
telescope alt: 60.000, az: 90.000, dome az: 114.285 deg
telescope alt: 70.000, az: 90.000, dome az: 116.795 deg
telescope alt: 80.000, az: 90.000, dome az: 115.961 deg
telescope alt: 0.000, az: 180.000, dome az: 195.688 deg
telescope alt: 10.000, az: 180.000, dome az: 195.500 deg
telescope alt: 20.000, az: 180.000, dome az: 195.741 deg
telescope alt: 30.000, az: 180.000, dome az: 196.489 deg
telescope alt: 40.000, az: 180.000, dome az: 197.915 deg
telescope alt: 50.000, az: 180.000, dome az: 200.364 deg
telescope alt: 60.000, az: 180.000, dome az: 204.563 deg
telescope alt: 70.000, az: 180.000, dome az: 212.184 deg
telescope alt: 80.000, az: 180.000, dome az: 132.560 deg
telescope alt: 0.000, az: 270.000, dome az: 281.824 deg
telescope alt: 10.000, az: 270.000, dome az: 281.814 deg
telescope alt: 20.000, az: 270.000, dome az: 282.165 deg
telescope alt: 30.000, az: 270.000, dome az: 282.975 deg
telescope alt: 40.000, az: 270.000, dome az: 284.456 deg
telescope alt: 50.000, az: 270.000, dome az: 287.077 deg
telescope alt: 60.000, az: 270.000, dome az: 292.066 deg
telescope alt: 70.000, az: 270.000, dome az: 304.223 deg
telescope alt: 80.000, az: 270.000, dome az: 15.060 deg

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Dome Sync Gateway not producing timely GOTO commands 1 month 3 weeks ago #14925

Thanks Wildi, it is great to have your help!

I looked up RTS2 - I didn't know about it, and it looks pretty neat. I see that it wants Ubuntu to compile. I am running a late model OS X on a Jurassic era Mac Mini (2010). Is that going to be a problem, or do you think it will work out of the box?

Thanks,

Scott

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Dome Sync Gateway not producing timely GOTO commands 1 month 3 weeks ago #14927

Hello Scott and Ferran

I have not seen RTS2 on OSX (and I would not try it, at least not for this purpose). There is an easier way: use Docker which provides an Ubuntu container on your OSX computer. But this is a several hours task.

My idea is, that Ferran produces a similar table with his code and depending on the results we know better where to dig deeper.
I read through my original notes and found that I was checking my code against Toshimi Taki's "reference implementation" saying it is identical (see www.geocities.jp/toshimi_taki/matrix/matrix.htm paragraph Applications and my similar plot: azug.minpet.unibas.ch/wikiobsvermes/images/9/97/DomeSync.jpg )

ciao, wildi
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Last Edit: by wildi.

Dome Sync Gateway not producing timely GOTO commands 1 month 3 weeks ago #14932

Dear Wildi - I think I will start by getting some numbers from the debug side of INDI - if I am still confused, I will go to the work of installing the code you mentioned!

My sincere thanks,

Scott

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Dome Sync Gateway not producing timely GOTO commands 1 month 2 weeks ago #14946

Hi,

I created a google spreadsheet with all the calculations for dome sync.
docs.google.com/spreadsheets/d/1FWN0S7kG...HIo/edit?usp=sharing

Editing the blue cells you get the telescope and dome azimutal coordinates in orange cells.

There you can check if INDI dome get the same result or if there is something wrong.

The difference with Toshimi Taki's solution is my solution allows E-W telescope adjustment.

Regards,
Ferran
The following user(s) said Thank You: knro

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