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

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

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

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

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

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

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

This looks straightforward! Thanks! I will get going on it this afternoon!

Scott

I forget to say if the telescope is at west of the mount, then you need to put OTA negative.

Hello all,

First, to fcasarra: Thanks for the spreadsheet! That I could do easily, and the results were interesting.

Here are the new tests from last night. The high level summary: The values calculated in the spreadsheet are different than those from INDI (Server, ICP, AT, etc), and appear to be even less correct than INDI.

Here is a detailed description:

1) I polar aligned the scope as an absolute positional reference.

2) I shown a flashlight through the polar scope port of my CGEM DX. It's wide illumination filled the port, and illuminated a point on the dome that is presumably within 1 degree of north. No amount of flashlight tipping would move the spot (it isn't a laser, it is a broad; see the attached picture named DefiningNorth). I defined the positioning of the dome to be at 0 degrees when the spot was centered on the shutter.

Continued from above:

3) Next, I decided to test the dome positioning at two positions that I think simplify the issues. I first put the scope on the East side of the mount dead flat, looking due north (see figure and picture). I believe this will remove any issues of offsets in pier position in the N-S direction. Thus, the only measurement problems I can have are E-W offsets, Up-Down offsets, and OTA length offsets.

In this position, the spreadsheet says the dome should be at 0.2°, INDI places the dome should be at 11°, and I estimate the dome actually needs to be at about 18° to be centered. Though it is hard to see in the picture, about 1/3 of my scope view is occluded by the dome in this position.

The software settings are shown in the attached image. Sorry for the crazy moire patterns. I also include the spreadsheet showing the 0.2° recommended position. Note that I have gzipped the file to allow it to be included here. I added .tar to the name also, to allow it to be uploaded, but it is NOT tar'd. Just rename it to DomeSlitEast.xlsx.gz, then gunzip it, and it should be a regular excel file.

4) Next, I repeated this test in the west. Note I changed the meridian setting in ICP to West. In this position, the scope was not occluded, but only just barely. The spreadsheet thought the angle should be -2.6°, INDI called for 341.8°, and I would estimate that it actually needed to be ~339°. Pictures, and spreadsheet below.

I interpret this to suggest that the the length of the OTA offset needs to be bigger, and the pier offset E-W larger as well.