×

INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

10Micron Mount Modelling

  • Posts: 73
  • Thank you received: 8
Sounds really exciting. I look forward to the future.
6 years 7 months ago #18791

Please Log in or Create an account to join the conversation.

  • Posts: 85
  • Thank you received: 40

Replied by Hans on topic 10Micron Mount Modelling

Hi all, I'm glad to see 10Micron mount modeling is getting more attention in INDI/EKOS-land.

The 10-Micron mount alignment models are made in the mounts themselves and are based on (currently up to 100) alignment points. The interesting case is where we plate solve these points so that the whole procedure can be automated. The INDI Alignment Subsystem could be used to select those points, have them plate solved and add the results as a new alignment point to the mount. This is what Michel's MountWizzard does too (it does a lot more).

The mount also wants temperature and air pressure information as it uses this to correct for their effects on pointing. A 'fun fact' is that we must not correct for temperature and air pressure ourselves when converting the plate solved J2000 results to JNow (confirmed to me by a 10Micron dev).

We should use the 10-Micron :newalig# , :newalpt , :endalig# commands to build models instead of just :CM# to 'sync' a point. Next step is to let the mount evaluate the model, optimize it and maybe remove certain points that show too large errors. I do not know if IAS has something similar. The mount can save and recall multiple alignment models.

Ideally I would like to see both MountWizzard and EKOS be able to help build 10Micron alignment models from Linux/Mac/Windows. MountWizzard is mostly Python and it would be really nice if it could be fully Python based. There are INDI client implementations in pure Python so that could be used. The J2000-JNow transformation it currently uses via ASCOM is based on SOFA with a mix of NOVAS helper functions ... I know of no Python-only library of it yet.

-- Hans
The following user(s) said Thank You: Craig
6 years 7 months ago #18802

Please Log in or Create an account to join the conversation.

  • Posts: 124
  • Thank you received: 28

Replied by Michael on topic 10Micron Mount Modelling

Hi Hans and others,

recently I got a python package for indi client to work. At least I could get an Image from the CCD Simulator. With the SOFA library I would do a C to python translation myself over time if there is no solution available. First I have to ask the guys at SOFA to get the allowance to use it in MountWizzard.

There is one question open for me: mightbe as well asked in this thread already. Actually I using the imaging programs to capturing *and* platesolving. Ideally I get an image as FITS file, where mount coordinates and plate solved coordinates were in.
I didn't find a feature or way to get EKOS platesolve an image from a client side. Does anybody know how this could be done ? This would help a lot.

Thanks

Michel
The following user(s) said Thank You: Craig
6 years 7 months ago #18856

Please Log in or Create an account to join the conversation.

You can use Ekos DBus interface to communicate with alignment module: api.kde.org/4.x-api/kdeedu-apidocs/kstars/html/index.html
If there is something missing you might need, let me know.
6 years 7 months ago #18857

Please Log in or Create an account to join the conversation.

  • Posts: 124
  • Thank you received: 28

Replied by Michael on topic 10Micron Mount Modelling

Jasem,

if I use the Bus interface of EKOS from my understanding there is no need for INDI (because I get all from that one interface). I guess, that I could access all Dbus API's via TCP connection. Is that right ?

Michel
6 years 6 months ago #18865

Please Log in or Create an account to join the conversation.

Michael,

From Python, you can communicate communicate with the DBus interface. Here is a tutorial about using the INDI DBus interface in KStars. But you'd want to use the Ekos DBus interface since the INDI interface is considered low level.
The following user(s) said Thank You: dolguldur
6 years 6 months ago #18866

Please Log in or Create an account to join the conversation.

  • Posts: 124
  • Thank you received: 28

Replied by Michael on topic 10Micron Mount Modelling

Jasem,

that's right if you stay on pure linux (or BSD) based systems. But MW support windows as well and I would stay with an OS independent solution if I am leaving the windows environment. So accessing Dbus from python is still a learning curve for me, but having a native python implementation for a remote Dbus client is really tricky. All other imaging suites offering a REST API for remote control, which makes thing much more easy. Is there anything like that in EKOS ?

Michel
6 years 6 months ago #18867

Please Log in or Create an account to join the conversation.

Currently there is no such system. I suppose one could wrap the DBus calls in REST API with a micro framework like Bottle py
6 years 6 months ago #18868

Please Log in or Create an account to join the conversation.

  • Posts: 85
  • Thank you received: 40

Replied by Hans on topic 10Micron Mount Modelling

Hi Michel,

I propose to use ERFA instead : github.com/liberfa/erfa "ERFA is a C library containing key algorithms for astronomy, and is based on the SOFA library published by the International Astronomical Union (IAU).
ERFA is intended to replicate the functionality of SOFA (aside from possible bugfixes in ERFA that have not yet been included in SOFA), but is licensed under a three-clause BSD license to enable its compatibility with a wide range of open source licenses. Permission for this release has been obtained from the SOFA board, and is avilable in the LICENSE file included in this source distribution."

I've tested ERFA myself and it gives the same results as SOFA github.com/d33psky/J2000-JNow

-- Hans
6 years 6 months ago #18871

Please Log in or Create an account to join the conversation.

  • Posts: 85
  • Thank you received: 40

Replied by Hans on topic 10Micron Mount Modelling

HI all,

For 10Micron mount modelling we need to add the following functionality to the driver :

First store the temperature and pressure. This will get used by :newalpt and/or :endalig# lateron.
  • :SRTMPsTTT.T# Sets the tempreature at the location of the telescope used in the refraction model to sTTT.T degrees Celsius. Returns 1# if OK, 0# on error.
  • :SRPRSPPPP.P# Sets the atmospheric pressure at the location of the telescope used in the refraction model to PPPP.P hPa. Returns 1# if OK, 0# on error.
Begin a new alignment specification. (This will not clear the active alignment model the mount is using.)
  • :newalig# returns V#
Next loop over up to 100 alignment points, per point get mount RA/DEC, pier side, local sidereal time, plate-solved RA/DEC (*) and store :newalpt
  • :GR# get mount right ascension. Returns HH:MM:SS.SS# (hours, minutes, seconds and hundredths of seconds)
  • :GD# get mount declination. Returns sDD:MM:SS.S# (degrees, arcminutes, arcseconds and tenths of arcsecond)
  • :pS# Pier side. Returns string "East#" or "West#"
  • :GS# Get local sidereal time
  • :newalptMRA,MDEC,MSIDE,PRA,PDEC,SIDTIME# Returns nnn# if OK with nnn the number of active points, E# if not
With
  1. MRA - the mount-reported right ascension, expressed as HH:MM:SS.S
  2. MDEC - the mount-reported declination, expressed as sDD:MM:SS
  3. MSIDE - the mount-reported pier side (the letter 'E' or 'W', as reported by the :pS# command)
  4. PRA - the plate-solved right ascension (i.e. the right ascension the telescope was effectively pointing to), expressed as HH:MM:SS.S
  5. PDEC - the plate-solved declination (i.e. the declination the telescope was effectively pointing to), expressed as sDD:MM:SS
  6. SIDTIME - the local sidereal time at the time of the measurement of the point, expressed as HH:MM:SS.S
End the new alignment model and compute a new alignment from the given alignment points.
  • :endalig# returns V# if new alignment model has been computed OK
Save the model.
  • :modeldel0NAME# DELete a model with name NAME (up to 15 case sensitive characters, spaces allowed). Returns 1# if OK, 0# on error
  • :modelsv0NAME# SaVe the model with name NAME. Returns 1# if OK, 0# on error
(*) We need to transform plate-solved J2000.0 coordinates to JNow as input for the :newalpt PRA ad PDEC parameters and JNow as SIDERES, however in this transformation we need to deliberately ignore everything that is related to refraction (like temperature, pressure, humidity, wavelength) and only correct for precession, nutation and light aberration. This can be done with SOFA/ERFA Atci13, or with Atco13 when all its refratcion parameters are set to 0.
The 10Micron mount then receives these 'half transformed' coordinates and corrects for refraction with the temperature and pressure it was given earlier with :SRTMP and :SRPRS (ignoring things like humidity and wavelength).

Lateron we can add functionality to manage the models with these
  • :getalst# Gets the number of alignment stars used in the current alignment model. Returns n#
  • :delalig# Deletes the current alignment model and stars. Returns #
  • :getalpN# Gets alignment information for star number N. Returns: E# on error or "HH:MM:SS.SS,+dd*mm:ss.s,eeee.e,ppp#" where HH:MM:SS.SS is the hour angle of the alignment star in hours, minutes, seconds and hundredths of second (from 0h to 23h59m59.99s), +dd*mm:ss.s is the declination of the alignment star in degrees, arcminutes, arcseconds and tenths of arcsecond, eeee.e is the error between the star and the alignment model in arcseconds, ppp is the polar angle of the measured star with respect to the modeled star in the equatorial system in degrees from 0 to 359 (0 towards the north pole, 90 towards east).
  • :delalstN# Delete alignment star N and recalculate the model. Returns 1# if OK, 0# on error
  • :modelcnt# Gets the number of alignment models. Returns: n#
  • :modelnamN# Returns the name of model number N or just # on error.
  • :modelld0NAME# Loads the model with the given NAME. Returns 1# if OK, 0# on error

I intend to add all this to the INDI driver. Does this line up with the EKOS Mount Modelling tool ?

-- Hans
The following user(s) said Thank You: dolguldur
6 years 6 months ago #19017

Please Log in or Create an account to join the conversation.

Sounds good so far. Why an external library is required for J2000 to JNow conversion? This is done in KStars.
6 years 6 months ago #19018

Please Log in or Create an account to join the conversation.

  • Posts: 124
  • Thank you received: 28

Replied by Michael on topic 10Micron Mount Modelling

Hi all,

just a short heartbeat from MountWizzard and support for INDI: So far the connections is made, I could take pictures via IP from EKOS. Still not that advanced
as I liked it to be, because there are some informations missing about camera status etc. Next steps would be to integrate MBox (refraction data) and telescope driver (for simulation purpose. Hope you will see a running beta soon.

BTW: MountWizzard runs now on Windows / MAC / Linux using QT and python 3.5

Michel
The following user(s) said Thank You: Jasem Mutlaq, Hans
6 years 5 months ago #20363

Please Log in or Create an account to join the conversation.

Time to create page: 0.497 seconds