gilmenel 0.3.0

Telescope guide star selection tools.

Gilmenel

Gilmenel: Sindarin. noun. meaning Star of the Heavens

• Sindarin Elvish as created by J. R. R. Tolkien

A framework for selecting stars in a target field that meet complex criteria defined by a telescope or instrument.

Given coordinates on-sky and a basic definition of a science instrument (basic instruments, along with some from the Southern African Large Telescope are included) stars can be selected for a specific purpose. The example is the output of the salt_guidestars.py script when pointed at the Jewel Box and with the --png flag enabled.

Installation

pip install gilmenel

Dependencies

For Ubuntu 18.04 and Python3:

# apt-get install python3-dev

$ sudo -H pip install -U pipenv

Libraries that might be required are:

# apt-get install default-libmysqlclient-dev
# apt-get install libssl-dev

Primary Python packages:

• astropy
• astroquery
• sqlalchemy
• matplotlib

Install DS9 for additional debugging:

# apt-get install saods9

Setup

$ make install

Place the config file 'docs/config.py' into the main project directory. Edit the file as required.

Removal

$ make uninstall

Testing

To run unit tests, execute:

$ make check

To run unit tests on source code change, execute:

$ make watch-check

To run coverage test, execute:

$ make coverage

Examples

Minimal example:

from astropy import units as u
from astropy.coordinates import SkyCoord

from gilmenel import gilmenel
from gilmenel import salt

gilmenel.init()

tarantula = SkyCoord(
    '05h 38m 38s', '−69:05.7', unit=(u.hourangle, u.deg)
)  # Tarantula Nebula

instr = salt.fif
instr.point_to(tarantula, pa=0 * u.deg)

stars = gilmenel.view_sky(instr)
guide_stars = gilmenel.find_best_stars(instr, stars)

print(guide_stars)

A full usage example can be found in salt_guidestars.py

Usage: salt_guidestars.py field [OPTIONS] [jewel_box|near_jewel|somewhere|boot es_void|unittest|regular|centre|offset|null|mb xgpS201906130009|mbxgpP201906130039|tarantula| sunflower|m83] PA [pfgs|fif]

eg:

$ ./salt_guidestars.py field jewel_box 0 pfgs

Catelogue

Asteria is designed to be run for a local or remote catalogue.

To download the whole-sky catalogue for SALT, run the command below. Please note that this is not recommended as A LOT of data (we're talking gigabytes here) will be downloaded.

$ ./catalogue/drop_db.sky
$ ./catalogue/create_db.py
$ ./catalogue/download_sky.py
$ ./catalogue/prepare_db.py

Should the catalogue download fail part-way through, inspect the files succeeded.tsv and failed.tsv for more details. Additional arguments can be passed to download_sky.py to begin in the correct place. Note that since data is downloaded and only committed to the database every 30 000 sources, a simple select query WHICH MUST INCLUDE THE LIMIT KEYWORD will show the last sources committed.

To view an image of the local catalogue, run:

$ ./catalogue/view_sky.py

To run the view command on remote machines without displays:

$ export MPLBACKEND="agg"

Database Operations

To see a summary of duplicates

select dup_count, count(dup_count) as row_count from (select count(source_id) as dup_count from Sources group by source) t group by dup_count order by dup_count;

To delete duplicate rows

delete from Sources where source_id not in (select min(source_id) from Sources group by source);

Notes

When using ds9 for debugging, there appears to be two different versions that interpret the command string differently.

ds9 -dsseso "00:42:44.404 +41:16:08.78"

Versus

ds9 -dsseso coord "00:42:44.404 +41:16:08.78"

The code might need to be changed to reflect the version locally installed.