SkyWatch

This is a quick repository containing some tools for visibility plots and coordinate transformations.

conv_ra_dec.py

A collection of four Python routines to convert input right ascension and declination to or from decimal degrees (from or to sexagesimal). Outputs are all floating point variables.

Calling examples:

import conv_ra_dec
RA_hours, RA_mins, RA_secs = conv_ra_dec.RA_degs_to_sexa(RA_degs_in)
RA_degs = conv_ra_dec.RA_sexa_to_degs(RA_hours, RA_mins, RA_secs)
Dec_idegs, Dec_mins, Dec_secs = conv_ra_dec.Dec_degs_to_sexa(dec_degs)
Dec_degs = conv_ra_dec.Dec_sexa_to_degs(Dec_degs_in, Dec_mins, Dec_secs)

Improvements planned:

• Add conversion from decimal to a sexagesimal string.
• Add conversion from sexagesimal strin to decimal.

visibility.py:

A code to calculate the visibility of a patch of sky to a given location on the Earth. Currently, it produces:

• A figure, which plots the height above the horizon as a function of time
• Also on the figure are tracks for the Moon and the Sun altitude
• A string output stating whether the source is visible, and if so when it is next visible and for how long.

Currently an internal Pandas table contains:

• Source right ascension, declination and altitude.
• Moon and Sun right ascension and declination.
• Moon illumination percentage.
• Distance between the source and the Moon.
• Moon and Sun altitude (elevation angle from the horizon).
• Whether it is day, night or astronomical twilight.

Improvements planned:

• Fill the background of the plot with green for the time period when the source is 30 degrees or more above the horizon.
• Object coordinates and observatory coordinates on the panel.
• Twilight lines.