deskephem - Modular CLI Astronomy

deskephem is a CLI astronomy calculator, that can print things like moon phases, approximate sunrise and sunset times, planet and star locations, and more.

$ deskephem moon phase # Werewolf early warning system
🌒 Waxing Crescent (5.0%)
$ deskephem sun rise set -l 40,-95 # Sunrise and Sunset
06:53 19:47
$ deskephem -l 30n,60w -E now,1h,+4h venus horiz
===================================================
         Date             Coordinates (Azi/Alt)    
===================================================
 2025-03-31T23:50:03  41°54′54.7″ -45°00′-31.5″    
 2025-04-01T00:50:03  56°49′18.1″ -35°00′-59.7″    
 2025-04-01T01:50:03  67°53′57.5″ -23°00′-10.4″    
 2025-04-01T02:50:03  76°46′8.2″ -11°00′-25.5″     
 2025-04-01T03:50:03  84°33′9.8″ +1°20′41.0″       
# Location and brightness of Uranus at William Herschel's first observation
$ deskephem -d 1781-03-13 -l 53n,1.8w Uranus horiz magnitude
278°45'42.91" 23°22'1.52" 5.60

It has a catalog of the planets, the moon and sun, and about 100 common stars. Of which it can print:

• Coordinates in the sky (equatorial, horizontal, ecliptic)
• Phase (Emoji, Illuminated Fraction, Name)
• Approximate Rise and Set times
• Brightness (Magnitude)
• Distance
• Angular Size
• Angles between other objects in the sky

It supports outputs in json, csv, and plain text. It can also generate tables of output:

$ time deskephem -l 35n,100w --ephem=-3h,1h,+3h sun horiz -Tcsv
Date,Coordinates (Azi/Alt)
2025-03-31T20:56:28,284°33′21.7″ -12°00′-45.4″
2025-03-31T21:56:28,294°35′42.9″ -24°00′-30.1″
2025-03-31T22:56:28,306°48′56.6″ -34°00′-53.9″
2025-03-31T23:56:28,322°31′54.9″ -43°00′-24.8″
2025-04-01T00:56:28,342°40′49.8″ -49°00′-8.6″
2025-04-01T01:56:28,05°53′2.9″ -50°00′-38.6″
2025-04-01T02:56:28,27°56′2.2″ -46°00′-36.1″

deskephem is a wrapper around the pracstro astronomy library.

$ time deskephem -E 1600-01-01,1mon,9999-06-01 mars ecliptic # Query is ran ~100k times
===================================================
         Date            Coordinates (Ecliptic)    
===================================================
 1599-12-31T18:09:24  143°04′10.6″ +3°48′36.4″     
 1600-01-31T18:09:24  133°03′30.5″ +4°31′51.0″     
[...]
1.89 user 0.20 system

Parameters

All input to deskephem is case insensitive

Options:

• Date: -d [DATE] (default: now)
• Observer Latitude/Longitude: -l [LAT,LONG] (default: none)
• Output format: -T [FORMAT] (default: term, options: csv, json, term, rawterm)
• Ephemeris generation: -E start,step,end (optional)

Arguments:

• Object being observed
• Properties

Properties

• Equatorial Coordinates: equ, equa, equatorial
• Horizon Coordinates: horiz, horizontal
• Ecliptic Coordinates: ecl, ecliptic
• Distance: dist, distance
• (Brightness) Magnitude: mag, magnitude, brightness
• Phase Info: phase
• Phase Emoji: phaseemoji
• Phase Name; phasename
• Phase Angle: phaseangle
• Angular Diameter: angdia
• Illuminated Percent: phaseprecent, illumfrac
• Rise and set times: rise, set
• Angle between objects: angbetween:{Object}

Input formatting

Dates:

• Relative Dates: +/-#y/mon/d/h/min/s (ex. +3mon)
• Time increments: #y/mon/d/h/min/s (ex. 1w)
• ISO format: YYYY-MM-DD[THH:MM:SS] (ex. 1970-01-01T14:40:25, 2000-04-52)
• Unix dates: @# (ex. @86400)
• Julian dates: ##j[d] (ex. 2451545)
• Now: now (ex. now)

Angles:

• Lat/Long: Angle,Angle (ex. 0,0, 30n,60w)
• Degrees: ###°/d[eg] (ex. 45deg)

Epehmeris Queries: Date (Start),Time Increment,Date (End)

Object:

• Object name: {name} (ex. moon, Sun, Arcturus)
• Raw coordinates: latlong:{lat,long} (ex. latlong:0,45w)