starteller-cli 1.2.1

A command-line tool for astrophotographers to find optimal viewing times for deep sky objects

StarTeller-CLI

A comprehensive command-line tool for astrophotographers and telescope enthusiasts to find optimal viewing times for deep sky objects throughout the year.

Given your location, StarTeller calculates when each object in the NGC/IC/Messier catalogs reaches its highest point during astronomical darkness. It accounts for altitude, direction, and dark sky conditions to help you plan observation sessions.

Installation

Install from PyPI (Recommended)

pip install starteller-cli
starteller

That's it! The starteller command will be available in your terminal.

Install from Source (Development)

If you want to modify the code or install the latest development version:

git clone https://github.com/ConnRaus/StarTeller-CLI.git
cd StarTeller-CLI
python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate
pip install .
starteller

Or run directly without installing:

git clone https://github.com/ConnRaus/StarTeller-CLI.git
cd StarTeller-CLI
pip install -r requirements.txt
python src/starteller_cli.py

How it works

1. Enter your coordinates (or use a saved location)
2. Set your output directory (or use a saved preference)
3. Set minimum altitude and optional direction filter
4. Get a CSV with optimal viewing times for ~13,000 deep sky objects

The first run downloads the NGC catalog and Addendum (~4MB) and calculates night darkness times for the year. Both are cached, so subsequent runs are fast.

Output

Results go to starteller_output/ by default, or a custom directory you set on first run. The CSV includes:

Column	Description
Object	NGC/IC/Messier ID
Name	Common name if available
Type	Galaxy, Nebula, Cluster, etc.
Messier	Messier number if applicable (e.g., M31)
Right_Ascension	Right Ascension in degrees (J2000)
Declination	Declination in degrees (J2000)
Major_Axis_arcmin	Major axis angular size in arcminutes
Minor_Axis_arcmin	Minor axis angular size in arcminutes
Position_Angle_deg	Position angle of major axis (N through E)
Best_Date	Date when object is highest at midnight
Best_Time_Local	Time of peak altitude
Max_Altitude_deg	Maximum altitude reached
Azimuth_deg	Azimuth at peak altitude (0°=N, 90°=E, etc.)
Rise_Time_Local	When it rises above your minimum altitude
Rise_Direction_deg	Azimuth when rising
Set_Time_Local	When it drops below minimum altitude
Set_Direction_deg	Azimuth when setting
Observing_Duration_Hours	Total time above minimum altitude
Visible_Nights_Per_Year	Nights meeting altitude/direction criteria
Dark_Start_Local	Start of astronomical darkness
Dark_End_Local	End of astronomical darkness
Timezone	Timezone used for local times

Options

Filters:

• Minimum altitude (default 20°) - objects must reach this altitude during dark time
• Direction filter - azimuth range, e.g., 90,180 for objects in the East to South

Included catalogs:

The output includes all ~13,000 objects from NGC, IC, Messier, Caldwell, and other catalogs from OpenNGC.

Python API

You can also use StarTeller programmatically:

from src.starteller_cli import StarTellerCLI

st = StarTellerCLI(
    latitude=40.7,
    longitude=-74.0,
    elevation=10
)

results = st.find_optimal_viewing_times(min_altitude=25)
results = st.find_optimal_viewing_times(direction_filter=(90, 180))  # East to South

File locations

Data and settings are stored in platform-specific directories:

Windows: %LOCALAPPDATA%\StarTeller-CLI\
Linux: ~/.local/share/starteller-cli/
macOS: ~/Library/Application Support/StarTeller-CLI/

This includes the NGC catalog, your saved location, and output directory preference. Cache (night calculations) goes to the platform's cache directory. Output CSVs go to your configured output directory (default: ./starteller_output/).

Requirements

• Python 3.8+
• Internet connection (first run only, to download catalog)

Dependencies: pandas, numpy, pytz, timezonefinder, tqdm

Data source

Catalog data comes from OpenNGC by Mattia Verga, licensed under CC-BY-SA-4.0.

License

AGPL-3.0-or-later (GNU Affero General Public License v3). See LICENSE.

The NGC catalog data is CC-BY-SA-4.0.