Licenses & Attributions

Open-Meteo — Weather Data

Weather data provided by Open-Meteo.com.

Licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).

NASA/JPL — Solar System Data

Solar and planetary ephemeris data courtesy of NASA.

Comet orbital elements from the JPL Small-Body Database (SBDB), maintained by NASA's Jet Propulsion Laboratory.

NASA material is not protected by copyright unless noted. See NASA Media Usage Guidelines.

NASA SDO & ESA/NASA SOHO — Live Solar Imagery

Real-time Sun images from the Solar Dynamics Observatory (SDO), a NASA mission launched in 2010. Instruments include HMI (visible light, magnetograms) and AIA (EUV wavelengths).

Fallback imagery from the Solar and Heliospheric Observatory (SOHO), a joint ESA/NASA mission. EIT instrument provides EUV images at 171, 195, 284, and 304 Å.

The 3D Sun globe texture is composited from daily SDO HMI Intensitygram Flattened (HMIIF) white-light images, projected into heliographic coordinates and assembled into a Carrington synoptic map. SDO/HMI data is produced by the HMI Science Team at Stanford University.

Both SDO and SOHO images are in the public domain under NASA media policy.

NASA APOD — Astronomy Picture of the Day

The Sky Digest features the Astronomy Picture of the Day (APOD), a service of NASA and Michigan Technological University.

Each APOD image may have its own copyright held by the individual astrophotographer or institution credited. Images by NASA are generally in the public domain; others are used with attribution as displayed alongside each image.

APOD data retrieved via the NASA Open APIs.

COBS — Comet Observations

Comet magnitudes and positions from the Comet Observation Database (COBS), operated by the Comet and Meteor Section of the Slovene Astronomical Union.

7Timer! — Astronomical Seeing & Transparency

Astronomical seeing and transparency forecasts provided by 7Timer!, a series of meteorological forecast products developed by Ye Yuan.

7Timer! is a free, open-source service. Data is used with attribution.

Windy.com — Satellite Cloud Imagery

Satellite cloud cover imagery provided by Windy.com via their embeddable map widget.

Windy.com content is subject to Windy Terms of Use. Non-commercial embedding is permitted with attribution.

CelesTrak — Satellite Orbital Data

Satellite TLE and GP orbital elements provided by CelesTrak, a 501(c)(3) non-profit operated by Dr. T.S. Kelso.

CelesTrak redistributes data originating from the 18th Space Defense Squadron (18 SDS) of the U.S. Space Force via Space-Track.org. U.S. government orbital data is in the public domain.

SGP.NET — Orbit Propagation

Satellite pass predictions computed using SGP.NET, a .NET implementation of the SGP4/SDP4 orbital propagation algorithms.

Licensed under the MIT License.

Three.js — 3D Graphics

3D Moon globe rendered using Three.js, an open-source JavaScript 3D library.

NOAA/EOG VIIRS — Light Pollution Data

Light pollution data derived from the VIIRS Nighttime Lights annual composites, produced by the Earth Observation Group (EOG) at the Colorado School of Mines.

The VIIRS Day/Night Band (DNB) instrument flies aboard the Suomi NPP satellite, a joint NASA / NOAA mission. Radiance values are converted to the Bortle scale using the calibration from Falchi et al. (2016), “The new world atlas of artificial night sky brightness”.

VIIRS nighttime lights data is publicly available. Please cite: Elvidge, C.D., Zhizhin, M., Ghosh, T., Hsu, F.-C., Taneja, J. (2021). Annual time series of global VIIRS nighttime lights derived from monthly averages: 2012 to 2019. Remote Sensing, 13(5), 922.

SixLabors ImageSharp — Image Processing

Image processing powered by SixLabors ImageSharp, a fully managed, cross-platform 2D graphics library for .NET.

Licensed under the Six Labors Split License — free for open-source and non-commercial use under the Apache License 2.0.

VizieR — Extended Star Catalog Data

Extended star data (proper motion, radial velocity, galactic coordinates, etc.) retrieved from the VizieR catalogue access tool, operated by the Centre de Données astronomiques de Strasbourg (CDS), France.

Data sourced from the XHIP catalog (Anderson & Francis, 2012). If you use this data in research, please cite: “XHIP: An Extended Hipparcos Compilation”, Anderson, E. & Francis, Ch., 2012, Astron. Lett., 38, 331.

VizieR is freely accessible for academic and non-commercial use. Please cite: Ochsenbein, F. et al. (2000), “The VizieR database of astronomical catalogues”, A&AS, 143, 23.

SIMBAD — Deep-Sky Object Data

Extended deep-sky object data (object types, redshifts, radial velocities, morphological types, multi-band magnitudes, distances, and cross-identifications) retrieved from the SIMBAD astronomical database, operated by the Centre de Données astronomiques de Strasbourg (CDS), France.

SIMBAD is freely accessible for academic and non-commercial use. Please cite: Wenger, M. et al. (2000), “The SIMBAD astronomical database”, A&AS, 143, 9.

QuestPDF — Certificate Generation

Exam certificates generated using QuestPDF, a modern .NET library for PDF document generation.

Licensed under the MIT License (Community plan).

NOAA/SWPC — Sunspot & Solar Region Data

Active sunspot region data provided by the NOAA Space Weather Prediction Center (SWPC), a division of the National Weather Service.

Data includes active region numbers, heliographic positions, sunspot counts, magnetic classifications, and flare probabilities, sourced from the Solar Region Summary.

U.S. government data — public domain, no copyright restrictions.