Common questions
Is the free tier really free forever? ▾
Yes. The Explorer tier is free forever, no credit card required. It gives access to 10,000 featured stellar objects, the full STEN renderer, and the constellation browser. It is not a trial - it does not expire.
What's in the "full catalog" vs the free 10,000 objects? ▾
The free tier includes the 10,000 most notable, named, and featured objects - all famous stars, all bright stars visible to the naked eye, named pulsars, and famous black holes like Cygnus X-1 and Sgr A*. The full catalog adds 490,000+ fainter HYG/Gaia stars, all 3,300 ATNF pulsars with real period data, and the full NASA Exoplanet Archive.
Can I cancel anytime? ▾
Yes. Monthly plans cancel at the end of the current billing period. Annual plans are non-refundable for the current year but can be cancelled to prevent renewal.
Does the API access count toward my browser subscription, or is it separate? ▾
API access is included in Education and Institution tiers. Standard ($9.99/mo) is a browser-only subscription and does not include API access. If you need only API access, use a standalone API plan. If you need both, the Education tier gives you the best value.
Is there an academic / non-profit discount? ▾
Yes - verified academic institutions and 501(c)(3) non-profits can apply for a 30% discount on Education and Institution plans. Contact us with your institution's email and we'll verify and apply the discount.
Can STEN be embedded on my own website or planetarium display? ▾
The STEN Explorer is embeddable via iframe on Education and Institution plans. The URL parameter system (/explorer.html?obj=NAME) makes it easy to deep-link to any specific object. Standalone embedding of sten.js into a third-party site requires an Institution plan - contact us.