About How Many Subs

Built by a smart-telescope owner who got tired of guessing. Every forum thread about a Seestar or a Dwarf ends with the same question, "how long should I image this?", and the same answer, "it depends". This site works out what it depends on.

The calculator and every page on the site come from one small photon-budget model, described in full on the methodology page. It is deliberately simple: a handful of published constants, catalogue data for 172 objects, and manufacturer specs for 16 telescopes. Simple means you can check it, argue with it and improve it.

Corrections

If a catalogue value is wrong, a spec has changed with a firmware update, or your real-world experience disagrees with a figure by a wide margin, email [email protected]. Numbers with sources get fixed quickly.

Support the site

The site has no paywall and no sign-up. If it saved you some money or a wasted purchase, you can tip it in bitcoin over Lightning: ⚡ [email protected]. Any amount is welcome, and it never changes a result.

Independence

The site is not affiliated with ZWO, DwarfLab, Vaonis, Unistellar, Celestron or any retailer. Gear and “where to buy” links are affiliate links to Amazon and to the retailers named beside them; they do not change the prices you pay and they do not influence the numbers, which come from the model alone.