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Aperture Math compares telescopes from the figures their brands and stores publish, then does the arithmetic in the open. This page lists every source, every rule and every gap.
Sources and dates
- Unistellar:
shop.unistellar.com/products.json(prices, USD) and unistellar.com/compare (specifications), read November 7, 2026. - Celestron:
celestron.com/products.json(1,399 products, prices) and the Specifications table of each product page, read November 7, 2026. - Sky-Watcher USA:
skywatcherusa.com/products.json(205 products) and the specification file its product pages load, read November 7, 2026. - Seestar (ZWO):
seestar.com/products.json, prices of the S30, S30 Pro and S50, read November 7, 2026. - High Point Scientific: product pages (price and availability from the page's structured offer, Specifications table), 46 models, read November 7, 2026, five seconds apart as its robots.txt asks.
- Formulas: Celestron knowledge base (magnification, highest useful power), Wikipedia (Dawes limit, Rayleigh criterion, limiting magnitude, exit pupil, true field), NASA NSSDCA fact sheets (apparent sizes). Each is quoted where it is used.
Coverage, and what is missing
49 complete new telescopes (37 with eyepieces, 12 smart), 42 of them priced at two stores. Not exhaustive: we left out tubes sold without a mount, used and refurbished items, and astrophotography rigs. Missing on purpose or by necessity:
- OPT (Oceanside Photo & Telescope): its site announces the company's closure; all 416 telescopes in its catalog showed as unavailable. No OPT price is used.
- Agena Astro and Amazon: not read (Agena's site refused our automated requests; Amazon prices may only be shown through its own tools).
- Vaonis's own store sells in euros; its models are priced from High Point Scientific only. Dwarflab's store did not answer in a readable format.
- Figures a brand does not publish (some weights, fields of view, focal lengths) stay "not published".
How tables are sorted
Tables are sorted by price (lowest price found, cheapest first) or by the figure the table is about (aperture, focal length). Within each row, stores are listed cheapest first. No other weighting exists.
How picks are chosen
Every "Our picks in 30 seconds" badge follows one written rule: the cheapest model that meets the condition written on the badge, among models in stock at the store our button links to. The conditions: 200 mm or more of aperture; finds objects for you (app-guided or GoTo); smart telescope; 125 mm and 1250 mm or more (Celestron's planet guideline); app-guided; Dobsonian of 150 mm or more; GoTo; 130 mm or more under $500; smart telescope with 100 mm or more. The rules live in construire.py and run on the data; we do not hand-pick.
Which store the button goes to
Unistellar models: Unistellar's store (it runs an affiliate program on Awin). Other models: High Point Scientific when it shows the model in stock (it runs an affiliate program on Refersion), otherwise the brand's store. The price tables always show every store we read, including those that pay us nothing. Commissions never change an order or a pick.
What we do not do
- We have not bought or tested any telescope; we never describe a view, a feel or a build quality from experience.
- No star ratings, scores or customer reviews.
- No discount computed by us: a struck-through price only when the store shows one.
- No countdowns or stock counters.
How often
Prices are read on the date printed next to them, not live. We plan a full re-read every month and before major sales (Black Friday, the holidays). Each page shows the date it was last changed.