About & editorial policy

Why this site exists

A telescope’s aperture sets a hard physical ceiling on what it can ever show you. How faint a star it reaches, how close a double it splits, how far you can push the magnification before you are just enlarging blur — all three fall out of one number, and none of them can be bought back with an accessory.

Almost nobody does that arithmetic before buying. The box leads with a magnification figure the optics cannot deliver, the listing repeats it, and the specification that actually decides the answer sits three rows down a detail table. Aperture exists to do the arithmetic in public: to take each telescope’s own published aperture and focal length and work out what it can physically do, in figures you can recompute yourself.

🔴 What we do not claim

We have never observed with any of these telescopes, and we never say we have. Nobody here has carried them to a dark site across three winters, and if we wrote that we had, you would have no way of checking it — which is exactly why so many sites write it.

There is no test bench, no reviewer with a fictional biography, and no invented location. We have not created an astronomer with twenty years under a mountain sky and a friendly headshot to make the figures feel more authoritative. It is a common tactic in this niche, and it contradicts the methodology printed on the same page.

What we trade for giving up those claims is that everything we do assert becomes checkable. That is a worse marketing position and a better deal for you.

How a figure gets onto a page

1. Every optical claim is computed, never repeated. Limiting magnitude, Dawes limit, focal ratio, exit pupil, true field of view, useful magnification and astrophotography sampling all come out of one shared file — src/lib/optics.ts — with the derivation written into the source beside each formula. Two pages cannot disagree about what a 200 mm mirror does, because there is only one place the answer is produced.

2. The formulae are cross-checked against a manufacturer’s own published figures. Celestron publishes full optical specifications for the NexStar 8SE (203 mm aperture, 2032 mm focal length), so we ran ours against theirs:

3. Where we disagree with a manufacturer, we say so rather than hide it. That last row is deliberate. Manufacturers quote 60× per inch of aperture; we use the conservative field rule of 50× per inch, because on a typical night it is the atmosphere and not the optics that sets the ceiling, and a reader who buys expecting 480× of usable magnification will be disappointed by the sky rather than by the telescope. We print the manufacturer’s number alongside ours so you can see the gap and decide. An open disagreement you can check is worth more than an agreement you have to take on trust — and it is the clearest demonstration we can give that the numbers here are produced rather than copied.

4. Recommendations follow the physics, not a preference. Where we name a telescope, the reasoning is the computed capability of the aperture it publishes, stated in the same figures as every other scope on the page. You can run our magnification and eyepiece calculators against any specification you like, including one we have never mentioned, and get the answer the same way we did.

Where the data comes from, and where it stops

Specifications are read only from a listing’s own detail table, never from its title. Titles are marketing copy, and a number in a title is frequently not the number it appears to be.

Some listings contradict themselves, and we refuse to compute from those. One telescope in our set advertises a 150 mm aperture while its own specification table says 114 mm. Those are two genuinely different telescopes, and there is no honest way to pick which half of the listing to believe. We flag the contradiction, show it, and keep that product out of every calculated figure on the site. A confidently wrong capability number is worse than an absent one.

We do not rank anything by portability, because the weight data is unusable. Amazon’s item-weight field mixes shipping weight, tube weight and full system weight without saying which: the same 305 mm collapsible Dobsonian reads 13.7 lb on one listing and 35 lb on another, and the lower of those is lighter than a 150 mm tabletop scope. Ranking on a field that inconsistent would produce a confident, sorted, wrong answer, so we leave it out and tell you the trade in words instead.

Prices and availability are captured on a date that is printed on the page, and they drift. Amazon listings also silently change to a different model, which is why an ASIN being wrong is one of the most useful things a reader can report.

What this method cannot tell you

It cannot tell you how a focuser feels after a year of use, whether a particular mount shakes in wind, how much sample-to-sample variation there is in a given manufacturer’s optics, or which supplier is honouring warranty claims this season. Those questions need hands on equipment over years, and we have not done that.

When you need that kind of answer, Cloudy Nights has decades of it, written by people with nothing to sell. We link there repeatedly and earn nothing when you go. A site that never sends you anywhere else is telling you something.

Where we are, and who we write for

Aperture is a US-focused publication, not a local business. Prices are in USD, products are sourced from Amazon.com, and figures use the conventions a US amateur will recognise — inches alongside millimetres, pounds for payload.

We do not publish a business address, and we would rather say why than leave a gap. A street address on a national publication signals a local shop we are not, and plenty of affiliate sites invent one precisely because it looks reassuring. We would rather tell you what we actually are: a small independent site that computes optical capability from published specifications, for readers anywhere in the country.

What we do take seriously is the thing geography actually changes here, which is your sky. Limiting magnitude assumes a dark, transparent site; under suburban light pollution expect one and a half to two and a half magnitudes worse, and where that changes the advice our pages say so.

Corrections

If a number here is wrong we want to know, and we would rather correct a page than defend it. Because every optical figure comes from one shared file, an error in a constant is an error on every page at once — which is deliberate, since it means fixing it once fixes it everywhere. Material corrections are made in place and the review date at the top of the page changes. All pages currently carry a review date of 20 August 2026. Reach us via contact.

Money

We are an Amazon Associate and earn a commission on qualifying purchases made through our links, under the tracking ID telescopious-20. It costs you nothing — the price is identical to going to Amazon directly, and the commission comes out of Amazon’s margin. The full details are on our affiliate disclosure page, including the part most sites omit: Amazon’s cookie lasts 24 hours and pays us on unrelated purchases too. No paid placements, no sponsorships, no gifted equipment, and no brand has seen a page before publication.