DWARFLAB Dwarf 3 Smart Telescope

The DWARFLAB Dwarf 3 is a £499 smart telescope: camera lenses on a tripod mount, controlled from a phone app, with auto-tracking, 4K capture and no eyepiece anywhere in the box contents. It takes fourth place in this guide on a 4.5 average from 428 Amazon ratings. It is also the entry whose spec sheet we could not catch out.

Start with the arithmetic that the refractors in this guide fail. The Dwarf 3's focal length description reads "35 mm f/4.28, 150 mm focal length, 737 mm equivalent focal length". Divide the 150 mm by the f/4.28 and you get 35 mm — the same figure the same sheet gives as the objective lens diameter. Divide the 737 mm equivalent by the 150 mm and you get a crop factor of 4.9, which is an 8.8 mm sensor; an 8.8 mm sensor behind a 150 mm lens gives a diagonal field of about 3.4 degrees, and the listing says 3.38 degrees. Three numbers, one answer. Compare that with the three telescopes in this guide whose own aperture and focal length produce f/2.5, f/2 and f/2. One figure is left over, and it is the one a buyer has no way to check: the Dawes Limit of 2.76 Arc Sec, which is the figure usually quoted for a roughly 42 mm aperture, not the 35 mm listed here.

Price is what the reviews argue about, not the machine. The £499 is called "expensive" in one long review that then says it is simplicity that makes it work, and "a small amount of money for what it does" in another. Everything on this page is taken from the Amazon listing and the reviews on it; we have not used the Dwarf 3, and no figure here comes from our own testing.