By Alexander Merz · Updated on · Details checked on 14 September 2026
Our latest articles on astronomy, stargazing and gear.
Lagrange Points Explained: L1 to L5, Distances and MissionsLagrange points explained: where L1 to L5 are, which are stable, how far they are from Earth and which telescopes orbit there.Read more →Vignetting: Causes and Correction in AstrophotographyVignetting explained: four causes of dark corners, why it shows more in astrophotos and how stopping down, adapters and flats help.Read more →Build Your Own Telescope: Dobsonian, Kit or Grinding Your Own MirrorBuild your own telescope: four routes from a cardboard spyglass to a Dobsonian with your own mirror – what you buy, what…Read more →Sonneberg Observatory: Visit, History and Plate ArchiveSonneberg Observatory in Thuringia, Germany: opening hours, tickets, observing evenings and the second-largest plate archive in the world.Read more →Reflection Nebula: What It Is, Why It Glows Blue and How to Observe ItReflection nebulae scatter starlight and glow blue. Examples such as M 78 and the Pleiades, what you see in a telescope and…Read more →Planetary Nebula: How It Forms, Finest Examples and How to Observe ItWhat is a planetary nebula? How it forms, why it glows green, the finest examples such as M 57 and M 27,…Read more →How to Photograph the Moon with Your Phone: Settings for iPhone and AndroidHow to photograph the Moon with your phone: why it turns into a white blob, which settings help on iPhone and Samsung,…Read more →Collimation: How to Align a Newtonian and Dobsonian, Step by StepCollimate your telescope without frustration: secondary mirror, primary mirror and star test step by step, checking a laser and how often to…Read more →Golden Handle on the Moon: 2027 Dates and Observing TipsThe Golden Handle on the Moon: all 2027 dates with times for Central Europe, where to look, which telescope is enough and…Read more →Emission Nebula: Why It Glows Red and How to See ItWhy emission nebulae glow red, the best-known examples by season and why they look grey in the eyepiece – plus UHC, OIII…Read more →Polar Alignment: How to Align Your Mount with the Celestial PoleHow to polar align an equatorial mount with a polar scope, an app or software: step by step, magnetic declination and the…Read more →Dark Nebula: What It Is, Famous Examples and How to See ThemWhat a dark nebula is, why stars form inside it and which ones you can see: the Great Rift with the naked…Read more →Chromatic Aberration: Cause, Colour Fringing in Telescopes and PhotosChromatic aberration explained: why lenses create colour fringes, longitudinal vs lateral error, what helps in photos and what works at the telescope.Read more →Exit Pupil: How to Calculate It, Table and the Right Size for Your EyeExit pupil explained: the formula for telescopes and binoculars, which size suits which object and why 5 mm is often enough from…Read more →Parts of a Telescope and How a Telescope WorksParts of a telescope explained with a labeled diagram: refractor, reflector and catadioptric, focuser, finder, star diagonal, Barlow lens and mounts –…Read more →How Big Is the Moon? Size & Comparison with EarthThe Moon is 3,474.8 km (2,159 mi) wide, about a quarter of Earth. Some 49 Moons fit inside Earth and it weighs…Read more →Best Telescope Under $500€500 / $500: 7 Telescopes by UseBest telescope under 500: the 8-inch Dobsonian gives the most aperture, the Maksutov the planets, a smart telescope the photos. 7 picks…Read more →Celestron NexStar 6SE: What 214 Owners ReportCelestron NexStar 6SE: specs, price and what 214 owners report. Superb on the Moon and planets, limited for deep-sky photos. Honest verdict…Read more →Kepler-22b: The “Earth Twin” That Probably Isn’t OneKepler-22b is 2.1 times the size of Earth and lies in the habitable zone. What we know in 2026 – and how…Read more →Nebra Sky Disc: What It Shows – and How to See It YourselfPleiades, crescent moon, solstices: what the Nebra sky disc shows, how old it is – and when you can see its scene…Read more →How Long Does It Take the Earth to Orbit the Sun?365 days, 5 hours, 49 minutes: the year explained exactly – with the leap-year logic and the myth about the Sun being…Read more →How Many Stars Are There? In the Sky and in the Universe3,000–6,000 with the naked eye, billions in the Milky Way, 10²²+ in the universe: the star counts – and what light pollution…Read more →How Big Is the Sun? Diameter, Circumference and MassThe Sun is 1,392,700 km across, 4.38 million km around and weighs as much as 333,000 Earths. All the numbers explained exactly.Read more →Stephenson 2-18: the largest known star – and what is uncertain about itStephenson 2-18 is the largest known star: 2,150 solar radii, 20 AU across – and why the record rests on a disputed…Read more →