Try GOLD - Free

ASTROPHOTOGRAPHY PROCESSING

BBC Sky at Night Magazine

|

February 2023

Reduce star trailing in your astro images, An easy processing tip to remedy stretched and unsharp stars

ASTROPHOTOGRAPHY PROCESSING

Astrophotography is an extremely rewarding aspect of astronomy, but as any astro-imager will know, conditions often aren't in our favour, which is why we have to take advantage of those rare clear nights whenever they come around. It can be disappointing, then, after capturing those precious images, to discover that they suffer from star trailing.

Slightly trailed stars can be caused by a misbalanced mount or one not quite correctly aligned with the polar axis, making your stars look either stretched or appear as short lines. It would be easy to delete your images and accept that your night's work was in vain, but wait: in some circumstances, you may be able to salvage something from those images by using a simple but effective tip.

In our example we took 21 images of Brocchi's Cluster, also known as the Coat Hanger Cluster, a tiny asterism shaped like a coat hanger in the constellation of Vulpecula. On cursory examination, the stacked image looked good, but when we looked more closely we noticed the stars were slightly trailed.

Star shape enterprise

MORE STORIES FROM BBC Sky at Night Magazine

BBC Sky at Night Magazine

Vaonis Vespera Pro smart telescope

Swift, effortless and seriously capable - this scope makes every session count

time to read

4 mins

November 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

25 years of life in orbit

Humans have now continuously occupied the International Space Station for a quarter century. Ben Evans celebrates the milestone and asks what's next

time to read

4 mins

November 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

How dark is your sky?

Discover the Bortle scale, a simple way to judge night-sky quality wherever you are

time to read

4 mins

November 2025

BBC Sky at Night Magazine

Comet 24P dives into the Beehive

A faint comet sneaks across M44 under moonlight this month. Can you catch it?

time to read

3 mins

November 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

Space conspiracies EXPOSED

Armed with hard science, Alastair Gunn takes apart 10 of the most popular and persistent space conspiracy theories

time to read

6 mins

November 2025

BBC Sky at Night Magazine

JWST discovers new Moon orbiting Uranus

At just 10 kilometres wide, this is the smallest satellite yet found around the ice giant

time to read

1 min

November 2025

BBC Sky at Night Magazine

Bresser PushTo AR-80/400 smart telescope with tripod

This bargain app-assisted starter set takes you from box to stars in minutes

time to read

4 mins

November 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

NASA finds new evidence for life on Mars

Biosignatures of potential ancient microbial life found in dry riverbed

time to read

1 mins

November 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

Finding peace in deeptime

Daily worries getting you down? Think about the scale of the Universe, says Mark Westmoquette - the Big Picture will make those anxieties so much smaller

time to read

2 mins

November 2025

BBC Sky at Night Magazine

Match your setup to your seeing

Optimise your gear to get sharper astrophotos whatever your sky conditions

time to read

3 mins

November 2025

Translate

Share

-
+

Change font size