Image Question.

[Russman (Russ)]

Hi, I took this photo last night, can anyone tell me why the stars around the edge look like little bird shapes? Might it just be what happens with the lens I was using? 50mm canon f/1.4

Also what have I photographed, I think its a star cluster

cheers & Merry Christmas.

[Jon (Jonathan)]

Hi Russ,

What you've got there is the Large Magellanic Cloud, a dwarf galaxy companion to our own galaxy about 160,000 light years away. It's a fascinating object full of nebulae,dust and other features, some of which are coming out nicely in your image.

The aberration at the edge of the field is called coma, and is a feature of many optical systems. It gets worse the faster the system, so you can reduce it by stopping down the lens from f/1.4 to something like f/3.2 or even slower. Of course, this will increase the exposure time required for the same level of detail.

This will also reduce the chromatic aberration - the little purple rings around the brighter stars.

[Russman (Russ)]

Thanks Jon,

I have a star tracker I made a while ago, I'll try it out with those settings and post results later!

Cheers man

[Russman (Russ)]

I tried out my star tracker but didn't align it properly so there was some vertical trailing of the stars, I was pretty disappointed as the image previews on the camera looked pretty good.

So here is a 5 image stack of 4.5 sec; f/1.4; ISO 6400 shots, (not tracked) processed in Photoshop CC. Hopefully I align it properly next time!