Tag: Explore scientific coma corrector

M3 Globular cluster

Finally there was a nice weather and no Moon. Summer nights are short; therefore it’s not optimal for deep space objects, which require very long integration time. Therefore I pointed my telescope this evening to globular cluster M3.

This cluster is located in constellation Canes Venatici and it’s one of the largest known clusters, because it contains around 500 000 stars.

Technical details:

Telescope:Newton 254/1000 mm
Aperture:254 mm
Focal length:1000 mm
MountGemini G53f
AutoguidingZWO 174MM, TS 60/240 mm
Camera:Mii G2 8300
Corrector:Explore scientific CC
Filters:Baader LRGB
Exposure:16xL 180s bin 1x1, 8xRGB 120s bin 2x2

Worldwide coma correction exercise


What is coma and why needs to be corrected. Coma is a special type of an optical aberration. It’s mainly visible in the astrophotography – the stars are deformed into comet-like shapes:

Fast Newtonian telescopes suffer from comatic aberration, mainly in the corners of the photos. These telescopes are nowadays very popular between amateur astrophotographers just like me, because they offer the best price/aperture ratio. There is easy way how to suppress the comatic aberration – coma correctors. There are many coma correctors on the market, but there are just a few published reviews or comparisons between them. Therefore I decided to perform the comparison myself. Quite big collection of coma correctors has assembled in my drawer ready to be tested: