about EP FOV and DSO dimemtion

[alfredbird]

I am a little bit confused now.

Wiki says NGC 5139 is about 36.3 arc sec, why it occupys more than 50% of my EP which should have FOV of 42 arc min.

EP 13mm, 65 FOV on a 1200mm F/4.7 10 inch dob, which gives FOV of 0.7 degree.


anyone can help me this those calculation? many thanks.

[Robh (Rob)]

Originally Posted by alfredbird

I am a little bit confused now.

Wiki says NGC 5139 is about 36.3 arc sec, why it occupys more than 50% of my EP which should have FOV of 42 arc min.

EP 13mm, 65 FOV on a 1200mm F/4.7 10 inch dob, which gives FOV of 0.7 degree.


anyone can help me this those calculation? many thanks.

Hi Alfred,

36'.3 is in fact 36.3 arcminutes. Jupiter is from 30 to 50 arcseconds in diameter, written 30" to 50".

Regards, Rob