[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Re: [ATM] Using Barlow to reduce Coma

Mark wrote:

>O.K., so if I were to pop in a 40mm plossl, then coma would look
>as bad with and without the Barlow?
>
>My common sense tells me that as I am only looking at half the field with 
>the barlow in, so
>it would be like looking at the centre area without the barlow -  which has 
>less coma!
>
If coma were linear with field angle (i.e.: half the field would
have half the coma), but the field were magnified twice as much
(2x Barlow), there would be no gain, would there?
_______________________________________________
ATM mailing list http://www.atmlist.net/