FOV with a barlow for photowork

EzyStyles (Eric) · #1 07-10-2006, 08:35 PM

Hi Guys,

My FOV is quite enormous with the 8" F/4 was wondering if maybe an ED 2x barlow or even a 3x help? what are the affects with a barlow for astrophoto work? I want to get right up close. This should increase the focal ratio?

thanks.

Striker (Tony) · #2 07-10-2006, 08:43 PM

Can be done Eric but you may not be able to get focus....borrow a barlow before you go buy one.

And yes it will slow down your scope meaning your going to need to take longer exposures and more exposures.

Thats why I am not that thrilled imaging at F10.

Give a 2x barlow a go.....3 x would be far too dificult to manage and at F12..well hardly worth while....you would have to image for 5 times your current exposure time for the same result.

janoskiss (Steve H) · #3 07-10-2006, 09:02 PM

Keep in mind exposire time goes like square of magnification:

2x barlow -> 4x the exposure
3x barlow -> 9x the exposure
etc

EzyStyles (Eric) · #4 08-10-2006, 05:45 AM

cheers guys thanks. that explains it. Anyone kind enough to lend me their 2" 2 x barlow?

janoskiss (Steve H) · #5 08-10-2006, 09:54 AM

How about the GSO 2" barlow from Bintel? They are pretty good units, and a bargain for $70-$80.

EzyStyles (Eric) · #6 08-10-2006, 01:00 PM

yea i saw that. any big advantages with the ED version?

janoskiss (Steve H) · #7 08-10-2006, 01:05 PM

Quote:

Originally Posted by EzyStyles

yea i saw that. any big advantages with the ED version?

dunno. marketability?