fine tuning ring ? (1 Viewer)

mark richards

Well-known member

• Sep 28, 2012

• #1

hi all got a hyperion 13mm eyepiece on pentax 80mm scope, would it be worth me getting a fine tuning ring...thinking of 14mm ,for extra reach...its all new to me...will i lose any light?...any help would be great...mark

 

P

Paul Corfield

Well-known member

• Sep 28, 2012

• #2

The 14mm ring would take the eyepiece to 10.8mm so there would be some loss of light, probably not a great deal though. Any form of extra magnification equals loss of light as long as the objective remains at the same diameter. The rings are fairly cheap and they don't affect image quality, so it's probably worth experimenting.

Paul.

 

mark richards

Well-known member

• Sep 28, 2012

• #3

thanks Paul...any idea what magnification that would give me...mark

 

P

Paul Corfield

Well-known member

• Sep 28, 2012

• #4

If you have the PF80ED-A then the focal length of the scope is 518mm. Divide that by the mm of the eyepiece to get the mag. 10.8mm would give 48X and 13mm almost 40X. The straight scope is 504mm so the mag will be slightly less if you have that one.

Paul.

 

mark richards

Well-known member

• Sep 28, 2012

• #5

thanks again...mark