Re: [Telescopes] Digest Number 590
- In a message dated 10/1/00 12:06:20 AM Eastern Daylight Time,
<< From: callforjim@...
Subject: Re: Binoviewers: The reality
Question: How much light is lost? Would it be less than practical to use
binoviewers with anything less than 6" or so? (not counting the moon.) >>
Well, consider the length of glass path the light has to travel through.
Several inches. Absorbtion accounts for a fair bit of true loss, but the
splitting of the light cone into two parts accounts for far more of it.
Using a binoviewer on an 8" scope reduces it's light to that of a
5.6" scope. So deepsky viewing is severely effected. For planets,
it's not a big issue.