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Re: Does anyone know what 80-a & 80-b filters are

Started by asterhunter, 12/10/2006 05:58AM
Posted 12/10/2006 05:58AM Opening Post
Brian,
You may have noticed how a redden sky looks darker and redder viewed through the blueish tint across the windshield of your car. Blue filters like the 80 series can do the same thing although the astronomical effect is much less striking. Blue filters work well on Mars and Jupiter. Some people use a light blue filter as an aid to splitting tight doubles. I would recommend getting a B+W brand filter. They make this in 46mm size, and I use a 48mm-46mm step down ring to put in on my 2" diagonal or my 2 to 1-1/4" adapter. I use the 81 and 85 series more often though. These "warnming" filters are particularly usefull on planets during the dawn and dusk hours, and I like using the 81A on Jupiter.

David E