Quote:
Originally Posted by skysurfer
I looked up Jupiter well before sunset with my 11cm ED without problems, but when I put a pol filter (way too large to screw it in as it is 52mm) behind the eyepiece and rotate it properly, the blue sky background is MUCH darker, while Jupiter does not get darker. This enhances contrast considerably, so awesome ! I could also find the nearby Alpha Librae, but not the moons.
This works best for objects 90 degrees from the Sun like Jupiter now.
So now I ordered a 1.25" pol filter to screw in my eyepieces or diagonal.
Any other experiences ?
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Hi,
See my article on Visual Astronomy and the Use of Filters. Towards the end I briefly discuss Lunar and Planetary Filters
http://www.iceinspace.com.au/63-680-0-0-1-0.html
I gave a talk at IISAC in 2012 on this.
It reduces irradiation (distortion of the colour change boundaries) which helps to improve the contrast !!
A Broadband Light Pollution Reduction Filter also can work very well as a planetary filter, as it does the same thing.
Cheers
John B