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Has anyone ever tried this

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#1 MG1962

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Posted 18 December 2012 - 01:28 AM

Would variable polarized filters have much effect on double stars where one companion is buried in the glare of the primary such as Sirius A and B

#2 Rachal

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Posted 18 December 2012 - 09:50 AM

If you have one, give it a shot on something easier like Rigel and see how it works. Interesting question. It would be nice if it would; one might have better luck with an occulting bar, however.

#3 MG1962

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Posted 18 December 2012 - 11:09 AM

I dont own one, and have never done enough Luna observing to consider the expense - Rigel would be an excellent target because I can already split that and can compare the performance

#4 Rachal

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Posted 18 December 2012 - 04:39 PM

Years ago I made an 'apodizing' filter using window screen, which is "supposed" to help with double stars. You might do a search to see if this is something that would interest you.

#5 blb

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Posted 18 December 2012 - 11:28 PM

Years ago I made an 'apodizing' filter using window screen, which is "supposed" to help with double stars. You might do a search to see if this is something that would interest you.


Easy to make and it works well. ;)

#6 Asbytec

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Posted 19 December 2012 - 12:35 AM

When apodizing, you really have to optimize the screen for high frequencies of double stars. Apodizing tends to slightly enlarge the spurious disc while greatly diminishing the bright ring pattern. This improves contrast at lower spacial frequencies starting about, say, 3 to 5 or more times the Raleigh limit depending on the mesh and radii used.

At these separations doubles would not qualify as close pair where ring brightness might matter. You might loose the dark space at the Raleigh limit observing a classic Raleigh pair and Dawes splits would be more difficult. Wider doubles might be more aesthetically pleasing, however, as well as larger planetary details.

Another trick to observing Sirius pup is to have very clean optics to reduce glare. Some folks have uses square aperture mask to change the shape of diffraction. But, a good neutral density filter might help, too.

#7 Ed Wiley

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Posted 19 December 2012 - 05:52 PM

You might be interested in these articles by Jim Daley. JDSO is always a good source for innovative techniques.

http://www.jdso.org/...mber4/Daley.pdf
http://www.jdso.org/...mber4/Daley.pdf

Ed






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