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Group Information

  • Members: 401
  • Category: Astrophotography
  • Founded: Jul 21, 2002
  • Language: English
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Description

This group is dedicated to the discussion of imaging filters including RGB, CMY, and Narrow band filters such as Ha, Sulfur, OIII ect. Please feel free to discuss these, offering advice and examples of images taken with various filter types for the benefit of all.

This stunning image of NCG281 is the product of 30 hours of imaging by Russ using a 20" f8 Ritchey. He mapped SII, Ha, and OIII as RGB and additionally Ha as luminence.

Image Credit: Russell Croman


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Re: Anybody here using a HeII filter??
Their were these laser scanners that computer identics was making. They had some filters made up. They worked fine straight ahead but off axis they would
Posted - Wed Nov 18, 2009 1:06 pm
 Lawrence D. Lopez
lawrence_d_l...
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Re: Omega Hb filter transmission test - Oh Oh
Hi, this filter will be returned for refund. I did an out-of-bandpass transmission test, 190-950nm. The file can be seen if file folder Filter tests, file
Posted - Tue Oct 27, 2009 2:22 pm
 ssb73q
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Omega Hb filter transmission test
Hi, I just couldn't resist the purchase of a $119 Omega 2" Hb filter sold on eBay. This filter is from a lot of 10, I purchased the first one, nine remain.
Posted - Mon Oct 26, 2009 11:20 pm
 ssb73q
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Re: Anybody here using a HeII filter??
Of course that is only an approximation; not all rays have the same angle on the filter. the on-axis rays are perpendicular the chief ray angle for a extreme
Posted - Tue Oct 20, 2009 10:51 pm
 Richard Crisp
s2hao3
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Re: Anybody here using a HeII filter??
Re: filters shifts to the red to compensate for fast optical systems ... If a NB filter has a flat top, the transmission profile is placed in a way that the
Posted - Tue Oct 20, 2009 7:50 pm
 Wolfgang Renz
wr_astro
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2009 22 4 15 21 1
2008 80 77 13 58 34 4 1 5 1 2 28
2007 17 31 59 6 33 44 60 38 31 16 4 71
2006 18 20 33 14 6 4 13 6 6 6 14 15
2005 2 8 6 7 14 28 23 33 114 35 69 51
2004 10 6 12 17 2 1 3 7 11 5 6 18
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2002 52 70 125 54 23 53
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