Filter Research

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A big thank you to everyone that has helped my on this pet project.  Without your contributions my research could not have been as thorough or enlightening!

Thank You's:

  • Special thanks to Brian and Joanne at Island Eyepiece & Telescope Ltd. (now gone) for providing me the data they had on Sirius Optics brand filters, and for providing a source for Lumicon colour filters, plus the help with all my other questions.

  • Thanks to Ted Ishikawa at Astro Hutech for providing me data on their IDAS line of filters as well as sample filters to test, and to Mia Ishikawa for her fast & courteous online purchasing support.

  • Many thanks to Manish and Sarah at Agena Astro for their great support with Baader Planetarium brand filters as well as lots of other bits and pieces.

  • Thank you to Vivien Zhao at Changchun New Industries Optoelectronics Tech Co. Ltd. in China for her help in making an otherwise impossible purchase of rare wavelength laser pointers possible (and affordable!).

  • Thanks to Adirondack Astronomy (now gone) for their quick and dependable supply of Astronomik brand filters and Lumicon brand filter changers.

  • Thanks to Stella Song at Optolong Optics Co. Ltd. for her friendly and courteous support including providing me with sample filters to test.

Filter Data Sources:

  • The images of deep-sky filter spectral responses I used in my analysis were found by me from all over the internet.  Some on manufacturer websites, some on reseller websites, and some buried in papers that were available online.  I have packaged all the source images together into a single downloadable archive for reference.  <deepsky filter source>

  • The Kodak Wratten and Colour Compensating filter spectral response data was published in older editions of the CRC Handbook of Chemistry and Physics (which is what I have), but is no longer in current editions.  I did happen to find a scanned in copy of this section of the book online in case anyone is interested. <transmission of wratten filters.pdf>

  • : A great site containing deep-sky filter spectral response data as measured by a third party with a spectrometer.  Note that Christian Buil's measured response of Meade brand filters showed a much lower response than quoted by the manufacturer, but I have chosen to use the manufacturer's data in my analysis.  His other plots match fairly well with the responses reported by the manufacturer.

  • André Knöfel      most extensive collection of transmission spectra

  • Thomas Klotzbücher  (link now broken) collection of transmission spectra

  • Mike Lockwood collection of measured filter spectra

  • Reiner Vogel website on filter spectra

  • Cloudy Nights user "dobrychemik" explanation on CN, and link to Google Drive with his reports

  • I have tried to very carefully and consistently take pictures of the spectrum of colour filters I have used in my research so that people can visually compare my filters to what they are using.  The resulting images are below.

Miscellaneous Filter Info Links:

Introduction  -  The Human Eye  -  Planetary Filter Research  -  Using Planetary Filters  -  Deep-Sky Filter Research  -  Using Deep-Sky Filters  -  References

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Last updated: 06-Jun-23

Copyrights to all content from the webpages hosted here belongs to Jim Thompson. Nov. 2009.