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Study of the effects of some commun astronomy filters on a street light high pressure sodium lamp spectrum
Attention : I have been told after posting this page that some large band pass filters are optimized for F4-5 while small band pass filters for F8-12 ...
Otherwise a shift towards the blue may occur !
The lamp (order = 0) is completely on the left
Acquisition : Defiltered Canon 300d, Jeulin 530l/mm in front of a Sigma 18-50 mm F3.5-5.6 used at 50mm and F5.6, 0.3s, 100 ISO

All thoses spectra have been done with SpectroTilt V0.4, using only one not too much tilted ligne of the original images.
Development of SpectroTilt is done actually to permit to blend more adjacent lines.
IMG_8222-Control-NoFilter


For more details on SON spectrum, please visit this interesting web page http://www.astrosurf.com/astro-images/spectro-buil/sodium/sodium.htm
IMG_8223-Lumicon-HalphaPass
IMG_8225-Lumicon-UHC
IMG_8227-Lumicon-OxygenIIIe
IMG_8222-Control-NoFilter
IMG_8228-Lumicon-HBeta-HorseHeadNebulaFilter
IMG_8229-IDAS-LPS-P2
IMG_8222-Control-NoFilter
IMG_8231-Celestron-LPR
IMG_8250-BaaderContinuum
IMG_8236-BaaderContrastBooster
IMG_8222-Control-NoFilter
IMG_8234-B&W-IRPass-RG695
IMG_8233-B&W-IRPass-RG830 or 950
IMG_8237-IMG_8237-Hoya-Tungstender
IMG_8222-Control-NoFilter
IMG_8238-MeadeSerie4000-BlueN°38Aooster
IMG_8239-Parks-OrangeN°21
IMG_8240-Celestron-GreenN°58
IMG_8222-Control-NoFilter
IMG_8241-Parks-Red-R25
IMG_8242-IRCutOld
IMG_8243-Baader-(UV-IRcut)
IMG_8222-Control-NoFilter
IMG_8244-Meade-YellowN°12
IMG_8245-Schüler-UV
IMG_8246-Red+IRCut-Astronomik-Type2c
IMG_8222-Control-NoFilter
IMG_8247-GreenIRCut-Astronomik-Type2c
IMG_8248-BlueIRCut-Astronomik-Type2c
IMG_8249-IRCut-Astronomik-Type2c
IMG_8226-Lumicon-MinusVioletumi

Above : effect of the standard 90mm Coronado sun H-Alpha filter.
Acquisition : Defiltered Canon 300d, Jeulin 530l/mm in front of a Sigma 18-50 mm F3.5-5.6 used at 50mm and F5.6, 0.3s, 100 ISO
(The rear filter is very dark then exposure has been increased 50x !)

Example of use of this page : I have found a new use for my LPS filter !

click for allmost original size images (1Mo) :

Auto / TV / TV-LPS

Link to a great page concerning the same subject :

http://www.astrosurf.com/buil/filters/curves.htm

Wratten Color filter curves (more on demand)

18a-21-22 23a-24-25 26-29-30 31-32-33 34-34a-35
36-38-38a 46-47-47a 47b-48-48a 49-49b-50 57a-58-59
66-70-72b 73-74-75   near IR