Good morning all
I have a kline baader filter for imaging but it still possible to use it visually with my herschel baader
K-line baader
- marktownley
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Re: K-line baader
Baader don't recommend it.
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- MalVeauX
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Re: K-line baader
Heya,
Here's the warning from Baader and why:
There's no inherent harm in using the filter for solar visually, the warning is to prevent people from using it without any primary filtration first, such as solar film (visual grade for visual of course). It will be safe behind that. It will not be safe, visually, behind photo grade film. Basically they just don't want someone to throw it into their visual scope's eyepiece and use it without any other filtration so they don't cook an eyeball. Mounted with a herschel wedge, you still likely need to use the supplied ND filter to grind down transmission for use. Ultimately though, there's no reason to use it visually since we cannot see this wavelength really.
Visually though its not useful. It's 394nm with 8nm bandwidth. This is near UV. There's zero unique features to be seen in this wavelength at 8nm bandwidth compared to green or red wavelengths that your eye is far more sensitive to. The only benefit is higher angular resolution, but this will not be realized by eye visually, only by camera sensor. Wavelengths near UV, like 393nm~395nm are really "imaging only" because our eyes are simply not sensitive to near UV wavelengths. You simply won't see much if anything, especially if older with yellowed cornea.
Very best,
Here's the warning from Baader and why:
Emphasis on "without an additional OD-reduction filter."Never look into the sun with the K-Line filter without an additional OD-reduction filter.
There's no inherent harm in using the filter for solar visually, the warning is to prevent people from using it without any primary filtration first, such as solar film (visual grade for visual of course). It will be safe behind that. It will not be safe, visually, behind photo grade film. Basically they just don't want someone to throw it into their visual scope's eyepiece and use it without any other filtration so they don't cook an eyeball. Mounted with a herschel wedge, you still likely need to use the supplied ND filter to grind down transmission for use. Ultimately though, there's no reason to use it visually since we cannot see this wavelength really.
Visually though its not useful. It's 394nm with 8nm bandwidth. This is near UV. There's zero unique features to be seen in this wavelength at 8nm bandwidth compared to green or red wavelengths that your eye is far more sensitive to. The only benefit is higher angular resolution, but this will not be realized by eye visually, only by camera sensor. Wavelengths near UV, like 393nm~395nm are really "imaging only" because our eyes are simply not sensitive to near UV wavelengths. You simply won't see much if anything, especially if older with yellowed cornea.
Very best,