Backwards filters? I lost track...

Equipment Filters Light Pollution Filter
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DanRossi avatar
DanRossi avatar
Hi everyone,

I'm in a bit of a bind.   I own 2" mounted Baader Moon and Skyglow Neodymium and IDAS NBZ filters.  I took both filters out of their mounting cells awhile ago and now I need to remount them. But......I cannot figure out which sides are the "front" (pointing towards the sky) and the "back" (pointing towards the camera). Doh! 

Here are additional details:

Baader Moon and Skyglow:  the images online show a purple sheen on the "front."  Using that as a reference, I put the filter in the direct sunlight and noticed one side indeed has a purple sheen, and the other side has a green sheen.  So I'm concluding that the purple side is the "front."

IDAS NBZ: unlike the Baader Moon and Skyglow filter, both sides of this filter look identical.  Both sides are reflective and have a silver sheen.  I'm thinking orientation doesn't matter for this filter.

I emailed both manufacturers this question, but I doubt I'll get a response until next week....and tonight is a clear night.

What are your thoughts?  Does it matter how the filter is oriented?

Thank you!
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Oscar Echeverri avatar
Oscar Echeverri avatar
From a filtering perspective, it shouldn't matter which orientation they're placed in.  I've always been told to place the filters with the most reflective surfaces facing skyward to reduce reflections toward the camera sensor.
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John Hayes avatar
John Hayes avatar
It does not matter which way the filters are oriented.  I can do a calculation to back it up but I'm too busy just right now to write it up so you'll have to take my word for it.

John
DanRossi avatar
DanRossi avatar
Oscar Echeverri:
From a filtering perspective, it shouldn't matter which orientation they're placed in.  I've always been told to place the filters with the most reflective surfaces facing skyward to reduce reflections toward the camera sensor.

Great thank you!
DanRossi avatar
DanRossi avatar
John Hayes:
It does not matter which way the filters are oriented.  I can do a calculation to back it up but I'm too busy just right now to write it up so you'll have to take my word for it.
DanRossi avatar
DanRossi avatar
John Hayes:
It does not matter which way the filters are oriented.  I can do a calculation to back it up but I'm too busy just right now to write it up so you'll have to take my word for it.

Thanks John! Your word is all I need!
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