Your typical black anodized coatings do not block infrared spectrum light, I am not sure if I am the only person seriously bugged by this, or maybe it is something that not alot of people are aware of.
I see alot of internal reflection issues lately and while they seem to usually be resolved, I cannot help but wonder how much contrast we are loosing in our images by shooting through black anodized focusers, filters, reducers, and camera bodies lined with black anodized coatings. Sure you can adjust contrast in post processing, but the data that you are loosing to poor contrast before it is recorded by the sensor is un recoverable.
In the past I had taken some example pictures with my dslr and an infrared pass filter, my black anodized telescope was a solid shiny silver behind a 720nm pass filter.
I have not tried a 540nm filter yet but I just ordered one for funzees to see what happens. Imagine the impact this contrast issue would have on Ha and SII.
It would be interesting to see a spectral analysis of generic anodized black to determine exactly where the "black" color drops off. Obviously to our eyes in the visible spectrum this is not an issue. Under infrared though, you have potential to create an ir reflective hotspot at worst and also negatively impact your contrast.
Today I found a company that produces a full spectrum anodized coating. Does anyone know anything about this product? https://www.pioneerm...k/optical-black
Would it be logical to start pushing manufacturers to adopt a higher standard coating? I have not intent to fill out an RFQ to get costing on this product, but assuming it is not fiscally unobtanium, maybe we could see something like this
in our future astro products.
If you have a dslr and an infrared pass filter I encourage you to take a snap shot of your gear an upload an image so people can get a better understanding of what I am talking about here.
Edited by calypsob, 18 February 2019 - 12:07 PM.