The Hidden Galaxy in near infrared.
An experiment with near IR photography on deep sky objects. Because my Baader filter set is still in backorder and I already have the 2 Astronomik IR-pass filters, I started a project in IR. I had intended those 2 filters anyway to try and capture these kinds of galaxy targets (IC342, the Hidden Galaxy) that are hidden behind the Milky Way band in infrared. The idea behind this was that light with a longer wavelength passies easier through the Milky Way dust and thus produces more contrast on these types of objects. Another nice thing is that the cool red stars in the IR804 filter are suddenly very bright compared to the hotter blue stars in the visible spectrum.
Now I have taken 3 filters and mapped them to RGB
(Red): IR804 (> 804nm): 30x300s:
(Green): IR642 (640 to 840nm): 30x240s
(Blue): Baader moon & skyglow (400 to 700nm): 75x240s
To see the 3 indivual unprocessed stacks take a look here:
https://www.instagram.com/p/CLfgHwkJzDY/?utm_source=ig_web_copy_linkThe amount of background brightness (light pollution) was many times less in the 2 IR channels than the Luminance. In hindsight, this seems logical to me because bluer light is scattered more in the atmosphere and therefore more reflected to the ground, causing more light pollution in the blue than in the red.
If I consider it this way, I would not really know why we often use an IR-cut filter for the luminance channel instead of a clear filter. (with the exception of refractors due to color error on the IR part of course).
All in all a pretty successful test and a special image with a little freaky color scheme 🙂
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