What do you get before a planetary nebula? A proto-planetary nebula, of course. But what do you get before that? A variety of carbon star in a cocoon of carbon dust and gas that makes it almost invisible in visible light. A proto-proto-planetary nebula, if you will. The most nearby example of this is CW Leonis (also with the infrared source designation IRC +10216), a carbon star "only" 320 light years away from us that is about 3 to 5 times more massive than our sun. Its so close that the tiny nebula around it is resolvable with an amateur scope like my 16". The trick is that in visible light the star is barely visible and the nebula is nearly completely invisible below 800nm, emitting all of its light in near-IR and IR! There is also a large bubble of UV emission that would fill the field of view here, but my telescope would have to be in space to detect that.
Conveniently, CMOS and CCD cameras can detect near-IR wavelengths beyond 700nm all the way up to 1000nm if you leave the UV/IR filter off. One shot color cameras see these colors as magenta because the blue pixel filters have increasingly large transmission as the wavelength heads from 750 to 1000nm, while the red pixel filters gradually drop off in transmission with rising wavelength. This produce color tints that give you a rough idea of the dominant emission band of an object.
I captured the large field in this image without a filter. You can see a 200% zoom in the left inset showing the nebula detail. I then imaged it again with an IRCut filter. You can see these in the right 4 insets showing the IRCut filter RGB image at the top right showing CW Leonis as a dim intensely red star and then the three insets below that showing the R, G and B channels. You can see that the star is simply missing in the G and B channels where no light escapes it carbon dust cloud. Without the any filter, the star bursts into brilliance powered by strong near-IR and IR emission.
There is a suggestion that CW Leonis has some sort of faint companion of unknown type in a recent paper reporting ALMA observations of the star. It must be incredibly dim as it doesn't seem to emit any visible light to speak of. I suppose the companion might be a brown dwarf? There is also a very extended bowshock nebula around the object emitting in UV (as I mentioned above). You can see an image here, along with more information on the star itself (I think the Wikipedia distance of 120pc is out of date):
https://en.wikipedia.org/wiki/CW_LeonisHere is a webpage with information about CMOS camera sensitivity at varying wavelengths:
https://ir-photo.net/ir_imaging.htmlThis has been in my staging area for a while - I simply forgot to go back and make it public. It was kind of a proof of concept test, but the result was interesting. Certainly worth a longer exposure to try to capture more of the nebula. Funny that this has a PGC galaxy catalog entry as you can see in the Astrobin plate-solve. It most definitely is not a galaxy!
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