This planetary nebula in Ursa Major is, like all planetary nebulae, an expanding cloud of gas and dust sloughed off a dying star. The star, which you can see in the center of the nebula, is a white dwarf, the super-hot core of what is left of the dying star. The filters used to take this shot cover three wavelengths common to planetary nebulae: Ha, NII, and OIII. In fact, the Ha filter's bandwidth is 12nm wide, and it takes in the NII line. The consequence is that I can't tell whether the red glow in this image comes from hydrogen or nitrogen. The OIII line is far more prominent, however. Ionized oxygen seems to dominate this planetary. M97's distance (and thus its size) are the subject of wildly varying reports, so I have no idea how far away this thing is.This image is 24x8' with the Astronomik Ha filter and 23x8' with the Astronomik OIII filter. The camera was the Atik 16, and the image was shot through the Orion 120mm achromat with the WO 0.8x II ff/fr, at f/4. Color was done with Cannistra's bi-color technique.
Here is the Ha [+ NII]:
Here is the OIII:
2 comments:
Nice detail on that, Val. I think I especially like the Ha image. I don't think I've gotten to see that much detail in the nebula structure before.
Thanks, Rory! It's a credit to the 120mm, I think. I'm continually surprised by it.
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