Mouseover for Effect
Narrowband
RGB
I promised you lobster and now I must deliver on that promise. But it’s the Lobster Nebula, not the delectable crustacean. M17 has many names – Lobster, Omega, Checkmark, Swan and Horseshoe, to name a few. While I can imagine a Prawn in IC4628 in Scorpius, I cannot for the life of me see a Lobster in M17, either in RGB or narrowband images! My attached narrowband image instead is highly reminiscent of a fire Sandy and I made in June at CAV on our 10 acre lot. M17 is bright and beautiful in the eyepiece and is awesome visually with filters. But there is not a lot of color differentiation in RGB or LRGB images. It’s narrowband where the Lobster Nebula reallygrabs you! The attached narrowband image is 9 hours 2×2 of Hubble palette (red=Sulfur II; green=Hydrogen-alpha; blue=Oxygen III) using the 14.5-inch RCOS and Apogee camera. The blue areas are hotter and orange-red areas relatively cooler. Narrowband images produce monotonous magenta stars so I did a 2 hour 2×2 RGB (red, green, blue “natural color) image in order to replace the magenta stars with RGB stars in the narrowband image. The attached animation (produced in Photoshop) illustrates this use of RGB stars in the narrowband image well. For once, I am not shooting low. M17 sits up nicely at a maximum of 44 degrees (1.43 atms.) at Chiefland.
http://apod.nasa.gov/apod/ap140527.html — Subaru/Hubble combo image; compare to my RGB image
http://www.eso.org/public/images/eso0925a/ — Close-up ESO image
http://www.cfht.hawaii.edu/HawaiianStarlight/HawaiianStarlight-AIOM.html — CFHT Gallery – go to “Previous” (July 2016) —Really DEEP M17!!
https://www.nasa.gov/multimedia/imagegallery/image_feature_768.html — Crazy close-up!!