IC 4603


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IC 4603 is a reflection-emission nebula located in the constellation Ophiuchus. This image depicts it only partially, because the nebula itself occupies an area of about 45×20 arcmin and the image is 36×36 arcmin. This is a very rich region, with many emission and reflection nebulae, in the Northern half of what is called the “Rho Ophiuci Region”. See wide field mosaic here. IC 4603 is illuminated by the star HD 147889, which is a 8.1 magnitude pre-main sequence B3 star. This massive, blue star (located just off left of center) is somewhat reddened by the surrounding dust, as most of the stars that can be seen in the image. Some regions of the nebula have been heated enough to emit in the red Halpha line. This color can be seen interspersed with the dominant reflection blue.

This image was started in 2015, but for some reason, it was kept in the drawer until Summer 2018, when I took the remaining images.

Additional Information


Name(s): IC 4603

Type: Reflection-Emission Nebula

RA:  16h 25m 24s

Dec: -24º 27’ 57”

Constellation: Ophiuchus

Size (arcmin): 45×20

Magnitude: +10

Distance: 420 ly


Date: 2015-07-08 thru 2018-08-26

Location: iTelescope.net, SSO near Coonabarabran, NSW Australia

Size (arcmin): 36×36

Telescope: Planewave CDK 20” f/6.8

Camera: SBIG STX16803 (4096x4096pix)

Guiding: Astrodon MonsterMOAG off-axis guider

Total exposure: 9.5 h (L: 3h15m; RGB: 6h15m)

Processing: CCDStack, Photoshop CC 2018

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