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Sh2-157 in Cassiopeia

RA= 23h 16 min; Dec = +60 deg 02 min

Date & Site:

Imaged on 8/20/17; Palomar Mountain, CA

Conditions: temps in the low 60's; calm; excellent seeing


Telescope: Takahashi FSQ 106, 540mm at f/5

Guider: SBIG Guidehead with AT 66mm refractor

Mount: AP 1100 CP3
Camera: ST-10XME; CFW10; Astrodon Ha, OIII, and SII (3nm) narrowband filters


Exposures: 2 hours each of Ha, OIII,and SII (15 min subs) for total of 6 hours

Color mapped using the Hubble palette with Ha assigned to Green, SII to red, and OIII to blue

Sharpless 2-157 is a diffuse nebular cloud rich in ionized hydrogen and bright young open clusters. The claw shaped portion contains ionized oxygen illuminated by radiation from a nearby open cluster containing a Wolf-Rayet star and several O-type stars (Citation Source)

~11,000 light years away

(image reduced to 60% of original size)

FOV = 96 x 65 arc minutes

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