Sharpless 136
Ghost Nebula
Reflection Nebula in Cepheus

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Sh2-136 is a reflection nebula, visually located in the constellation Cepheus, in the midst of a nice, dense star field, as seen from earth. It is a very large Bok globule.

This ghostly nebula is approximately 1470 light years from us; it has an armspan of about 8 light years across (assuming that distance from us is correct).


Technical Information:

LRGB: 687:165:180:240 (a bit over 21 hours of total exposure time); Luminance layer is a blend of 41 fifteen-minute images through the luminance filter, and 24 three-minute images through the luminance filter; Red channel is 11 fifteen-minute images through a red filter; Green channel is 12 fifteen-minute images thorugh a green filter; the Blue channel is 12 twenty-minute images through a blue filter. All images were unbinned.

Equipment: RC Optical Systems 14.5 inch Ritchey-Chrétien carbon fiber truss telescope, with ion-milled optics and RCOS field flattener, at about f/9, and an SBIG STX-16803 with internal filter wheel (SBIG filter set), guided by an SBIG AO-X/STX Guider, all riding on a Bisque Paramount ME German Equatorial Mount.

Image Acquisition/Camera Control: Maxim DL, controlled with ACP Expert/Scheduler, working in concert with TheSky X.

Processing: All images calibrated (darks, bias and sky flats), aligned, and combined in Pixinsight. Color combine in Pixinsight. Some finish work (background neutralization, color calibration, gradient removal, noise reduction and deconvolution) done in Pixinsight; some finish work (Neat Image noise reduction, LRGB combination, contrast and saturation adjustment) was done in Photoshop CC.

Location: Data acquired remotely from Sierra Remote Observatories, Auberry, California, USA.

Date: Images taken on many nights during September of 2022. Image posted October 31, 2022.

Date: Image scale of full-resolution image: 0.56 arcseconds per pixel.

Seeing: Generally good

CCD Chip temperature: -25C

Copyright 2022 Mark de Regt

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