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Sh2-80
Sh2-80
Merrill's Star
WR 124
Wolf-Rayet Star and Nebula in Sagitta

Click here for uncropped versions: 100% uncropped (4061x4076) 65% uncropped (2640x2650) 40% uncropped (1624x1630)
Click on image to toggle between the color version and the grayscale Ha version

 

Sh2-80 is a small, fairly dim and obscure (seldom imaged) Wolf-Rayet nebula, visually located in the constellation Sagitta. It was not discovered until 1938. WR 124 is the bright star at the center of the nebula, a Wolf-Rayet star creating the nebula. WR 124 is one of the fastest known "runaway stars," explained here. There's more on this particular star here

When I looked at the full, uncropped image on my computer screen (the image above is severely cropped; uncropped images can be viewed by clicking on the links above the image above), I was surprised and thrilled to see a tiny (about 7 arseconds across), bright red ring, obviously a planetary nebula, in the image. Alas, I was not the first to notice this nebula, which was discovered by another amateur in 2013. It is named after him, Lilge 1. To see this pretty little thing, click on the link to the uncropped versions given above, and you will find the tiny red ring about halfway between Sh2-80 and the right edge of the image (just below and to the right of the two moderately bright blue stars). This full-resolution cutaway from that area of the uncropped version shows the little planetary nebula:


Sh2-80 is thought to be about 21,000 light years from us, and it is expanding at the rate of about 93,000 mph/150,000 kph. It is about six light years across.

The James Webb Space Telescope has imaged this little nebula, here

There are about 13,000 stars in the uncropped field, which is slightly larger than a full moon; there are a lot of stars in the sky that we don't see!

Click on the image to toggle between a color version and a pure Ha version. Normally, pure Ha does not make an interesting version of a tiny nebula, but I think it does a good job of illustration the roiling going on in a Wolf-Rayet nebula.

 

Technical Information:

(HaL)(HaR)GB: Ha:L:R:G:B--460:480:165:210:240 (a total of almost 26 hours of exposures); luminance layer consists of blend of 32 fifteen-minute images using a luminance filter and 23 thirty-minute images using an Ha filter; R channel is a blend of 11 fifteen-minute images through a red filter, the Ha data also used in the luminance layer; G consists of 14 fifteen-minute images taken through a green filter, while B is the combination of 12 twenty-minute images taken through a blue filter.

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 (using NormalizeScaleGradient) in Pixinsight. Color combine in Pixinsight. Narrow-band data blended into the luminance and color layers in Pixinsight. Some finish work (GradientCorrection, background neutralization, color calibration, NoiseXTerminator, BlurXTerminator) done in Pixinsight; some finish work (LRGB combination, saturation adjustment) was done in Photoshop CC.

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

Date: Images taken on many nights from July into December of 2024. Image posted March 5, 2025.

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

Seeing: Variable, with individual calibrated luminance images having FWHM varying from 1.8 to 2.7 arcseconds.

CCD Chip temperature: -25C

Copyright 2024, 2025 Mark de Regt

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