M51
NGC 1052 Group
Optics:   Ritchey–Chrétien 20" F/8.2 (4166mm FL) Processing:   PixInsight, Photoshop
Camera:   SBIG STXL-11000 with Adaptive Optics Date:   September 2022
11 Megapixel (4008 x 2672 16-bit sensor) Location:   Columbus, Texas
Exposure:   LRGB = 520:90:80:100 minutes Imager:   Kent E. Biggs
NGC 1052 is a massive elliptical galaxy with recent estimates of its mass placing it over 100 billion suns, all contained within about 120,000 light years. At 63 million light years away it lies in the direction of the constellation Cetus, the whale or sea monster. Light collected in this image left NGC 1052 shortly after the extinction event that killed our planet’s dinosaurs. Discovered by William Herschel in 1785, NGC 1052 is the eponym of the somewhat famous NGC 1052 Group that may also include galaxies NGC 1042 and NGC 1047 in this image as well as many others not visible (see annotations by hovering over the image). NGC 1052’s triaxial elliptical shape (three axes of different radii) is a very common one and distinguishes it from spiral galaxies like NGC 1042, in that it has very little structure. Close to the nucleus of NGC 1052 are jets of material traveling outward and nearly the speed of light. They are not visible here, but what is visible is an apparent jet of material in the lower part of the image; it has been slightly overexposed in the annotation.

Within the astronomical community, NGC 1052 group became more famous recently with the discovery of two very diffuse but associated elliptical galaxies NGC 1052-DF2 and NGC 1052-DF4 which seem to have little to no dark matter. Dark matter is a hypothetical form of matter we have never touched or examined directly yet thought to make up about 85% of the universe. Dark matter does not interact with electromagnetic fields so does not reflect or emit light; therefore, it is very difficult to detect. It does, however, seem follow the laws of gravity. For example, NGC 1052 has the mass of 100 billion suns, yet observations show within that same area, there is 4 times as much matter, or 414 billion suns. We call it dark matter since it cannot be detected directly with any telescope instrumentation, but only by its gravitational influence. NGC 1052-DF2 and -DF4 (just outside the frame of this image) are now famous for seeming to have little to no dark matter, which is somewhat unusual and needs further investigation to better understand them.

Also associated with the NGC 1052 group is spiral galaxy NGC 1042 (hover over image to see annotation; also see enlarged image below). It is a spiral galaxy nearly 26 times fainter than NGC 1052, yet still clearly visible with great detail of blue color indicating star formation and red emission nebulae. While it visually seems to be in the NGC 1052 group of galaxies, measurements of its distance range from 14 to 54 million light years, placing it significantly closer to us than NGC 1052.

Other galaxies in this image such as NGC 1048, and most of the PGC objects are behind the NGC 1052 group and much further away, perhaps as distant as 500 million light years! Hover over the image to see enlargements of these objects.

Finally, one odd object in this image is the green star just right of and below center. Green stars in an image usually indicated the color correction is incorrect since there are no actual green stars in the universe. Our eyes, and cameras imitating our eyes, never see green stars since star colors only represent the peak output of light, say in the red or blue part of the spectrum. Since green is smack dab in the middle of the visible spectrum, stars that peak output in green have also about equal amounts of blue and red output as well, thereby they always appear white, not green to our eyes and cameras. The fact that this star is very green is puzzling, and a mystery which someday I may solve.

Stats for NGC 1052 with alternate name of MCG -1-7-34, IRAS 2386-828, and PGC 10175 are as follows: RA: 02h 41m 04.9s; Dec: -08° 15' 22"; Mag: 10.4 (V); B-V: +0.94; Size: 3.0'x2.4'; Class: E4; Inclination: 118°.

NGC 1042