NGC 404, Ghost of Mirach

NGC 404
NGC 404: Star Mirach (β Andromedae) and the ghost galaxy NGC 404; 500 mm Cassegrain 3625 mm f/7.2; SBIG STL11K; 95+15+15+15 min LRGB; Bernese Highlands; © 215 Radek Chromik

History

The galaxy NGC 404 was discovered on September 13, 1784 by the German-British astronomer William Herschel with his 18.7 inch reflector and cataloged as II 224. [277].

Since NGC 404 is very close to the star β Andromedae, the galaxy was not even drawn on some star maps, as it would otherwise be covered by the star's symbol. It so happened that this galaxy was mistaken for a newly discovered comet by some amateur astronomers. [105]

Physical Properties

NGC 404 or Mirach's Ghost is a spiral galaxy of the SA(s) type, with tightly wound spiral arms. The The axis of rotation points in our direction, which is why it appears circular with a diameter of 6.1 arc minutes. The core of this galaxy is very bright. The visual brightness is 10.3 mag, but the surface brightness is only 14.0 mag. The distance of this galaxy is 8 million to 8.2 million . Light years indicated and it is supposed to move 178 km/s from the center of the local group. [134]

«Catalogue of Principal Galaxies (PGC)», Paturel et al. 1989 [144]
DesignationsPGC 4126: NGC 404, UGC 718, MCG 6-3-18, CGCG 520-20, IRAS 1066+3527
Right Ascension (J2000.0)01h 09m 26.9s
Declination (J2000.0)+35° 43' 04"
Morphological TypeL
Dimensions3.9' x 3.9'
Visual Magnitude11.2 mag
Radial Velocity (HRV)-45 km/s
Position Angle°

Finder Chart

The location of the galaxy NGC 404 is so memorable that even an inexperienced stargazer would find it straight away. It is only about 7 arc minutesnorthwest of the 2.1 mag bright star Mirach (β Andromedae) away. One should not be confused by possible ghost images of Mirach in the eyepiece. Although these look similar, they do not always have the same position relative to the star.

Chart NGC 404
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

Visual Observation

NGC 404
NGC 404: Pencil drawing; 300 mm f/4 Newton, 300-fach; © 15. 12. 1996 Bernd Nies

300 mm aperture: In order to be able to see the galaxy well, the bright star Mirach should be positioned outside the edge of the image field. From NGC 404, only the brighter central region can be seen at a low magnification of up to about 160 times, which can be seen as a weak, round, diffuse spot. If one does not know that there is a galaxy immediately next to Mirach, one can easily mistake it for a reflection of the star on the lenses in a poorly coated eyepiece, which some also did. This is why I named the galaxy Mirach's Ghost.

At an even higher magnification, such as 300 times, the galaxy reveals more of its structure. The center of the galaxy reveals its stellar core, which can be seen particularly well with averted vision. The brightness of the galaxy is significantly higher in the middle area.

300mm f/4 Newton
Bernd Nies, 1996

References

105A Star-Hop from Andromeda by Alan M. MacRobert; S&T 12/93, p.45
134Lyon-Meudon Extragalactic Database (LEDA); leda.univ-lyon1.fr
144Catalogue of Principal Galaxies (PGC); Paturel G., Fouque P., Bottinelli L., Gouguenheim L.; Astron. Astrophys. Suppl. Ser. 80, 299 (1989); cdsarc.unistra.fr/viz-bin/cat/VII/119 (2021-02-18)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)