Basic object information

Name: M 31
Popular name: Andromeda Galaxy
Type of object: Galaxy
Magnitude: 4.3
Surface brightness: 12.6 mag/sq arcmin
Size: 189.1'x61.7'
Position angle: 35°

Position (epoch of date)

Right ascension: 0h 42m 53s
Declination: +41° 17' 12"
Constellation: Andromeda

Local information

Altitude:  32° 53' 6"
Azimuth: 298° 31' 56"

Rise: 9h 22m 19s  
Transit: 18h 50m 19s
Set: 4h 22m 17s  

Star atlas chart numbers:

Herald-Bobroff Astroatlas, Chart C-38
Millennium Star Atlas, Charts 105-106 (Vol I)
Sky Atlas 2000.0, Chart 4
Uranometria 2000 Chart 60, Vol 1


Revised NGC/IC Catalog Data

Wolfgang Steinicke, Feb 2001

Names and designations

M 31
PGC 2557
NGC 224
UGC 454
MCG 7-2-16

Type of object: Galaxy

Catalog position for epoch J2000.0

Right ascension:	00h 42m 44.3s
Declination:		+41° 16' 06"


Object information

Magnitude: 4.3
Size: 189.1'x61.7'
Position angle: 35°

Object classification: Sb      
Remarks: ZWG 535.17, Andromeda nebula

Saguaro Astronomy Club v7.2 Catalog Data

Saguaro Astronomy Club, August 2000

Names and designations

M 31
NGC 224

Type of object: Galaxy

Catalog position for epoch J2000.0

Right ascension:	00h 42m 44.4s
Declination:		+41° 16' 08"

Constellation: Andromeda

Object information

Magnitude: 3.4
Size: 189.1'x61.7'
Position angle: 35°

Object classification: Sb
Description: !!!eeB,eL,vmE
Notes: Local Group;Andromeda Galaxy;nearest spiral

LEDA Catalog Data

Lyon-Meudon Extragalactic Database (LEDA) supplied by the LEDA team at the CRAL-Observatoire de Lyon (France)

Names and designations

PGC 2557
MESS 31
NGC 224
UGC 454
MCG 7- 2- 16
CGCG 535- 17

Position information

Right ascension (J2000.0):	00h 42m 44.4s
Declination (J2000.0):		+41° 16' 08"
(Coordinates have high accuracy)

Galactic longitude:	121.17°
Galactic latitude:	-21.57°

Supergalactic longitude:	336.45°
Supergalactic latitude:	12.55°

Size and shape information

Apparent major isophotal diameter (D25): 184.5'
Mean error in log10 diameter: 0.025
Ratio of major to minor axes (R25): 3.04
Mean error in log10 R25: 0.052
Major axis position angle: 35°
Inclination between line of sight and polar axis: 77.710°
Apparent corrected diameter: 192.8'
Lyon galaxy group membership number: 11

Morphological information

Morphological type: Sb    
Morphological type code: 3.031
Error in morphological type code: 0.407
Luminosity class code: 2.000
Error in luminosity class code: 0.343

Magnitude and colour index information

Total B magnitude: 4.308
Error in B magnitude: 0.303
Mean surface brightness: 21.517 mag/sq arcsec
Error in surface brightness: 0.490 mag/sq arcsec
Total U-B colour index: 0.500
Total B-V colour index: 0.920
Effective U-B colour index: 0.560
Effective B-V colour index: 1.010
21cm line width at 20% of peak (w20): 535.615 km/sec
Error in w20: 9.791 km/sec
21cm line width at 50% of peak (w50): 510.020 km/sec
Error in w50: 7.052 km/sec
Central velocity dispersion: 161.4 km/sec
Error in log10 velocity dispersion: 0.098
21cm line flux in magnitude: 6.147
Error in 21cm line flux in magnitude: 0.153
Far infrared magnitude: 5.661
Galactic extinction in B mag: 0.408 mag
Extinction in B mag due to inclination: 0.669 mag
21cm self-absorption in magnitude: 0.078 mag
Luminosity index: 0.447
Total apparent corrected B mag: 3.234
Total apparent corrected U-B colour index: 0.331
Total apparent corrected B-V colour index: 0.742
Mean surface brightness within isophote 25: 23.613 mag/sq arcsec
Maximum rotational velocity: 248.9 km/sec
Error in log10 rotational velocity: 0.010
Corrected 21cm line flux in magnitude: 6.069
21cm index bt-am21c in magnitude. 2.835

Radial velocity information

Heliocentric RV from radio measurements: -300.9 km/sec
Error in radio measurements: 6.5 km/sec
Heliocentric RV from optical measurements: -291.5 km/sec
Error in optical measurements: 27.3 km/sec
Mean heliocentric RV: -300.4 km/sec
Error in mean measurements: 6.3 km/sec
RV with respect to local group: -13.4 km/sec
RV with respect to GSR: -122.7 km/sec
RV corrected for infall of LG onto Virgo: -115.8 km/sec
RV with respect to the 3K CMB: -575.4 km/sec
Absolute B magnitude: -21.721

User Notes

Notes for M31