Sketch of Messier 91 (NGC 4548)
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Observation Notes:
M91 appeared circular with a strongly condensed core. A prominent bar crossed the disc at a PA of about 80 degrees. The western half of this bar appeared to be a bit brighter. I couldn’t detect any hint of the extended spiral arm structure.
Sketch/DSS Photo Comparison of Messier 91 (NGC 4548)
Object Information:
M91 is a barred spiral galaxy in the Virgo cluster that is receding at about 400 km/sec. Since the cluster as a whole is receding at 1,100 km/sec, the galaxy moving through the cluster at 700 km/sec. It was discovered by Charles Messier in 1781, and is also cataloged as NGC 4548, UGC 7753, MCG+03-32-075, H II-120, h 1345, GC 3093, CGCG 099.096, VCC 1615, IRAS 12328+1446, PGC 41934.
| Subject | M91 (NGC 4548) |
| Classification | Barred Spiral Galaxy (SBb) |
| Position* | Coma Berenices [RA: 12:35:27.2 / Dec: +14:29:48] |
| Size* | 5.4′ x 4.3′ – PA: 150° (Bar = 65 °) |
| Brightness* | 10.4 vMag; 11.0 bMag; 13.6 Surface Brightness |
| Date/Time | APR 27, 2009 – 12:50 AM (APR 27, 2009 – 07:50 UT) |
| Observing Loc. | Flagstaff, Arizona – Home |
| Instrument | Orion SkyQuest XT8 Dobsonian (203 mm dia./1200 mm F/L) |
| Eyepieces/Mag. | Pentax XW10 (120X) |
| Conditions | Clear, calm, porch lights |
| Seeing | 5/10 |
| Transparency | Mag 5.8 NELM |
| *Sources | SEDS; NGC/IC Project; DSS; Starry Night Pro Plus 5; Atlas of the Messier Objects – Ronald Stoyan |