Messier 109

Observation Notes:

I didn’t pick up a lot of detail in this galaxy. It displayed an elliptical shape with a strongly condensed core that almost looked double in nature, due to an overlapping foreground star. The galaxy was elongated west-southwest to east-northeast, with a core that seemed to push northwest to southeast. I estimated its dimensions at 2.5′ x 4′.


M109 is a barred spiral that displays a shape reminiscent of the Greek letter Theta. It is about 55 million light years away and receding at 1,142 km/sec. It is a member of the Ursa Major Cloud. It was discovered by Pierre Méchain in 1781. Charles Messier listed it under number 99 in a preliminary manuscript, but it was not added to the official catalog until 1953 when Owen Gingerich added it.

Subject M109 (NGC 3992)
Classification Spiral Galaxy (Type SBb I)
Position* Ursa Major [RA: 11:57:36 / Dec: +53:23:28]
Size* 7.6′ x 4.9′
Brightness* 9.8 vMag. / 10.6 bMag / 13.4 Surface Brightness
Date/Time February 25, 2006 – 03:30 AM
(February 25, 2005 – 10:30 UT)
Observing Loc. Anderson Mesa, AZ
Instrument Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L)
Eyepieces/Mag. 10 mm (120X)
Conditions Clear, calm, 18°F
Seeing 3-4/10
Transparency Mag 6.8 NELM
*Sources Orion’s The Sky Software
NGC/IC Project

*Based on published data.