M89 is another member of the Virgo Cluster of galaxies. It's a small magnitude +10.0 elliptical galaxy (type - E0) discovered by Charles Messier on March 18, 1781. On this bumper night for Messier he also discovered seven other Virgo galaxies and re-discovered globular cluster M92 in Hercules. Recent observations indicate that M89 may be nearly perfectly spherical in shape. This is unusual because all other known ellipticals are elongated. However, it's possible that the spherical nature of M89 is purely a visual affect resulting from its orientation from our perspective.

The galaxy is not as bright as some other group members and therefore a challenging small telescope object. Messier's original discovery observation acknowledges this: "extremely faint and pale and it's not without difficulty that one can distinguish it". The galaxy is best seen with large telescopes but generally featureless and rather unexciting through most amateur instruments.

M89 is located in Virgo just south of the Virgo-Coma Berenices constellation boundary. It's positioned roughly 60% along an imaginary line connecting stars, Denebola (β Leo - mag. +2.1) and Vindemiatrix (ε Vir - mag. +2.8). Slightly brighter spiral galaxy M90 is 0.75 degrees northeast of M89. One degree southeast of M89 is fine barred spiral galaxy M58 with supergiant elliptical galaxy M87 located about a degree west of M89.

The Virgo galaxies are best seen during the months of March, April and May.

M89 Elliptical galaxy by the Hubble Space Telescope (NASA, The Hubble Heritage Team (AURA/STScI))

Finder Chart for M89 (also shown M49, M53, M58->M60, M64->M66, M84->M88, M90, M91 and M98->M100)

Finder Chart for M89 (also shown M49, M53, M58->M60, M64->M66, M84->M88, M90, M91 and M98->M100) - pdf format

When viewed through a 200mm (8-inch) telescope M89 appears as a faint, round, small featureless diffuse ball of light. It has a total apparent diameter of about 5 arc-minutes although visually it's about half this size. The view somewhat resembles a distant globular cluster but even larger scopes fail to reveal much more.

M89 is 55 million light-years distant which corresponds to a spatial diameter of 80,000 light-years. The galaxy also features a surrounding structure of gas and dust that extends up to 150,000 light-years from the centre. It's estimated to contain 100 billion stars.

M89 Data Table

Messier89
NGC4552
Object TypeElliptical galaxy
ClassificationE0
ConstellationVirgo
Distance (kly)55000
Apparent Mag.10.0
RA (J2000)12h 35m 40s
DEC (J2000)12d 33m 23s
Apparent Size (arc mins)5.1 x 4.7
Radius (light-years)40,000
Number of Stars100 Billion

Sky Highlights - July 2017

The Planets
This Month's Guide

Algol Minima
Algol eclipse dates and times for July

Meteor Shower
Southern Delta Aquariids (Aquarids) meteor shower peaks on July 29

Northern Hemisphere
Evening
West:- Mercury (mag. -0.5 to +0.3) (second half of month)
Southwest:- Jupiter (mag. -2.0)
South:- Saturn (mag. +0.2)
Midnight
West:- Jupiter
South:- Saturn
East:- Neptune (mag. +7.8)
Morning
Southwest:- Saturn
South:- Neptune
Southeast:- Uranus (mag. +5.8)
East:- Venus (mag. -4.1)

Southern Hemisphere
Evening
West:- Mercury (second half of month)
Northwest:- Jupiter
East:- Saturn
Midnight
West:- Jupiter
North:- Saturn
East:- Neptune
Morning
West:- Saturn
North:- Neptune
Northeast:- Venus, Uranus

Deep Sky

Small telescopes:-
Messier 13 - M13 - Great Hercules Globular Cluster
Messier 92 - M92 - Globular Cluster
Messier 11 - M11 - The Wild Duck Cluster (Open Cluster)
Messier 7 - M7 - The Ptolemy Cluster (Open Cluster)
Messier 6 - M6 - The Butterfly Cluster (Open Cluster)
Messier 4 - M4 - Globular Cluster
Messier 8 - M8 - Lagoon Nebula (Emission Nebula)
Messier 16 - M16 - Eagle Nebula (Emission Nebula with Open Cluster)
Messier 20 - M20 - Trifid Nebula (Emission and Reflection Nebula)

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