by Jim King
By the time you read this column, I expect the new year will be well on its way. With the JWST having been launched, hopefully we will be treated to answers to some nagging questions. Freely admitting I am not an expert, my understanding is JWST will be working hand in hand with Hubble. What an exciting future for astronomy!
For my own meager contributions in this column, since we have been on this journey for a while, new objects in easily observable time frame are getting a little hard to come by. This month’s trio M5, M13 and M83 are easily seen… as long as you don’t mind staying up until well after midnight.
So, here we go.
(An important jargon jogger: Messier uses the descriptive term “nebula” since he was frequently using a 3.5 inch telescope which had difficulty resolving dim stars. It appears that he thought “nebulae” were not gas clouds, but simply unresolved star clouds. Therefore, in our descriptions, we must mentally separate Messier’s “nebulae” from the real thing. He does differentiate nebulosity from luminosity.)
M5 Globular cluster (2 easy) * The fifth object in Messier’s catalogue is a powerful and dynamic sight in telescopes of all sizes. Even at low power, M5 is a slightly stellar conflagration with a blazing heart. A wide and loose, slightly elliptical exterior becomes increasingly tight toward a starlike center. The cluster looks as if it is collapsing under the force of gravity, triggering atomic reactions is its core. With a 7mm eyepiece, the entire cluster seems electric, bursting with fiery sparks.
Messier note: (Observed May 23, 1764) Beautiful nebula discovered between Libra and Serpens, close to the sixth magnitude star Flamsteed 5 Serpentis. It does not contain any stars; it is round, and may be seen under a good sky with a simple one-foot refractor
NGC note: Very remarkable, globular cluster, very bright, large, extremely compressed in the middle, stars from 11th to 15th magnitude.
Data: Messier 5 aka NGC 5904
Con: Serpens Mag: 5.7
RA: 15h18.5m Dec: -2.04
M13 Globular Cluster (2 easy) * M13 is generally considered the finest globular cluster in the northern skies, mainly because it is visible to the naked eye in a well-known grouping of stars that sails high overhead in the summer sky. It is a swollen mass teeming with perhaps 100,000 to a half-million stars spread across 135 light years or more. A typical globular contains tens of thousands to hundreds of thousands of stars.
Messier notes: (observed June 1, 1764) Nebula without a star, discovered in the belt of Hercules. It is circular and bright, the center being brighter than the edges, and is visible with a one foot refractor.
NGC notes: Very remarkable globular cluster of stars, extremely bright, very rich, very gradually extremely compressed in the middle, stars from 11th magnitude and fainter.
Data: Messier 13 aka NGC 6205 aka Great Hercules Cluster
Con: Hercules Mag 5.8
RA: 16h41.7m Dec: +36.28
Dist.: 23,150 ly
M83 Mixed Spiral Galaxy (2 easy) *
O’Meara states, “M83 is one of my favorite galaxies in the Messier list. It’s bright, and a mesmerizing sight through the telescope. Its details seem unending, owing to their subtle complexity. In other words, though bright and impressive, its details pose a challenge, which should inspire you on many nights of observing this extragalactic treasure.”
Messier notes: (Observed February 17th, 1781) Nebula without a star, close to the head of Centaurus. It appears as a faint, even light, but is so difficult to see with the telescope, that the slightest illumination causes it to disappear.
NGC note: A very remarkable object. William and John Herschel found it very bright, very large, extended toward position angle 55 degrees, especially light in the middle to a nucleus.
Data: Messier 83 aka NGC 5236 aka Southern PInwheel
Con: Hydra Mag 7.6
RA: 13h37.0m Dec: -29.52
Dist.: 15 million ly
* Sky Tools offers an observability scale of 1 – 6, with 1 being “Obvious” and 6 being “Very Challenging”. The rating scale I use is based on a Celestron SCT 8 Evolution telescope at the HAS dark site on a moonless night.
Ex astris, scientia, y’all!
Want more? Check out the HAS website under “Programs”/Messier Challenge/HAS 45