M29 Open Cluster in Cygnus
| Target | Type | R. A. | Dec. | Constellation | Magnitude | Size |
| M29 | Open Cluster | 20h 23m 57s | +38° 30′ 00″ | Cygnus | +6.6 | 10.0 arcmins |
Overview
When Charles Messier first glimpsed this cluster in 1764, he thought it contained “seven or eight very bright stars”.
We now know that the cluster contains at least 80 stars (and maybe as many as 200) in a patch of sky just 10 arcminutes wide, which is one-sixth of a degree.
M29 shines on the edge of naked eye visibility at magnitude +6.6, meaning it can be seen from a dark sky location with good eyesight. If you can see it unaided, you’ll observe what looks like a star just off from Sadr (Gamma Cygni), which is the star marking the crossing of the Swan’s wings over its body in the constellation of Cygnus. You’ll see more detail on this in the Finder Charts section, below.
The cluster is about 1,800 light-years away from Earth and makes for a beautiful, delicate view under low magnification and a wide field.
Finder Charts
M29 is an easy object to find, given its close association with a bright star in one of the night sky’s most recognizable constellations.
The first image below, taken from SkySafari, shows the location of Cygnus, and M29 within it, at 10pm in the middle of July. Stars are shown to magnitude 5.0 and no planets are shown. Cygnus is midway between the east horizon and the zenith.
Zooming in to the constellation of Cygnus, it’s a simple task to identify the star Sadr (Gamma Cygni). This marks the crossing point between the swan’s wings and its body. M29 is less than 2° away from Sadr.
In the finder chart below, note how close M29 is to Sadr. Stars are shown to magnitude 5.0.
In the final finder chart, see how it’s a simple star hop from Sadr to M29. The blue ring is a 1° field of view. Center your field on Sadr and travel southwards less than 2° to M29.
You’ll know when you have it in your sights as you’ll see a loose grouping of fainter stars. The brightest stars in the field form a readily recognized trapezoid shape, as shown in the image below.
Let’s take a look at this area of the sky through different telescope types.
Individual Telescope Views
The following views will help you find M29 in different telescope types by presenting the images as your telescope will show them. The first image is with a black sky and white stars, the second picture is the same image but presented in inverse monochrome. Black stars on a white background is often easier to use at the telescope. Each image can be clicked on for a full-screen version.
Upright View – This is what your eyes see unaided and through a reflex or red-dot finderscope
Upside-down view – This is what reflectors and magnifying finders show, and refractors / Cassegrains without a star diagonal
Mirrored View – Refractors and Cassegrain models with a star diagonal show this view
Observation
This is a loose association of stars that, as mentioned earlier, is best viewed at a lower power. This will give you a larger field of view and let you enjoy the beauty of the cluster as a whole.
A smaller telescope reveals at least a dozen stars that can be resolved, including the trapezoid box imaged above. Imagine how much brighter this would be if it weren’t for the dust between us and M29 which dims it by as much as three magnitudes.
The main challenge you should take on when observing a cluster likme this is a star count. How many resolved stars can you see in this region, using averted vision and patience?
As you increase magnification, letting fainter stars come into view, how many do you see? More importantly, perhaps, does this tightening in of your view (as the field shrinks) diminish or enhance your enjoyment of this cluster as a whole?
PDFs for Printing
Each of the star maps above is reproduced as a pdf below. Each star map has a number in [square brackets] beneath it which corresponds to the file number below. If you want image [M29-1], for example, click the ‘download’ button next to it below and you’ll be able to open it as a printable pdf.