C36, Spiral Galaxy in Coma Berenices
| Target | Type | R. A. | Dec. | Constellation | Magnitude | Size |
| C36 (NGC 4559) | Spiral Galaxy | 12h 35m 58s | +27° 57′ 35″ | Coma Berenices | +9.8 | 10.6×4.8 arcmin |
Overview
This galaxy, on the edge of magnitude ten, is about 29 million light-years distant. As a member of the Coma I Group of galaxies, it is gravitationally interacting with at least 20 other galaxies and possibly as many more again. C36 is one of the brighter members of the Group.
Herschel first observed this distant oasis of stars in April 1785. He didn’t know of galaxies back then but, today, we’ve classified it as some way between a barred and unbarred spiral type.
Its 40 billion sun mass is spread across 100,000 light-years of space, giving it roughly the same area as our own Milky Way.
It almost looks face on to us in the image below but is actually tilted at 69° away from us. And, despite the serenity of the picture, C36 is actually whisking away from us at over 500 miles (820km) per second.
Finder Charts
In the first star chart (from SkySafari 6) you can see that NGC 4559 (C36) is on the right arm of the small constellation of Coma Berenices.
It’s easiest to locate using the Big Dipper (Plough) which is ringed orange, and the bright stars Arcturus and Denebola, both of which are highlighted in the chart below.
This SkySafari 6 chart shows how the sky looks facing west at 10 pm in mid-July. Stars are shown to magnitude five and the moon and planets are not shown.
Helpfully, C36 is practically on the imaginary line joining two of Comma Berenice’s brightest stars, Beta and Gamma. They both look the same brightness to us and the galaxy we’re looking for is closer to Gamma.
In this last finder chart, stars are shown to magnitude 10.0 to show the detail between Gamma CB and NGC 4559. The star 31 CB is visible to the naked eye at magnitude 4.9 and so acts as a useful waymarker: C36 is practically midway between it and Gamma CB.
In the last section, you’ll discover what you should expect to see of this galaxy once you’ve got it in your eyepiece.
Individual Telescope Views
The following views will help you find C36 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. Stars are shown to magnitude 10.0. The large circle is a 1° field of view and Gamma Comae Berenices is shown in each chart.
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
The faint hazy glow from this galaxy revealed at low magnification is cemented by an arc of three pinprick stars at its southern end.
Note the obvious elliptical shape of this galaxy as you use averted vision to try and tease out any extra detail that you can.
Like many of the galaxies we enjoy inside the VAC, this one has a brighter core that’s more readily seen when we increase the magnification a little bit. It’s at this stage that concentration reveals that the ghostly glow we see is not of a uniform brightness, although it’s practically impossible to tie down the brighter and fainter areas.
Those of us fortunate enough to be looking through a large telescope will see more detail, and note that the edge of our oval galaxy is not marked by clean lines, but by misty wisps that extend outwards.
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 [C36-1], for example, click the ‘download’ button next to it below and you’ll be able to open it as a printable pdf.