C52, Elliptical Galaxy in Virgo
| Target | Type | R. A. | Dec. | Constellation | Magnitude | Size |
| C52 (NGC 4697) | Elliptical Galaxy | 12h 48m 36s | -05° 48′ 03″ | Virgo | +9.3 | 7.1×4.2 arcmin |
Overview
William Herschel discovered the galaxy we now know as NGC 4697 in April 1784, recording it to be “very bright” and “…suddenly much brighter in the middle.” Indeed, this is a relatively bright galaxy, the largest member of a group of 17 or so gravitationally bound galaxies. The NGC 4697 group is itself a member of the larger Virgo II Group of galaxies on the southern edge of the Virgo Supercluster.
The 52nd entry of the Caldwell Catalog is about 40 million light-years away from us, although scientists are not certain of its exact distance, which could be as far as 76 million light-years. Assuming that 40 million is more or less the correct distance, that gives this galaxy a diameter of 150,000 light-years. What we’re more certain of is that a supermassive black hole lurks at the center of this galaxy, with the mass of 100 million suns.
There are few star-forming regions in this galaxy, which mainly consists of older, low-mass stars. These exhibit lives in the region of nine to 15 billion years. However, it’s X-ray signatures suggest it’s home to many neutron stars, suggesting it had many massive, bright stars as part of its make-up in its past.
It’s bright magnitude, from the equivalent light of 70 billion suns, make this a pleasing discovery even in the eyepiece of a smaller telescope.
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Finder Charts
Our first finder chart for C52 (NGC 4697), giving the view at 10 p.m. in mid-June, shows that to find it we should use the Big Dipper’s (Plough’s) ‘handle’ to help us “arc to Arcturus” and then use that bright star to help us discover Spica, in Virgo..
This SkySafari 6 finder chart shows stars to magnitude 5.0 and the moon and planets are not shown.
When you’ve identified the constellation of Virgo in the southwest at this time, you’re ready to zoom in to the next chart.
The next step is to identify the southern side of the constellation that’s home Theta and Gamma Virginis because our galaxy is southwest of the center of the line joining those two stars. Both Theta and Gamma Virginis are a very bright magnitude 3.5.
Honing in on the galaxy itself is more tricky because it’s some distance from any bright stars. The best way to do it is to use a chain of five stars of similar brightness from HR 4837, east of Porrima (Gamma Virginis), to HR 4856 which is inside the same 1° field of view as C52.
The faintest of these stars is just brighter than magnitude 8, so all are easily viewed inside a magnifying finderscope or binoculars.
The individual telescope views below give a better view of how this galaxy will appear in your eyepiece.
Individual Telescope Views
The following views will help you find C52 in different telescope types by presenting the images as your telescope will show them. Stars are shown to magnitude 11 and the magnitude 6.3 star HR 4856 is visible in each image. The first image in each pair 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 bright galaxy and a small telescope reveals some structure at low magnification. In particular, you should quickly see that the core has a brighter and denser quality than the surround.
At higher magnifications, the oval shape of the galaxy becomes clearer, and we can begin to see that the angle of its plane is tipped away from us. The longer axis is roughly oriented southeast to northwest.
When we use greater power on this galaxy, we can see better graduation in the brightness as it steps from the core to the outer edges. Take the time to marvel that we can see so much detail in an object so far away that light from it has taken 40 million years to arrive here.
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 [C52-1], for example, click the ‘download’ button next to it below and you’ll be able to open it as a printable pdf.