Challenge #4 – C67, Spiral Galaxy in Fornax
| Target | Type | R. A. | Dec. | Constellation | Magnitude | Size |
| C67 (NGC 1097) | Spiral Galaxy | 02h 46m 19s | -30° 16′ 30″ | Fornax | +9.3 | 10.6×6.4 arcmin |
Overview
This beautiful barred spiral galaxy was first observed by William Herschel in October 1790, who described it as “Very bright… [with] a very bright nucleus.” For those of us saddled with worse skies and possibly smaller scopes than Herschel, we’ll see it as a bright(ish) circular disc.
Practically face-on to us, this displays an obvious bar crossing its heart in the ESO image below. It travels with a companion galaxy, which we can see as the smaller glowing oval with a brighter center in the top right corner of the image. This causes the larger galaxy to be disrupted by the gravitational interaction.
The galaxy is about 45 million light-years away and is a Seyfert galaxy, i.e. it has a bright, active center, rich in star formation. Jets shoot from its core that are believed to be the remains of a captured dwarf galaxy. Scientists believe that, at its core, this galaxy hosts a supermassive black hole ten times larger than the one at the center of the Milky Way (140 million times more massive than the sun).
This spiral galaxy is believed to be about 120,000 light-years in diameter.
Finder Charts
To find the tiny, faint constellation of Fornax, this galaxy’s home, begin by identifying the obvious views of the Great Square of Pegasus and Orion, both of which are circled orange below.
This first chart shows how the sky looks facing west at 10 pm in mid-September. Stars are shown to magnitude five and the moon and planets are not shown. C67 is shown as a green oval and labelled as NGC 1097.
Four of the brighter stars of Fornax are labelled in the second chart below, where stars are still limited to magnitude five. You’ll note that the brightest of these is magnitude 3.8, so it does take a little bit of effort to identify.
However, once you’ve isolated the right region, you need to focus on the star at the crux of the constellation, Beta Fornacis, because this is closest to our target.
The easiest way to land in the correct area is to identify the star cluster M52. This bright cluster shines at magnitude 6.9 and is readily visible with any kind of magnification.
Stars in this final chart are shown to magnitude seven. Use a large field of view – the circle in this chart is 1.5° – to hop from Beta Fornacis to HR 858, a magnitude 6.4 star northeast of Beta. When you have that, place it at the extreme eastern edge of your field of view and NGC 1097 (C67) will be in your view.
In the last section, you’ll discover what you can see of this beautiful galaxy.
Individual Telescope Views
The following views will help you find C67 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 1.5° field of view and the star HR 858 is the brightest one near the E marker on the field of view circle.
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
As I mentioned in the opening section, the view through a smaller backyard telescope at low power is a broadly circular disc of fuzzy light. It’s faint and the brighter core could be confused for a star.
With your eyes adjusting to the view and perhaps using averted vision, you’ll see that the outline is more of a fat oval than a circle, running in a northwest-southeast direction.
This is a relatively bright galaxy and will take to higher powers. These reveal more structure but it does need careful viewing.
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 [C67-1], for example, click the ‘download’ button next to it below and you’ll be able to open it as a printable pdf.