Challenge #2 – C31, The Flaming Star Nebula in Auriga
| Target | Type | R. A. | Dec. | Constellation | Magnitude | Size |
| C31 (IC 405) | Bright Nebula | 05h 16m 12s | +34° 16′ 00″ | Auriga | +10.0 | 30×19 arcmin |
Overview
The magnitude-six star AE Aurigae provides the illumination for this emission nebula which was first discovered in 1892 by J. M. Schaeberle but had actually been captured on photographic plates a year before that by other amateur astronomers.
It lies near the open cluster M38 and is about five light-years wide and 1,500 light-years distant. Ina wide-field image, this nebula can be seen to cover about one degree of the sky.
While it is a challenging object for smaller telescopes, it is possible to see it with the right conditions in support.
Finder Charts
The first sky chart, from SkySafari 6, shows the view at 10 pm in the middle of January, looking northeast. Stars are shown to magnitude 5.0 but the moon and planets are not shown.
The brightest, most obvious constellations visible in this direction are Orion and Cassiopeia. We’re looking for Auriga, the charioteer constellation, home of the Flaming Star. Auriga is ‘above’ Orion’s head.
Still showing stars to magnitude five, this second chart reveals the bright stars Capella (which is the sixth brightest star in the sky) amd Elnath, properly known as Alpha Aurigae and Beta Tauri respectively. C31 lies almost on the imaginary line that connects these two.
With stars now shown to magnitude seven, look for a collection of fainter stars on the edge of being visible to the naked eye: 14, 16 and AE Aurigae. It’s the last of these, AE Aurigae, that provides the light for this nebula.
We’re now ready to attempt observation of this nebula.
Individual Telescope Views
The following views will help you find C31 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. Stars are shown to magnitude 10.0 and the star AE Aurigae is the bright star near the north marker of the 1.5° field of view circle shown in each image.
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 object gets its name from German astronomer Max Wolf who noted the nebula “looks like a burning body from which several enormous curved flames seem to break out…” and so, today, this is the flaming nebula. I’m sorry to tell you that, like all nebulae spied from the backyard, you might not call to mind such a vivid description but the view is, nevertheless, a good one.
Although accentuated by a hydrogen beta or a narrowband filter, we can, in fact, see the nebulosity in a medium-sized scope at low magnification without any such aid, provided your sky is dark. The outline of C31 is a reminiscent of a fat ‘J’.
As mentioned earlier, it’s the star AE Aurigae that lights this scene and we can see it as the brightest of a small asterism of stars.
Be under no illusion: while it’s not too hard to see this object, it is a challenge to discover any detail. You’ll need to patiently spend time with it to tease out any identifiable structure, made tougher by needing to stay with low magnification because its low light emission makes it disappear in higher strength views.
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 [C31-1], for example, click the ‘download’ button next to it below and you’ll be able to open it as a printable pdf.