Nestled within the spring constellation Sextans lies the Spindle Galaxy. When viewed through a telescope, it resembles a spindle—or needle. We see this galaxy edge-on from Earth, giving it this lens-like appearance. The astronomer William Herschel discovered the galaxy on a winter day in February 1787.
NGC 3115 is about 32 million light-years away and is classified as a lenticular galaxy. Lenticular galaxies like NGC 3115 contain a disk and a central bulge of stars but lack a detectable spiral pattern like our Milky Way. In fact, you can see this brighter central bulge in telescopes (see my sketch below).
Also, at the heart of this bulge lies a remarkable phenomenon: a supermassive black hole. Despite its massive size, this gravitational behemoth displays a peculiarly subdued behavior, emitting only faint traces of radiation. It doesn’t appear to be growing anymore. In fact, astronomers are intrigued by the apparent quiescence of this black hole, which contrasts sharply with the active and energetic behavior observed in other galaxies hosting supermassive black holes.1
My Observations
| Date | March 17, 2024 |
| Time | 9:19 p.m. |
| Location | Seattle, WA |
| Magnification | 169x |
| Scope | Meade 8″ SCT |
| Eyepiece | 12mm |
| Seeing | Average |
| Transparency | Average |
The stars appear fainter this March night due to the half-moon high above them. I direct my scope’s guide towards the starless sky on the southeast horizon, hoping to see NGC 3115 come into view. As the scope slowed, a silver sliver appeared quite clearly. It’s a faint line, for sure, with a noticeably brighter center.
I agree with the description by Robert Burnham’s observation that this galaxy has an “usually high surface brightness which permits the use of the fairly high powers; it appears to the eye in amateur telescopes much as it does on the photographic plate.“2 This is true as my photo below looks much like my own sketch above.
Exposure Time: 12 minutes by Wayne McGraw
Key Stats
| Constellation | Sextans |
| Best Viewing | Spring |
| Visual Magnitude | +9.1 |
| Absolute Magnitude | -20.8 |
| Distance from Earth | 31 million ly |
| Diameter | 65,000 ly |
| Apparent Size | 7.1 x 3.0 arcmin |
| My Viewing Grade | B- |
| Designations | NGC 3115, Caldwell 53, C 53, H 1.163 |
Sources
Banner photo credit: NASA/CXC/Univ. of Alabama/K. Wong et al; Optical: ESO/VLT. The file is licensed under the Creative Commons Attribution 4.0 International license.
1 Galaxy NGC 3115 – NASA. (n.d.). Retrieved March 30, 2024, from https://www.nasa.gov/image-article/galaxy-ngc-3115/
2 Burnham, R. (1978). Celestial Handbook: An Observer’s Guide to the Universe Beyond the Solar System. Dover Publications Constable.
Sketch and Seestar photo by Wayne McGraw
The Garden Astronomer 