NGC 7817 — Sbc in Pegasus
Sbc in Pegasus, 3.3 arcminutes across, its light 111 million years old. Measured by HyperLEDA, photographed by Pan-STARRS1. Recorded once.
About NGC 7817
What you are looking at
NGC 7817 is a spiral of the same broad class astronomers give the Milky Way: a moderate bulge and clearly drawn arms. Its disc is turned almost exactly side-on to us: the galaxy appears as a narrow blade of light, and its dust as a dark seam running along it. From edge to edge its visible disc spans about 106,000 light-years, close to the width of the Milky Way.
What astronomers have recorded
SIMBAD, the reference database astronomers use, classes it as an HII galaxy, glowing with clouds of hydrogen lit by young stars. It is cited in 172 scientific papers indexed by SIMBAD, and recorded there under 20 different catalogue designations.
When this light set out
The light that reaches us from NGC 7817 today set out about 111 million years ago, when the first flowering plants had appeared. The galaxy is moving away from us at about 2,309 km/s (5.2 million mph), carried by the expansion of the universe.
Finding it in the sky
In the sky, NGC 7817 sits within the constellation Pegasus. It is best placed on autumn evenings: around 9:30 pm in October it stands about 71° high in the south, seen from the middle of the United States.
Its neighbours
At almost the same distance from us, and so its neighbours in space as well as on the sky: NGC 7798 (1.1° away on the sky, at least 2,050,000 light-years from it).
By apparent size it is number 420 of the 12,657 galaxies on the Galaxy Origins register.
Measurements
| Catalogue | PGC 279 |
|---|---|
| Morphological type | Sbc |
| Angular diameter | 3.29′ |
| Right ascension | 00h03m58.9s |
| Declination | +20°45′08.5″ |
| Constellation | Pegasus |
| Inclination | 90.0° |
| Light travel time | 111 million years |
| Bar | not recorded |
Check every figure above in the NASA/IPAC Extragalactic Database
What is sold
A print of this galaxy and the record of the calculation, once. When it sells it leaves the register and is not offered again. We assign no names and no ownership — nobody can sell you those.
At 3.3 arcminutes this is a Exceptional galaxy, which is the tier where a real photograph shows clear structure and dust lanes. The tier comes from the measured diameter, not from a price list.
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