Sceptrum — Double Star in Eridanus
HIP 21594; 53 Eridani
About Sceptrum
Description
Sceptrum, 53 Eridani, is a K-type giant of spectral class K1 III about 110 light-years away. It shines at magnitude 3.87. Sceptrum is a remnant of an obsolete constellation — "Sceptrum Brandenburgicum," invented by Gottfried Kirch in 1688 and abandoned by modern astronomy.
Observing Tips
Sceptrum lies in the central part of Eridanus. Its warm amber color is clear in binoculars. Best observed October through February.
History
The name Sceptrum comes from the obsolete constellation Sceptrum Brandenburgicum (the Brandenburg Scepter), created in 1688 by Gottfried Kirch as a tribute to the House of Brandenburg. The constellation was not retained when the IAU standardized constellations in 1930, but the name Sceptrum for this star survived. The IAU formally adopted the name in 2017.
Fun Facts
Sceptrum is a rare example of a star name preserving the memory of an obsolete constellation. Historical constellations like Sceptrum Brandenburgicum, Antinous, Quadrans, and Robur Carolinum have mostly faded from modern usage — the surviving star names are linguistic fossils of earlier cartographic fashions.
Observe
1Physical Properties
2Position & Identifiers
3How easy to split?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | V. hard | V. hard | V. hard |
| 150 mm Newton 150mm Newt. | V. hard+ | V. hard+ | V. hard+ |
| Celestron C8 (203 mm SCT) C8 203mm | V. hard+ | V. hard+ | V. hard+ |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Multiple Star System
Separation over time
Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.
Eyepiece View
A: 3.9 · B: 7.0 · Sep: 0.9″ · PA: 10° · N up, E right
Unresolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
7
Size Comparison
8
Compare Stars
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Spectral Classification
10
Hertzsprung-Russell Diagram
11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
15Stellar Notes
16
Light Travel Time Machine
17
Relativistic Travel
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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