15 κ Cas
ILLUSTRATION FROM SPECTRAL TYPE BC0.7Ia · 15 200 K · VARIABLE, MAG 4.14–4.21 · TIMING NOT TO SCALE
OVERVIEW
] STAR15 κ Cas is a BC0.7Ia blue-white star in the constellation Cassiopeia, shining at apparent magnitude 4.17 (). It is catalogued as HD 2905, HIP 2599 and HR 130.
- WHAT IT IS
- Blue-white star
- HOW BRIGHT (V)
Bright enough for the naked eye, under a sky dark enough.
OBSERVING
] FROM WHERE YOU AREWhat it takes to see 15 κ Cas for yourself. Everything in this part of the page is worked out for a real horizon, a real night and the equipment you say you have.
Say where you are, and this line says when 15 κ Cas is worth going out for.
THROUGH AN EYEPIECE
] 150 MM TELESCOPE · 25 MM EYEPIECEBright enough to see with your eyes alone, once you are away from town lights. It will be a point of light in anything: a star is far enough away that no aperture on Earth gives it a width, and all the equipment changes is how easily you find it.
- 48×
- 1.08
- 1.25
- 13.0
- APPARENT MAGNITUDE ()
- 4.17 · within reach
APPARENT PLACE
] EQUINOX J2026.7Where a telescope has to be pointed today, which is not quite where the catalogue records the object: the coordinate grid itself has turned since the year 2000 the catalogue is referred to.
- RIGHT ASCENSION
- DECLINATION
- GRID TURNED SINCE
- 13.7
- PROPER MOTION SINCE
- 0.12
Computed for 2026-08-27 00:00 UT. Two things separate it from the catalogued position above: 15 κ Cas has moved under its own proper motion, and the coordinate grid has turned under it — about fifty arcseconds a year of precession since 2000, and the small nodding of the Earth’s axis on top of that. Aberration and refraction are not included, and neither is parallax; each is under an arcminute, which is also about as well as the catalogued position is known. The same figure for any date.
VARIABILITY
] ALPHA CYGNI PULSATING SUPERGIANT- RANGE, AS SAMPLED
- 4.14 – 4.21
No period is published for this star, so there is no cycle to count. The catalogue records that it varies and by how much, and not how often.
The range is the spread the Hipparcos satellite measured, converted to the visual scale. It is approximate: the satellite sampled the star on a schedule of its own, and where a star spends little of its cycle at an extreme — the floor of an eclipse, most obviously — the sampling can miss it altogether. The classification is the General Catalogue of Variable Stars’s. These elements as data.
CATALOG DATA
] 11 FIELDSThe raw catalogue values, as the source published them, with the error bars where one was published — sorted by what each set of figures is about rather than by the order they happened to be stored in.
WHAT IT IS MADE OF
What the object is in itself, rather than how it happens to look from here.
- Spectral type
- Variability
- Alpha Cygni pulsating supergiant
- Variability type ()
- ACYG
HOW BRIGHT IT IS
What the light adds up to, measured through one filter at a time. A magnitude is a brightness on a backwards scale — the smaller the number, the brighter the object.
- Colour index (B−V)
- Variable magnitude, brightest
- Variable magnitude, faintest
WHERE IT IS AND HOW IT MOVES
Position, motion across the sky and the size it covers on it. These are measurements of the object as seen from here, so every one of them depends on where here is.
- Proper motion (RA)
- 3.99
- Proper motion (Dec)
- −2.1
- Radial velocity
- −2
OTHER NAMES AND NUMBERS
The identifiers other catalogues file this object under, for anyone joining this data to theirs.
- Variable-star designation
- Kap Cas
WHERE THESE FIGURES CAME FROM
Which catalogue, paper or model each of the fields above was read from, where the source named one.
- Spectral type from
- SIMBAD (2024A&A...690A.176N, quality C)
ALSO KNOWN AS
] 4 DESIGNATIONS- Bayer/Flamsteed 15 κ Cas
- HD HD 2905
- HIP HIP 2599
- HR HR 130
LOOK IT UP ELSEWHERE
] 3 SERVICESEach link carries the identifier printed beside it. Nothing on this page is a measurement of our own, so a number that disagrees with one of these is worth reporting — and a service that has never catalogued this object under this name will say so plainly.
- SIMBADHR 130
Cross-identifications, measured values and the reference behind each of them.
- ADSobject:"HR 130"
Papers indexed against this object rather than against the string, newest first.
- VizieR5″ around 8.2500 +62.9318
Every published table with a row at this position, searched by coordinates rather than by name.
CITE THIS PAGE
] DR1This page is live and its numbers move when an upstream refreshes, so the citation names the release the rows belong to rather than the day you read them. The release itself is frozen, republished as a bundle, and is what a data-availability statement should point at.
SpaceCatalog. 15 κ Cas [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-2905
@misc{spacecatalog_hd-2905,
author = {{SpaceCatalog}},
title = {{15 κ Cas}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/hd-2905},
note = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}
}The values above were taken from HYG Database v4.1 — CC-BY-SA-4.0. Citing this page does not replace citing that catalogue, and its licence is share-alike: the terms reach whatever you build from these rows.