HD 166841
ILLUSTRATION FROM MEASURED TEMPERATURE · 10 700 K · 90.2 L☉
OVERVIEW
] STARHD 166841 is a B8/9V blue-white main-sequence star in the constellation Pavo, 609.6 from Earth, shining at apparent magnitude 6.32 (). It is catalogued as HIP 89674 and HR 6808.
- WHAT IT IS
- Blue-white main-sequence star
- HOW FAR
- 609.6
- HOW BRIGHT (V)
The light arriving now left it that long ago.
Bright enough for the naked eye, under a sky dark enough.
THE MODEL
] RADIUS FROM THE LUMINOSITY AND THE TEMPERATURECALCULATED · NOT AN OBSERVATION · RADIUS FROM THE LUMINOSITY AND THE TEMPERATURE · MEASURED TEMPERATURE · 10 700 K · 90.2 L☉
Drawn from the radius from the luminosity and the temperature and from the same properties the picture at the top of this page uses, at the distance a flight to it would stop. Drag it, or use the arrow keys, to look from another direction. The stars behind are the 498,631 this catalogue holds real distances for, drawn from where the camera actually is — but every one of them is within 170 parsecs of the Sun and this object is much further out, so what is in the frame is that whole neighbourhood seen from outside it, piled into a knot around the Sun. The rest of the sky from here is not something this catalogue knows.
OBSERVING
] FROM WHERE YOU AREWhat it takes to see HD 166841 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 HD 166841 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. Its brightest companion sits 2.40″ away, which at 48× is split, with the two all but touching.
- 48×
- 1.08
- 1.25
- 13.0
- 2.40 · split, with the two all but touching
- APPARENT MAGNITUDE ()
- 6.32 · within reach
A is where the pair was the year it was measured — the ones above, in 2008, and a pair in a real orbit has moved since. The brightest companion is 3.6 magnitudes down on the star itself, which makes it a harder split than the angle alone suggests: the glare of the brighter one is what you are separating it from.
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
- 16.0
- PROPER MOTION SINCE
- 0.45
Computed for 2026-08-27 00:00 UT. Two things separate it from the catalogued position above: HD 166841 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.
DOUBLE STAR
] 1 PAIR| COMPONENTS | SEPARATION | POSITION ANGLE | MAGNITUDE | MEASURED |
|---|---|---|---|---|
| — | 2.4″ | 300° | 9.9 | 2008 |
Separation and position angle are as measured in the year given; a position angle is measured from north, through east. Washington Double Star Catalog 18180-6814.
SPECTRUM
] A SPECTRUM OF ITS TYPENo survey in this catalogue has measured HD 166841’s own spectrum: the one that reaches deepest saturates on the brightest stars, and no spectrograph has been pointed at the whole sky. What is drawn below is the average of several real stars of the same class, B8 V. It shows what a star like this one shows, and every line named on it is a line of the type rather than a measurement of HD 166841.
A star gives out light at every wavelength at once. The dark gaps are atoms in the thin gas above its surface, each one removing the single colour it is able to absorb — which is how a list of ingredients is read off something nobody will ever touch.
Point at a labelled line — or an element above — to see which atom makes it and where it falls.
Pickles (1998) stellar spectral flux library. B8 V — the average of several real stars of this type, not an observation of any one star. Sampled every 5 angstroms; 1,895 points rebinned onto 1,024 log-spaced display points and normalised to the median flux. Brightness is scaled to this spectrum’s own middle value, so the shape is the measurement and the height is not. The 5 lines named above are the ones that stand clear of the scatter and of the features around them; a spectrum at this sampling holds many more that it cannot separate. The samples themselves, as JSON, CSV or VOTable.
CATALOG DATA
] 10 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
- Surface temperature
- 10 691
- Luminosity
- 90.1986
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)
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)
- 0.44
- Proper motion (Dec)
- −16.97
- Radial velocity
- 22
OTHER NAMES AND NUMBERS
The identifiers other catalogues file this object under, for anyone joining this data to theirs.
- Washington Double Star id
- 18180-6814
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 (1975MSS...C01....0H, quality D)
- Stellar parameters from
- Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)
ALSO KNOWN AS
] 3 DESIGNATIONS- HD HD 166841
- HIP HIP 89674
- HR HR 6808
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.
- SIMBADHD 166841
Cross-identifications, measured values and the reference behind each of them.
- ADSobject:"HD 166841"
Papers indexed against this object rather than against the string, newest first.
- VizieR5″ around 274.5040 -68.2293
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. HD 166841 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-166841
@misc{spacecatalog_hd-166841,
author = {{SpaceCatalog}},
title = {{HD 166841}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/hd-166841},
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.