V391 Vul
ILLUSTRATION FROM SPECTRAL TYPE B8 · 11 700 K · VARIABLE, MAG 7.26–7.32 · TIMING NOT TO SCALE
OBSERVING
] FROM WHERE YOU AREWhat it takes to see V391 Vul 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 V391 Vul is worth going out for.
THROUGH AN EYEPIECE
] 150 MM TELESCOPE · 25 MM EYEPIECEToo faint for your eyes alone. Binoculars reach it. Its brightest companion sits 0.50″ away, which at 48× is blended into one star.
- 48×
- 1.08
- 1.25
- 13.0
- · AB
- 0.50 · blended into one star
- · AD
- 2.20 · split, with the two all but touching
- · AC
- 2.00 · split, with the two all but touching
- APPARENT MAGNITUDE ()
- 7.29 · within reach
A is where the pair was the year it was measured — the ones above, between 2015 and 2021, and a pair in a real orbit has moved since. The brightest companion — AB — is 3.0 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
- 15.0
- PROPER MOTION SINCE
- 0.12
Computed for 2026-08-27 00:00 UT. Two things separate it from the catalogued position above: V391 Vul 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
] SLOWLY PULSATING B STAR- RANGE, AS SAMPLED
- 7.26 – 7.32
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.
DOUBLE STAR
] 3 PAIRS| COMPONENTS | SEPARATION | POSITION ANGLE | MAGNITUDE | MEASURED |
|---|---|---|---|---|
| AB | 0.5″ | 118° | 10.31 | 2021 |
| AC | 2″ | 116° | — | 2015 |
| AD | 2.2″ | 104° | — | 2015 |
Separation and position angle are as measured in the year given; a position angle is measured from north, through east. Washington Double Star Catalog 19316+2659.
CATALOG DATA
] 12 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
- Slowly pulsating B star
- Variability type ()
- LPB
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)
- 0.91
- Proper motion (Dec)
- −4.33
- Radial velocity
- 0
OTHER NAMES AND NUMBERS
The identifiers other catalogues file this object under, for anyone joining this data to theirs.
- Variable-star designation
- V391 Vul
- Washington Double Star id
- 19316+2659
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 (1993yCat.3135....0C, quality E)
ALSO KNOWN AS
] 3 DESIGNATIONS- HD HD 184059
- HIP HIP 96034
- Variable star V391 Vul
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 184059
Cross-identifications, measured values and the reference behind each of them.
- ADSobject:"HD 184059"
Papers indexed against this object rather than against the string, newest first.
- VizieR5″ around 292.9016 +26.9866
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. V391 Vul [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-184059
@misc{spacecatalog_hd-184059,
author = {{SpaceCatalog}},
title = {{V391 Vul}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/hd-184059},
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.