OVERVIEW
] STAR CLUSTERPleiades is an open cluster in the constellation Taurus, 444.0 from Earth, shining at apparent magnitude 1.20 (). Other catalogues list it as C 0344+239, M 45 and MWSC 305, among 5 designations in total. It has been known since antiquity.
The Seven Sisters: a young open cluster close enough that its brightest members are naked-eye stars, still wrapped in the blue haze of the dust they are drifting through.
- WHAT IT IS
- Open cluster
- HOW FAR
- 444.0
- HOW BIG ON THE SKY
- 2.50
- HOW BRIGHT (V)
The light arriving now left it that long ago.
About 4.8 full Moons wide.
Bright enough for the naked eye, under a sky dark enough.
THE MODEL
] LIGHT ALONG THE RAYCALCULATED · NOT AN OBSERVATION · ANGULAR SIZE AT THE CATALOGUED DISTANCE · OPEN CLUSTER · MAJOR AXIS 150′ · POSITION ANGLE 90° · NO SURFACE — DRAWN AS A VOLUME · MEMBERS DRAWN, NOT COUNTED
A cloud of gas glowing at the lines its class emits, brightest in the middle and fading through the colour of the outer gas. The shape of it is the catalogued class; the flattening is the catalogued axis ratio read as the object's own shape rather than as a tilt, because this is not a disc and its ellipticity is not an inclination. Nothing measured the depth, so what is drawn is the roundest object that matches the ellipse the catalogue holds. Every member is drawn at the one temperature its class implies; how many are drawn is a drawing choice and not a population. 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, at their real positions and drawn from where the camera actually is — so the constellations are wrong, and that is the point. This is the sky from there, not the sky from here.
IMAGES
] 1 FRAMES- NASA, ESA, AURA/Caltech, Palomar Observatory
Public domain
OBSERVING
] FROM WHERE YOU AREWhat it takes to see Pleiades 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 Pleiades is worth going out for.
THROUGH AN EYEPIECE
] 150 MM TELESCOPE · 25 MM EYEPIECEBright enough to pick out with your eyes alone, and from a lit street as well as a dark one. Pleiades covers 2.50° of sky against a of 1.08°, so at 48× it is wider than the field — sweep across it.
- 48×
- 1.08
- 1.25
- 13.0
- SIZE ON THE SKY
- 2.50
- FILLS OF THE FIELD
- more than 100% of the width
- APPARENT MAGNITUDE ()
- 1.20 · within reach
Pleiades is not a point of light, so the limit above is the wrong one to hold it against: the same brightness spread over 2.50° of sky is harder than a star of it, and goes first. Catalogued sizes are measured to a photographic contour, and the part an eye sees is usually smaller.
APPARENT PLACE
] EQUINOX J2026.8Where 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
- 22.5
- PROPER MOTION SINCE
- none published
Computed for 2026-10-11 00:00 UT. No proper motion is published for Pleiades, so nothing here moves the object; what separates this from the catalogued position above is the coordinate grid turning under it — about fifty arcseconds a year of precession since 2000, and the small nodding of the Earth’s axis on top of that. The catalogue it came from publishes no error for that position, so nothing here says how far this arithmetic can be trusted — the digits above are as precise as the place they were computed from, and no more. Aberration, parallax and refraction are left out. Aberration swings every position by up to twenty arcseconds over a year; parallax stays under an arcsecond for all but the nearest stars; refraction is nothing overhead and about half a degree at the horizon, where it answers to the air, not the sky. The same figure for any date.
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.
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.
- Apparent magnitude ()
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.
- 7
- Redshift (z)
- Major axis
- 150
- Minor axis
- 150
- 90
OTHER NAMES AND NUMBERS
The identifiers other catalogues file this object under, for anyone joining this data to theirs.
- Also known as
- SEVEN SISTERS, Seven Sisters
- OpenNGC type code
- OCl
- Wikidata item
- Q13423
- Wikipedia article
- Pleiades
ALSO KNOWN AS
] 5 DESIGNATIONS- Common name Pleiades
- IAU cluster C 0344+239
- Messier M 45
- MWSC MWSC 305
- OpenNGC Mel022
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.
- SIMBADM 45
Cross-identifications, measured values and the reference behind each of them.
- ADSobject:"M 45"
Papers indexed against this object rather than against the string, newest first.
- VizieR600″ around 56.8692 +24.1053
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. Pleiades [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/m45
@misc{spacecatalog_m45,
author = {{SpaceCatalog}},
title = {{Pleiades}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/m45},
note = {Catalogue entry, data release DR1 (2026-08-21). Values from OpenNGC.}
}The values above were taken from OpenNGC — 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.
That catalogue asks for this acknowledgement: OpenNGC, Mattia Verga (github.com/mattiaverga/OpenNGC). Fields derived from it stay under CC BY-SA 4.0.
RECENT ACTIVITY
] 2 ITEMS- What’s Up: October 2026 Skywatching Tips from NASA2026-10-01 · NASA · MISSION UPDATE
- What’s Up: October 2026 Skywatching Tips from NASA2026-10-01 · NASA · RELEASE
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