Castor Position and Visibility Tonight
Where is Castor right now?
Castor is located in the constellation Gemini. It is currently above the horizon at an altitude of 46° toward the north-east, with an apparent magnitude of 1.93.
Castor visibility on 2026-10-27
Castor Visible from early morning until sunrise
Castor rise and set timetable
| Time | Elevation | |
Moonrise, 98.9% illuminated  | 19:51 | -50° |
| Astronomical observing session begins | 20:01 | -48° |
| Castor rise | 00:11 | |
| Astronomical observing session ends | 05:35 | 58° |
| Twilight end (−12°) | 06:00 | 59° |
| Castor transit | 06:14 | 59° |
| Civil sunrise | 06:25 | 59° |
| Sunrise | 06:47 | 58° |
| Moonset | 08:26 | 46° |
| Castor set | 12:16 |
Track Castor position throughout the night
← 27 October 2026 →
| Time | |
| Altitude | |
| Azimuth |
Shift the map to change the time and observe Castor changing position in the night sky.
Star system description: Castor
Castor is a multiple system. The bright visual AB pair is separated by 5.4″; the much wider companion is recorded separately (69.6″).
Pair AB has a measured separation of 5.4″; a telescope may be needed to split it.
The diagram uses the latest WDS measurements; north is up and east is right. Measurements may be from different years. Unconnected groups are arranged separately; close pairs may merge, and pairs without reliable geometry are omitted.
Technical details: Castor
| Property | Value |
|---|---|
| System identifier | WDS 07346+3153 |
| Bayer / Flamsteed designation | α Gem |
| Constellation | Gemini |
| System type | multiple star system |
| Right ascension (RA) | 07h 34m 35s" |
| Declination (Dec) | 31° 53' 17s |
| Component | AB |
| Primary magnitude | 1.93 |
| Secondary magnitude | 2.97 |
| Separation (arcseconds) | 5.4″ |
| Position angle | 51° |
| Discovery year | 1778 |
| Last observed | 2023 |
| Spectral type (primary/secondary) | A1V+A4Vm |
| Number of observations | 1520 |
6 components are identified in WDS; this is not a count of resolved stars.
Components of Castor
Each row is a separate WDS component pair. Measurements may come from different years.
| Component | Primary magnitude | Secondary magnitude | Separation (arcseconds) | Position angle | Last observed |
|---|---|---|---|---|---|
| AB | 1.93 | 2.97 | 5.4″ | 51° | 2023 |
| Aa,Ab | 1.93 | — | — | — | 2021 |
| AC | 1.93 | 9.83 | 69.6″ | 164° | 2023 |
| AD | 1.93 | 10.07 | 178.3″ | 222° | 2023 |
| Ba,Bb | 2.97 | — | — | — | 2021 |
| BC | 2.97 | 9.83 | 73.8″ | 168° | 2020 |
| CD | 9.83 | 10.07 | 154.9″ | 244° | 2015 |
Notes
- V: Proper motion indicates a physical pair.
Data source: Washington Double Star (WDS) Catalog. Maintained by the U.S. Naval Observatory; thanks to the WDS team.
Finder Chart for Castor
Castor Passage Through Night
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Current position of Castor
| Time | 03:58 |
| Latitude | 1.35208 |
| Longitude | 103.82 |
| Elevation | 46° |
| Azimuth | 43° |
Here you can see the current position of Castor on the map, as well as its positions for rise and set. This tool lets you track its movement throughout the night with accurate, up-to-date information.
When Is Castor Visible Throughout the Year?
Castor will remain visible until May 29, when it moves too close to the Sun and temporarily disappears from the night sky.
| Date | Wed, 28 October 2026 |
| Astronomical observing session begins | 19:55 |
| Astronomical observing session ends | 05:28 |
| Astronomical observing duration | 10h 33m |
| Rise | 00:07 |
| Set | 12:12 |
| Elevation at transit | 59° |
| Transit time | 06:10 |
| Equatorial coordinates | RA: 07h 34m 35s", Dec: 31° 53' 17s |
| Magnitude | 2 |
| Constellation | Gemini |
The graph illustrates the annual visibility pattern of Castor, including its daily appearances and transit times. The vertical axis shows the hours of the day and the horizontal axis spans the year. The reddish area marks when the object is above the horizon, while the white line marks its daily transit.
You can also see when Castor is visible throughout the year in a table with exact rise, transit, and set times for each date.
You can also see when Castor is visible throughout the year in a table with exact rise, transit, and set times for each date.
Astrometric and Physical Parameters of Castor
Coordinates and Visibility
| Right Ascension | 07h 34m 36s |
| Declination | 31° 53′ 18″ |
| Magnitude | 1.93 |
| Constellation | Gemini |
| Elevation | 45.7° |
| Azimuth | 42.9° |