M 102 Deep sky · Galaxy in Draco · M 102 · NGC 5866
Spindle Galaxy
The disputed Messier object. This site follows most observing lists in taking it to be the Spindle Galaxy in Draco — but Messier may never have seen it.
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- Type
- Galaxy
- Designations
- M 102 · NGC 5866
- Constellation
- Draco
- Apparent magnitude
- 9.9
- Apparent size
- 6′ × 3′
- Position (J2000)
- RA 15h 06m · Dec +55° 46′
The full Moon, about 31′ across, is 4.9 times as wide. The Sun comes no nearer to it than 67°, around late September, so it is never lost in the Sun’s glare, which reaches about 15° out.
When to see it
On the night of Thu 6 May 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | Never sets | 01:09 · 86° | — |
| New York EDT | Never sets | 01:03 · 75° | — |
| Singapore GMT+8 | 19:07 | 01:14 · 36° | 07:21 |
| Sydney GMT+10 | 23:22 | 00:05 · 0° | 00:48 |
Common questions
- Can I see it from 50° north?
- Yes, on any clear night of the year. From there it never sets: it is circumpolar, circling the pole and still 16° up at its lowest.
- Can I see it from 35° south?
- No. From there it never rises: you would have to travel north of 34° south before it cleared the horizon at all.
- When is the best time of year to see it?
- Around early May, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by early August it is highest in the early evening, and in early February not until the hours before dawn.
- How bright is it?
- Magnitude 9.9 in total, but that light is spread over 6′ × 3′ of sky: on average 21.6 magnitudes per square arcsecond. Against a dark country sky that average stands out; a city’s glow drowns all but its brightest parts.
- Naked eye, binoculars or telescope?
- Binoculars. At magnitude 9.9 it is past the eye, but a 50 mm pair under a dark sky reaches about magnitude 11.0.
History
Pierre Méchain, who reported it, wrote in 1783 that it was a mistake — a second sighting of the Pinwheel. Some catalogues still file it that way; the galaxy here fits the description Messier printed.
Look for
A small telescope shows a bright, lens-shaped streak. Photographs show a thin lane of dust running exactly along its middle: a disc galaxy seen edge-on.
Look for
From 50° north and 35° north it is circumpolar and never sets; from the equator it climbs to 34°; from 35° south it never rises.
Look for
Magnitude 9.9 against the faintest star each can show: the eye under a city sky, 4.5 (5.4 short); the eye under a dark country sky, 7.0 (2.9 short); 50 mm binoculars under that dark sky, 11.0 (1.1 to spare); a 100 mm telescope there, 12.5 (2.6 to spare). Those limits are for a point of light; its light is spread over its whole size, so it needs some of that margin in hand. Through 7×50 binoculars, whose field is about 7.1° across, it spans 1% of the field’s width; through a 100 mm telescope at 50×, a field about 1° across, it spans 11% of the field’s width.