M 100 Deep sky · Galaxy in Coma Berenices · M 100 · NGC 4321
Blowdryer Galaxy
A grand-design spiral in the Virgo Cluster — the galaxy Hubble photographed to show its new, corrected eyesight.
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- Type
- Galaxy
- Designations
- M 100 · NGC 4321
- Constellation
- Coma Berenices
- Apparent magnitude
- 9.3
- Apparent size
- 7′ × 6′
- Position (J2000)
- RA 12h 23m · Dec +15° 49′
The full Moon, about 31′ across, is 4.2 times as wide. The Sun comes no nearer to it than 17°, 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 25 Mar 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT | 16:50 | 00:11 · 54° | 07:33 |
| New York EDT | 18:11 | 01:06 · 65° | 08:01 |
| Singapore GMT+8 | 19:16 | 01:17 · 76° | 07:17 |
| Sydney GMT+11 | 19:52 | 01:08 · 40° | 06:23 |
Common questions
- Can I see it from 50° north?
- Yes. It rises and sets, and at its highest it stands 56° up in the south.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 39° up in the north.
- When is the best time of year to see it?
- Around late March, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by late June it is highest in the early evening, and in late December not until the hours before dawn.
- How bright is it?
- Magnitude 9.3 in total, but that light is spread over 7′ × 6′ of sky: on average 22.1 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 9.3 it is past the eye, but a 50 mm pair under a dark sky reaches about magnitude 11.0.
History
After astronauts fitted Hubble with corrective optics, its first images included this galaxy. Hubble later measured its Cepheids to work out how fast the universe expands.
Look for
It is in the northern part of the Virgo galaxy field. A small telescope shows a faint round glow with a brighter centre.
Look for
From 50° north it climbs to 56°; from 35° north it climbs to 71°; from the equator it climbs to 74°; from 35° south it climbs to 39°.
Look for
Magnitude 9.3 against the faintest star each can show: the eye under a city sky, 4.5 (4.8 short); the eye under a dark country sky, 7.0 (2.3 short); 50 mm binoculars under that dark sky, 11.0 (1.7 to spare); a 100 mm telescope there, 12.5 (3.2 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 2% of the field’s width; through a 100 mm telescope at 50×, a field about 1° across, it spans 12% of the field’s width.