Imaging
from Puerto Rico with a 12-inch telescope, Efrain Morales Rivera
captured the supernova in M101 on August 29th when the outburst was
still 12th magnitude. North is to the right.
Efrain Morales Rivera
The M101 supernova is still at its peak. Supernova 2011fe, which
erupted in the nearby galaxy M101 three weeks ago, leveled off at about
magnitude 9.9 and remained that bright for a week. It's now showing
signs of starting to fade; see an up-to-date light curve. Judge its brightness yourself using the comparison-star charts you can generate courtesy of the American Association of Variable Star Observers (AAVSO)
(enter star name SN 2011fe, and choose predefined chart scales "A" and
"C". The two brightest stars on the "A" chart are the last two the the
Big Dipper's handle).
Bright moonlight washed the sky last week, but now (September 16th) a
window of moonless observing time starts opening up right after
nightfall.
This is the brightest supernova that's been visible from mid-northern
latitudes in three decades. It's well within visual reach of a 3- or
4-inch scope. Although it looks like an ordinary star, it's at least
1,000 times more distant than any other star that's visible in amateur
telescopes from northern latitudes.
You'll probably be using the supernova to find M101, not the other way
around; the galaxy (off the handle of the Big Dipper) is diffuse and
easily wiped out by any skyglow. See our article, The M101 Supernova Shines On.
Friday, Sept. 16
Jupiter shines to the right of the waning gibbous Moon once they rise shortly after dark.
Saturday, Sept. 17
By 10 or 11 p.m. the Big
Dipper has swung around to lie level low in the north-northwest. The
farther south you are, the lower the Dipper will be. If you're in Miami
it'll be partly below the horizon.
Sunday, Sept. 18
Jupiter's moon Io casts
its tiny black shadow on Jupiter tonight: from 12:50 to 3:00 a.m. Monday
morning EDT (9:50 p.m. to 12:00 midnight Sunday evening PDT). For a
listing of all of Jupiter's satellite events and Red Spot transits this
month, good worldwide, see "Action at Jupiter" in the September Sky & Telescope, page 54.
Monday, Sept. 19
Cygnus has a reputation
for being poor in deep-sky objects despite its Milky Way richness. But
maybe that's because you've never tried teasing out the Berkeley
clusters at the center of the Northern Cross. See Sue French's Deep-Sky
Wonders article, charts, and photos in the September Sky & Telescope, page 56. Plan your observing session for after dinnertime, when Cygnus is at its highest and the Moon isn't yet risen.
Tuesday, Sept. 20
Last-quarter Moon (exact
at 9:39 a.m. EDT). The Moon rises around midnight daylight saving time,
in the feet of Gemini left of Orion.
Wednesday, Sept. 21
Jupiter's moon Ganymede
disappears into eclipse by Jupiter's shadow off the planet's western
limb early Thursday morning around 3:30 a.m. EDT. Ganymede reappears out
of eclipse closer to Jupiter's limb around 5:34 a.m. EDT.
The waning Moon passes Mars and Regulus in the early hours of the morning.
Thursday, Sept. 22
Before dawn tomorrow, look
east and you can spot Mars upper left of the waning Moon, as shown here.
Is this the first time you've seen Mars this year?
Friday, Sept. 23
The September equinox
occurs at 5:05 a.m. EDT this morning, when the Sun crosses the equator
heading south for the season. Fall begins in the Northern Hemisphere,
spring in the Southern Hemisphere.
As summer turns to
fall, the Sagittarius Teapot moves west of due south right after dark
and tips steeply, as if pouring away the last of summer.
Saturday, Sept. 24
Jupiter's Great Red Spot
crosses the planet's central meridian around 2:02 a.m. Sunday morning
EDT (11:02 p.m. Saturday evening PDT).
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