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Solar wind
speed: 325.3 km/sec
density: 1.4 protons/cm3
explanation | more data
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: C1
2151 UT Nov21
24-hr: M1
1113 UT Nov21
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 21 Nov 13
Crowded near the sun's SW limb, sunspots AR1893 and AR1897 pose a threat for M-class solar flares. Credit: SDO/HMI
Sunspot number: 95
What is the sunspot number?
Updated 21 Nov 2013

Spotless Days
Current Stretch: 0 days
2013 total: 0 days (0%)
2012 total: 0 days (0%)
2011 total: 2 days (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Since 2004: 821 days
Typical Solar Min: 486 days

21 Nov 2013

The Radio Sun
10.7 cm flux: 147 sfu
explanation | more data
Updated 21 Nov 2013

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 1
explanation | more data
Interplanetary Mag. Field
Btotal: 3.4 nT
Bz: 0.5 nT south
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 21 Nov 13
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA. is now posting daily satellite images of noctilucent clouds (NLCs), which hover over Earth's poles at the edge of space. The data come from NASA's AIM spacecraft. The north polar "daisy" pictured below is a composite of near-realtime images from AIM assembled by researchers at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP).
Noctilucent Clouds
Switch view: Europe, USA, Asia, Polar
Updated at: 09-02-2013 11:55:02
NOAA Forecasts
Updated at: 2013 Nov 21 2200 UTC
0-24 hr
24-48 hr
15 %
15 %
01 %
01 %
Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2013 Nov 21 2200 UTC
0-24 hr
24-48 hr
10 %
10 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
20 %
20 %
10 %
10 %
Thursday, Nov. 21, 2013
What's up in space

When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.

Northern Lights - a Guide

EARTH DODGES SOLAR FLARES: Solar activity is moderately high this week, but the eruptions (including an X-flare on Nov. 19th) have had little effect on our planet. The flare sites are concentrated near the sun's SW limb where a cluster of active sunspots is rotating off the Earthside of the sun. NOAA forecasters estimate a waning 20% chance of M-class flares and a 1% chance of X-flares as the active regions depart. Solar flare alerts: text, voice

ISON, THE DAWN COMET: Comet ISON is plunging toward the sun and brightening as it heads for a perilous close encounter on Nov. 28th. This morning, with the "final countdown" clock at T-7 days, Juan Carlos Casado photographed the sundiver over the Teide Observatory in the Canary Islands:

"The comet is over the distant island of Gran Canaria," he says, "while in the central cloud we can see the planet Mercury. ISON was at the limit of naked-eye visibility, but it was an easy target for my SLR camera with a small telephoto lens (85 mm focal length) on a static tripod and 6 seconds of exposure."

Because Comet ISON is moving into the rosy glow of dawn, it will soon be impossible for cameras on Earth to track it. NASA's fleet of solar spacecraft are about to take over. Later today, Comet ISON will enter the field of view of the STEREO-A spacecraft. The Heliospheric Imager on STEREO-A will pick up the comet just as Earth-bound telescopes begin to lose it. In the days that follow, STEREO-B, SOHO and the Solar Dynamics Observatory will join the hunt, providing continuous views of Comet ISON all the way to perihelion (closest approach to the sun) on Nov. 28th. Stay tuned!

Realtime Comet ISON Photo Gallery
Ephemerides: Comet ISON, Comet Lovejoy, Comet Encke, Comet LINEAR X

WHY IS COMET ISON GREEN? Taken by hundreds of people around the world, the pictures of Comet ISON we receive every day vary widely in quality, context and camera settings. However, they all seem to have one thing in common: the comet looks green. Why? To answer this question, Italian amateur atronomers Paolo Corelli and Dario Comino used a high-dispersion spectrometer to analyze light from the comet's atmosphere. Here are there results:

The spectrum of Comet ISON is dominated by a green spectral line from diatomic carbon (C2). This substance is common in the atmospheres of comets, and it glows green when illuminated by sunlight in the near-vacuum of space. The spectrum also shows a weaker but still significant blue emission line from C2. Comet ISON's mixture of green and blue light gives it the aqua hue seen in many long-exposure photographs. Finally, the spectrum reveals a contribution from atomic oxygen. This element is familiar to readers of as a source of green light in auroras.

Realtime Space Weather Photo Gallery

Realtime Aurora Photo Gallery

Realtime Comet ISON Photo Gallery

  All Sky Fireball Network
Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on

On Nov. 21, 2013, the network reported 18 fireballs.
(11 sporadics, 5 Leonids, 2 Northern Taurids)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

  Near Earth Asteroids
Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.
On November 21, 2013 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2011 JY1
Nov 14
6.7 LD
54 m
2001 AV43
Nov 18
3 LD
52 m
2013 VK13
Nov 19
8.1 LD
26 m
2010 CL19
Nov 25
37.6 LD
1.3 km
2013 NJ
Nov 26
2.5 LD
190 m
2011 YD29
Dec 28
6.1 LD
24 m
2007 SJ
Jan 21
18.9 LD
1.9 km
2012 BX34
Jan 28
9.6 LD
13 m
2006 DP14
Feb 10
6.2 LD
730 m
Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.
  Essential web links
NOAA Space Weather Prediction Center
  The official U.S. government space weather bureau
Atmospheric Optics
  The first place to look for information about sundogs, pillars, rainbows and related phenomena.
Solar Dynamics Observatory
  Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever.
  3D views of the sun from NASA's Solar and Terrestrial Relations Observatory
Solar and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
Daily Sunspot Summaries
  from the NOAA Space Environment Center
  the underlying science of space weather
Space Weather Alerts
  more links...
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