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Solar wind
speed: 292.8 km/sec
density: 2.1 protons/cm3
explanation | more data
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: C1
1848 UT Oct20
24-hr: C2
0840 UT Oct20
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 20 Oct 13
Sunspot AR1875 poses a threat for M-class solar flares. Credit: SDO/HMI
Sunspot number: 149
What is the sunspot number?
Updated 20 Oct 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

20 Oct 2013

The Radio Sun
10.7 cm flux: 133 sfu
explanation | more data
Updated 20 Oct 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: 2.8 nT
Bz: 2.3 nT south
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 18 Oct 13
Solar wind flowing from this coronal hole should reach Earth on Oct. 21-22. 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 Oct 20 2200 UTC
0-24 hr
24-48 hr
25 %
25 %
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 Oct 20 2200 UTC
0-24 hr
24-48 hr
25 %
15 %
05 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
20 %
20 %
20 %
20 %
Sunday, Oct. 20, 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

ORIONID METEOR SHOWER: Earth is passing through a stream of debris from Halley's Comet, source of the annual Orionid meteor shower. Forecasters expect the shower to peak on Monday, Oct. 21st, with about 20 meteors per hour. The best time to look is during the hours before local sunrise when the constellation Orion is high in the sky. [meteor radar] [sky map]

Lunar interference will be a problem during the peak. All but the brightest Orionids will be wiped out by glare from the waning full Moon. Fortunately there are some bright ones. NASA's All Sky Fireball Network captured this Orionid fireball shining through the moonlight over Georgia on the morning of Oct. 20th:

For more information about what NASA cameras are seeing, scroll down this page to the all-new section "All Sky Meteor Network." Meanwhile, amateur photos of Orionds are available in the gallery.

Realtime Meteor Photo Gallery

FAINT ECLIPSE OF THE HUNTER'S MOON: As Oct. 18th came to a close, a dusky shadow fell across the southern half of the full Hunter's Moon. It was a faint "penumbral" lunar eclipse. Observing from the Canary islands, Frank A. Rodriguez Ramirez photographed the Moon (left) two hours before and (right) at the moment of maximum eclipse:

"We had bad weather for the eclipse," says Rodriguez Ramirez. "I captured these pictures between small holes in clouds."

A penumbral eclipse happens when the Moon passes through the pale outskirts of Earth's shadow. It is much less dramatic than a total lunar eclipse. In fact, when observers are not alerted beforehand, they often do not realize an eclipse is underway. Nevertheless, the subtle shadow of Earth is visible to the naked eye if you know it's there. Scan the gallery for more examples.

Realtime Space Weather Photo Gallery

MOONLIGHTS: "For five nights in a row we have seen amazing auroras above Abisko National Park," reports tour guide Chad Blakley of Abisko, Sweden. "Last night I spent most of the evening on the shore of Lake Torneträsk. I was able to capture several thousand images of the Northern Lights dancing over the lake while the glow of the full Moon illuminated the nearby mountain peaks." After daybreak, he put the images together to make a must-see video:

"I have spent countless nights out under the auroras but there was something very special about listening to the waves gently crash along the shore as the lights played overhead," says Blakley. "I think I have the best job in the world!"

The auroras could continue dancing in the nights ahead--especially on Oct. 21st when a solar wind stream is expected to reach Earth. NOAA forecasters estimate a 20% chance of polar geomagnetic storms when the stream arrives. Aurora alerts: text, voice.

Realtime Aurora Photo Gallery

GREEN COMET, RED PLANET: Comet ISON, which will fly through the atmosphere of the sun on Nov. 28th, is now flying past the planet Mars. The green comet and the Red Planet are just 1o apart in the eastern sky before dawn. Parks Squyres photographed the odd couple from his private observatory in SaddleBrooke, Arizona, on Oct. 16th:

Mars is almost as bright as a 1st-magnitude star, easy to find in the constellation Leo near the blue star Regulus. The comet, on the other hand, is invisible to the unaided eye. Mid-sized backyard telescopes are required to see it.

"I used a Celestron 11-inch telescope," says Squyres. "The image is a stack of 80 15-second exposures."

The comet is green because its vaporizing nucleus emits diatomic carbon, C2, a gas which glows green in the near-vacuum of space. Mars is red because its rocky surface is widely rusted. The two colors make a heavenly ensemble. Amateur astronomers, if you have a GOTO telescope, enter these coordinates, and let the exposures begin.

Realtime Comet ISON Photo Gallery

  All Sky Fireball Network
NEW: 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 Oct. 20, 2013, the network reported 28 fireballs.
(17 sporadics, 8 Orionids, 1 chi Taurid, 1 southern Taurid, 1 Leonis Minorid)

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 October 20, 2013 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2013 UB
Oct 19
1.6 LD
20 m
2000 DK79
Nov 10
49.1 LD
3.0 km
2011 JY1
Nov 13
8.2 LD
57 m
2001 AV43
Nov 18
3 LD
52 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
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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