You are viewing the page for Apr. 19, 2015
  Select another date:
<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids Internet Shopping Sites high quality binoculars excellent weather stations all-metal reflector telescopes rotatable microscopes
Solar wind
speed: 385.3 km/sec
density: 8.2 protons/cm3
explanation | more data
Updated: Today at 2348 UT
X-ray Solar Flares
6-hr max: B7
2135 UT Apr19
24-hr: C2
0719 UT Apr19
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 19 Apr 15
Sunspots AR2321 and AR2324 pose a threat for Earth-directed M-class solar flares. Credit: SDO/HMI

Sunspot number: 114
What is the sunspot number?
Updated 19 Apr 2015

Spotless Days
Current Stretch: 0 days
2015 total: 0 days (0%)

2014 total: 1 day (<1%)
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%)

Updated 19 Apr 2015

The Radio Sun
10.7 cm flux: 148 sfu
explanation | more data
Updated 19 Apr 2015

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 3
explanation | more data
Interplanetary Mag. Field
Btotal: 4.9 nT
Bz: 1 nT south
explanation | more data
Updated: Today at 2349 UT
Coronal Holes: 19 Apr 15

Solar wind flowing from the indicated coronal hole should reach Earth on April 22. Credit: SDO/AIA.
Noctilucent Clouds The southern season for NLCs has come to an end. The last clouds were observed by NASA's AIM spacecraft on Feb. 20, 2015. Now attention shifts to the northern hemisphere, where the first clouds of 2015 should appear in mid-May.
Switch view: Ross Ice Shelf, Antarctic Penninsula, East Antarctica, Polar
Updated at: 02-28-2015 02:55:03
NOAA Forecasts
Updated at: 2015 Apr 19 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: 2015 Apr 19 2200 UTC
0-24 hr
24-48 hr
30 %
35 %
05 %
10 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
30 %
30 %
35 %
45 %
Sunday, Apr. 19, 2015
What's up in space

Learn to photograph Northern Lights like a pro. Sign up for Peter Rosen's Aurora Photo Courses in Abisko National Park.

Lapland tours

INCOMING CME, STORMS POSSIBLE ON EARTH DAY: Yesterday, April 18th, a magnetic filament attached to sunspot group AR2321 erupted, producing a C5-class solar flare. A movie from NASA's Solar Dynamics Observatory shows the filament splitting the sun's atmosphere as it hurtles away from the blast site:

Part of the escaping filament formed the core of a faint CME, which is now heading almost directly for Earth. The cloud should reach our planet during the late hours of April 21st. In combination with a solar wind stream already en route, the impact could spark geomagnetic storms around the poles on April 22nd, Earth Day.

This is a minor CME launched by a minor C-class flare, so it is natural to expect only minor storms when the CME arrives. Indeed, that is probably what will happen. It is notable, however, that the intense geomagnetic storm of March 17, 2015, was triggered by a C-flare/CME combo only a little more intense than this one. The "St. Patrick's Day Storm" reminds us that any CME impact can produce a significant disturbance. Auroras for Earth Day, anyone? Stay tuned. Aurora alerts: text, voice.

Realtime Aurora Photo Gallery

SUNSPOT SUNRISE: The sun is peppered with so many spots, observers are beginning to notice them at sunrise--no filters required. Jett Aguilar "spotted" the dark cores this morning when the sun came up over Quezon City, the Philippines:

"At sunrise on April 19th I took an image of the sunspot-spotted sun rising over the Sierra Madre mountains of Luzon," he says. "I used an unfiltered Canon 300 mm f/4 lens with a 2x Canon extender on a Canon 7D DSLR. Exposure was 1/2000 sec at f/45, ISO 100."

Photographers should take note of these settings. Most of the sunspots pictured above will remain visible for another 5 to 7 days, providing daily photo-ops at sunrise and sunset. Flares are likely, too. The largest sunspots in the image (AR2321 and AR2124) have 'beta-gamma' magnetic fields that harbor energy for M-class explosions. Solar flare alerts: text, voice

Warning: Even when the sun is dimmed by low-hanging clouds or haze, it can still damage your eyes. Sunlight magnified by unfiltered optics is dangerously bright. If you chose to photograph the low sun, as Aguilar did, use the camera's LCD screen for safe viewfinding. Never look into the eyepiece of an unfiltered camera or telescope when the sun is in the field of view.

Realtime Space Weather Photo Gallery

CORONAL HOLE: NASA's Solar Dynamics Observatory (SDO) is monitoring a hole in the sun's atmosphere--a "coronal hole." It is colored deep-blue in this extreme UV image of the sun taken by SDO on April 17th:

Coronal holes are places where the sun's magnetic field opens up and allows solar wind to escape. In the image, above, the sun's magnetic field is traced by white loops. Arrows show the flow of material out of the hole.

Holes in the sun's atmosphere are not unusual; they appear several times each month. A stream of solar wind flowing from this particular coronal hole will probably reach Earth on April 22--the same time as the CME discussed in the news item above. This means we could have auroras for Earth Day. Stay tuned. Aurora alerts: text, voice

Realtime Space Weather Photo Gallery

Realtime Eclipse Photo Gallery

Realtime Comet 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 Apr. 19, 2015, the network reported 11 fireballs.
(11 sporadics)

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 April 19, 2015 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2015 HJ
Apr 14
9.3 LD
16 m
2015 GA1
Apr 16
2.5 LD
21 m
2015 GL13
Apr 16
0.5 LD
8 m
2015 GY12
Apr 19
13.7 LD
31 m
2015 HE1
Apr 21
3.3 LD
16 m
2015 HD1
Apr 21
0.2 LD
15 m
2015 GB14
Apr 28
8.9 LD
38 m
5381 Sekhmet
May 17
62.8 LD
2.1 km
2005 XL80
Jun 4
38.1 LD
1.0 km
2012 XB112
Jun 11
10.1 LD
2 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...
©2010 All rights reserved. This site is penned daily by Dr. Tony Phillips.
©2019 All rights reserved.