Wednesday, November 27, 2013

SDO's Comet ISON Perihelion Event Website

Comet ISON  November 15, 2013. Credit and copyright: Damian Peach
From the SDOisGo Blog

Tomorrow Thursday, November 28, SDO will watch Comet C/2012 S1 (ISON) fly by the Sun at 1844 UT (1:44 pm ET). We have designed a website to share the SDO images with the public. Here are some tips on the SDO Comet ISON Perihelion Page. The top bar has a couple of links and drop-down menus. You can view a movie which shows the different areas SDO will point (off-pointing- when SDO is not pointing directly at the sun) and explore the orbits of Comets ISON and Lovejoy (from 2011, not the current one). The 3-D interactive works with many browsers (but not Safari). It allows you to examine two sungrazing comet orbits and see the views of different satellites. Under resources are pointers to websites that discuss Comet ISON.

Three views for the perihelion of Comet ISON The home page will have images from four of the AIA wavelengths during each the views (off points), Approach, Perihelion, and Departure. These wavelengths were chosen because in December 2011, when Comet Lovejoy passed perihelion, it was very bright in these wavelengths, and we believe they are the best choice for Comet ISON. We will not see a normal comet tail. The glowing material is forced to move along the Sun's magnetic field. It will look like a cloud moving along and away from the orbit of the comet. You can watch for Comet ISON using either the kiosk mode or mp4 movies. If you select "View kiosk" a new page will open and a series of images at that wavelength will be shown. As data becomes available your kiosk display will automatically add the new images. At the end of each 1-hour phase you will be looking at about 300 images. The movie will flip through all of the data and you can watch for the comet to appear. You can run/pause the display, step through the frames, and force an update. If you pause the display you can use the slider to flip back and forth in the images. New images are available in sets of 5 every minute. If you select "Download mp4" an mp4 movie that has all of the images currently available will be sent to your machine and you can use the movie controls on your webpage to view the images. You have to re-load the mp4 every 5 minutes to get the latest data. The mp4 movies will only be updated every 5 minutes! Join SDO and watch for Comet ISON on November 28 or join our Google+ hangout from 1:00pm-3:30 pm EST (18:00UT - 20:30UT)! A great way to spend a few hours of the American Thanksgiving Day.

Thursday, November 14, 2013

Welcome to November- Satellite Month

As we all wait for the perihelion of the sun-grazing Comet ISON at the end of the month we look the the pre-dawn and post-sunset night sky for a view of the many satellites that zip across the night sky.  Please check out the November Page on satellites for tips for finding Satellites in the Night Sky. Please join the SDO team on November 28th for the perihelion of Comet ISON.  You can follow along @NASA_SDO on Twitter or on the SDO Comet ISON page . We will also be hosting a Google+ Hangout on November 28th - more on that soon.

 From the SDOisGO Blog about Comet ISON.
Now that November has arrived it's time to get ready for Comet C/2012 S1 (ISON). On November 28 (yes, Thanksgiving Day) at 1:45 pm ET, Comet ISON will fly only 730,000 miles above the surface of the Sun. Even though it is moving as fast as 375 km/s (840,000 mph), the Sun will heat Comet ISON, causing it to sublimate and leave a lot of water and grit behind. Comet ISON is about 2 km across, much bigger than Comet Lovejoy in December 2011, and it will leave a lot of itself behind.

Once the stuff sublimates we will watch for it to light up the corona in the AIA bandpasses. We saw Comet Lovejoy in 7 of the 10 bandpasses in December 2011. This time we will point SDO toward three different places where the comet is predicted to be. One will be centered about the time of perihelion for a half hour on each side of perihelion. The other two will point toward the paths the comet will use to approach and leave the Sun and take data for an hour at each place. The offpoints are much larger than the one we did for Comet Lovejoy in 2011. We expect that the comet debris will look a lot smoother for Comet ISON because the magnetic field that far from the surface is also smoother.
Hubble Image From NASA Solar System Exploration
The near-realtime SDO images will be available as self-updating movies at a dedicated website that is being tested and will soon be ready. Until then, there is an ISON campaign website with a lot of good pictures and information about Comet ISON, written by people who study comets. You can also look at the Know Your Night Sky blog for observing hints, especially after perihelion as Comet ISON climbs away from the Sun towards the North Star.

During November we will talk about how much stuff we should see coming off Comet ISON, why the signatures of a sungrazing comet could be like how supernovae work, and how a belt going around two pulleys can help us to understand sungrazing comets.
Make November a month for Sun and comet watching!

Friday, September 20, 2013

September 22 - Autumn Equinox

Taken by June Gronseth via
There have already been some great aurora displays this year and with the Autumn equinox just around the corner and more sunspot activity coming to the Earth side of the sun, we should get a good show in the next couple of weeks.  Remember there are several of aurora resources on the September page for looking for aurora if you are not among the lucky people who live in the higher latitudes and get to see the aurora out of your kitchen window.








Visible light image from the Solar Dynamics Observatory 9/20/13


What do Sunspots have to do with Aurora?

Sunspots themselves are not that important for aurora, but solar activity is what causes aurora and sunspots are where solar activity usually comes from, hence more sunspots usually means more solar activity and more aurora.  The sun is currently in what is called solar maximum, which normally indicates increases solar activity, however there has not been a great deal of solar activity lately. Despite this lack of sunspot activity there has been enough solar activity to create some wonderful Aurora, and hopefully this new cluster of sunspots rotating into view will mean even more aurora in the coming weeks.









Why does the equinox have any impact on Aurora?

From David Hathaway- NASA Marshall
Late August or early September is often called aurora season by residents at higher latitudes. This is because the aurora can more easily be seen due to the end of the midnight sun and night. The vernal or Spring equinox should really be called aurora season, but aurora are seen at both equinoxes. Studies have shown that during both the fall and spring equinoxes geomagnetic disturbance and thus aurora are twice as likely as during summer and winter. This figure by solar physicist David Hathaway of NASA Marshall Space Flight Center uses 75 years of data to show the relationship between the number of geomagnetic disturbances and the time of the year. For a long time scientists did not know what made equinoxes special. Using data from space missions such as THEMIS, scientists now know that it is all about geometry. THEMIS showed us that there are special magnetic ropes connecting Earth's upper atmosphere directly to the sun. During the spring and fall equinox the geometry of the Earth with respect to the sun is such that its magnetic field is best oriented to connect with the sun. (From C. Alex Young at The Sun Today)

Friday, August 9, 2013

Perseid Meteor Shower August 11-12

Photo by Jack Fusco Photography via EarthSky
We are getting close to the peak of the Perseid Meteor shower on the evening of August 11 through the morning of August 12.  NASA is going to host a live webchat with NASA astronomer Bill Cooke and his team members Danielle Moser and Rhiannon Blaauw from the Meteoroid Environment Office at NASA's Marshall Space Flight Center.  If it is cloudy in your area you can also watch a live webstream of the meteor shower.



The best way to observe the meteor shower is lying flat on your back looking straight up in an dark area with open sky.  The meteors will appear from all directions, so keep a look out.  Give your eyes plenty of time to adjust to the darkness is can take between 20 and 30 minutes.  For everything you needed to know about the Perseid Meteor shower and viewing them check out Earth Sky's Perseid page.

Why do we at NASA study meteor showers? Meteor dust can help scientists to answer some very surprising questions about the Earth's atmosphere and can help to map out complex wind patterns. This can help us to understand the how the atmosphere circulates.  Mineral analysis of meteors can also help to answer questions about the origins of the solar system.   

Thursday, August 1, 2013

Welcome to Know Your Night Sky! In the next 5 months we will introduce you to a number a cool things you can look at in the night sky and a number of events that are happening related to the night sky.  The first month, August, is dedicated to meteors.  During the month of August we will post fun facts about meteors and why we study them at NASA.

NASA/Ron Garan from the Space Station
 We would also encourage you to go out and see your own meteor, and it is a great month to do that because the Perseid meteor shower is happening this month.  The peak will be August 11 and 12. Check out the theme pages for more information about each month's topic.