Archive for category General
All Helioviewer services (helioviewer.org, JHelioviewer and the embed functionality) will be temporarily suspended today (30 January 2013) to allow for maintenance of our server. We anticipate that services will be suspended at around or before 1700 UT and will resume again at around 2230 UT at the latest (could be much earlier). We apologize for any inconvenience this may cause.
From today’s SDO blog entry:
Today, starting at 1315 UTC (8:15 am ET), SDO will execute the EVE Field of View maneuver followed by the HMI/AIA Flatfield at 1630 UTC (11:30 am ET). During these maneuvers the science data will be interrupted. These maneuvers and last weeks’ Delta-H thruster firing were flipped in the schedule published earlier.
Instruments can degrade in the harsh environment of space, and so it is important to calibrate at regular intervals to make sure that we have the best data available at all times. SDO therefore occasionally makes special maneuvers that enable the measurements to be made that can be used to help calibrate the instruments onboard. Whilst these maneuvers are going on, some of the AIA and SDO images may look unusual.
SDO has three instruments onboard: AIA, HMI and the Extreme Ultraviolet Experiment, EVE. The EVE instrument is designed to measure the solar extreme ultraviolet (EUV) irradiance. The EUV radiation includes the 0.1-105 nm range, which provides the majority of the energy for heating Earth’s thermosphere and creating Earth’s ionosphere (charged plasma). The majority of EVE data are time-series of measurements of the spectral content of solar extreme ultraviolet irradiance, although some low spatial resolution x-ray images are also taken by the EVE Solar Aspect Monitor (SAM) instrument (see the example below). EVE gives us lots of information on the spectral content of the Sun’s radiation changes with time, which is very important for understanding the Earth-Sun connection.
A total solar eclipse will be visible in the Southern Hemisphere on November 13.
Eclipse first contact begins at approximately 20:36 UT on November 13 and continues until approximately 23:48 UT on November 13. Live streaming of the eclipse is available at http://www.ustream.tv/cairnseclipse2012. Please go to
for many more details concerning this eclipse. An interactive map is available here.
Hurricane Sandy is currently approaching the East Coast of the United States. Winds from the hurricane are expected to cause widespread power outages in the next 48 hours (Oct 29-30). Since an unplanned power outage to a server can cause severe damage, we are taking the precautionary measure of shutting down the Helioviewer server. The server will shut down in the next hour. We expect to be back online by Wednesday 31st October EST at the latest, contingent on the weather and the availability of power. We apologize for the inconvenience this will cause.
Helioviewer.org and JHelioviewer are both back online after last week’s outage.
The downtime was caused by a problem encountered while expanding our storage capacity, which has since been fixed.
We are currently in the process of restoring images from some earlier years and as a result certain images may not be accessible over the next couple days.
We apologize for any inconvenience this may cause.
You may have noticed that we currently do not have any images available, even although the website is up and running. This is because we are experiencing some technical difficulties upgrading our image capacity. We are diagnosing the problem at present, and we will make images available as soon as we possibly can. We apologize for the interruption to our services.
All Helioviewer Project services will be brought down beginning at approximately 21:00 UT on 25th September 2012. This is a planned outage, and is required to perform necessary maintenance. Helioviewer.org and the JHelioviewer server at the Goddard Spaceflight Center will be unavailable. Helioviewer Project images used by third party applications will also be unavailable. We expect to return to normal service at approximateky 13:00 UT on 26th September 2012. We apologize for this necessary but brief interruption in our services.
ESA Summer of Code in Space 2012 (SOCIS) is a program run by the European Space Agency. It offers student developers stipends to write code for various space-related open source software projects. Through SOCIS, students will be paired with mentors from participating project teams, thus gaining exposure to real-world software development. The program is inspired by (but not affiliated or related in any way to) Google’s Summer of Code initiative.
YouTube and Helioviewer.org user otraLoly shared this short video of the return of Comet 96P/Machholz to the LASCO-C3 field of view. Thanks for sharing your video! More images of the comet will be available soon on Helioviewer.org.
Comet 96P/Machholz has an orbital period of about 5.2 years, which means it has been seen before in LASCO observations. Here is an example image from 2007
and five years before that in 2002,
The dates for the entry of Comet 96P/Machholz were obtained from the transit page of the LASCO instrument. It is projected to be visible in the LASCO C3 field of view from July 12 – 17, and it may also be visible in the images from the STEREO A/B coronagraphs.
SDO AIA and HMI images are currently lagging behing real time by about 18 – 22 hours. This is due to some necessary hardware upgrades in the processing pipeline that have interrupted the flow of images. The availability of LASCO, EIT, COR1, COR2, EUVI and SWAP images is unaffected by these hardware upgrades. We expect that the lag in SDO AIA and HMI images compared to real time will be caught up in the next few hours. We apologize for the interruption in availability of near real time AIA and HMI images.
Sometimes, instruments that are not specifically designed to observe the Sun can see something from the Sun. This was the case with Fermi, a gamma ray telescope operated by NASA. Its primary mission is to study the most energetic features and events in the Universe, such as supermassive black holes and the merging of neutron stars. Sometimes, however, the Sun makes an appearance in Fermi data. The following GOES X-class flare on March 7th, 2012
was an intense source of gamma-rays. SDO-AIA is not designed to observe gamma-rays. However, Fermi saw the gamma rays from this event. For a great explanation of what Fermi saw from the Sun, check out the following video.
The movie below shows the PROBA2-SWAP view of the transit so far:
Venus appears to swing north and south in this movie – this was predicted by the operators of SWAP at the Royal Observatory of Belgium Solar Data Influences Center. It is caused by the orbit of the PROBA2 spacecraft around the Earth creating very different points of view of at different times in the orbit.
More movies to come!
Alongside of our coverage of the last Transit of Venus that most of us will get to see (the next one will be in 2117 for those of you who are particularly ambitious!) we are also launching a new online discussion forum: community.helioviewer.org.
Here, users can share interesting features and events they find and get help identifying solar phenomena. In addition to forums on topics such as “transits and eclipses” to “coronal mass ejections,” we also have other sections including “solar physics” and “heliophysics” for anyone interested in learning more about the science that goes on behind the pretty pictures and movies.
Check it out and let us know what you think!
EIT has been taking special images of the transit. From the vantage point of SOHO, Venus does not appear to cross the disk of the Sun. In the image below, the EIT image is in green.
Just to the north you can see the dark disk of Venus.
More to come with AIA, very soon!
We hope you have the opportunity today to view this event safely. Due to expected heavy traffic to NASA websites concerning today’s Transit of Venus, we are reproducing in full the safety advice given at NASA’s safe solar viewing site. We will carrying images as they become available to us, as will many other sites, including live streaming from Mauna Kea, Hawaii.
Safe Solar Viewing
The transit of Venus is a rare and striking phenomenon you won’t want to miss— but you must carefully follow safety procedures. Don’t let the requisite warnings scare you away from witnessing this singular spectacle! You can experience the transit of Venus safely, but it is vital that you protect your eyes at all times with the proper solar filters. No matter what recommended technique you use, do not stare continuously at the Sun. Take breaks and give your eyes a rest! Do not use sunglasses: they don’t offer your eyes sufficient protection.
Fantastic Viewing Resources
- Dr. Doug Duncan, astronomer, Department of Astrophysical & Planetary Sciences, Univ. of Colorado and Director of Fiske Planetarium
- Definitive advice on viewing the sun safely; by B. Ralph Chou, MSc, OD.
- Six ways to see the transit!; by Chuck Bueter
Viewing with Protection — Experts suggests that one widely available filter for safe solar viewing is number 14 welder’s glass. It is imperative that the welding hood houses a #14 or darker filter. Do not view through any welding glass if you do not know or cannot discern its shade number. Be advised that arc welders typically use glass with a shade much less than the necessary #14. A welding glass that permits you to see the landscape is not safe. Inexpensive Eclipse Shades have special safety filters that appear similar to sunglasses, but these filters permits safe viewing. Eclipse shades are available through retailers listed at http://www.mreclipse.com/Totality/TotalityApC.html under “Solar Filters.”
Telescopes with Solar Filters — The transit of Venus is best viewed directly when magnified, which demands a telescope with a solar filter. A filtered, magnified view will clearly show the planet Venus and sunspots (http://skyandtelescope.com/observing/objects/sun/article_101_1.asp). Never look through a telescope without a solar filter on the large end of the scope. And never use small solar filters that attach to the eyepiece (as found in some older, cheaper telescopes.) See “Solar Filters” as cited above for retailers.
Pinhole projectors — These are a safe, indirect viewing technique for observing an image of the Sun. While popular for viewing solar eclipses, pinhole projectors suffer from the same shortcomings as unmagnified views when Venus approaches the edges of the Sun. Small features like the halo around Venus will not likely be discernible. Pinhole projectors and other projection techniques are at http://solar-center.stanford.edu/observe/.
Related projection methods — One viewing technique is to project an image of the Sun onto a white surface with a projecting telescope. http://www.skyandtelescope.com/observing/objects/sun/Solar_Projection.html and http://www.astrosociety.org/education/publications/tnl/05/stars2.html. Others follow:
- The Exploratorium demonstrates how to view a planet in transit safely by projecting the image with binoculars. http://www.exploratorium.edu/transit/how.html.
- The Sunspotter telescope viewer (recommended for younger viewers) is commercially available from Learning Technologies Inc. at http://www.starlab.com.