Archive for May, 2012

June 5/6 – Transit of Venus

Next week we get to see one of the rarest of solar system events, a transit of Venus across the disk of the Sun.
As seen from Earth, Venus will appear to cross the face of the Sun. The eye will see Venus as a tiny black dot moving across the Sun. Historically, the transit of Venus was used to measure the distance from the Earth to the Sun. Transits of Venus occur in pairs about 8 years apart, and each pair occurs about once every 100 years. The last transit was on June 4, 2004. The next one is June 5-6, 2012. The next one after that is in 2117! will be providing near-real time images of the transit from AIA, SWAP and EIT. Please note that we expect a very high level of interest in this event and consequently a high level of demand on our resources.

The transit across the disk of Sun starts (first ingress) at June 5 22:09:38 UT and ends (last egress) at June 6 04:49:35 UT. However, Venus may be visible in AIA, EIT or SWAP maybe one or two hours earlier depending on the physical extent of the coronal emission over the limb of Sun.

Here’s what you need to know to enjoy this rare solar-system event.

Essential Information

(1) Will I be able to see it?

Some places will be able to see it, others won’t. Check out the map below to find out if you will be able to see it from your location.
Visibility map for the transit of Venus

This map also shows where the transit is visible from. If you live somewhere where you can’t see the transit, or if the Sun is obscured, there are many places online where you can see it as it happens. will be providing near-real time images of the transit from AIA, SWAP and EIT.

(2) When is it happening?

Use the following link to find out when the transit will be visible at your location:

(3) How can I watch it safely?

The Sun is EXTREMELY BRIGHT and PRECAUTIONS MUST BE TAKEN to VIEW THE TRANSIT SAFELY. Without proper precautions, you can severely and permanently damage your eyesight. Please follow proper procedures as detailed here.

We hope to see some fabulous images and movies from this event. Good observing!

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PROBA2/SWAP images now available on

We are pleased to announce that images from the Sun Watching Active Pixel (SWAP) instrument on board the European Space Agency’s PRoject for On Board Autonomy (PROBA-2) spacecraft are now available through

The Proba satellites are part of ESA’s In-orbit Technology Demonstration Programme, missions dedicated to the demonstration of innovative technologies. In-orbit demonstration is the last step on the technology development ladder. New technology products need to be demonstrated in orbit, particularly when users require evidence of flight heritage or when there is a high risk associated with use of the new technology. In-orbit demonstration is achieved through experiments on carriers of opportunity, such as the International Space Station, or through dedicated small satellites such as the Proba series, which was created to increase the availability of flight-testing opportunities.

PROBA-2 was launched on 2nd November 2009 from the Plesetsk Cosmodrome in northern Russia. SWAP started taking images of the Sun later in November 2009, and has been in operation ever since (we will be making these earlier images available as well as the most recent observations). SWAP demonstrates the space-based use of an image capture technology different from that used on AIA.

SWAP provides a wider field of view compared to AIA or EIT. It also is in a slightly different orbit than AIA, and so was able to observe the recent annular eclipse on May 20, 2012, whereas AIA did not see it. Check out this movie made by the SWAP team, or make your own at

SWAP will also observe the upcoming transit of Venus, and due to the orbit of SWAP the predicted path will make for some interesting movies. AIA will also see the transit, but will see a different path.

For many more details on the science goals and operation of PROBA-2 and SWAP please visit the PROBA-2 Science Center. Thanks to the Royal Observatory of Belgium for providing these images to the Helioviewer Project, and we hope you enjoy them. Please let us know if you have any further questions.

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Server Maintenance: Tuesday, May 29 (14:00-16:00 UT) and JHelioviewer will be unavailable on Tuesday, May 29 from approximately 14:00UT – 16:00UT for planned server maintenance. We apologize for any inconvenience this may cause.

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Local network problems causing data lag and possible accessibility issues

We are currently experiencing some issues with our local network. Users of may experience some difficulties in reaching the site, and users of JHelioviewer may experience difficulties in streaming data. The network problems are also making it difficult for us to acquire the most recent images; hence, SDO AIA and HMI images are currently lagging well behind near real-time.

Our network engineers are aware of these problems, and are working on them. We apologize for the interruptions to our services. We will be back to normal operations as soon as possible.

Helioviewer Team.

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