Archive for the ‘Planck’ Category

Start of the Normal Operations!

August 29, 2009

The results of a two week mini-survey finished on 27th August. All went well, so the all sky surveys, due to last 15 months, have now begun!

More information available from ESA.

Results from the mini-survey are being analyzed but we’re not allowed to say anything about them until something official is released.

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Minisurvey and First Results!

August 15, 2009

This weekend Planck should be moving from performance verification phase and into observations that are closer to full scale operations with the start of a minisurvey that will be very similar to (indeed, if all goes well, part of) the main all sky survey.

Meanwhile, the very first results from Planck have been presented at the International Astronomical Union General Assembly in Rio. These show a few scans around the sky and demonstrate Planck’s ability to detect the CMB ‘dipole’, which is due to Planck’s motion relative to the CMB frame of reference (this motion is due to the motion of Planck around the sun, the sun around the galaxy and of the galaxy relative to the background).

Sadly I don’t have any pictures of this yet as none have been released, but hopefully we will get something we can show you before long.

Planck moves from commissioning to PV phase

July 28, 2009

Latest news from ESA:

’24 July: The In-Orbit Commissioning Review finalised successfully on 21 July. We are now officially in Calibration and Performance Verification (CPV) Phase ! The activities planned in the CPV plan in fact started already in June, interleaved with commissioning activities. So far everything is behaving nominally, and the CPV activities are being carried out largely according to plan, which explains why there has been little to report in this page. A few anomalies in the first two weeks of July – all now under control – have induced some slip in the schedule. It is now expected to start the First Light Survey around the 8th of August. The First Light Survey is a two-week period which makes the transition from CPV Phase into Routine Phase. So routine surveying of the sky should start in the last week of August.’

This means the instruments are working properly, that we’ve moved into calibration observations and that, by the end of August, the all sky surveys should be underway.

This is a major and very positive step forward!

Nearly ready!

July 5, 2009

Planck is now officially the coolest place in the known universe with the detectors for the High Frequency Instrument now at their operating temperature of 100mK – just 0.1 degree above absolute zero. The spacecraft is also nearly at its destination, with the final maneuvering burn made to set it in orbit around the L2 point, 1.5 million kilometers from Earth.

Science observations coming soon!

Planck at the Royal Society

June 13, 2009

[cross-posted from Planck UK site]

The Planck mission will be represented at this year’s Royal Society Summer Science Exhibition. This prestigious event, hosted every year at the Royal Society, in London, allows around 20 different groups of scientists to present their work, covering all fields of science. This year, scientists from around the UK working on Planck and Herschel will be presenting an exhibit entitled “From the oldest light to the youngest stars: the Herschel and Planck missions“.

The exhibition is completely free to members of the public, and is open from Tuesday 30th June until Saturday 4th July. We will have scale models of Planck and Herschel, and will allow visitors to explore both the Universe and the world around them at different wavelengths. A key attraction should be an infrared camera, which will allow people to have their infrared portrait taken. There will also be an interesting way of viewing the sky at a number of wavelengths, and of course freebies to take away. The stars of the show, though, should be the scientists themselves. We will be there to explain what we are doing with these exciting missions, and to answer all the questions you might want to ask.

So if you’re in London on a couple of weeks, pop in to the Royal Society and see the exhibition. With 21 exhibits covering a huge range of groundbreaking research areas there should be something for everyone – and there’ll almost certainly be something that grabs your attention that you had no idea existed.

LFI Switch on!

June 5, 2009

Yesterday two major milestones were passed in making Planck operational.

Firstly the sorption cooler was switched on. This is needed to get the instruments, especially the HFI, to the temperatures needed for them to operate properly.

Secondly, the LFI, the Low Frequency Instrument, was switched on. We’ve not in a position to take science data with it yet, but the switch on went well, and the instrument replied that it is healthy.

Today will be spent making a course correction maneuver that will put Planck into orbit around L2. This burn will take 30 hours and use most of the fuel on board. So today is a big day!

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Tracking Planck and Herschel

May 21, 2009

As well as the official ESA ground stations which are tracking Planck and Herschel, a group of (mainly) Spanish astronomers have been observing them with optical telescopes.  They’ve also identified a few other pieces of the Ariane 5 upper stage travelling along with them, as well as the Sylda adapter which separated them within the rocket fairing.

Optical observations of Planck, Herschel and the Sylda adapter

Optical observations of Planck, Herschel and the Sylda adapter

On their “Images” page, you can see some light curves – which show how the brightness of the objects varies with time – for Herschel, Planck, Sylda, and a few other fragments.  The vertical axis, labelled “R”, is the brightness in astronomical units of “magnitudes“.  For comparison, the faintest stars visible with the naked eye are around magnitude 6, and a higher number means fainter – I’m sure this made sense to Ptolemy and Hipparchus.  In fact, the scale is logarithmic, so a magnitude of 17 is about 10,000 Ifainter than magnitude 6, putting them at around the same brightness as a small asteroid or a larger Kuiper Belt Object.

Light curves of Herschel, Planck and a few other fragments

It’s interesting to see that Herschel brightens by about 2.5 magnitudes (about a factor of 10) at one point.  There is one very plausible explanation for this: the timing coincides pretty much with the orbital manoeuvre which Herschel executed on 18th May, which must have oriented the solar panels to a more favourable angle for reflecting sunlight back to Earth.  Planck and the other fragments show smooth gradual declines in brightness over time as they get further from Earth.

So here’s where I make a prediction, just as any scientist should.  I predict that Sylda and the fragments will eventually fall back to Earth and burn up, so they might brighten a little.  They’re almost certainly in elliptical orbits so may vary slightly as their distance from Earth changes, and also if they’re spinning or tumbling at all. [I’ve been corrected by Bill Gray (see comment), who informs us that Sylda and the fragments will end up in heliocentric orbits – i.e. orbiting the Sun]. Planck’s brightness should stabilise when it reaches its final orbit around L2, as its angle realtive to the Earth and Sun should stay pretty much constant.  I predict that Herschel, however, will show slight variations in brightness as it slews to point at various objects around the sky – though it has to keep its solar panels pointed somewhere towards the Sun.  Whether the variations will be large enough to observe with telescopes on Earth remains to be seen.

If you want to see how far Planck and Herschel are from Earth, then you can use the JPL Horizons catalogue.  It’s somewhat self explanatory, but the output can look a little technical.  Change the “Target Body” and search for “Herschel” or “Planck”.  You also have to make sure that the time span covers the range you want.  For teh table output, I recommend selecting “Obsrv range and rng rate” and “One-Way Light-Time” – though there are many to choose from (though not all applicable).  You can set some of the units in the “optional” section.  When you hit “Generate ephemeris” you’ll get a table showing the numbers you’ve requested, and even a table explaining what they all mean.  There are a few options if you want to export the results to a file your favourite spreadsheet programme can read, so you can make your own plots.  You can play with a few other things too, such as setting the observer location to L2 (by putting “@392” in the “Lookup Named Location” box).  It’s not certain that the orbital parameters used are exactly what Planck and Herschel will actually use, but they’re probably not too far off.

On their “Images” page, you can see some light curves – which show how the brightness of the objects varies with time – for Herschel, Planck, Sylda, and a few other fragments.  The vertical axis, labelled “R”, is the brightness in astronomical units of “magnitudes“.  For comparison, the faintest stars visible with the naked eye are around magnitude 6, and a higher number means fainter – I’m sure this made sense to Ptolemy and Hipparchus.  In fact, the scale is logarithmic, so a magnitude of 17 is about 10,000 Ifainter than magnitude 6, putting them at around the same brightness as a small asteroid or a larger Kuiper Belt Object.

Latest News

May 20, 2009

According to the latest ESA news release, Planck is doing well. The critical 4K cooler has been switched on as well as the HFI instrument. Tests on the slewing system have also been completed successfully.

Herschel says goodbye to Planck

May 15, 2009

The animation you can find here shows the last view that Herschel had of the launch vehicle still holding Planck.

Well on the way…

May 15, 2009

The radiation monitors on Planck and Herschel show that both spacecraft have now gone through the Van Allen Radiation Belt. They’re well and truly away from Earth now and, by this evening, will be 1/3 of the way to the Moon.