Thursday 29 March 2007

More about Saturn: The hexagon.

The Cassiny Mission has captured a geometric feature encircling the north pole of Saturn. Unfortunatelly for SciFi fans, it is not a geometric monolith. Is is an hexagonal pattern, created by the confluence in high latitudes of atmosphere winds. The hexagon is similar to Earth's polar vortex, which has winds blowing in a circular pattern around the polar region. On Saturn, the vortex has a hexagonal rather than circular shape. The hexagon is nearly 25,000 kilometers (15,000 miles) across. Nearly four Earths could fit inside it.

The new images taken in thermal-infrared light show the hexagon extends much deeper down into the atmosphere than previously expected, some 100 kilometers (60 miles) below the cloud tops. A system of clouds lies within the hexagon. The clouds appear to be whipping around the hexagon like cars on a racetrack. The hexagon appears to have remained fixed with Saturn's rotation rate and axis since first glimpsed by Voyager 26 years ago. The actual rotation rate of Saturn is still uncertain.

Based on the new images and more information on the depth of the feature, scientists think it is not linked to Saturn's radio emissions or to auroral activity, as once contemplated, even though Saturn's northern aurora lies nearly overhead.

A full history coverage and complementary and high resolution images can be found in the Cassini webpage. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.

Monday 19 March 2007

The Giant Planets ESAC Night

After some periode of bad weather, skies cleared and during the nigth of March, 17th-18th we performed some pending observations. Thus, Leo Metcalfe, Eugenio Salguero and me came to ESAC equiped with our telescopes. It could be our closest oposition time to observe Saturn in good conditions. At the end it was a cold night with water&ice condensation problems but we were able to record some good images using the Leo's telescope and a Toucam Pro Webcam with NIR blocking and pass filters. The following pictures illustrate our sucessful results.

The following image is the result of the processing with Registax of a video track (20 seconds) recorded at 2007-03-18 02:13 GMT with the Leo's telescope (25" F5 Newtonian Reflector wiht Dobsonian mount), a Phillips ToucamPro Webcam with a NIR blocking filter and a 3x Barlow lens.

The next image was obtained processing a video track recorded at 2007-03-18 02:31 GMT with the same equipment but substituting the filter by a NIR pass filter.

And this image is the result of the combination of both the visible and the NIR images. This false colour combination allows a good discrimination between the different elements of the planet, the ring composed by dust and ice that reflects very well the NIR but wiht moderated absortion in the visible and the planet atmosphere that reflects well in all the wavelenghts with a some NIR absortion.

At the end of the night, Jupiter achieved a good height over the horizon to observe it in the same way. However, the seeing still was very large. As a consequence the results were not very good. The following image is a visible image obtained processing a video track recorded at 2007-03-18 05:13 GMT.

This image image is a NIR image obtained processing a video track recorded at 2007-03-18 05:17 GMT.

And this image is the result of the combination of both the visible and the NIR images. In this case, some structure is clearly visible in the planet atmosphere. The planet atmosphere reflects well in all the wavelenghts but some areas present some NIR absortion that increases the contrast between them.

Tuesday 6 March 2007

Lunar Eclipse sequence from Leicester! posted an image sequence and a video by Darren Baskill. His comments about the eclipse were as follows:

" The changing colour of the sky during the eclipse was spectacular! From full-moon white to light-pollution red and back again in just two hours! In the photograph, each Moon is separated by just 15 minutes. The same photographs are available as a small 900kb time-lapse movie. Photo details: Canon 10D"

Monday 5 March 2007

2007 total moon eclipse around the world

From Germany :

From Chile :

From Jaen :

From Thailandia :

... and from Brasil :

Total Lunar Eclipse of 20070303 - VI

Finally the eclipse party was a complete success. The night cleared and everything was as planned. Despite some tracking and connecting problems, the online webcast of the eclipse was very sucessfull too. It allowed to follow the eclipse by people from very cloudy sites. The following animation resumes the observed and webcasted event.

Saturday 3 March 2007

Total Lunar Eclipse of 20070303 - V

Lastest NEWS (around 18:00 CET): The sky has cleared a lot. It is far from the optimal conditions but we hope it is good enought to see the moon and the eclipse. If the weather forecast finally is correct it will improve during the night. Therefore, the club confirms the star party as scheduled.

The ESAC astronomy club will also transmit on-line the event in the following link:

Friday 2 March 2007

Total Lunar Eclipse of 20070303 - IV

Last NEWS: At this moment (around 15:00 CET) low clouds are present at ESAC. However, the sky seems to be clearing and weather forecast is quite optimistic (see the meteo links in the right colum of the blog). Therefore, by the moment the star party schedule is maintained.

Confirmation here around 18:00 CET.

Total Lunar Eclipse of 20070303 - III

For the moment the weather forecast for tomorrow's Total Lunar Eclipse is reasonable.

However, in case the Star Party has to be canceled this will be announced on Saturday around 15:00 CET on the ESAC Astronomy Club web page and blog.

This is the final programme:

(times in Central European Time = Local Time)
19:30 - 21:00 Arrival of people with telescopes
Parking at LAEFF only for people with telescopes
only people with heavy telescopes to drive up the SATAN hill

21:00 - 21:30 Arrival of public
Parking at the usual place close to the entrance

21:30 - 21:45 Introduction talk by Mark Kidger about the Lunar Eclipse in B.4

22:00 - 01:00 Astro Night with telescopes on the SATAN hill

Apart from the lunar eclipse (details below) we will observe many other objects like:

The Pleiades
The Double Cluster
Orion and its nebula
Saturn (the "ringplanet")
various open and globular clusters of stars

Michel G. Breitfellner
ESAC Astronomy Club President