Geminids meteor shower on December 13th

The Geminid meteor shower peaks this year on the 13th December. The constellation will be in the east by 9pm and the Moon will not be rising until about 11:30pm.

The map above shows Gemini at 11:30pm on the 13th December just as the Moon is rising. The radiant of the meteor shower is marked. Look to the south for the best views of any meteors. Rates are predicted to about 100 per hour, although this assumes idea conditions. Don’t forget to wrap up warm!

Clear skies,
Ian Smith

Novembers talk, “Exploring our star from space”

Professor Richard Harrison is the head of the Space Physics Division and Chief Scientist at RAL. He has been a solar physicist for 35 years and he graced us a few years ago on the subject of hardware in space, exploring the Sun, in particular with the two STEREO observatories (=Solar-TErrestrial-RElations-Observatory) which were launched in October of 2006. Both have two helioscopic imagers (HI), one looking at the Sun and one looking past the Sun. The craft were launched so that one lagged behind the Earth and the other went ahead (hence: STEREO Ahead and Behind). I pinched that from my April 2011 writeup and I want to say I am glad that we have such amazing gadgets monitoring the Sun, especially as we have been watching a major sunspot group 12192 reappearing after causing concern in October. Bob may have something to say about it, please!
The SOHO solar observatory has been going strong for 19 years and its main observing wavelength is in UV, 171 Angstrom (1710 nm). STEREO has been observing in 304 Angstrom, a near UV wavelength which picks up helium radiation, so is ideal for identifying CMEs (coronal mass ejections), potentially harmful to us on Earth.
STEREO A has a slightly smaller orbit than STEREO B is now about to lap its partner on the inside as they come together in the middle of 2015, by which time we will be on that side of the Sun in our orbit. Both satellites are tilted slightly so that they don’t look directly at the Sun – they only need to capture one ten million millionth of the Sun’s light. We do lose information at times when the Sun is between us and them, as happened when we temporarily lost contact with STEREO B last month.

We are lucky that so much is happening just down the road from us. The RAL space facility has 230 staff and has had a part in designing, building and testing 208 instruments in space. At present it is situated near the Harwell mound (Oxfordshire cross-country runners will know that well by now) but will be moving to another site near the main entrance, where the ESA (European Space Agency) will also be setting up a site.

The forerunner to RAL started 82 years ago with the Ionosond pole, sending pulses into the ionosphere to be picked up by ground-based radar.

As before, Professor Harrison was enthusiastic and informative, and he managed to give a plug for an interesting website, Urthecast, which is a high resolution video from the ISS, allowing you to monitor the Earth. Magic!

A difficult Lunar occultation of Saturn

On October 25th Saturn will be occulted by the Moon. The Sun will still be up when the occultation begins so if you decide to try for this event please be very, very careful not to accidently look at the Sun.

For Abingdon, the occultation begins at 17:03 BST, when Saturn will disappear behind the dark limb of the Moon.

At 18:07 BST Saturn reappears from behind the bright limb of the Moon. By now the Sun will have (just) set, but the Moon will only be 6 degrees above the horizon.

Clear Skies.

Opposition of Uranus

Uranus is at opposition on the night of October 7th 2014. See the map below:

The map above is for 8pm BST on the evening of the 7th October. At opposition the Earth is between the planet and the Sun. This means Uranus will rise at sunset and set at sunrise, so you have all night to view the planet. It will be at its highest at about 1:00pm BST on the 8th October.

You will need a pair of binoculars or a telescope of any size at x100 to see it’s disk. Being so far away (19.2AU from the Sun) it has a very small angular size: between 3 and 4 arcseconds. Its just big enough for you to see it is a non stellar point, but it is very small. It will have a blue/green colour.

Clear Skies,
Ian