Brought to you by Dr. Roy Gretton, Journal Editor of The Nottingham Astronomical Society.
Please note, the NAS new permanent venue for our main meetings on the first Thursday in the month. Nottingham Emmanuel School, Gresham Park Road, West Bridgford, Nottingham, NG2 7YF.
The $10 billion James Webb Space Telescope (JWST) is by far the most powerful and the most complex of all the telescopes that have been launched into space thus far. Building the instrument and sending it accurately to its required position, almost a million miles from Earth, has been one of the most challenging feats of science and technology ever attempted, and to the immense relief of everyone on the project team, things have thus far gone according to plan, in spite of the vast number of components that had to work perfectly. The JWST is a reflecting telescope with a main mirror 21 feet across (huge compared with the Hubble telescope’s mirror diameter of less than 8 feet), making it six times as powerful as the Hubble. Such a huge mirror has to be made up of separate hexagonal segments, 18 in this case, each one coated with gold, and these had to be folded away into the nose of the rocket for launch into space, then unfolded with great precision after it had left Earth. Throughout the mission, the infrared instruments on board will have to be kept at a temperature below -220 degrees Celsius, hence the huge heat shield that protects the telescope from the Sun’s radiation.
Launched last December, its scientific mission will begin properly this summer, after commissioning and testing; so astronomers can expect some exciting results to be released over the coming months. At the beginning of June, NASA was predicting that the first full-colour images and spectroscopic data would be made public on July 12th, after which we can expect a steady stream of results to appear. So watch out for some stunning pictures! The JWST will enable us to see older and more distant objects than has been possible up to now – objects up to 100 times fainter than the Hubble telescope can detect. It is hoped that the JWST will be able to see the very first stars and galaxies that formed after the Big Bang. At the other end of the age/distance scale, it will be used to study nearby objects within our Solar System, including planets and satellites, asteroids and comets. And in the ‘middle distance’, two rocky exoplanets (planets orbiting stars a few dozen light-years away) have already been selected for special ‘geological’ study. As with every new space mission, colossal quantities of data will be beamed back to Earth, keeping researchers busy for years, perhaps decades, to come.
The Night Sky in July and August
Regular followers of this column will be aware that we have been starved of opportunities for observing planets in the evening sky for some months now, because the bright ones have been grouped together in the morning sky, when most of us are in bed. This will slowly change, but we shall have to wait a little longer for the best views.
Saturn, in the constellation of Capricornus, will be at opposition to the Sun, closest to Earth and therefore brightest, in the first half of August, but it will still be quite low down, about 22 degrees above the southern horizon. Even so, the beautiful ring system will be well worth a look for anyone with a moderate-sized telescope. Jupiter won’t be at its best until late September, but even in early August it can be seen rising like a bright star shortly before midnight, due east in the constellation of Pisces. We won’t see Mars at its best until early December, but if you wish to see it rising in late July or early August you will need to stay up until after 2 am – hardly worth the effort, because if you wait until December, the Red Planet will be almost six times brighter by then. As has been the case for much of this year, Venus continues to lurk in the morning sky, rising about an hour before the Sun as July gives way to August.
As regards shooting stars, one of the annual highlights of the summer is the advent of the Perseids on August 13th. But 2022 is practically the worst year for seeing them, as the Moon will be Full on the previous night, and bright moonlight makes meteors very difficult to see.
Phases of the Moon
| July | August | |
| First Quarter | 7th | 5th |
| Full Moon | 13th | 12th |
| Last Quarter | 20th | 19th |
| New Moon | 28th | 27th |
