Bath Astronomers

February Night Sky

Mars is technically visible in the night sky for much of the year, but for reasons I have explained before, its distance from the earth varies by a huge factor, and much of the time it presents only a very small disc where your chances of seeing anything more than a bright red blob are small. That is true this month, but there is added interest, since at the end of the month Mars will pass very close - less than a degree, so in the same field of view at low power in some telescopes - from Uranus. The closest approach is on February 27. If you have never seen Uranus, or have difficulty in finding...

Read more...

January Night Sky

Our early evening skies this month  are dominated by Venus shining a brilliant white in the south west, setting at around 9pm. It is an impressive sight with the naked eye, but  a disappointing one in a telescope. The wall to wall toxic cloud cover of our near twin planet presents a uniformly white appearance over the illuminated part of the disc, which for most of this month resembles a half-moon. And that is all you will see. It is so bright that any variation in the tone of the cloud cover will be impossible to detect. If you want to observe Venus through a telescope it is better to do so in daytime....

Read more...

December Night Sky

The recent run of clear nights has been good for observing, but also, of course, cold. This will be a test of your cold weather clothing. I find people new to observing may bring sensible coats, hats, gloves etc, but often  neglect their feet. You really need to bring boots that provide some insulation, and ideally are waterproof, plus thick socks. Wellies won't do. Mountain walking boots are fine. If you have skiing gear, that should do very well. The other problem is the telescope. Lenses and mirrors exposed to the night sky will tend to dew up, though dew shields and various electrical heating...

Read more...

November Night Sky

This  is a good month for enjoying galaxies in the Andromeda region, as it is pretty well overhead at about 11 pm towards the end of the month when the Full Moon is out of the way. Star (!) billing, of course, goes to M31, the Great Andromeda Nebula. I usually find it via the distinctive "W" shape of Cassiopeia - just follow the pointy part of the W down by one length of the letter, and a bit to the right, and there it is. If you are in a reasonably dark location, and your eyes are dark adapted, it should be obvious. ( If it is not, then it is a poor night, and you might as well head for the pub!)...

Read more...

October Night Sky

If you have been struggling to find Neptune low in the south in September, then October offers an easier target as Uranus comes to opposition on the 15th of the month. It is still in Pisces, but is now well above the celestial equator, and is continuing its steady climb north in our skies (and it will be back at the Gemini/Taurus border where Herschel first discovered it in the early 2030s, having by then done just three orbits of the sun since ). However, there is no need to wait that long for a good view! Uranus at opposition is magnitude 5.7 or so, and so in theory visible with the naked eye under...

Read more...

September Night Sky

Neptune comes to opposition on September 2, and this is the best month to try to observe this elusive planet. It might seem strange that Neptune is so much harder to find than Uranus. The two planets are comparable in size and nature, and both are in the outer reaches of the solar system. But Neptune is much further out from the Sun than Uranus - an average of 4.5 Billion km to Uranus' 2.9 Billion. This has a double whammy effect on Neptune's apparent brightness from the Earth. The distance of Uranus to the Sun is only about 63% of Neptune's, but that means that Neptune only gets about 40% of the amount...

Read more...

August Night Sky

August brings one of the year's major meteor showers - the Perseids. The term shower is rather is misnomer, as it implies a constant stream for its duration. What you get is a steady trickle, typically of one every few minutes. The maximum is due on the night of 11 Aug. There will be a first quarter moon, but very low in the south, so it should not provide much visual interference. All you need do is to get a comfortable seat looking skywards, ideally roughly facing east, but the direction doesn't matter much. And then just watch for as long as you feel comfortable. If it suits you to stay up late,...

Read more...

July Night Sky

Midsummer is our one chance to look at the night sky in the direction of the galactic centre. This is in Sagittarius, which never rises far above the southern horizon. (Our compensation is that we in the northern hemisphere are better placed to look at nearby galaxy clusters in Virgo and Coma Berenices!). We can't see all the way to the galactic centre in visible light, as dark clouds of interstellar dust  get in the way, but if we look in that general direction there are many interesting nebulae  near enough to be seen in binoculars, and offering very good views in a good size telescope....

Read more...

June Night Sky

June has the shortest, and least dark, nights, and therefore is generally not a good time for observing. This June, however,we have two planets at or near opposition. Mars came to opposition late in May, and Saturn reaches it in early June. This is good, and bad, news. The good news is that planets, or at least the brighter ones, are easy to see in twilight, and can be seen better than in a fully dark sky when they are almost blinding through a telescope. The bad news is that if they are at opposition at this time of year they will be very low in the sky - they are opposite the sun, and therefore...

Read more...

May Sky

A slight change of title this month, as I will concentrate on the transit of Mercury on May 9. A transit is the term used when a celestial object passes in front of a bigger one from the relevant view point, and can therefore at least in theory be seen against the bigger object's disc. In the solar system, the most commonly observed transits are those of Jupiter's four Gallilean moons, which frequently pass in front of Jupiter from our viewpoint -  though  spotting them is another matter, even when you know they are there! (If the object passing in front is comparable in apparent size to the object...

Read more...