Don’t let the longer days during the summer spoil your astronomy – here are ten sights you can see even when the Sun is in the sky.
Warning! If you are attempting to view any of the objects mentioned here, you need to be very careful especially if using a telescope or other optical aid, as even a glimpse of the Sun through any optics, unless properly filtered, including a camera lens, can severely damage your eyesight!
1. The Moon
Yes, you can see the Moon in the daytime! In fact, you’ve probably noticed it and wondered why you can. Because the Moon is quite reflective it is bright enough to be seen during daylight hours, when the Sun is low in the sky. Turn binoculars or a telescope on to it and see it in all its glory. It will give you the opportunity to see phases that perhaps you wouldn’t normally get a chance to view otherwise.
2. The Sun
Only ever look at the Sun if you have proper filters for your telescope. Look for sunspots and ‘granulation’ if you have a white light filter. If you don’t have a filter you can project the Sun on to a piece of card using a small refractor telescope, but be careful here, too. Make sure the finder scope is capped off and use a piece of card around the tube to cast a shadow; otherwise you won’t see the Sun’s image.
The planet Venus is often seen in twilight either soon after sunset or shortly before dawn. Depending on where it is in its orbit it will either appear as a partly illuminated globe or a crescent. It’s very bright, so bright in fact that it is even possible to see it in full daylight if you know where to look, but be careful here, it can often be quite close to the Sun so check its position carefully before you attempt this.
Mars is much harder to see than Venus as it is much fainter, but it is possible to see it in twilight soon after sunset or shortly before dawn. It is possible to pick it up in a telescope in daylight but in order to do this you’ll either need a ‘GoTo’ computerised telescope or an equatorially mounted telescope with good setting circles and an ephemeris or chart showing you the position of Mars on the day you are looking.
Jupiter is easily bright enough to be seen in quite bright twilight so no need to wait until after dark to go hunting for this wonder of the Solar System. It is often one of the first ‘stars’ to come out in the twilight and you will notice that it has a slightly yellowish tinge. Again, with a ‘GoTo’ telescope it is possible to see Jupiter in broad daylight.
There are several stars which can be seen in fairly bright twilight, but it is possible to see one or two of the very brightest stars during the day when the Sun is still low in the sky. You’ll need a telescope to spot them, but one to look out for is the star Sirius which can be found in the summer in the late afternoon low down in the south.
Most comets which grace our skies are quite faint, requiring a telescope to be seen at all. However, there are occasionally comets which are very bright and can be seen with the naked eye or binoculars at least in the twilight. We may have one such comet to view later this year. Comet ISON is due to pass by the Sun in November and if it survives the gravitational tug of our star, it could put on quite a show.
8. The ISS
The International Space Station orbits the Earth several times a day and depending on where it is in its orbit it can be possible to see it from your location. Its solar power panels are highly reflective and catch the sunlight, bright enough to be seen in twilight. If you would like to know when it might be visible for you, visit the website www.heavens-above.com. It looks like a steadily moving ‘star’ travelling west to east.
9. Iridium flares
The Iridium satellite constellation consists of a network of telecommunications satellites that orbit the Earth and because of the unique shape of their reflective antennae they frequently catch the sunlight and focus it on a small area of the Earth for a few minutes. Because of this effect they can become one of the brightest objects in the sky for those few moments, an effect known as an Iridium flare. They are predictable and www.heavens-above.com will let you know when you might see one.
10. Atmospheric phenomena
The Sun and Moon, in conjunction with our atmosphere, can produce fascinating lighting effects. Sundogs are one such effect. These can be seen as a small arc of a rainbow either side of the Sun in a hazy or lightly clouded sky. They are caused by ice crystals high up in our atmosphere refracting the sunlight. Crepuscular rays are shafts of sunlight penetrating through the clouds in a very dramatic way. They are parallel rays of light emerging from theSun, which is hidden by clouds.