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The brightest asteroid, Vesta, is beginning to put on a show in the night sky. You can easily see Vesta for yourself with binoculars. Vesta is currently in the distinctive constellation of Leo, the lion, and it will remain there over the next few weeks, making the asteroid simple to find.
You can find Vesta in the “haunches” of Leo, which are marked out by a bright trio of stars. In mid-January, Vesta was shining at magnitude 7, making it a target for your binoculars. It also showed up easily in sky photos taken with a digital camera.
Over the next few weeks, Vesta will brighten until it reaches a point called opposition, because it is on the opposite side of the sky to the Sun. Vesta will be about two and a half times brighter, and shine at magnitude 5.8.
This is theoretically just within the limits of naked-eye visibility, though you would need an exceptionally clear, dark sky to see it with just your eyes and no optical aid.
Vesta will lie at a distance of 204 million km from Earth (127 million miles) when it is at opposition.
Vesta is also known as (4) Vesta because it was the fourth asteroid to be discovered, in 1807. It is one of the larger of many thousands of asteroids, which are rocky objects circling the Sun between Mars and Jupiter. Vesta takes 3.6 years to orbit the Sun.
Under normal circumstances, Vesta is the brightest of the asteroids, becoming brighter even than the largest of these bodies, Ceres, which is now classed as a dwarf planet.
Like Ceres, it has been been studied in detail by NASA’s Dawn mission, but both bodies appear as no more than points of light in a telescope or binoculars. (I say “under normal circumstances” because a potentially hazardous asteroid called Apophis will make such a close approach to the Earth in April, 2029, that it will briefly shine at third magnitude and be visible without optical aid.)
It will be easy to find and see asteroid Vesta in the early months of 2021 because it will lie in the conspicuous zodiacal constellation of Leo. Our charts will help you see asteroid Vesta. They show the track across the sky that it will make between mid-January and late April, 2021.
So make the most of this opportunity to see asteroid Vesta while it is bright and also easy to locate.
How to photograph asteroid Vesta
If you have a camera that is capable of taking manual exposures lasting more than a few seconds, you can try to take a photo of Vesta yourself. You will need to keep the camera steady, preferably by mounting it on a tripod, and pointed towards the stars of Sagittarius and Scorpius.
Open the camera lens to its widest aperture if you can and set the camera’s “film speed”, or ISO rating to a high number of 400 or above so that it is more sensitive to faint light. If you in a location free from light pollution, and the Moon is not bright in the sky, you might be able to go up to 1600 or even 3200.
The camera will need to be set to manual focus rather than autofocus as starlight is generally too dim for most cameras to be able to lock onto it. Turn the lens to infinity (the little squiggle resembling a figure 8 lying on its side). You can achieve even sharper focus if your camera has “live view” and you can see a bright star on your screen while you are focusing.
Use a cable release, if you have one, to avoid shaking the camera. An alternative would be to set the camera’s shutter-delay feature (usually between 2 and 10 seconds) between pushing the button and the photo being taken. Usually this facility is used to allow you to get into your own photo, but it works equally well in allowing the camera to settle down once you’ve fired the shutter!
Using a standard lens, you should be able to open the shutter for 15 seconds or so before the motion of the stars across the sky becomes apparent. This is due to the rotation of the Earth. Longer exposures will record the stars as trails rather than points of light, which is still a pleasing effect if that is what you want! With a telephoto lens, the effect is more noticeable, and your exposures will need to be shorter than 15 seconds.
Take a range of shots, using different exposure times and ISO ratings, and see which gives you the best results. Nowadays, in this digital age, you can find out almost immediately by checking your camera’s screen. Later you can use Photoshop or an alternative piece of software on your computer to adjust brightness and contrast to enhance your photo if you need to. Good luck!
