Comet C/2020 F3 (NEOWISE) is a retrograde comet with an almost parabolic orbit, discovered on March 27, 2020, by the NEOWISE space telescope (short for “Observer of infrared objects with a wide field of view of a near object”). At the time of its discovery, it was 312 million km from the Sun with a very weak magnitude +17. This is about 25 thousand times less than the light from the faintest star that can be seen with the naked eye. It could only be observed with large telescopes. But not now. We tell all about the comet, which is now clearly visible.
What is this comet? Why is everyone discussing it?
In July, C/2020 F3 (NEOWISE) gave hope to all amateur astronomers. They hoped that perhaps she would become a tantalizing object for skywatchers. The expectation was great, especially after the two previous comets – ATLAS and SWAN – had waned earlier this year.
When we talk about the brightness of C/2020 F3 NEOWISE, we mean its magnitude. This is the parameter that measures the brightness of an object in the sky. The lower the value, the brighter the subject. The brightest stars in the sky have zero or first magnitude. As of July 5, 2020, its visibility was about 1.5 magnitude.
Comet C/2020 F3 (NEOWISE) has successfully survived its closest approach to the sun (perihelion). Unlike its predecessors in 2020 – the ATLAS and SWAN comets, NEOWISE showed a perfectly round and well-compacted apex along its entire approach to the Sun. The look of ATLAS and SWAN already predicted a possible collapse. As a result, both of these objects really disappeared long before they reached the vicinity of the Sun.
Long before the perihelion of the comet on Friday (July 3), some amateur astronomers were sure that the comet would remain untouched, which would give it at least a 70% chance to survive in close contact with the Sun.
As a result, on July 3, the comet was 44 million km from the Sun and was exposed to temperatures up to 593°C. After this, a quick movement to the northeast, and then to the east will quickly carry it away from the vicinity of the Sun in the following days due to the sharp inclination of the comet to the orbital plane of the planets.
Where is the comet visible? Will, I see her from my region?
Now the comet is visible in the Northern hemisphere of the Earth from the equator and up to 60°C. w. This means that it is visible in the northern cities. It is also visible in Eurasia.
Can a comet be seen with the naked eye?
Yes, it is possible. Without special optical instruments, it is visible, albeit weakly, against the background of morning twilight. If you live no further than 55°C. w. and you have excellent eyesight, then you can try to see it. And some observers even manage to see her dusty tail. Since yesterday, NEOWISE has become confidently visible to the naked eye.
And where to look to see a comet?
In the predawn sky, low above the northeastern horizon, the comet is visible against the background of the constellation Auriga. The landmark may be the Capella star – this is one of the brightest stars in the night sky, and NEOWISE is now located just below it.
A few days later, on July 13, the comet will transfer to the constellation Lynx. From July 18-30, NEOWISE can be found in the northern part of the sky, near the constellation Ursa Major. The bucket of the constellation can become a reference point, the comet will be just below it.
What instruments should be used to observe the comet?
Almost any optical device will come in handy: a telescope, monoculars, binoculars, telescopes – the comet will be visible in any case (subject to other conditions). 20-30 minutes of observation will allow you to notice the comet moving against the background of stars.
How much time do I have? How long can a comet be observed?
At the moment, the comet is at a close distance from the Sun. Because of this, the bright twilight sky makes it difficult to see it in all its glory. NEOWISE will travel up the northern sky until July 20. The best time to observe is from July 10 to 30, in the dark. In this case, the observers are likely to detect a comet without special instruments. Yes, the farther the comet moves away from the Sun, the less its brightness will be. However, it is precisely the exit to the dark, not the twilight sky that will improve the conditions for observation, in any case, its tail will be most bright since it will reflect light.
Over time, the shape of the tail will also change: it will become wider and will become like a fan.
It is possible to observe the comet without binoculars and telescopes until August 5. By then, NEOWISE is too weak.
How to make a photo of a comet on your own?
When photographing a comet, like other stellar objects, it is imperative to use a tripod. It makes no sense to take it offhand and that’s why. For photography, you will need long exposures (from 1 to 10 seconds) and the inevitable handshake will smear the picture. When setting the shutter speed, consider the aperture and focal length of the lens. It is optimal to use telephoto lenses up to 600 mm, but you can also use “portrait” lenses from 50 mm. They are the most common.
If you want less noise in the photo, use a photosensitivity value (ISO) of no more than 1600. The starting point of ISO is highly dependent on the photosensitivity of the lens.