At the beginning of this year, the NEOWISE space telescope discovered its latest comet, a distant and unobtrusive object.
At the time of its discovery on March 27, the comet ̵
But in July the comet NEOWISE raised hope that after two previous comets it would become an attractive object for sky observers (ATLAS and SWAN) failed early this year.
If we talk about the comet’s brightness below, we’ll discuss its size – a measurement of the brightness of an object in the sky. The smaller the size, the brighter the object. The brightest stars in the sky are zero or first size. The faintest stars, visible to the eye on dark, clear nights, are sixth in size. Stars of the first size are 100 times brighter than stars of the sixth size.
Connected: Comet SWAN: A brilliant “icy wanderer” in photos
A comet spell for the third time?
The NEOWISE comet survived its closest approach The sun, (Perihel) in contrast to its predecessors from 2020, comets ATLAS and SWAN. Until it approached the sun, NEOWISE showed a perfectly circular and well-compacted head, or coma compared to the weak, wispy, almost Ghostly coma, displayed by Comet ATLAS and the “hammer head” looks Coma of the comet SWANwho predicted a possible separation. As it turned out, these two objects actually disappeared long before they came close to the sun.
Michael Mattiazzo, an experienced Australian comet watcher, was confident long before NEOWISE’s arrival on Friday (July 3) that NEOWISE would remain intact, offering at least a 70% chance of surviving its close contact with the sun.
And apparently it was! The comet was 44 million km from the Sun on July 3 when it was exposed to temperatures up to 593 degrees Celsius. After that, a quick move northeast and then east due to the comet’s sharp orbit tendency to orbit the planets will quickly remove it from the vicinity of the sun in the following days.
Astrophotographer Chris Schur discovered the comet NEOWISE from Payson, Arizona, today (July 5).
“The comet continues to be breathtaking, and its tail rises first over the plateau about 20 miles away,” Schur told Space.com while sharing a photo with an Explore Scientific AR152mm telescope. “I could see it visually easily with a certain degree of tail with the naked eye. Beautiful yellow color in the scope.”
A high flyer!
Originally, NEOWISE was not expected to be much brighter than the ninth or tenth size, so it is only accessible to people with good binoculars or small telescopes. During the spring, observers in the southern hemisphere observed the very rapid brightening of this object as its distances from the sun and earth decreased. Consensus of observations on May 10 resulted in an order of magnitude of +9.9.
Barely a month late, on June 7th, the comet was on the other side of the sun, 117 million km from the star and 236 million km from Earth. The brightness had increased 12-fold to +7.2. As projected onto the sky, the comet was barely 24 degrees from the sun (a closed fist at the end of an outstretched arm covers 10 degrees of the sky) and the two quickly banded together. Shortly afterwards, the comet was lost to observers in the increasing sunlight.
But from June 22nd to 27th, the comet was in the range of Solar and heliosphere observatory (SOHO). SOHO is a cooperative mission between the European Space Agency (ESA) and NASA. The spacecraft is stationed in a halo orbit around L-Lagrangian Sun-Earth L1, a position approximately 1.5 million km (930,000 miles) away from Earth. At this time in space, SOHO’s orbital period corresponds exactly to Earth’s orbital period. From this orbit, SOHO can watch the sun 24 hours a day.
With its wide angle and the spectrometric coronagraph (LASCO-3), which can produce an artificial eclipse, NEOWISE could be monitored when it approached the sun. During this time, the comet appeared to brighten significantly, with comet expert Charles Morris estimating +1.7 magnitude shortly before leaving the field of the LASCO-3 camera. The comet NEOWISE also appeared to have developed a fairly bright, if short and blunt, fork-shaped dust tail.
And then, quite unexpectedly, amateur astronomers were able to sight the comet NEOWISE before sunrise from July 1st.
“Wow – it was very bright, close to +1,” Ray Brooks of Arizona Sky Village near Tucson saw the comet through binoculars and told Space.com. “If the comet were at a decent height in the dark, it would be a spectacular object with the naked eye.”
On the morning of July 4th, Brooks saw the comet NEOWISE’s forked double-tail break through the top of a nearby mountain, followed by the head of the comet.
Another zealous comet observer from Arizona is the astronomer Carl Hergenrother from Tucson, who saw NEOWISE on July 1st and July 2nd and described that it appears at least as bright as a star of the first size, although it is very low and low on the horizon against a bright is twilight sky.
And the respected comet expert John E. Bortle from Stormville, New York, was amazed at the comet’s performance to date.
“In theory, the comet should not yet brighten noticeably because its distance from the sun is only slightly decreasing from day to day at this point, which leads me to believe that the current brightness of the comet does not depend mainly on its distance from the sun, but is experienced a kind of progressive slow outbreak, “he said.
Is this a big comet emerging?
Comets fall into two categories. “Ordinary” comets are weak fuzz balls that can only be seen with the help of good binoculars or a telescope. For example, tonight there may be eight or ten such comets in our sky.
Then there are the “big” comets, which become bright enough to be clearly visible to the naked eye and are accompanied by a striking tail of dust and gas. Unfortunately, such displays do not appear very often. In the average human lifespan, you may have a chance to see maybe four if you are very happy.
The last large comet that was visible from the northern hemisphere was Comet Hale-Bopp 1997, but is NEOWISE developing into one? Based on the latest brightness estimates, the NEOWISE comet might not meet the criteria, although as soon as it becomes visible in darker skies it should be fairly obvious, especially outside of light-polluted cities.
When and where to look
The focus is on NEOWISE, which we visualize in two diagrams. one for the morning sky and the other for the evening sky. The timeframes apply to the beginning (morning) and end (evening) of nautical twilight when the sun is 12 degrees below the horizon, which is approximately 80 minutes before sunrise and 80 minutes after sunset for those who live in mid-northern latitudes . The lines extend directly from the sun and show the likely direction in the sky of the comet’s tail if one should develop.
In the morning sky, the first views of NEOWISE could already be seen on July 5 or 6 in the morning sky very deep above the northeastern horizon. Towards July 11, the comet reached a height of almost 10 degrees – for comparison: 10 degrees correspond approximately to the width of your fist, which is held at arm’s length. Then, over the next 10 days, it will gradually slide back towards the north-northeast horizon and finally disappear from the dawn perspective.
From July 12th, a far better viewing perspective will be available in the evening sky if it appears deep in the northwest sky. In the following evenings, the comet quickly climbs higher into the sky.
On July 22, NEOWISE is closest to Earth, a distance of 103 million km. By July 25, the comet appears 30 degrees (“three fists”) from the west-northwest horizon when darkness falls. And on July 30th and 31st, the comet will pass north of the fine cluster of Coma Berenices or Berenice’s Hair.
Although the comet weakens on consecutive July evenings, it is farther from the sun, sets later, and is visible in a darker sky. When we move into August, the comet is very well positioned for observers with small telescopes.
Amateur watchers should look for the most favorable conditions. Even a bright comet like this can be extinguished by thin horizon clouds, haze, damp air, smoke, twilight light, city lights or moonlight. Naturally, binoculars or Telescopes just improves the view.
For those interested in technology or for those who own a “GoTo” telescope, the following ephemeris comes from calculations by Daniel Green. The positions are valid for 8 p.m. Eastern Daylight Time every fourth day and provide the correct ascent and descent of the comet. Next comes the comet’s extent or angular distance from the sun, followed by the constellation the comet is in, and finally an approximate predicted size.
Exciting times lie ahead. NEOWISE is here. “Comet” understood!
|5th July||05h 07.20m||+ 34 ° 04.8 ‘||16 °||Auriga||0.7|
|July 9th||06h 34.38m||+ 40 ° 24.3 ‘||20 °||Auriga||1.2|
|July 13th||07h 24.78m||+ 45 ° 41.0 ‘||24 °||lynx||2.0|
|17th July||08h 40.20m||+ 48 ° 11.1 ‘||29 °||Ursa Major||2.7|
|21 July||10h 06.66m||+ 46 ° 01.9 ‘||36 °||Ursa Major||3.5|
|July 25th||11h 20.33m||+ 39 ° 40.1 ‘||43 °||Ursa Major||4.3|
|29th of July||12h 12.71m||+ 31 ° 40.6 ‘||50 °||Coma Bernices||5.1|
|August 2nd||12h 48.45m||+ 24 ° 06.0 ‘||55 °||Coma Bernices||5.9|
|6th of August||13h 13.52m||+ 17 ° 41.2 ‘||58 °||Coma Bernices||6.6|
Joe Rao is a lecturer and guest lecturer at the Hayden Planetarium in New York. He writes about astronomy for Natural History Magazine, the Farmers’ Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook.