ピーク
2020-03-23T23:38:18+00:00
不久后肉眼就能看到ATLAS彗星
C / 2019 Y4(ATLAS)正在向太阳飞奔-可能在历史书籍中占有一席之地。
C / 2019 Y4彗星(ATLAS)于2月16日在西班牙加那利群岛上方的天空中漂浮。在1月27日至2月16日之间，彗星的亮度从11.5增至10，彗星的彗星大小从2弧分增加到2.5弧分。
就像观看电视节目或电影连续剧的最后一章一样，您几乎激动得发抖但您不知道自己是否会经历一生，大失所望，或者最终得到了可以接受的东西。
现在，很有可能彗星C / 2019 Y4(ATLAS)会很棒。也许这将是您有史以来最神奇的事情-历史书的一颗伟大的彗星。这是我们可能期望的。
过去到现在
Y4是在2019年12月29日通过小行星地面撞击最后警报系统(ATLAS)搜索程序发现的，这是几项自动的天空调查，旨在寻找可能穿越地球的小行星。发现彗星本质上是这项工作的副产品。当时，C / 2019 Y4的强度微弱至19.6，位于距太阳近3个天文单位的位置，几乎是离我们的恒星两倍的距离，距离火星。(一个天文单位，即AU，是地球与太阳之间的平均距离。)
3月中旬，Y4 ATLAS激增了4个数量级，有传言称它会不断变亮，达到8级。但是早在2000年，C / 1999 S4(LINEAR)就采用了同样的方法并迅速解散。
David Levy写道：“彗星就像猫。他们有尾巴，他们随心所欲。” 尽管有最好的观察和理解，但这些肮脏的雪球仍会在没有通知的情况下从火星轨道上飞走，甚至比太阳更远，Y4 ATLAS在4月初到达了距离。
这里的描述涵盖了我们可能会看到的东西：像Comet C / 1975 V1 West这样在1976 年交付的出色显示器。对这一代彗星抱有希望，并意识到，即使在最坏的情况下，它仍然是一个不错的双筒望远镜。
位置，位置
从现在开始，直到北半球的彗星在5月31日到达近日点，ATLAS才最接近太阳并绕着我们的恒星进行急转。北纬40至60度的观察员靠近舞台，北纬50至55度的观察员获得前排座位。从5月28日开始，赤道和南部地区将有一个不错的一周，但是Y4保持低位并迅速消失在远处，就像从快速行驶的汽车的后窗上看到的物体一样。
到4月中旬至下旬，包括4月22日的新月，ATLAS已经很大，并且距离较远。请注意，所报告的幅度是积分的，本质上将其所有光线都粉碎为一个点，而不是在昏迷和尾巴之间散布出去。肉眼很难看到2级，但从城市出发，光污染将看不到大的光环。Y4在北极星和耀眼的卡佩拉之间徘徊，可能类似于偏斜的仙女座星系。
到5月中旬，ATLAS的亮度仅次于金星！在深蓝色的航海暮色中，它只有15°高，随着日历的滴答声逐渐降低。避免从城市以南的位置进行观察-毫无意义的是透过圆顶观看。取而代之的是，向北开阔的田野可让您观察得尽可能长。
要记住的尾巴吗？
我们对彗星尾巴的倾斜观察非常完美。气体尾巴从被紫外线电离的原子发光，并在太阳风中向后直吹(远离太阳)。起初，人眼会呈现灰色，即使在8英寸范围内，三月影像中熟悉的绿色也能变成明亮的祖母绿。随着电离的增加，它可能会变为蓝色。在湍流中寻找扭结，并在“断开事件”期间保持警惕，以防尾气折断，当尾气似乎折断，然后在短时间内重整。Spaceweather.com可能会发布天体理发的提前通知。
灰尘的尾巴在一个狭窄的帆形风扇中从核心散开，弯曲离开北极星，朝北斗七星移动。与典型的观测站点相比，真正黑暗的天空可以使长度增加一倍。寻找条纹-条纹是由于活动点面向太阳旋转(每次旋转会打开和关闭)时周期性地喷出灰尘而产生的条纹。最大的未知数：Y4 ATLAS是一种粉末状的碎石堆，产生的尾巴很微弱，可溶解成虚无？还是运气用尘土飞扬的雪球打在我们身上，雪球的尾巴构成了我们在旧画中看到的宏伟的剑？一点极光或夜光云将真正使灯光秀结束。
使用一定范围的放大倍率。至关重要的是，在视线允许的情况下尽可能放大核心。Hale-Bopp彗星生产的螺旋状喷流在一个小时内为使用高功率的患者观察者带来了明显变化。
祖父母关于小时候看到的彗星的故事将是关于尾巴的，而不是关于头部的亮度。当尘埃落在我们和太阳之间时，就会出现超亮的尾巴。这是因为在这种配置下，尾巴从地平线以下吸收阳光并将其向前散射。2006年，麦克诺德彗星的壮观尾巴出现在32°低角处。对于ATLAS，我们48°的观察几何形状可适度增强1至2级幅度-仍然可以。
Perihelion：超越日光？
5月25日至31日这一周是我们拍摄Y4标志性图片并打造我们毕生难忘的一周。ATLAS从字面上看是越过太阳，每天都在增亮。整个晚上，尾巴的上半部分仍在地平线上方，从而将视线向下拉。随着分钟的流逝，尾巴变亮，克服了升起的橘黄色和黎明的黄色，直到到达彗星的明亮头部，升空了地平线。继续使用该示波器来选择内部昏迷的低对比度细节-如果可能的话，可以日出。
即使Y4的核心仅与维纳斯相抗衡，它还是整个星期的日间目标，永远不会比太阳近11°。警告！始终采取预防措施，以防未经过滤的望远镜或双筒望远镜意外指向太阳并造成永久性失明。
如果天空是深透明的蓝色，并且ATLAS超出了我们的预期，则我们可能会抓住一个历史悠久的日光彗星难以捉摸的奖杯。现在，只有时间会证明一切。
Comet ATLAS may soon be visible to the naked eye
C/2019 Y4 (ATLAS) is racing toward the Sun — and possibly a place in the history books.
By Alister Ling | Published: Wednesday, March 25, 2020
RELATED TOPICS: COMETS | OBSERVING
Y4ATLAScrop
Comet C/2019 Y4 (ATLAS) floats in the skies above the Canary Islands, Spain, on February 16. Between January 27 and February 16, the comet brightened from magnitude 11.5 to 10 and its coma grew from 2 to 2.5 arcminutes in size.
Martin Vd Dussen, Jos J. Chamb
Like watching the final chapter of a show or movie series, you’re almost trembling with excitement — but you don’t know whether you’ll have the experience of a lifetime, suffer a grand disappointment, or end up with something that’s just OK.
Right now, odds are that Comet C/2019 Y4 (ATLAS) will be wonderful. Just maybe it will be the most amazing thing you will ever see — a great comet for the history books. Here’s what we might be able to expect.
Past to present
Y4 was discovered on December 29, 2019, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) search program, one of the several automated sky surveys looking for potential Earth-crossing asteroids. Discovering comets is essentially a byproduct of this endeavor. At the time, C/2019 Y4 was a feeble magnitude 19.6 and located at nearly 3 astronomical units from the Sun — almost twice as far from our star as Mars. (One astronomical unit, or AU, is the average Earth-Sun distance.)
In mid-March, Y4 ATLAS surged 4 magnitudes, fueling rumors that it will just keep getting brighter, peaking at magnitude 8. But back in 2000, C/1999 S4 (LINEAR) dropped the same amount on its approach and dissolved rapidly.
David Levy wrote that “Comets are like cats. They have tails and they do whatever they want.” Despite the best observations and understanding, these dirty snowballs can fizzle out with no notice even farther from the Sun than Mars’ orbit, a distance Y4 ATLAS reaches at April’s start.
The description here covers what we’re likely to witness: a fantastic display like Comet C/1975 V1 West delivered in 1976. Stay hopeful for the comet of a generation and realize that, at worst, it will still be a nice binocular object.
PathofATLAS
Between the end of March and the middle of June, ATLAS will slip through several familiar constellations and come close to some easily identifiable bright stars, including Capella, Aldebaran, and Betelgeuse.
Alison Klesman (via TheSkyX)
Location, location
The Northern Hemisphere has great seats from now right up until the comet reaches perihelion on May 31, when ATLAS makes its closest approach to the Sun and performs a sharp turn around our star. Observers from 40 to 60 degrees north latitude are close to the stage, with those from 50 to 55 degrees north getting front-row seats. Equatorial and southern locations get one decent week starting May 28, but then Y4 stays low and fades quickly into the distance, like an object viewed out the back window of a fast-moving car.
By mid- to late April, which includes the New Moon on April 22, ATLAS is already large and diffuse for its distance. Note that reported magnitudes are integrated, which essentially crunches all its light into a point, rather than spreading it out between the coma and tails. Magnitude 2 is easy for the unaided eye, but from the city a big halo will be invisible through the light pollution. Streaking halfway between Polaris and brilliant Capella, Y4 might resemble a lopsided Andromeda Galaxy.
By mid-May, ATLAS is second in brightness only to Venus! During the deep blue of nautical twilight, it is only 15° high, dropping lower as the calendar ticks onward. Avoid observing from locations just south of a city — there’s no point looking through a light dome. Instead, an open field to the north lets you observe as long as possible.
ATLASMay15small
On May 15, ATLAS is bright but low on the northern horizon an hour after sunset for mid-northern latitudes. Try to find a dark location from which to view it, with no major populated areas to your north, for the best views.
Alison Klesman (via TheSkyX)
A tail to remember?
Our slanted view of the comet’s evolving tails is perfect. The gas tail glows from atoms ionized by ultraviolet light and blows straight back (away from the Sun) in the solar wind. Appearing gray to the human eye at first, the familiar green hue in March’s images effloresces into a brilliant emerald even in 8-inch scopes. It may transition to blue as ionization ramps up. Look for kinks in the turbulent flow and remain on the alert for the gas tail breaking during a “disconnection event,” when the tail appears to break away and then reforms a short time later. Spaceweather.com may publish advance notice of the celestial barber cut.
The dust tail spreads out from the core in a narrow sail-shaped fan, curving away from Polaris and up toward the Big Dipper. A really dark sky can double the length compared to a typical observing site. Look for striations — streaks resulting from the periodic ejections of dust as active spots rotate to face the Sun, turning on and off with each spin. The big unknown: Is Y4 ATLAS a lightly powdered rubble pile that produces a meager tail that dissolves into nothingness? Or does luck strike us with a dust-choked snowball whose tail forms the magnificent sword we see in paintings of old? A touch of aurora or noctilucent clouds would really top off the light show.
Use a range of magnifications. Crucially, zoom in to the core as much as the seeing conditions allow. Comet Hale-Bopp produced spiral jets that visibly changed in an hour for patient observers using high power.
Grandparents’ stories about a comet they saw when they were kids will be about the tail, not how bright the head was. Extra-bright tails happen when the dust lies between us and the Sun. That’s because in such a configuration, the tail takes the sunlight from below the horizon and scatters it forward. In 2006, Comet McNaught’s spectacular tail occurred with a low angle of 32°. For ATLAS, our viewing geometry of 48° gives a modest 1- to 2-magnitude enhancement — still mighty fine.
CometMcNaught
Comet McNaught sports a spectacular, arcing tail across the sky in January 2007. Will Y4 ATLAS do the same?
ESO/H.H.Heyer
Perihelion: Pushing past daylight?
The week of May 25 to 31 is the week when we take the iconic pictures of Y4 and forge our memories of a lifetime. ATLAS is literally diving past the Sun, brightening a magnitude per day. The top half of the tail remains above the horizon all night, drawing our view downward. As minutes flow by, the tail brightens, overcoming the rising oranges and yellows of dawn until it reaches the brilliant head of the comet, lifting off the horizon. Keep using that scope to pick out low-contrast details of the inner coma — past sunrise if possible.
Even if the core of Y4 only rivals Venus, it is a daytime target for a whole week, never closer than 11° to the Sun. WARNING! Always take precautions against an unfiltered scope or binoculars accidentally pointing at the Sun and causing permanent blindness.
If the sky is a dark transparent blue and ATLAS exceeds our expectations, we might snag the elusive trophy of a historical daylight comet. Right now, only time will tell.
Look for regular announcements and recent images here at Astronomy.com.
C / 2019 Y4(ATLAS)正在向太阳飞奔-可能在历史书籍中占有一席之地。
C / 2019 Y4彗星(ATLAS)于2月16日在西班牙加那利群岛上方的天空中漂浮。在1月27日至2月16日之间，彗星的亮度从11.5增至10，彗星的彗星大小从2弧分增加到2.5弧分。
就像观看电视节目或电影连续剧的最后一章一样，您几乎激动得发抖但您不知道自己是否会经历一生，大失所望，或者最终得到了可以接受的东西。
现在，很有可能彗星C / 2019 Y4(ATLAS)会很棒。也许这将是您有史以来最神奇的事情-历史书的一颗伟大的彗星。这是我们可能期望的。
过去到现在
Y4是在2019年12月29日通过小行星地面撞击最后警报系统(ATLAS)搜索程序发现的，这是几项自动的天空调查，旨在寻找可能穿越地球的小行星。发现彗星本质上是这项工作的副产品。当时，C / 2019 Y4的强度微弱至19.6，位于距太阳近3个天文单位的位置，几乎是离我们的恒星两倍的距离，距离火星。(一个天文单位，即AU，是地球与太阳之间的平均距离。)
3月中旬，Y4 ATLAS激增了4个数量级，有传言称它会不断变亮，达到8级。但是早在2000年，C / 1999 S4(LINEAR)就采用了同样的方法并迅速解散。
David Levy写道：“彗星就像猫。他们有尾巴，他们随心所欲。” 尽管有最好的观察和理解，但这些肮脏的雪球仍会在没有通知的情况下从火星轨道上飞走，甚至比太阳更远，Y4 ATLAS在4月初到达了距离。
这里的描述涵盖了我们可能会看到的东西：像Comet C / 1975 V1 West这样在1976 年交付的出色显示器。对这一代彗星抱有希望，并意识到，即使在最坏的情况下，它仍然是一个不错的双筒望远镜。
位置，位置
从现在开始，直到北半球的彗星在5月31日到达近日点，ATLAS才最接近太阳并绕着我们的恒星进行急转。北纬40至60度的观察员靠近舞台，北纬50至55度的观察员获得前排座位。从5月28日开始，赤道和南部地区将有一个不错的一周，但是Y4保持低位并迅速消失在远处，就像从快速行驶的汽车的后窗上看到的物体一样。
到4月中旬至下旬，包括4月22日的新月，ATLAS已经很大，并且距离较远。请注意，所报告的幅度是积分的，本质上将其所有光线都粉碎为一个点，而不是在昏迷和尾巴之间散布出去。肉眼很难看到2级，但从城市出发，光污染将看不到大的光环。Y4在北极星和耀眼的卡佩拉之间徘徊，可能类似于偏斜的仙女座星系。
到5月中旬，ATLAS的亮度仅次于金星！在深蓝色的航海暮色中，它只有15°高，随着日历的滴答声逐渐降低。避免从城市以南的位置进行观察-毫无意义的是透过圆顶观看。取而代之的是，向北开阔的田野可让您观察得尽可能长。
要记住的尾巴吗？
我们对彗星尾巴的倾斜观察非常完美。气体尾巴从被紫外线电离的原子发光，并在太阳风中向后直吹(远离太阳)。起初，人眼会呈现灰色，即使在8英寸范围内，三月影像中熟悉的绿色也能变成明亮的祖母绿。随着电离的增加，它可能会变为蓝色。在湍流中寻找扭结，并在“断开事件”期间保持警惕，以防尾气折断，当尾气似乎折断，然后在短时间内重整。Spaceweather.com可能会发布天体理发的提前通知。
灰尘的尾巴在一个狭窄的帆形风扇中从核心散开，弯曲离开北极星，朝北斗七星移动。与典型的观测站点相比，真正黑暗的天空可以使长度增加一倍。寻找条纹-条纹是由于活动点面向太阳旋转(每次旋转会打开和关闭)时周期性地喷出灰尘而产生的条纹。最大的未知数：Y4 ATLAS是一种粉末状的碎石堆，产生的尾巴很微弱，可溶解成虚无？还是运气用尘土飞扬的雪球打在我们身上，雪球的尾巴构成了我们在旧画中看到的宏伟的剑？一点极光或夜光云将真正使灯光秀结束。
使用一定范围的放大倍率。至关重要的是，在视线允许的情况下尽可能放大核心。Hale-Bopp彗星生产的螺旋状喷流在一个小时内为使用高功率的患者观察者带来了明显变化。
祖父母关于小时候看到的彗星的故事将是关于尾巴的，而不是关于头部的亮度。当尘埃落在我们和太阳之间时，就会出现超亮的尾巴。这是因为在这种配置下，尾巴从地平线以下吸收阳光并将其向前散射。2006年，麦克诺德彗星的壮观尾巴出现在32°低角处。对于ATLAS，我们48°的观察几何形状可适度增强1至2级幅度-仍然可以。
Perihelion：超越日光？
5月25日至31日这一周是我们拍摄Y4标志性图片并打造我们毕生难忘的一周。ATLAS从字面上看是越过太阳，每天都在增亮。整个晚上，尾巴的上半部分仍在地平线上方，从而将视线向下拉。随着分钟的流逝，尾巴变亮，克服了升起的橘黄色和黎明的黄色，直到到达彗星的明亮头部，升空了地平线。继续使用该示波器来选择内部昏迷的低对比度细节-如果可能的话，可以日出。
即使Y4的核心仅与维纳斯相抗衡，它还是整个星期的日间目标，永远不会比太阳近11°。警告！始终采取预防措施，以防未经过滤的望远镜或双筒望远镜意外指向太阳并造成永久性失明。
如果天空是深透明的蓝色，并且ATLAS超出了我们的预期，则我们可能会抓住一个历史悠久的日光彗星难以捉摸的奖杯。现在，只有时间会证明一切。
Comet ATLAS may soon be visible to the naked eye
C/2019 Y4 (ATLAS) is racing toward the Sun — and possibly a place in the history books.
By Alister Ling | Published: Wednesday, March 25, 2020
RELATED TOPICS: COMETS | OBSERVING
Y4ATLAScrop
Comet C/2019 Y4 (ATLAS) floats in the skies above the Canary Islands, Spain, on February 16. Between January 27 and February 16, the comet brightened from magnitude 11.5 to 10 and its coma grew from 2 to 2.5 arcminutes in size.
Martin Vd Dussen, Jos J. Chamb
Like watching the final chapter of a show or movie series, you’re almost trembling with excitement — but you don’t know whether you’ll have the experience of a lifetime, suffer a grand disappointment, or end up with something that’s just OK.
Right now, odds are that Comet C/2019 Y4 (ATLAS) will be wonderful. Just maybe it will be the most amazing thing you will ever see — a great comet for the history books. Here’s what we might be able to expect.
Past to present
Y4 was discovered on December 29, 2019, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) search program, one of the several automated sky surveys looking for potential Earth-crossing asteroids. Discovering comets is essentially a byproduct of this endeavor. At the time, C/2019 Y4 was a feeble magnitude 19.6 and located at nearly 3 astronomical units from the Sun — almost twice as far from our star as Mars. (One astronomical unit, or AU, is the average Earth-Sun distance.)
In mid-March, Y4 ATLAS surged 4 magnitudes, fueling rumors that it will just keep getting brighter, peaking at magnitude 8. But back in 2000, C/1999 S4 (LINEAR) dropped the same amount on its approach and dissolved rapidly.
David Levy wrote that “Comets are like cats. They have tails and they do whatever they want.” Despite the best observations and understanding, these dirty snowballs can fizzle out with no notice even farther from the Sun than Mars’ orbit, a distance Y4 ATLAS reaches at April’s start.
The description here covers what we’re likely to witness: a fantastic display like Comet C/1975 V1 West delivered in 1976. Stay hopeful for the comet of a generation and realize that, at worst, it will still be a nice binocular object.
PathofATLAS
Between the end of March and the middle of June, ATLAS will slip through several familiar constellations and come close to some easily identifiable bright stars, including Capella, Aldebaran, and Betelgeuse.
Alison Klesman (via TheSkyX)
Location, location
The Northern Hemisphere has great seats from now right up until the comet reaches perihelion on May 31, when ATLAS makes its closest approach to the Sun and performs a sharp turn around our star. Observers from 40 to 60 degrees north latitude are close to the stage, with those from 50 to 55 degrees north getting front-row seats. Equatorial and southern locations get one decent week starting May 28, but then Y4 stays low and fades quickly into the distance, like an object viewed out the back window of a fast-moving car.
By mid- to late April, which includes the New Moon on April 22, ATLAS is already large and diffuse for its distance. Note that reported magnitudes are integrated, which essentially crunches all its light into a point, rather than spreading it out between the coma and tails. Magnitude 2 is easy for the unaided eye, but from the city a big halo will be invisible through the light pollution. Streaking halfway between Polaris and brilliant Capella, Y4 might resemble a lopsided Andromeda Galaxy.
By mid-May, ATLAS is second in brightness only to Venus! During the deep blue of nautical twilight, it is only 15° high, dropping lower as the calendar ticks onward. Avoid observing from locations just south of a city — there’s no point looking through a light dome. Instead, an open field to the north lets you observe as long as possible.
ATLASMay15small
On May 15, ATLAS is bright but low on the northern horizon an hour after sunset for mid-northern latitudes. Try to find a dark location from which to view it, with no major populated areas to your north, for the best views.
Alison Klesman (via TheSkyX)
A tail to remember?
Our slanted view of the comet’s evolving tails is perfect. The gas tail glows from atoms ionized by ultraviolet light and blows straight back (away from the Sun) in the solar wind. Appearing gray to the human eye at first, the familiar green hue in March’s images effloresces into a brilliant emerald even in 8-inch scopes. It may transition to blue as ionization ramps up. Look for kinks in the turbulent flow and remain on the alert for the gas tail breaking during a “disconnection event,” when the tail appears to break away and then reforms a short time later. Spaceweather.com may publish advance notice of the celestial barber cut.
The dust tail spreads out from the core in a narrow sail-shaped fan, curving away from Polaris and up toward the Big Dipper. A really dark sky can double the length compared to a typical observing site. Look for striations — streaks resulting from the periodic ejections of dust as active spots rotate to face the Sun, turning on and off with each spin. The big unknown: Is Y4 ATLAS a lightly powdered rubble pile that produces a meager tail that dissolves into nothingness? Or does luck strike us with a dust-choked snowball whose tail forms the magnificent sword we see in paintings of old? A touch of aurora or noctilucent clouds would really top off the light show.
Use a range of magnifications. Crucially, zoom in to the core as much as the seeing conditions allow. Comet Hale-Bopp produced spiral jets that visibly changed in an hour for patient observers using high power.
Grandparents’ stories about a comet they saw when they were kids will be about the tail, not how bright the head was. Extra-bright tails happen when the dust lies between us and the Sun. That’s because in such a configuration, the tail takes the sunlight from below the horizon and scatters it forward. In 2006, Comet McNaught’s spectacular tail occurred with a low angle of 32°. For ATLAS, our viewing geometry of 48° gives a modest 1- to 2-magnitude enhancement — still mighty fine.
CometMcNaught
Comet McNaught sports a spectacular, arcing tail across the sky in January 2007. Will Y4 ATLAS do the same?
ESO/H.H.Heyer
Perihelion: Pushing past daylight?
The week of May 25 to 31 is the week when we take the iconic pictures of Y4 and forge our memories of a lifetime. ATLAS is literally diving past the Sun, brightening a magnitude per day. The top half of the tail remains above the horizon all night, drawing our view downward. As minutes flow by, the tail brightens, overcoming the rising oranges and yellows of dawn until it reaches the brilliant head of the comet, lifting off the horizon. Keep using that scope to pick out low-contrast details of the inner coma — past sunrise if possible.
Even if the core of Y4 only rivals Venus, it is a daytime target for a whole week, never closer than 11° to the Sun. WARNING! Always take precautions against an unfiltered scope or binoculars accidentally pointing at the Sun and causing permanent blindness.
If the sky is a dark transparent blue and ATLAS exceeds our expectations, we might snag the elusive trophy of a historical daylight comet. Right now, only time will tell.
Look for regular announcements and recent images here at Astronomy.com.