We have a bright comet in the dawn sky for a few days. Comet C/2020 F3 NEOWISE has brightened rapidly over the past few weeks, now about 1st magnitude it can just be seen against the glow of dawn.
I took along Hodepodge to serve as a tracking mount for the TV-76mm scope and a couple cameras to do some comet shooting. The Canon 6D would go with the small ‘scope, the EOS-M5 with a tripod for wide angle shots.
Driving up Waikoloa road I was troubled by a bank of clouds in the Waimea saddle, thus I elected to head for the Humuʻula saddle instead. I ended up in the lava fields along the Mauna Loa access road. The view was perfect, and I had just enough time to get the mount and camera setup as the comet rose.Continue reading “A Bright Comet in the Dawn”
A modest comet is currently crossing the evening sky, at about 8th magnitude C/2018 W2 Africano can be appreciated in small telescopes. Last week I decided to add it to the target list for a few images.
The many images are registered on the comet during processing. Each image showing the motion of the comet as it moves fairly quickly among the stars in the hour or so the camera was taking frames. Thus the stars become multicolored streaks in this combined image…
2019 is looking to be a pretty ordinary year for events, with a few decent events to look forward to. The highlights will be a sunset total lunar eclipse on January 20th, the η-Aquariids meteor shower in early May, a transit of Mercury in November, and a nice set of planetary conjunctions in the sunset and sunrise.
There are dozens of posts scheduled here on DarkerView to remind my readers of these and many more events before they occur. Frankly, I need the reminder myself. Stay tuned for all of the great events the sky of 2019 will offer us.
The remainder of this post is a quick summary of the events our sky has to offer in 2019.Continue reading “The Island Sky for 2019”
A trip past the sun may have selectively altered the production of one form of water in a comet – an effect not seen by astronomers before, a new NASA study suggests.
Astronomers from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, observed the Oort cloud comet C/2014 Q2, also called Lovejoy, when it passed near Earth in early 2015. Through NASA’s partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed the comet at infrared wavelengths a few days after Lovejoy passed its perihelion – or closest point to the sun.
Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun.
This February will feature a very close approach of Comet 45P/Honda–Mrkos–Pajdušáková. The comet will pass about 0.08AU (11.9 million km or 7.4 million miles) from Earth on February 11th, making it an easy telescopic object, and a marginal naked eye comet at around 6th magnitude.
This is a short period comet with an orbit only 5.25 years long. At aphelion it orbits out very close to Jupiter, while at perihelion it is well inside the orbit of Venus. As such it may occasionally pass very close to Earth.
The comet itself is rather interesting. Discovered in 1948 the comet has been a the frequent target of scientific observation as it may pass quite close to Earth. In 2011 it passed about 0.06AU from Earth and was the target of radar observations.
Currently in the evening sky the comet is sinking into the sunset rather rapidly. It will pass by the Sun around the end of January to appear in the morning sky. It will rise rapidly above the dawn, by February 5th it will be rising at 3:22am, about four hours before the Sun. On the day of close approach, February 11th, the comet will rise well before midnight in the northern sky.
The comet is predicted to remain quite bright, around 7th magnitude or better for all of January and most of February, possibly peaking at around 6th magnitude near close approach to the Earth. As this is a well observed comet these magnitudes are likely to be reasonably accurate.
Of course any comet getting this close to us will catch the attention of the doomsday preachers and assorted apocalyptic predictions. Comet 45P is already a bit of a YouTube celebrity with quite a few videos filled with dire predictions.
I predict that we will have a pretty comet in the new year’s sky to provide a nice target for telescopic observations and astrophotographers. I would suggest making a point to get out and observe this comet as it passes by.
A team led by astronomers from the Jagiellonian University in Krakow, Poland, recently used the W. M. Keck Observatory in Hawaii to observe and measure a rare class of “active asteroids” that spontaneously emit dust and have been confounding scientists for years. The team was able to measure the rotational speed of one of these objects, suggesting the asteroid spun so fast it burst, ejecting dust and newly discovered fragments in a trail behind it. The findings are being published in Astrophysical Journal Letters on March 20, 2015.
Unlike the hundreds of thousands of asteroids in the main belt of our solar system, which move cleanly along their orbits, active asteroids were discovered several years ago mimicking comets with their tails formed by calm, long lasting ice sublimation.
Then in 2010 a new type of active asteroid was discovered, which ejected dust like a shot without an obvious reason. Scientist gravitated around two possible hypotheses. One states the explosion is a result of a hypervelocity collision with another minor object. The second popular explanation describes it as a consequence of “rotational disruption”, a process of launching dust and fragments by spinning so fast, the large centrifugal forces produced exceed the object’s own gravity, causing it to break apart. Rotational disruption is the expected final state of what is called the YORP effect – a slow evolution of the rotation rate due to asymmetric emission of heat.
Sunday night I shot a wide-field image of the comet as it passed near the Pleiades star cluster. I am somewhat disappointed by the image. The skies over Waikoloa are just not conducive to wide-field imaging. And with a couple scheduled mountain days I did not have the option to take the gear up to where conditions are better. Not and get any sleep. Still, it is not a total disaster…
The first good night for comet imaging since the moonlight has departed the evening sky. If is wasn’t clouds it was heavy haze and vog. With a good Saturday night I set up the ‘scope in the driveway and shot for a couple hours on comet C/2014 Q2 Lovejoy.
This is not a properly processed shot, rather just a quick stack of the longer exposures. The real image will be a few days before I can get about to processing it. Still, a lot of interesting detail in the tail…