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05/25/2020 – Ephemeris – Comet SWAN is in our skies in evening twilight
When I recorded this program on the evening of the17th there was hope that Comet SWAN would have achieved naked-eye visibility. It did earlier this month when it was too far south for us to see from 45° North latitude. Predictions now are for it to be 7th magnitude, 2.5 times dimmer than the faintest star visible to the unaided eye.
This is Ephemeris for Memorial Day, Monday, May 25th. Today the Sun will be up for 15 hours and 10 minutes, setting at 9:15, and it will rise tomorrow at 6:03. The Moon, 3 days past new, will set at 12:18 tomorrow morning.
Comet SWAN just might be visible in binoculars tonight by about 10:30 p.m. with binoculars or a small telescope low in the northwestern sky. A pointer to it is the bright star Capella also in that direction. Comet SWAN will be located in the direction of 4 o’clock (to the right and a bit down) by 10 degrees angle, the width of your fist held at arms length. It will be a small fuzzy spot. I doubt you would spot the comet’s tail. It is a thin ion or gaseous tail that is revealed in photographs only. Over the next week it will be moving toward Capella and on June 1st will be just below Capella but half as bright as it is now. There’s another comet coming. Comet NeoWISE will be visible in our skies by late July if it holds up.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
Comet SWAN
Comet SWAN track against the stars for 10 pm May 25 to June 3, 2020 with Mercury and Venus for the 25th They will be moving too. Comet labels show month-day and magnitude. However add 4 to the magnitude to get the approximate actual magnitude. The comet would be hard to spot in binoculars even in a dark sky. But who knows, the comet might flare up and be visible. Created using Cartes du Ciel (Sky Charts).
Northwestern horizon tonight at 10 pm May 25, 2020 with a scale that’s close to that of the image above. The comet is not bright enough to show here. Created using Stellarium.
In Memoriam
Today as we prepare to send humans into space from American soil for the first time in 9 years we pause to remember those who gave their lives for our country. For purposes of this program that includes those courageous enough to sit on top of or beside a million pounds of explosives to be launched into space. From the three astronauts who died in the Apollo one file in 1967, the explosion of the Space Shuttle Challenger in 1986, to the disintegration of the Columbia in 2003, 17 Americans and other nationals have died in NASA space accidents. The Russians too have lost cosmonauts in the exploration of space. Brothers and sisters in the quest for knowledge and to expand the horizons of human habitation. Per aspera, ad astra, Through difficulties to the stars!
A listing of Astronaut and Cosmonaut deaths: http://www.aerospaceweb.org/question/history/q0114.shtml
The Vatican Observatory Calendar
Being Catholic, I occasionally check the Vatican Observatory Foundation website. Besides the director of the Vatican Observatory is Brother Guy Consolmagno SJ, a fellow Michigander, born in Detroit. There were a couple of items on the May calendar that caught my eye.
Today, was marked as Memorial Day, but also Towel Day. Towel Day? It’s the 42nd anniversary of the first BBC Radio broadcast of Douglas Adams’ Hitchhiker’s Guide to the Galaxy. And if you don’t know the significance of a towel or the number 42, I won’t spoil it for you.
Also May 15th was the 300th birthday of Maximilian Hell SJ, first director of the Vienna Observatory, who also observed the transit of Venus in1769 from northern Norway. The crater on the Moon Hell is named for him. I’ve always had fun showing the crater a day or two after first quarter and mentioning that the crater Hell is named after a priest.
05/18/2020 – Ephemeris – Comets are fragile, especially this month’s crop
This is Ephemeris for Monday, May 18th. Today the Sun will be up for 14 hours and 57 minutes, setting at 9:08, and it will rise tomorrow at 6:09. The Moon, half way from last quarter to new, will rise at 5:04 tomorrow morning.
Last month most of us astronomers were looking forward to seeing at least two naked-eye comets this month, with another just below naked-eye visibility. Our hopes have been dashed with the first two, Comet ATLAS is disintegrating and Comet SWAN has stopped brightening, and at its brightest, which would be barely visible in a dark sky, would be invisible in bright twilight, where it will be located. Comets are unpredictable. Each is their own beast. They are small bodies of ices dust and bits of rock. When they come inside the orbit of Jupiter the Sun’s heat sublimates their frozen gasses which shoot out along with dust and build a huge tenuous head called a coma that can be larger than Jupiter and a tail that extends millions of miles (kilometers).
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet ATLAS disintegrates as witnessed by the Hubble Space Telescope. Currently there are 5 nuclear fragments being separately tracked. The color here is most not likely the true visual color. Click on the image to enlarge. Credit: NASA/ESA Hubble Space Telescope.
04/23/2020 – Ephemeris – New Comet SWAN
This is Ephemeris for Thursday, April 23rd. Today the Sun will be up for 13 hours and 54 minutes, setting at 8:38, and it will rise tomorrow at 6:42. The Moon, 1 day past new, will set at 9:18 this evening.
Let’s get a preview of the newly discovered Comet SWAN. It was discovered using the Solar Wind Anisotropies or SWAN camera on the SOHO spacecraft hanging out a million miles (1.5 million km) sunward of the Earth. The SWAN instrument is the only one on the spacecraft not pointed at the Sun. Its to study where the solar wind interacts with the interstellar medium of hydrogen. The comet must have been producing an extraordinary amount of hydrogen to be noticed, so the comet may have had an outburst, and it may fade to its normally dim self after a while. That means it may not be naked-eye by the middle of next month. Assuming this was no outburst, the comet will make its naked-eye debut low in the northwest near the end of twilight in late May. I’ll have updates as we go.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet C/2020 F8 (SWAN) photographed by Ariel Rodriguez, La Reja, Argentina. Click on the image to enlarge. Retrieved from Seiichi Yoshida’s web site. See link below.
Bob Moler's Ephemeris Blog 