05/29/2020 – Ephemeris is completing 45 trips around the Sun

This is Bob Moler with Ephemeris for Friday, May 29th. Today the Sun will be up for 15 hours and 17 minutes, setting at 9:19, and it will rise tomorrow at 6:01. The Moon, at first quarter today, will set at 2:55 tomorrow morning. This is the last program of Ephemeris’ 45th orbit of the Sun. Monday we start the 46th orbit. In case you’re confused, one orbit of the Sun equals one year. I consider the Earth a space station orbiting the Sun in roughly 365 and a quarter days. The orbital time is also marked by the seasons due to the Earth’s axial tilt, seeing the Sun from different directions, and also looking out in space at night to the procession of stars and constellations that slowly change throughout the year giving us the parade of the seasonal constellations. Now in the evening the winter stars have moved behind the Sun. The spring constellations are in the south in the evening, and some of the summer stars are rising in the eastern sky at the same time. The planets that orbit the Sun with us are the wild card: their complex gyrations baffled the ancients who thought the Earth to be stationary.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

I got extremely busy Thursday evening getting our astronomy club newsletter out that I forgot to post this item, which is why this post is a day late. Not much astro news in it anyway.  However at this moment the SpaceX dragonship Endeavour is on its way to the International Space Station.

05/28/2020 – Ephemeris – The Moon tonight and the origin of the lunar seas

This is Ephemeris for Thursday, May 28th. Today the Sun will be up for 15 hours and 15 minutes, setting at 9:18, and it will rise tomorrow at 6:01. The Moon, 1 day before first quarter, will set at 2:25 tomorrow morning.

Tonight’s Moon is a fat crescent. The lower or southern part of the Moon are brighter. These are the lunar highlands, the more rugged crater filled part of the Moon. The darker areas are the so-called lunar seas, huge lava filled craters. Note that they appear to be roughly circular. They are thought to be the result of large asteroid impacts that occurred four billion years ago during what is known as the late heavy bombardment. The late heavy bombardment is still controversial. One theory has that the outer planets changed their orbits in time disrupting the two areas of small bodies, the asteroid belt inside Jupiter’s orbit and the Kuiper belt beyond Neptune, sending some of them into the inner solar system.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The Moon at low magnification this evening, May 28, 2020 with the English names for the visible lunar seas. Created using Stellarium.

05/27/2020 – Ephemeris – Let’s look at the naked-eye planets for this week

This is Ephemeris for Wednesday, May 27th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:17, and it will rise tomorrow at 6:02. The Moon, 2 days before first quarter, will set at 1:49 tomorrow morning.

Let’s look at the naked-eye planets for this week. Venus is our evening star shining brightly in the northwest. It will be our evening star for only another week and defeated by twilight for most of that time. A tiny crescent can now be seen in binoculars. It will cross between the Earth and the Sun on June 3rd. It will set tonight at 10:16 p.m. It’s only 27.6 million miles (44.5 million km) away. Mercury is making an appearance above and left of Venus now. In the morning sky there are three planets in the south and southeast. Bright Jupiter will rise first at 12:39 a.m. Followed by Saturn at 12:54 a.m. Mars, is stretching its lead left of Saturn and will rise at 2:44 a.m. Its now down to 96 million miles (155 million km) away, as the Earth slowly overtakes it at the rate of about 5 million miles (8 million km) a week.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Venus & Mercury in twilight tonight at 10 p.m. May 27, 2020. Created using Stellarium.

The Moon in a small telescope this evening May 27, 2020 with some seas and craters labeled. Created using Stellarium.

The Morning planets at 5 am. Created using Stellarium.

The planets as seen in a telescope with the same magnification. Venus, Jupiter and Saturn on the night of May 27/28, 2020. Apparent diameters: Venus, 56.49″. larger than Jupiter, at 44.24″; Saturn, 17.70″, rings, 41.22″. Mars at 9.06″ won’t be added until it reaches 10″. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Chart).

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on May 27, 2020. The night ends on the left with sunrise on the 29th. The closeness of Jupiter and Saturn in the morning sky unfortunately overlays planets and labels. Click on the image to enlarge. Created using my LookingUp program.

 

05/26/2020 – Ephemeris – The first launch of humans to orbit from American soil in 9 years could happen tomorrow

This is Ephemeris for Tuesday, May 26th. Today the Sun will be up for 15 hours and 12 minutes, setting at 9:16, and it will rise tomorrow at 6:03. The Moon, 3 days before first quarter, will set at 1:07 tomorrow morning.

As of Sunday when I’m recording this NASA and SpaceX are still GO for the launch of two American astronauts to the International Space Station tomorrow. This will be the first human launch from the United States since Space Shuttle Atlantis left this same launch pad 39a left on July 8th, 2011. On that flight Doug Hurley was pilot, and he will command this flight. He visited the ISS twice, however his wife Karen Nyberg also visited the ISS twice, however the last time she stayed nearly 6 months. Bob Behnken the second astronaut is also a space shuttle veteran with two construction flights to the ISS and like Hurley is married to an astronaut, Megan McArthur who flew on the last Hubble Space Telescope repair mission.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

SpaceX Demo-2 astronauts Bob Behnken (left) and Doug Hurley. Credit: SpaceX.

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.

05/22/2020 – Ephemeris – Venus hangs out with Mercury and the Moon this weekend

This is Ephemeris for Friday, May 22nd. Today the Sun will be up for 15 hours and 5 minutes, setting at 9:12, and it will rise tomorrow at 6:06. The Moon is new today, and won’t be visible

Low in the northwest shortly after sunset our brilliant evening star Venus may be seen. It’s getting closer to the Sun every evening. This is an illusion because Venus is in the process of passing between the Earth and the Sun, so it’s not getting closer to the Sun, but it is getting closer to us at 29 million miles (46.8 million km) today. Mercury has passed Venus and is now to the left and a bit above Venus as seen at 10 p.m. Both are pretty close to the horizon, so you may have to move to a spot with a low northwestern horizon. Tomorrow night the day old sliver of the Moon will be spotted just below both of them. It should be quite a sight with these two planets and the Moon in the twilight, just after sunset.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Venus, Mercury, Moon animation for 10 pm May 22nd, 23rd and 24th, 2020. The Moon is shown 3 times actual size in an attempt to show its phase. Created using Stellarium and GIMP.

05/21/2020 – Ephemeris – A star cluster in a most unusual spot

This is Ephemeris for Thursday, May 21st. Today the Sun will be up for 15 hours and 3 minutes, setting at 9:11, and it will rise tomorrow at 6:07. The Moon, 1 day before new, will rise at 6:16 tomorrow morning.

High in the south at 10:30 p.m. or so is a tiny and faint constellation of Coma Berenices, or Berenice’s hair. In it are lots of faint stars arrayed to look like several strands of hair. The whole group will fit in the field of a pair of binoculars, which will also show many more stars. The hank of hair supposed belonged to Berenice II, Queen of Egypt, in the 3rd century BCE. Coma Berenices is the second closest star cluster to us at only 250 light years away, after the Hyades, the face of Taurus the bull a winter constellation. It’s in an odd spot for a galactic star cluster, which are supposed to lie in the plane of the Milky Way. It’s actually seen at the galactic pole, as far as possible away from the milky band. It’s a matter of perspective because it’s so close to us. It’s still really in the plane of the Milky Way.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Coma Berenices and galactic coordinated showing how close to the galactic pole it is. The bright star Arcturus at the left edge.  Leo’s hind end is at the lower right. Created using Cartes du Ciel (Sky Charts).

Approximate 7 power binocular field of view of the Coma Berenices Star Cluster. Created using Cartes du Ciel (Sky Charts).

Note: There is another cluster in the constellation.  It’s called the Coma Cluster.  It’s a cluster of over a thousand galaxies a bit over 300 million light years away.

05/20/2020 – Ephemeris – Let’s look at the naked-eye planets for this week

This is Ephemeris for Wednesday, May 20th. Today the Sun will be up for 15 hours and 1 minute, setting at 9:10, and it will rise tomorrow at 6:08. The Moon, 2 days before new, will rise at 5:49 tomorrow morning.

Let’s look at the naked-eye planets for this week. Venus is our evening star shining brightly in the west northwest. It will be our evening star for only the next 2 weeks. A tiny crescent can now be seen in binoculars. It will cross between the Earth and the Sun on June 3rd. It will set at 11:05 p.m. It’s only 30 million miles (48 million km) away. Mercury is making an appearance just below Venus now. In the morning sky there are three planets close together in the south and southeast. Bright Jupiter will rise first at 1:07 a.m. Followed by Saturn at 1:22 a.m. Mars, is stretching its lead left of Saturn and will rise at 3:00 a.m. Mars continues to get closer. Its now down to 101million miles (163 million km) away, as the Earth slowly overtakes it at the rate of about 5 million miles (7 million km) a week.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Venus and Mercury as it should appear at 10 pm low in the northwest over the Lake Michigan horizon. May 20, 2020. Created using Stellarium.

Jupiter, Saturn and Mars seen in the southern sky at 5:30 am tomorrow morning May 21, 2020. Created using Stellarium.

The planets as seen in a telescope with the same magnification. Venus, Jupiter and Saturn on the night of May 13/14, 2020. Apparent diameters: Venus, 52.76″, larger than Jupiter, at 43.37″; Saturn, 17.51″, rings 40.80″. Mars at 8.66″ won’t be added until it reaches 10″. Mercury is gibbous at 6.04″. The ” symbol means seconds of arc (1/3600th of a degree.) Note that Jupiter has two moons in transit, with another behind the planet. The transiting moons are nearly invisible, so only one moon, Callisto is visible. Created using Cartes du Ciel (Sky Charts).

Jovian satellite events (Subtract 4 hours from UT to get EDT)

Moon      Event          Date         UT
Europa:   Shadow start:  21 May 2020  2:36
Ganymede: Shadow end:    21 May 2020  5:50
Europa :  Shadow start:  21 May 2020  6:13
Ganymede: Transit start: 21 May 2020  7:02
Europa:   Transit start: 21 May 2020  8:22
Europa:   Shadow end:    21 May 2020  8:58
Ganymede: Transit end:   21 May 2020 10:24

Source: The Pluto Project https://www.projectpluto.com/jevent.htm

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on May 20, 2020. The night ends on the left with sunrise on the 21st. The closeness of Jupiter and Saturn in the morning sky unfortunately overlays planets and labels. Click on the image to enlarge. Created using my LookingUp program.

05/19/2020 – Ephemeris – Venus will leave the evening sky in 15 days

This is Ephemeris for Tuesday, May 19th. Today the Sun will be up for 14 hours and 59 minutes, setting at 9:09, and it will rise tomorrow at 6:08. The Moon, 3 days before new, will rise at 5:25 tomorrow morning.

In 15 days Venus will leave the evening sky by passing between the Earth and the Sun in what astronomers call an inferior conjunction. Eight years ago, June 6th 2012, Venus went through another inferior conjunction. That time it passed directly between the Earth and the Sun so we could see the black spot that was Venus cross the face of the Sun as a rare Transit of Venus. Eight years before that, on June 8th 2004, we had another transit. However we will not see another in our lifetimes. The next one will occur in 2117. With the June 3rd conjunction Venus will pass north of the Sun from our vantage point, since Venus’ orbit is tilted a bit more than 3 degrees to the Earth’s orbit. So enjoy Venus while you can, unless you want to get up really early next month.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Transits of Venus-Two hits and a miss. Image created using Cartes du Ciel (Sky Charts).

Earth and Venus have a 13:8 orbital resonance.  That is Venus orbits the Sun 13 times in the same time that the Earth orbits the Sun  8 times. So Venus has the same position in our skies it had 8 years ago.  Actually the resonance is not perfect The resonance comes out 2.4 days short. So events like inferior conjunctions like the ones in the example above back track two and a fraction days from the 8 year interval.

Venus goes through a 584 day cycle from one inferior conjunction to the next.  Five of those cycles equals 7.994 years. The Maya were well aware of this and one of their calendars was based on the Venus-Earth relationship.

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.