04/12/2021 – Ephemeris – Human space flight began 60 years ago today

This is Bob Moler with Ephemeris for Monday, April 12th. Today the Sun will be up for 13 hours and 21 minutes, setting at 8:24, and it will rise tomorrow at 7:01. The Moon, 1 day past new, will set at 9:05 this evening.

60 years ago today Yuri Gagarin a Soviet Air Force pilot became the first cosmonaut and first person to orbit the Earth in his Vostok-1 spacecraft. The event has been celebrated around the world since 2001 as Yuri’s Night. Gagarin was strictly a passenger on his flight, but was given a key to override the automated functions of the spacecraft to take over manually if needed. He ejected from the capsule as planned to land by parachute. His flight came three weeks before the United States and NASA launched Alan Shepard on his sub-orbital flight in his Freedom 7 Mercury Capsule on May 5th 1961. It wasn’t until February 20th the next year that John Glenn made three orbits of the Earth in his Friendship 7 Capsule to match Gagarin’s feat.

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

Addendum

Yuri Gagarin in his space suit and helmet.

Vostok-1 rocket at launch carrying Yuri Gagarin on his single orbit of the Earth. The current Soyuz rocket is a direct descendant of the R-7 used for Yuri Gagarin’s flight and the Soviet’s first ICBM.

The Vostok capsule upon landing. Gagarin was ejected from the capsule at 7 kilometers altitude to land with his own parachute rather than trying to survive a rough hard earth landing in the capsule.

Yuri’s Night logo

04/12/2016 – Ephemeris – Can you tell the Jovian moons apart without a program?

Ephemeris for Yuri’s Night, Tuesday, April 12th.  The Sun will rise at 7:02.  It’ll be up for 13 hours and 21 minutes, setting at 8:24.   The Moon, 1 day before first quarter, will set at 2:22 tomorrow morning.

It’s the 55th anniversary of Yuri Gagarin’s flight as first human to orbit the Earth.  Speaking of orbits, we can see Jupiter’s 4 largest moons orbit that planet in small telescopes.  Their orbits are nearly edge on to us, so they seem to move back and forth from one side to the other of the planet in pretty much a straight line.  So how can you tell them apart without a reference?  The four moons from Jupiter in order are Io, Europa, Ganymede, and Callisto.  They are not normally arranged like that.  Ganymede is the brightest and Callisto the dimmest, and is usually the farthest away.  Io is usually the closest appearing and has a slight reddish hue due to its sulfurous volcanic surface, and Europa is the dimmer moon close in to Jupiter.  Io also can be seen to noticeably move in an hour.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

One of my old pictures of Jupiter. Callisto is obvious from its far left position and dimmer brightness. On the right, the farthest is Ganymede due to its brightness and position. Inside of it is Europa, again, dimmer than Ganymede and inside position is probably Europa. That leaves Io, which may be trying to duck behind Jupiter, as a bump in the left edge of the planet.

Jupiter and its moons as simulated by Cartes du Ciel for tonight, 10 p.m. April 12, 2016. The bodies, from let to right are Ganymede, Callisto. a background star, Jupiter, Io, and Europa.