A Tail of Two Comets

   April 1990 Comet Austin (1989c1) now getting brighter approaching naked-eye visibility.
   April 2020 Comet ATLAS (2019c1) predicted to brighten to naked eye visibility has now apparently broken apart.

   30 years ago, April 1990, I wrote the first of what was to become a continuing column about Earth and Space called Scope on the Skies for Science Scope Magazine. This is the Professional Journal for Middle School Science Teachers and is published by the National Science Teaching Association (NSTA)

   That April 1990 column, Comet Watch – “Comet Austin”, was about a potential naked-eye visible comet discovered by New Zealand Astronomer Rod Austin during December 1989. The comet was appropriately named Comet Austin 1989c1. The comet increased in brightness over the months following its discovery reaching around 4th magnitude and naked-eye visibility the following May of 1990.

   This month as Comet ATLAS (2019c1) was showing signs of becoming a bright comet it broke apart. This was reported a few days ago and the break-up has since been tentatively confirmed.

   
   
   

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April Perigee Moon is Super!

   Our Moon reaches perigee, (closest to Earth), for this orbit, on Tuesday April 7th. At that time the Moon will be at a distance of 26.98 Earth diameters, 221,772 miles (356,908 km) from the Earth.
   This separation distance between the Earth and our Moon is the closest perigee for the year making this full Moon a ‘super-Moon’.

   On the day of the perigee Moon the 14.5-day old Full Moon will be over the eastern horizon around mid-evening and about 7o from the blue-white star Spica in the constellation Virgo the Harvest Maiden.

   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*
   *Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   
   
   
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.


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Venus and the Pleiades – Miss it?

   Last night, April 3rd the inner planet Venus was in the middle of a 3-day cruise across the members of the open star cluster the Pleiades. This is a not so often occurring celestial event that requires a bit of coordination between the orbit of Venus and the location of the Pleiades. Every year Venus will be near the Pleiades but it is only every 8 years around the beginning of April that Venus will pass across the Pleiades as it is doing this year.
   Has your local weather has been like mine these past few days with overcast skies. Then last night “adding insult to injury”, we had sleet and ice ensuring that any view of the Venus and Pleiades would be limited to pictures on Twitter! This was the only picture I was able to get on April 1st as clouds were moving in.
   So if you did indeed miss it there is always a next time – 8 years from now on, April 3rd, 2028 you will have another opportunity as the graphics below show.


   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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The Moon and the Lion

   Saturday April 4th the 11.5-day old waxing gibbous Moon will be high above the southern horizon at sunset local time and the Moon will be about 4-5o from the heart of Leo the Lion, the star Regulus.

   If your skies are clear look toward the west for Venus to be very close, on the east side, of the open star cluster the Pleiades. Both will easily fit within the field of view of binoculars or a telescope with a low-magnification eyepiece.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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Venus and the Sisters

   This week will be one of those weeks of planet viewing that will be remembered. The early morning skies have 4 of the visible planets arranged along the ecliptic over the eastern to southern horizon. In the evening skies there is the inner planet Venus moving eastward away from the Sun and rapidly, at least in terms of orbital speed, toward the open star cluster the Pleiades. This is a group of several hundred stars bound together by their respective gravitational attraction, and is located on the shoulder of Taurus the Bull.
   Venus, as a planet closer to the Sun than the Earth, will move more each day than the apparent speed of the Sun, which is based on the Earth’s orbital speed of about 0.98o each day. Venus being closer to the Sun will move approximately 1.6o each day.
   So over the course of 2-3 days the planet Venus will move across the stars of the Pleiades as this animated graphic is showing. It is set for 1-day intervals from April 2nd to the 5th. As Venus moves across the stars it will make for a great view either through binoculars or telescope.


   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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March Moon at Ascending Node

   Tuesday March 31st the 7.5-day old first quarter Moon will be crossing the plane of the ecliptic moving north. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic. The ecliptic is actually the Earth’s orbit, and the Moon’s orbit is inclined about 6o from the ecliptic. So there are two node intersections, the ascending and descending nodes.

click on graphic to see it larger   While the first quarter Moon is at its ascending node further to the west, lower than the Moon, is the planet Venus. Over the next couple of days Venus will pass across the open star cluster the Pleiades.
  

   Does our Moon actually go around the Earth as many graphics show? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*
*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   
   

   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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Planets on the Move

   Sometimes there are opportunities to observe the visible planets as they move along their respective orbital paths. Right now is one of those times when there are visible planets in both the evening and morning skies. And they are arranged such that you are able to see, not directly, but over a day at a time you are able to observe how planets closer to the Earth or Sun move relative to planets further away.
   The inner planet Venus, by itself in the evening skies, will pass across the stars of the Pleiades as this animated graphic shows. It is set at 1-day intervals and goes from April 2nd-5th.
   In the morning skies you will find three planets, Saturn, Mars, and Jupiter close together over the southeastern horizon before the Sun rises. Keep an eye on Mars as it moves past the slower moving Saturn.
   Shortly before sunrise the innermost planet, Mercury, rises and will also be visible as this graphic set for March 31st shows.


   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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