Inner Meets Outers – In A Triple Conjunction

   Sunday morning February 28th the innermost planet, Mercury, and two of the ringed outer planets, Jupiter and Saturn, will be in a triple conjunction as Mercury moves eastward past Saturn and then Jupiter. Mercury will be about 3-4o from Saturn and about 2-3o from Jupiter.
   All three will almost fit within the field of view of binoculars and should make for an interesting contrast in apparent magnitudes however Jupiter (-1.97) far outshines Mercury (0.30) and Saturn (0.71).

   
   
   

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.

Moon on the Move – Always


   Over the next few evenings the waxing gibbous Moon will move eastward passing by the open star cluster known as the Beehive Cluster this evening and then in a couple of days, as a full Moon, will be close to the heart of Leo the Lion the star Regulus.
   While the Moon may be close to the open star cluster the waxing gibbous Moon with its considerably greater apparent magnitude will outshine the star cluster making it not visible. Wait a few days and then aim your binoculars or low power eyepiece for a better view.

   
   
   

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.

Sun Not In Pisces-2021


  According to the pseudoscience of astrology the Sun enters the constellation of Pisces the Fishes on Thursday February 18th. In fact the actual position of the Sun is still within the boundary of the constellation of Aquarius the Water Bearer, as this graphic shows. The Sun had just entered Aquarius 2 days ago.

   Read a little more about how astrology has the Sun incorrectly placed in a previous blog, and in another blog discussing the effects of precession.

   
   
   

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.

February Moon at Apogee

   Our Moon reaches apogee, (furthest from Earth), for this orbit, on Thursday February 18th. For this apogee the 7.25-day old waxing crescent Moon will be at a distance of 31.70 Earth diameters, 251,282 miles (404,400 km) from the Earth.

   On the date of the apogee Moon the nearly first quarter Moon will be high above the southern horizon and will be within a few degrees from the planet Mars.


   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 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.


Also Follow me and other great resources at Feedspot.

The Moon, Mars, and NASA’s Perseverance

   Thursday evening February 18th the 7-day old almost first quarter but still waxing crescent Moon will be about 3o from the ‘Red Planet’ Mars. Despite the -11.75 apparent magnitude of the Moon Mars, with an apparent magnitude of 0.75, will still be visible.

   
   NASA Perseverance is scheduled to land on Mars on 18 February 2021, at around 20 UT or 2 pm CST.

   
   
   
   
   
   
   
   

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.


Also Follow me and other great resources at Feedspot.

Moon – Uranus Conjunction

   Wednesday evening February 17th the 6-day old waxing crescent Moon will be about 3-4o from the outer and ringed Planet Uranus. While the Moon with an apparent magnitude of -11.5 will certainly be visible, Uranus with an apparent magnitude of 5.81 will not!

   
   
   

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.


Also Follow me and other great resources at Feedspot.

Eppur Si Muove


   February 15th is Galileo Day.
   Quoting Galileo, “and yet it still moves”, in reference to the Earth actually orbiting the Sun. So how to acknowledge his achievements and contributions to modern Science? Read on…

   Jupiter’s Moons
   One enjoyable pasttime is to observe the constantly changing four largest moons orbiting Jupiter. Sometimes known as the Galilean Satellites, they are: Io, Europa, Ganymede, and Callisto. Named after Galileo who made many observations of the moons and from these observations and other observations led him to question the Geocentric model of the solar system. These four planet-sized moons are visible as small bright stars on either side of Jupiter and depending on the time and date of viewing their arrangement around Jupiter is never the same as this animated graphic, set to 1-Earth day intervals, is showing.
   Recreate Galileo’s observations of the Galilean satellites through the use of an online simulation, the Java applet, Juplet. Input dates or times to see the position of the four Galilean satellites.
The Juplet will display the planet and the satellite configuration for the date and time on the computer, or you could easily edit the date and time, and after pressing the Enter key see a different configuration. To keep track of these changes the position of each satellite relative to Jupiter could be drawn on a data table similar to Galileo’s data table.

   This video, ‘Orbs of Jupiter’, was one of the videos I made for a live musical performance at the Gottleib Planetarium at Science City in Kansas City MO. The original videos were made for full-dome projection – this one has been flattened. Music was written by Richard Johnson and performed by Rebecca Ashe (Flute) and Cheryl Melfi (Clarinet). Live and pre-recorded Electro-acoustical sampling by Richard Johnson and Daniel Eichenbaum. The soundtrack for the video is from the live performance by Dark Matter.

   
   
   

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.


Also Follow me and other great resources at Feedspot.

Springtime on Mars!

A Martian Year

A Martian Year – at One Earth Month Intervals

   Four days ago, February 2nd, we ‘celebrated'(?) Groundhog Day where in the Northern Hemisphere if the groundhog sees its shadow there will be 6 more weeks of winter. Coincidentally on Saturday February 6th it is the spring equinox on the planet Mars as the planet transitions from its winter season to spring during its 684 Earth day orbit around the Sun. However there are no groundhogs on Mars! So there may be clear skies but given daily temperatures on the Martian surface to me it looks like spring time all the time, albeit rather cool!
   Seasons on Mars are marked by the planet’s heliocentric longitude coordinates using the position of Mars along its orbit around the Sun. Each seasonal start/ending point is 90 degrees apart, but because of its elliptical-shaped orbit each Martian season is of varying lengths.

   I’m not exactly sure why this particular date is used but by international agreement astronomers have selected April 11th, 1955 as 0 degrees for year 1 of this Martian calendar. What this works out to is that on Saturday February 6th, Earth time, it is the start of spring for year 36 using the aforementioned calendar system.

Year 35
0 degrees — Spring Equinox — March 23 2019
90 degrees — Summer solstice — October 08 2019
180 degrees — Fall Equinox — April 08 2020
270 degrees — Winter Solstice — September 02 2020

Year 36
0 degrees — Spring Equinox — February 06 2021
90 degrees — Summer solstice — August 25 2021
180 degrees — Fall Equinox — February 24 2022
270 degrees — Winter Solstice — July 21 2022

Learn a little (or a lot) more about the exploration of Mars at the NASA Explore the Moon to Mars website.

   
   
   

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.


Also Follow me and other great resources at Feedspot.

Mars at Eastern Quadrature

orbital-positions   Monday February 1st the position of the planet Mars, with respect to the Earth and the Sun, places this planet at what is called eastern quadrature. At that orbital position Mars, and actually any outer planet, is at a 90 degree angle from the Earth as this graphic shows, and the banner graphic at the top of the page shows. Think first quarter Moon as that is a fair comparison of the relative positions of Earth, Sun, and Mars.

   At this position Mars follows the Sun across the sky from east to west as the Earth is rotating, meaning that Mars rises after the Sun and then sets after the Sun. Mars, with an apparent magnitude of 0.45, is about 5o from the 5.8 magnitude Uranus.

   
   
   

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.


Also Follow me and other great resources at Feedspot.

The Twins Point the Way

   Wednesday evening January 27th the nearly full Moon, a 14-day old waxing gibbous Moon, will be about 6-7o from the star Pollux, one of the two twin stars of Gemini the Twins. The other ‘twin star’, the other brother, is Castor.

   Off to the west over the southern horizon are the planet Mars and Uranus. Further west is Neptune, and the Dwarf Planets Eris and Ceres. Earlier in the evening, after sunset local time the innermost planet Mercury is over the western horizon.

   
   
   

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.


Also Follow me and other great resources at Feedspot.