Mercury at Inferior Conjunction

orbital-positions   Wednesday December 13th the innermost planet Mercury reaches inferior conjunction. At inferior conjunction Mercury will move between the Earth and the Sun – much like the position of the Moon at new phase. The graphic to the right shows the planet positions relative to the Earth and Sun for both inner planets and outer planets.

   While at this inferior conjunction Mercury will not be directly in line with the Earth and the Sun – on the ecliptic. Mercury has an orbital inclination of 7o with respect to the ecliptic. So like our Moon, Mercury during each complete orbit, will cross the plane of the ecliptic moving north (ascending node) and also moving south (descending node). For this inferior conjunction Mercury will be north of the ecliptic.

   
   
   

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.

Taurus Sniffs the Moon!

   Saturday evening November 2nd the 14.5-day old waxing gibbous Moon (full Moon tomorrow) will be a couple of degrees from the reddish star Aldebaran in Taurus the Bull. Aldebaran is at one end of a v-shaped open star cluster, the Hyades, that makes up the face of Taurus. Because of its reddish color it has been described as the angry eye of the bull.
   Normally the Hyades are a great view with binoculars as is the Pleiades, another open star cluster that is often described as a ‘baby dipper’.

   
   
   

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 Sagittarius

  According to the pseudoscience of astrology the Sun enters the constellation of Sagittarius the Archer on Wednesday November 22nd. When in fact the actual position of the Sun is still within the boundaries of the constellation of Libra the Scales.

   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.

2017 Summer Solstice on Mars

A Martian Year

A Martian Year – at One Earth Month Intervals

   Monday November 20th is the summer solstice on the planet Mars as the planet transitions from spring to summer during its 684 Earth day orbit around the Sun. 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 11 April, 1955 as 0 degrees for year 1 of this Martian calendar. What this means is that on Monday November 20th, Earth time, it is the start of summer for year 34 using the aforementioned calendar system.

Year 34
0 degrees — Spring Equinox — May 05 2017
90 degrees — Summer solstice — November 20 2017
180 degrees — Fall Equinox — May 20 2018
270 degrees — Winter Solstice — October 16 2018

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 07 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 Journey to Mars web site.

   
   
   

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 Conjunction with Mars and Spica


   Tuesday morning November 14th the waning crescent Moon will be within a few degrees from the ‘Red Planet’ Mars and the bluish-white star Spica in Virgo the Harvest Maiden. Then as this animated graphic illustrates the waning crescent Moon will pass by Jupiter and then Venus over the next few days.

   
   
   

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.

Venus – Jupiter Close Conjunction

   Monday Morning November 13th the inner planet Venus and one of the outer planets, Jupiter, will have a very close conjunction with Venus coming within less than one-half degree from Jupiter. Adding to the celestial scenery is the planet Mars and the 25-day old waning crescent Moon.

   Both should make for a striking view with binoculars or a low-power telescope eyepiece, or as a picture. Venus will be shining at a -3.9 apparent magnitude compared with Jupiter’s -1.7 apparent magnitude.
This graphic shows a view using a 25mm eyepiece on a 6″ Dobsonian 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.

Jupiter at Solar Conjunction


Thursday October 26th the planet Jupiter reaches conjunction with the sun, in effect behind the sun as we view the two from Earth. Jupiter will reappear later next month in the morning skies rising before the Sun rises.


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.