Moon in Conjunction with Saturn



   Thursday May 31st and Friday June 1st the just past full Moon, a waning gibbous Moon, will pass by one of the four the ringed planets, the planet Saturn. Both rise after sunset local time and will be over the western horizon before sunrise the following morning.

   
   
   
   
   
   

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 in Conjunction with Spica, then with Jupiter


   This evening, May 25th the 10.5-day old waxing gibbous Moon will be about 6-7o from the blue-white star Spica in Virgo the Harvest Maiden. Then, over the next 2 nights the Moon will continue moving eastward and will pass by the planet Jupiter. The Moon will be about 8-9o to the east west from Jupiter on the 26th, and less then 5o east from Jupiter on the 27th.

   
   
   

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.

It’s All About Exposure

   Last night after sunset I set out to try and capture a picture of Venus less then 1o from the open star cluster M-35, near the feet of the Gemini Twins. Additionally the first quarter Moon was within about 1.5o from the star Regulus, the ‘heart’ of Leo the Lion, and also easily seen as the bottom of the backward question shape this constellation is best known for. Since my western skies are illuminated by the lights from an athletic field, and the eastern suburbs of Kansas City, MO. the limiting magnitude is around 2 or 3, meaning that the dimmest stars easily seen in that direction have to be at least 3rd magnitude or brighter. So with that in mind I took over 60 pictures with various camera settings but the skies were just too bright to capture the light from the stars making up M-35.

   Then I turned my attention to the Moon and Regulus. Regulus was close enough to the Moon that it’s light was nearly washed out by the Moon’s reflected Sun light. The difficulty of catching both has to do with camera settings. For example opening the shutter and increasing the exposure time washes out the Moon but allows Regulus to be seen.
   I use a Cannon Rebel EOS T7i with a touch screen allowing me to change settings very easily and see the effect in the change in real time.
   Camera settings: 300 mm; f/13; 1/40 sec.; ISO-400


   For this picture I increased the exposure time but left the other settings as they were. The Moon is larger in this picture because I zoomed in on the original before cropping it for this blog.
   Camera settings: 200 mm; f/13; 5 sec.; ISO-400

   
   
   
   
   

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.

It’s the Autumn Equinox on Mars

   Tuesday May 22nd is the autumnal equinox on the planet Mars as the planet transitions from 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. At the Martian spring equinox Mars is at 0o longitude.
   Each seasonal start/ending point is 90 degrees apart, but because of an elliptical-shaped orbit each Martian season is of varying lengths. Mars is at its greatest distance from the Sun, aphelion, before it reaches the Martian summer solstice when Mars is at 70o longitude. Perihelion, its closest to the Sun, is when Mars is at 250o longitude.
   Eccentricity of Mars and Earth for comparison.
Mars: 0.0934 – Earth: 0.0167

   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 Tuesday May 22nd, Earth time, it is the start of autumn of 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 22 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.

   Learn a little (or a lot) more about Mars at the NASA/JPL Mars Curiosity mission web site.
   Or read about the InSight mission currently on its way to Mars.

   
   
   

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.

Venus and Moon Are In Conjunctions

   Monday evening May 21st the first quarter Moon and the inner planet Venus will each be in their own respective conjunctions. Venus is within 1o from the open star cluster, M-35, located near the foot of Castor, one of the Gemini Twins. Venus currently shines with an apparent magnitude of -3.96, and at that brightness will outshine the 5th magnitude of M-35.

    Nonetheless the two should be visible with binoculars, as this graphic simulates, as well as a couple of 3rd magnitude stars nearby.


   Further toward the east, and unmistakable is the first quarter Moon. During the night hours the Moon, as it orbits eastward, will pass within about 1.5o from the star Regulus in Leo the Lion. Since Regulus is very close to the ecliptic there is a good chance that the Moon and Regulus will have a regular repetitive pattern or cycle of conjunctions. As in the months that Regulus is above the horizon, which include the next two months, June 18th and July 15th.

   
   
   

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 Really in Gemini

  According to the pseudoscience of astrology the Sun enters the constellation of the Gemini Twins on Monday May 21st. When in fact the actual position of the Sun on this date is still within the boundary of the constellation of Taurus the Bull, as this graphic and the banner graphic show.

   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 more observing information for this month.

May Moon at Ascending Node

   Sunday May 20th the waxing crescent Moon will be crossing the plane of the ecliptic moving north relative to the ecliptic. 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.

   On Sunday evening May 20th the 5.5-day old waxing crescent Moon will be just within the boundaries of Leo the Lion and about 14o west (right) from the ‘Heart’ of the Lion, the star Regulus.

   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)

Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

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 Venus


   Last evening, 17 May, the 2.5-day young waxing crescent Moon was in conjunction with the inner planet Venus.
   Canon EOS Rebel T7i: 163 mm; f/9; 0.8 sec.; ISO-400

   
   
   
   Canon EOS Rebel T7i: 135 mm; f/7.1; 0.6 sec.; ISO-400

   
   
   
   
   
   

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.

May Perigee Moon in Conjunction with Venus

   Our Moon reaches perigee, (closest distance from Earth), for this orbit on Thursday May 17th. At that time the Moon will be at a distance of 28.52 Earth diameters (363,800 km or 226,055 miles) from the Earth.

   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*

   Thursday evening May 17th, shortly after sunset local time (8:26 CDT), look toward the western horizon for a conjunction between a thin 2.5-day young waxing crescent Moon and the inner planet Venus. The two will be about 5.5o apart. The respective apparent magnitudes of Venus (-3.95), and the Moon (-10.22) will make an interesting contrast. Despite the difference in the apparent magnitude of Venus and the Moon, which one appears brighter? Do they appear to be similar in apparent magnitude, or brightness?


   Using binoculars the Moon and Venus will be seen as forming the base of a small triangle with the open star cluster, M-35 (apparent magnitude 5.5) forming the point of the triangle.
   (the size of Venus and Moon are not to correct scale and in this graphic have been enlarged for the image)

   *Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

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.

Sun Enters Taurus

view-from-earth-may   Monday May 14th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Aries the Ram and into the constellation of Taurus the Bull. This is the true or actual position of the Sun as opposed to the pseudoscience of astrology which usually has the astrological Sun one constellation ahead or east from the Astronomical Sun’s position.
   
   
   
   
   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.