Mars, Moon, and the Bees

Click on image to see full size.

Click on image to see full size.

   Monday morning, 2 September, look toward the eastern horizon and you will see many familiar stars and constellations as well as the planets Mars, Jupiter, and the very thin 26.6 day old waning crescent Moon. The stars and constellations, however, are those of the northern hemisphere winter evening skies and include the 6 constellations making up the winter hexagon asterism: Orion, Taurus, Auriga, Gemini, Canis Minor, and Canis Major.
Click on image to see it full size.

Click on image to see it full size.

   However, the focus right now is a little lower and above the eastern horizon. There you will find the constellation of Cancer the Crab. This sort of inverted Y-shaped star pattern is not only the current location for Mars and the Moon, it is also where you will find one of the best binocular or low power telescope eyepiece celestial objects. This is the open star cluster M-44, or more commonly known as the Beehive Cluster. Estimated to be about 500 light years distant the star cluster shines at a relatively bright 4th magnitude. This brings it just into the ‘seen as a fuzzy or smeared patch of light’ range.
   In my suburban location with the lights of the Kansas City metropolitan area mostly toward the west and north I am able to see M-44. This of course, is after being outside for a few minutes at least allowing the eyes to dark adapt. With my 10×50 binoculars or with the telescope I keep in my truck, a 4.5 inch reflector (Edmund Astroscan), M-44 looks great.

   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Moon and Star Clusters

Click on image to see full size.

Click on image to see full size.

   Before sunrise on Friday morning 30 August look toward the east for the group of stars and constellations making up a familiar part of the northern hemisphere winter skies. Part of this group, temporarily, is the waning crescent Moon as it works its way eastward. The Moon will be within the field of view of 7×50 binoculars from two open star clusters. M-35 is an open star cluster that is approximately 2800 light years distant and contains several hundred stars shining with a combined brightness of around 5th-6th magnitude.
   Just one-half degree from M-35 is the much fainter star cluster NGC-2158.
Click on image to see full size

Click on image to see full size.

This is a much smaller and fainter group of stars that are estimated to be around 11,000 light years distant and has an apparent magnitude of between 8 and 9.
   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Mercury Goes to Extremes

   mercury-aniToday the innermost planet Mercury reaches a point along its orbit around the Sun where it is more or less at a right angle from the Earth and the Sun, as the banner graphic at the top of the page shows. As viewed from above Mercury is to the right from the Sun, while from the backyard view on the Earth’s surface Mercury is also to the right from the Sun, or on its west side. This puts Mercury in the morning skies rising before the Sun rises and leading the Sun across the sky from east to west as the Earth rotates from west to east.

Earth, Inner Planets, and the Ecliptic

Earth, Inner Planets, and the Ecliptic

   From our backyard perspective we view the planets at more or less the same level because the 8 planets orbit the Sun on or close to the plane of the ecliptic, the Earth’s orbit extended outward from the Sun. So from this perspective the two inner planets appear to move back and forth, left to right to left, as they orbit the Sun. Today Mercury is at the ‘turning point’ on the right side of the Sun, which places Mercury at its greatest western elongation, or at its maximum angular separation from the Sun as seen from Earth. Today Mercury is approximately 20 degrees from the Sun. Due to its closeness to the Sun Mercury never gets more than around 30 or so degrees from the Sun which means that Mercury never rises or sets more than about 2 hours from the Sun. (The Earth rotates approximately 15 degrees every hour)

Click here to learn a little (or a lot) about the innermost planet Mercury from two MESSENGER web sites.

30 July - 5:30 am CDT

30 July – 5:30 am CDT

   While out observing Mercury look a little higher to the right for the planets Mars and Jupiter, plus some of the stars of the northern hemisphere winter season. While these two outer planets are also to the west from the Sun they do not have an elongation position as outer planets orbit the Sun beyond the Earth’s orbit rather than between the Earth and the Sun. Outer planets do reach a 90 degree angle relative to the Earth and the Sun but it is known as either east or west quadrature.

30 seconds worth of Mercury from the Orbit performance.

   
   Click here to go to the Qué tal in the Current Skies web site for more observing information.

It’s Aries Time

Along the Ecliptic

Along the Ecliptic

   At 5 p.m. CDT (22 UT) on the 18th, today, the sun in its apparent eastward motion along the ecliptic crosses the boundary between the constellations Pisces the Fishes and Aries the Ram as it enters the area of the sky containing the stars of Aries. This graphic shows the real position of the Sun on this date.
   The banner graphic at the top of this page shows a larger view of the area including the point, Vernal Equinox, where historically it was used to mark the starting point for the change of seasons from northern hemisphere winter to spring. This celestial position is referred to as the ‘First Point of Aries‘ even though the Sun is no longer at that position at the start of spring around March 20th. The shift of approximately one month is a result of a long term motion known as precession, or precession of the axis. precession circlePrecession is a wobble like motion the Earth has caused by the gravitational pull of the Sun and to a lesser extent, the Moon. The Earth leans at an angle of 23.5 degrees and over time, about 26,000 years the Earth wobbles and the poles of the Earth trace out a circle where any star on or near the precession circle will be the pole star.
   Another effect of precession, as the Earth wobbles, is that the celestial coordinate system, which is based on the Earth’s geographical coordinate system (latitude and longitude) moves or shifts toward the east with respect to the stars and constellations. The stars in the background stay fixed, more or less, in their location, while the celestial coordinates move as the Earth is precessing. The result is that several centuries ago the sun was in Aries at the start of spring, now the Sun is further west across Aries and has nearly precessed into Pisces.

      Click here to go to the Qué tal in the Current Skies web site for more observing information.

March 2013 Equinox

   Today is an equinox day meaning that for us in the northern hemisphere winter is ending and spring has sprung. For our counterparts south of the equator summer is ending and fall is beginning. From a geographical perspective we would describe the Sun as being over the Earth’s equator, and as this graphic shows there would be an equal amount of daylight and night on our planet as a result.
    At the equator the sun is directly overhead and from that latitude you have no shadow, just a ‘blob-like’ shadow at your feet as this picture of my feet taken at mid-day in Quito Ecuador shows.

    Regardless of your hemispheric preference get outside and cast a shadow!

  Northern hemisphere spring begins at 6:02 am CDT when the Sun reaches the celestial coordinates of 0 hours and 0 degrees as it moves northward along the ecliptic crossing the celestial equator. To learn more about the celestial coordinates click here to read a previous post about seasons and the equinox.

   Click here to see the online world sunlight map used to make the day/night graphic above.

sun-earth
   Click here to go to the NASA Sun-Earth Days web site.

   Here is a short series of hourly pictures taken during the day on the September equinox on the equator in Quito Ecuador at Collegio Menor San Francisco de Quito, a private school that I visited and did the SunShIP project with (Sun Shadow Investigation Project).

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Click here to go to the Qué tal in the Current Skies web site for more observing information.