About Bob Riddle

Currently: Retired from the physical classroom (May 2017) but not yet finished learning and teaching. Column Editor, Scope on the Skies - Science Scope Magazine (National Science Teaching Association); NASA/JPL Solar System Educator Program, and Solar System Ambassadors Program.

Waxing Crescent Moon – Mars Conjunction

   Friday evening March 19th look for the 6.7-day old waxing crescent Moon to be about 3o from the ‘Red Planet’ Mars, and about 5-6o from the reddish star Aldebaran in Taurus the Bull. All three should just barely fit within the field of view of 7×50 binoculars.

   
   
   

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.

A 3-for-1 Moon Event!

               Apogee – Descending Node – Conjunction with the Pleiades
   
Apogee Moon
   Our Moon reaches apogee, (furthest from Earth), for this orbit, on Thursday March 18th. For this apogee the 6.6-day old waxing crescent Moon will be at a distance of 31.77 Earth diameters, 251,841 miles (405,300 km) from the Earth.

Descending Node
   The 6.6-day old waxing crescent Moon crosses the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.

Conjunction with the Pleiades
   The apogee Moon, at nearly first quarter phase, will be above the western horizon and will be within a few degrees from the open star cluster the Pleiades. This should make for a good view with binoculars.


   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 return to bobs-spaces.

Birds of Galveston Island

   I like to hike and especially the higher the hike (not me!) the happier I seem to be. Less O2, or something in the way I am wired! I don’t know, but this past week my wife and I were at sea-level while staying in Galveston, Texas. Thus giving me an opportunity for a level, no hill, hike along the shoreline and inland.
   Along the shoreline we encountered mostly Sea Gulls – curious how they stand on one leg.
   From studying the area before we went there allowed me to find Galveston State Park and a series of trails amongst the salt-marsh wetlands about 0.5 miles inland from the shoreline. The state park is a habitat for a variety of land and water animals, but early in the morning there seemed to be more birds than during an afternoon visit.
   Other than the day walking along the shoreline the rest of the days had skies that were mostly overcast with thin clouds giving the sky a whitish bland coloring. All pictures were taken using a Canon T7i DSLR with a 250 mm lens and a variety of lens settings. Pictures have been zoomed in and cropped from their original 6000×4000 size to 1920×1280.
   Salt-marsh wetlands panorama looking toward the southwest


   
   
   

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 Enters Astronomical Constellation Pisces the Fishes

11 March 2014   Thursday March 11th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Aquarius the Water Bearer and into the constellation of Pisces the Fishes. 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.

Neptune at 2021 Solar conjunction

   Wednesday March 10th the outer ringed planet Neptune will reach a point in its respective orbit where Neptune will be on the opposite side of the Sun as viewed from here on Earth. Neptune, or any of the other outer planets (Mars to Neptune), dwarf planets, or small solar system bodies beyond the Earth’s orbit, will all eventually reach this position on the opposite side of the Sun known as solar conjunction.
   For the two inner planets, Mercury and Venus, when they are at a similar position on the opposite side of the Sun, they are at superior conjunction.
   
   
   

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.

Waning Crescent Moon – Saturn/Jupiter/Mercury Conjunctions

Tuesday and Wednesday mornings, March 9th and 10th, the thin waning crescent Moon wil be passing by the planets Saturn. Jupiter, and the inner planet Mercury. On the 9th the 26-day old waning crescent Moon will be about 3-4o from Saturn and on the 10th the 28-day old Moon will be about 4-5o and about 6-7o from Mercury.


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.

Earthkam Week

   Several times each year a down-looking camera on the International Space Station (ISS) is made available by NASA for making picture requests for the surface of the Earth. The camera is the Sally Ride Earthkam and as the blog title says, this is Sally Ride EarthKam Week. As these pictures, show our planet has a remarkably diverse surface.
   A popular thing to do is choose an orbital path and follow it across a part of the Earth you are interested in. Maybe where you live, a place you have visited or want to visit? Zoom in to see more detail, especially where the orbital path (the red one – for daylight), crosses. If satisfied click on the red line and make your request.
   Participating in the program requires registering so you can receive e-mail notifications of the next Earthkam week. I am registered as a classroom Teacher however any educator may apply. This would be great for Scout groups, or any other group interested in learning more about our planet, not to mention learning about NASA and its missions to Earth as well as off world endeavors.

                        Pictures from March 3-5 2021 Earthkam Week

   
   
   

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 at Southernmost Declination

click on graphic to see it larger   Our Moon does not follow a path with the Earth around the Sun that is parallel with the Earth’s orbit, the ecliptic. The Moon is tilted or inclined by approximately 5.14o from the Earth’s orbital path meaning that there are places where the Moon’s orbital path intersects or crosses the Earth’s orbital path, the ecliptic. At up to 3 times each month the Moon will cross the ecliptic moving south or north in what is called a node crossing – one ascending and the other descending.

    However with regard to the celestial equator, an extension of the Earth’s equator into space, the maximum declination for our Moon, as measured from the celestial equator, could be as much as about 28.64o either north or south based on the Earth’s axial tilt of 23.5o plus the Moon’s inclination angle 5.14o (23.5 + 5.14 = 28.64o).

    This month our Moon reaches a maximum southernmost declination of 25.2o on Sunday March 7th.

   
   
   

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.

Mercury at Western Elongation

   On Saturday March 6th Mercury, the innermost planet, will reach its orbital position known as greatest western elongation at 27.3o. At that moment Mercury, the Sun, and the Earth, would be arranged in something close to approximating a right angle as this graphic shows. Even though it sounds confusing, at western elongation for either Mercury or Venus the inner planet will be to the right of the Sun as we view them, meaning that at western elongation an inner planet rises in the east before the Sun rises. And at eastern elongation with the inner planet on the left side of the Sun the inner planet follows the Sun across the sky setting after the Sun sets.

   From our perspective the orbits of Mercury and Venus appear to move from one side of the Sun to the other – out to the left (east) from the Sun to eastern elongation, then reverse and move westward (inferior conjunction) between the Earth and the Sun to western elongation. From there the inner planet moves eastward going behind the Sun (superior conjunction) and eventually reappearing on the eastern side of the Sun for an eastern elongation. Repeat over and over – do not stop!

   Mercury is currently visible in the morning skies before the Sun rises. This inner planet is steadily moving past Jupiter after having passed by Saturn last week.

   
   
   
   
   

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 Dodges the Scorpion at Descending Node

   Friday March 5th the 22-day old last quarter Moon crosses the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.

   On the date of the descending node the 22-day old last quarter Moon will be over the southern horizon at sunrise local time, and about 3-4o from the reddish star Antares in Scorpius the Scorpion.

   
   
   
   
   

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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