Podcaster: Rob Webb

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Title: Observing With Webb in May 2021

Organization: Physics teacher at Pequea Valley High School

Link: ; ;
follow me : @MrWebbPV on Twitter and Instagram

This podcast is found on: Podbean page, Stitcher, and iTunes.  There’s also a video version on YouTube Channel.

The Pequea Valley Planetarium and its events and updates are on Facebook, Twitter, and Instagram as @pvplanetarium.


A total lunar eclipse if you’re lucky, a great apparition of Mercury, and all the naked-eye planets visible make May of 2021 an action-packed month.

Bio: Rob Webb is a physics, astronomy, and sustainability teacher at Pequea Valley High School in Pennsylvania. His passions include teaching, astronomy, astrophotography, planetariums, running, reading, and golf. A proud graduate of Dickinson College in 2005, he also obtained a Master’s Degree in Science Education from Penn State University after conducting research in regards to the current state of planetariums in Pennsylvania. Feel free to contact him at

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A total lunar eclipse if you’re lucky, a great apparition of Mercury, and all the naked-eye planets visible make May of 2021 an action-packed month.

         Welcome to Observing With Webb, where a high school astronomy teacher tells you what you’re looking at, why it’s so cool, and what you should check out later this month…at night. 

Naked-eye PLANETS

Sunset – Mars, Mercury, Venus

  • Mars (W) – Look W after sunset to find the non-twinkling reddish-orange dot, much brighter than everything around it. Mars will move up through Gemini.  It starts off about halfway up the sky in May, and ends only about 15˚ above the horizon at the end of June. 
  • Mercury (WNW) – Pretty much visible all month, VERY low in the WNW after sunset.  You’ll need a clear horizon, but if there were a good time to find Mercury, this month is it.  Mid-May is perhaps the best time, since that’s when it’s highest in the sky, and a thin crescent Moon is nearby to help guide you (details later).  Or perhaps the 28th, when very bright Venus (300x brighter than Mercury) is about ½˚ away, making a great guidepost, even though both will be very low on the horizon.
  • Venus (WNW) – Starts its “evening star” appearance late in May, and stays around 10˚ above the horizon at dusk throughout May, never really getting more than 15˚ above the horizon this time around.

Throughout the night – None at the moment

Morning – Saturn, Jupiter

  • Saturn, Jupiter – The two gas giants are in the SE, getting higher and rising earlier each day.  Look SE in the morning (after 3am in the beginning of the month, after 12:30am by the end).  Jupiter will be on the left, with Saturn to the right about 15˚. 


Waning Gibbous (Mostly lit, rises later at night)

Last Quarter Moon – 3rd (Visible from midnight into the morning)

Morning Crescents (look East in the AM)

New Moon – 11th (darkest skies)

Evening Crescents (look West after Sunset)

First Quarter Moon – 19th (Visible until midnight)

Evening Gibbous (Mostly lit, after Sunset)

Full Moon – 26th (Visible all night)

May 3rd – 5thClose Encounter – Moon, Saturn, Jupiter – Before sunrise in the SE, between 3:30am and 6am EDT on these mornings, a beautiful crescent Moon will be passing by our two biggest gas planets.  On the 3rd, the Moon will be down and to the right of Saturn. On the next morning (the 4th) the Moon under and between Jupiter and Saturn, making a great triangle.  Then on the 5th, the crescent Moon hangs out just 7˚ below and to the left of Jupiter.

May 12th – 16thClose Encounter – Moon, Venus, Mercury, Mars – Each of the solar system’s terrestrial planets get a nice visual close encounter with our Moon this week.  Every night, get out there right after sunset and find yourself a good clear view of the WNW horizon. Each night, Venus will be the lowest and brightest planet, with Mercury just 8˚ above it, and dim, and Mars about 35˚ above the horizon in Gemini. On the

           12th: An extremely thin and barely visible crescent Moon will be less than 1˚ away from bright Venus, both VERY low on the horizon.

           13th: A slightly thicker Moon will now be just 3˚ to the left of Mercury, and considerably higher above the horizon.

           14th: A thicker and higher Moon will be directly between Mercury and Mars

           15th: The Moon will be 3˚ down and to the right of Mars

           16th: The Moon will be above Mars.

May 26thTOTAL LUNAR ECLIPSE – Missed it by THAT much!  East coasters will not really be able to see anything, however, the further West you are, the more likely you’ll be able to catch a glimpse of the partial portions of the eclipse.  If you want the best view, either go to the middle of the Pacific Ocean, or head to eastern Australia. More info here.

May 30th – June 3rdClose Encounter – Moon, Saturn, Jupiter – After 2am but before sunrise, go out and look SE for the Moon, Jupiter, and Saturn.  Each day, Jupiter will be the brightest point of light, with Saturn almost two fist-widths to the right.  The Moon creeps up to them from the right on May 30th, is closest to Saturn on the 31st, and then closest to Jupiter on June 1st.  The Moon then moves to the left of Jupiter for the 2nd and 3rd.


Use a sky map from to help you out.

After Dinner, Before Bed:

Leo, Big Dipper, Bootes – Leo will be high in the South, almost straight above you. It has a backward question mark with a right triangle to the left of the question. If you look above Leo, behind you and high in the sky, you should find the Big Dipper: seven very bright stars that form a spoon shape. Now if you take the handle of the Dipper, follow its curve to the next bright star you see, about 30˚ away, which is Arcturus. “Follow the arc to Arcturus.” That’s the brightest star in Bootes, which looks like a kite. Take that same curve, and follow it about another 20˚ to “speed on to Spica”, the brightest star in Virgo, one of my favorite constellations, since it reminds me of the Dickinson Mermaid.

Before Work:

Lyra, Hercules, Hercules Cluster – Look pretty much straight above you, and find the brightest star up there. You’ll notice a parallelogram attached to it. This is the brightest star Vega, part of the constellation Lyra, the harp. Next to that is a keystone shaped constellation called Hercules. On the right side of the keystone is a small cluster of stars known at the Hercules Cluster, which is a collection of hundreds of stars on the outskirts of our galaxy. Given how high it is in the sky right now, you might catch its faint fuzziness with your naked eye, but a set of binoculars or a small telescope will really help you see it.

End of podcast:

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