Astronomical League

The high altitude of the noon sun on the June solstice is due to the tilt
of Earth's Polar Axis

On June 21,
the northerly direction of Earth's axis reaches its maximum tilt towards the sun.

From the pen of the late Nicholas La Para of the Chester County Astronomical Society.

The daytime thin crescent moon
occults Venus

On June 17, 2026 ...
The thin crescent moon passes in front of – i.e., occults – Venus in daylight hours. The moon approaches Venus from its west. Therefore, its dark side blocks Venus first. Sometime later, Venus emerges from behind the moon's daylight side. This is its eastern side, or from an observer's earthbound perspective, towards the western horizon.

Observing Activity
1 Begin about 15 minutes before the occultation.
2 Situate yourself so that the sun is placed behind a building. Make sure that you can't inadvertently look at the sun.
3 Look about 2 handspans on a fully extended arm (4 fist–widths) east of the blocked sun.

On the day before the event, rehearse spotting Venus.

4 Use binoculars to scan the area.
5 Its location along the lunar rim depends on your location on Earth.
6 Depending on your location, Venus takes up to 30 seconds to completely disappear or emerge.

Venus should be easy to spot due to its high surface brightness. The moon, however, will be a more difficult target due to its washed-out and blued surface.

Disappearance Emergence
Boston 4:01 edt 5:09 edt
New York 3:54 edt 5:12 edt
Washington 3:49 edt 5:12 edt
Atlanta 3:40 edt 5:08 edt
Miami 4:07 edt 5:26 edt
Chicago 2:25 cdt 3:51 cdt
New Orleans 2:39 cdt 3:55 cdt
Minneapolis 2:15 cdt 3:38 cdt
Kansas City 2:14 cdt 3.41 cdt
San Antonio 2:27 cdt 3:25 cdt
Denver 12:56 mdt 2:19 mdt
Albuquerque 12:58 mdt 2:12 mdt
Salt Lake 12:46 mdt 2:06 mdt
Tucson 11:56 mst 12:56 mst
Seattle 11:41 pdt 12:52 pdt
San Franciso 11:34 pdt 12:45 pdt
Los Angeles 11:41 pdt 12:46 pdt

The early evening western sky June 16 & 17, 2026

The crescent moon passes Mercury and Jupiter, then Venus.

Look to the west 60 minutes after sunset on June 16 & 17.
• On the first evening, the crescent moon full with earthshine glows right of Jupiter and above Mercury. Use binoculars to positively spot Mercury struggling in the remaining twilight.
• Castor and Pollux will be almost lost in the twilight. Again, binoculars help greatly.
• The next evening finds a somewhat thicker crescent moon glowing above brilliant Venus.
• Binoculars reveal a hidden surprise. The Beehive Cluster, M44, is immediately below the moon on June 17.
• Two nights later, brilliant Venus crosses just north of the Beehive.

End your day with this captivating scene!

Beta Lyrae

Where is Beta Lyrae in the sky?

• On summer evenings, the bright star Vega shines nearly overhead. (It the fall, Vega lies high in the northwest.) It is the primary star of the small constellation Lyra. (It is also 0.75º wnw of M57, the Ring Nebula.)
• Stretching from Vega's southeast are four dim stars in the shape of a parallelogram.
• Beta Lyrae is the star at the parallelogram's southwest vertex.

Your Observing Project

• Viewing through binoculars helps greatly.
• Closely examine the brightness of Beta Lyrae each night for up to two weeks. Try not to miss a night. (Yes, weather is always a problem!)
• Determine its estimated magnitude by interpolating the stated magnitudes for Delta, Gamma, and Zeta.
• Construct a graph showing the brightness of Beta over the two week period.

What you are seeing

• Beta Lyrae A consists of two stars, A1 & A2, of unequal brightness and size. They are so tightly separated that a telescope can not split them.
• When the dimmer but larger star, A2, is off to either side of the brighter, A1, the system appears at its maximum brightness of 3.4 magnitude. (Positions 1, 3)
• As the dimmer star orbits in front of the brighter, their total magnitude drops to the deep minimum, because the dimmer star is partially blocking the brighter one. (2)
• Again, when the dimmer star is off to the other side, the system is at maximum brightness. (3)
• When the dimmer star passes behind the brighter one, it is partially blocked causing the system's brightness to reach its secondary (shallow) minimum at 4.3 magnitude. (Position 4)

A project to serve
the seeing impaired

by James Somerville Edgar, editor RASC Observer's Handbook

My blind friend, Christine in Toronto, asked me to create a sky map on my new carver showing the circumpolar constellations. Her husband Jason didn't know it then, but he was buying it for Christine's birthday in mid-March!

So I selected a nice piece of maple, laminated into a 15-inch square, and carved it for her. I put small brass screws into the brighter stars, for the tactile sensation. There is even one each for Alcor and Mizar. The brighter the star, the larger the screw.

Christine and I had a FaceTime session after she received the carving. She touched the carving while I described what she was feeling. She was "over the moon!"

Zubeneschamali
Libra's Beta star is its brightest.

To find Beta Librae:
• Locate 2.8 magnitude Alpha Librae (Zubenelgenubi) midway between Spica and Antares.
• 9º northeast – that is about the angular size of a fist-width on an extended arm – of Alpha is the slightly brighter 2.6 magnitude Beta (Zubeneschamali).

Star colors vary according to the surface temperature of the star. Blue-White is hottest with deep red being the coolest. While green wavelengths are emitted, they are not distinguished by the human eye because the eye is overwhelmed by the all the other wavelengths.

Carefully examine Beta Librae:
• View through binoculars or a small telescope.
• Slightly de-focus the star.

Astronomy with an Opera-Glass, Garrett Serviss

"... Beta has a singular greenish tint ..."

Olcott's Field Book of the SKIES

"Beta Librae is green in color. Early writers mention the brilliance of this star. Claudius Ptolemy gives it as equal to Antares. One of these two stars has possibly varied in light since ancient times."

Webb's Celestial Objects for Common Telescopes

"... its beautiful pale green hue, very unusual among conspicuous stars; deep green, like deep blue, is unknown to the naked eye."

Beta Librae Characteristics:
• Spectral class: B8 V,
• Color: Blue-white
• Surface temperature: 11,900 K

What color do you see?

If you can see only one celestial event this June,
see this one.

Brilliant Venus passes bright Jupiter

Look to the west-northwest 60 minutes after sunset in early June as the Venus/Jupiter gap narrows.

• On June 8, brilliant, unmistakeable Venus lies slightly below and right of the lesser Jupiter.
• The next evening finds Venus having moved slightly above Jupiter.
• Then on succeeding evenings, Venus pulls above Jupiter, while the mighty planet drops toward the horizon.
• Enhance the view by using binoculars.
• All the while, the much dimmer Mercury lies close to the horizon in the bright twilight.

End your day with this enchanting meet-up!

June 6, 2026 – 82nd anniversary of D-Day.

What was the moon's phase during D-Day and why was that so important?

Correct response:
A. The moon’s phase was roughly 6 hours shy of being full. That was important because
• it would provide a sufficient amount of light on the night of June 5 into June 6 for landing preparations to be made,
• moonlight would be bright enough to illuminate the countryside allowing gliders to land behind enemy lines,
• and the tides would be low during the estimated landing times and would remain low for a couple of hours. Low tide was about 5:20 a.m. and the next high tide was about 11:00 a.m.

When the landings began, the moon was low in the southwest near Antares. It set at 6:08 a.m., 10 minutes after sunrise, beginning the "Longest Day."