Updated May 20, 2019
As dusk proceeds these May evenings the first star to appear is Sirius, which is getting very low in the west southwest as of this writing and is about to fade from view. The other constellations of winter are doing the same as, one by one, they fade into the evening twilight. Mars is the only planet out at dusk, appearing to the right of the feet of Gemini. It appears far below and slightly to the right of Pollux and Castor. Bright Capella is getting lower in the northwest while Vega shines well up in the east northeast, leading the Summer Triangle up from the eastern horizon. Deneb is the next corner star to appear (it is very low in the northeast as it gets dark, depending on your latitude), followed shortly by Altair.
The Constellations of Spring are starting to slip toward the western horizon, being nearly overhead at nightfall. Leo the Lion is one such constellation, beginning to tilt down toward the western horizon on its way to exiting the sky later in the summer. Regulus is the brightest star of the constellation, leading much of the pattern across the sky. It marks the bottom of the backwards-question-mark-shaped asterism, known as the Sickle of Leo, which also includes bright Algieba, a nice telescopic double. Behind Leo is Virgo, the brightest star of which is Spica. Spica is nearly due south and forms the bottom of a gigantic asterism, the Diamond of Virgo, which involves five constellations. Upper left from Spica is bright Arcturus; almost the same distance but upper right of Arcturus is fainter Cor Caroli, the brightest star of the constellation Canes Venatici. Take the same distance but go lower right (all this assumes you are facing south) and you will reach Denebola, the easternmost bright star of Leo. This is an asterism that is 50 degrees tall and is found nearly due south at nightfall.
The Moon was Full on May 18 and is now a waning crescent rising several hours after sunset. It just passed Jupiter and will go past Saturn May 22-23. Jupiter now rises before 11 pm local time as it moves closer to its June 10 opposition, with Saturn following about a month later, on July 9. Jupiter is found in Scorpius and Saturn sits in Sagittarius. The next bright planet to appear is Venus, which is very low in the eastern sky one half hour before sunrise. Binoculars would help find this object.
Go to https://www.skyandtelescope.com/observing/sky-at-a-glance/this-weeks-sky-at-a-glance-may-17-25/ where you will find the current “Sky at a Glance” (currently for the week ending May 11). There are lots of links to interesting news stories and additional observing projects for those who are interested. Last January’s total lunar eclipse featured a meteor impact flash seen and imaged widely. This event took place just as totality was getting started. One of the many imagers, Nicolas Lefaudeux, posted his images to his website. These images feature realistic views of recent total lunar eclipses as well as the meteor impact flash and other types of images. A nice montage of the total lunar eclipse was assembled by Doug Holland, it can be viewed at this website.
Due to construction of the observatory addition we have not been able to do any further work on the solar observatory telescope. Once this project is complete, the Prairie View Observatory Complex will house 3 domes, including the existing Solar Observatory, and two new domes. For updates on this progress check out https://www.pvamu.edu/pvso/cosmic-corner/project-summary-2/. Also, more information and images about the expansion (along with the existing Solar Observatory) at https://sites.google.com/view/saganti-astro/home. The two new domes will house our Meade 16-inch advanced telescope and a new 0.6 meter (24-inch) PlaneWave Corrected Dall-Kirkham telescope. The design features these two domes situated east and west of a visitor’s center, which is immediately north of the existing Solar Observatory. First light for the new observatory could happen as early as Spring 2019. Keep checking back for updates.
Juno, the spacecraft, continues to send back spectacular images. You can find them at https://earthsky.org/space/juno-spacecraft-image-nov-2018-eichstadt-doran and https://www.missionjuno.swri.edu/junocam/processing?ob_from=&ob_to=&phases%5B%5D=PERIJOVE+15&perpage=16. Juno has been approved to continue orbiting Jupiter until at least July 2021. For more information about this mission in general visit www.nasa.gov/juno. You can also visit http://www.cnn.com/2016/06/30/health/juno-jupiter/index.html which has some additional interesting facts about the mission.