A Taste of Celestial Winter in July

The dawn lunar crescent displays bright earthshine as it rises over Lake Superior near Duluth in July 2019. Earthshine is sunlight reflected from the Earth to the moon and then back to our eyes. Watch for a similar scene on Tuesday morning, July 6. Bob King

It may be different where you live, but someone turned up the heat this month. The air feels like hot breath, but sweeter, filled with delicious scents of green plants, pine sap and flowers. You know it's summer when the Summer Triangle unfurls across the southeastern sky at nightfall, and Scorpius drags his tail along the horizon. 

This is the view facing east-northeast about 90 minutes before sunrise on Tuesday, July 6. The moon and Pleiades should be well visible without optical aid. The Hyades cluster may require binoculars for a good view because it's lower in the sky. Stellarium

Most of us seek shade during the day. After the stress of sunlight departs at dusk, we slow our pace and open our senses to new sights and smells. I'll often stroll late at night when the temperature's dropped into the 60s, and the fireflies are active. As entrancing as evenings are, billowing heat returns in full force the next day along with its cargo of flies and mosquitos. Everything wants a piece of you when the mercury rises. 

If you're missing winter's slower pace and frosty chill, even a little, I have a remedy. Tomorrow morning, July 6th, a beautiful crescent moon will appear between two of that season's beloved star clusters, the Pleiades or Seven Sisters, and the Hyades. It's too hot to sleep anyway, right?

Looking like the curved blade of a scimitar, the moon will be just 3 1/2 days before new phase and shine a short distance below the Pleiades. For a good view, find a location with an open view to the northeast. You'll see them best starting about an hour and a half before sunrise. Although the clusters will fade in the growing dawn light, the crescent will remain visible until sunrise. Binoculars will provide even better views, especially of the clusters and earth-lit portion of the moon. 

Mercury stands about 5° high in the northeastern sky for the next week or two. It brightens during  that time from magnitude 0.2 to -1.0. Stellarium

If you stick around until 45 minutes before sunrise and have an unobstructed northeastern horizon, look for Mercury. Although not its best appearance of the year, it's not bad either. The planet reached greatest elongation from the sun on July 4th. Over the next two weeks it hovers about 5° high (three fingers held together horizontally at arm's length) 45 minutes before sunup. Find your local sunrise time here. 

On July 8th, an extremely thin lunar crescent will appear 4.5° to the left of the planet. On either morning, stream a little Christmas background music from your phone, and you might just feel the tingle of winter. If only for a moment.

Recently, Frank Timmes, the senior lead editor of the American Astronomical Society (AAS) Journals. interviewed me about my work for Sky & Telescope magazine. We talked about writing, making connections to the night sky and other fun astronomy topics. Since you might be interested in the discussion, which lasts a half-hour, I thought I'd post it here. Thank you for watching!