Wow, there’s a lot of cool stuff going on in the night sky this week. I can’t wait til this pattern of East Coast thunderstorms lets me see it! Let me give a quick rundown, in the order of my own particular interest and excitement. Your mileage may vary.
Mars at Opposition
Mars is back, and it’s making quite a show! Mars is at opposition (directly opposite the Sun) on the evening of Thursday, July 26 – so rising in the east just as the Sun sets. It is BRIGHT, about Mag -2.8, brighter than Jupiter, and in fact the brightest it’s been in 15 years! Part of its current brightness is due to an enormous, global dust storm enveloping the planet right now. While the rover Opportunity hunkers down (and we really hope it’s doing ok), all that dust is proving to be very reflective and giving the already bright Mars an overall brightness boost.
Unfortunately, this means that Mars, at its biggest, brightest, and closest, is also not much to look at – unless you really like dust clouds. Right now it looks an awful lot like Venus… shrouded in mystery. Hopefully the dust will settle down before we get too far away. In the meantime, pan your telescope west – Saturn is still high in the south, and Jupiter in the southwest. Venus will be in the evening sky for a while yet as well.
The Moon (Eclipsed for Some)
On Friday, the full Moon will be just to the east of Mars as they rise, almost together. For those who CAN see the Lunar Eclipse this month (by which I mean, almost everybody NOT living in the Americas), this will be special – ruddy Mars and an eclipsed Moon, right next to each other.
You may have seen news articles referring to this eclipse as the longest this century – and it will be, if you live in the Eastern Hemisphere. Regions from East Africa through to the eastern edge of India will have the best view. The long duration is due to two factors –
- The Moon is passing right through the center of Earth’s shadow, as opposed to out by the edge.
- The Moon is at apogee – its farthest distance from Earth – during the eclipse. This makes the apparent size of the Moon fairly small (what’s the opposite of “Supermoon”?) and so it will take longer to move through the shadow.
Totality begins at 19:30 UT, and ends at 21:13 UT. This is squarely in the middle of the day for the Americas, and the Moon is on the wrong side of the planet. By the time it rises on the US East Coast, beautifully pairing right next to Mars, it will be well clear of Earth’s shadow. Oh well.
This month’s full Moon is the “Buck Moon”, indicating the time of year when whitetail bucks start to show new antlers. (Alternatively, it’s the “Thunder Moon”, and given the weather pattern around my house recently, I don’t doubt it).
Comet Pan-STARRS (C/2017 S3)
It’s been a while since I’ve been able to go comet-hunting. C/2017 S3 (there are LOTS of Comet Pan-STARRSes) is a “new” one, at least as far as us humans know. It’s coming to us fresh from the Oort Cloud, coming into the solar system almost 90 degrees out of plane, from “above” the disk of the solar system. The farther north you are, the easier this is to spot. Everybody north of about 45 deg N latitude can see it almost all night long. Those farther south can see it in the early morning, before dawn.

NOT Comet Pan-STARRS, but one can hope…
As a new comet, we don’t know what to expect – but over the past few weeks, it has had at least two outbursts of dust and gas which has made it brighten significantly, and glow bright green. I was waiting for a weather window earlier this week, and lost my chance – brightness suddenly dropped back from binocular to telescope territory, and I missed it.
But it’s getting closer – Right now it’s near the bright star Capella, in Auriga, heading straight “down” northeast in the morning sky, into Gemini. Closest approach to Earth will be on Aug 7, so we’ve got a couple more weeks for it to brighten again. A day later, it will start to disappear into dawn twilight as it whips underneath the Sun’s south pole. Perihelion is on Aug 15. Detailed positions and projections can be found here. I’ll keep looking and keep you posted.
Delta Aquariids
This meteor shower peaks next Sunday, the 29th. It’s a dim shower, with a radiant south of the equator, and generally more easily visible from the Southern Hemisphere, AND its peak happens to coincide with a bright Moon this year. BUT, it comes from a diffuse cloud of debris that lasts for weeks, and despite its relatively low rate (20 meteors per hour), it has a tendency to produce some pretty significant fireballs that trail impressive ionized tails.
Something about the makeup of the dust in this cloud makes fireballs more prevalent than in the typical shower… so while we’re out looking at all the other goodies, don’t write off the chance to see an impressive meteor as well!
So, here’s to clear skies! Go grab a telescope, binoculars, a blanket, and go enjoy the sky this week – there’s a lot to take in!!
Get Out There
Troy
http://www.flying-squirrel.org