Perseid Report, Curiosity Spies Old Riverbed And Winter Arrives At Dawn

A fainter Perseid meteor (around 2nd magnitude) streaks above a line clouds lit by light pollution early this morning August 12. Details: 20mm lens at f/2.8, ISO 1250 and 45 second exposure. Photo: Bob King

It’s not much of a Perseid photo, but it’s all I’ve got to show from last night. Conditions were far from ideal in Duluth for the peak of the Perseid meteor shower. Lots of high clouds snuffed out the fainter meteors. Around 1 a.m. as rates were picking up, heavier clouds rolled in and I had to call it quits. How did you fare?

Not that there weren’t some great meteors – I saw 26 during about two hours of casual viewing; a couple were as bright as Jupiter and some came in pairs one right after the other. All were white or yellow and moved swiftly. Despite clouds, this rate seemed lower than expected.

The graph shows the zenithal hourly rate (ZHR) of the Perseid meteor shower. It spiked on Saturday afternoon (U.S. time) and stayed at a fairly high level into the night. It’s dropping off now as Earth moves out of the meteor stream. Credit: International Meteor Organization

Observers submitting reports to the International Meteor Organization’s Perseid website reported a maximum of 97 meteors per hour around 1:30 p.m. (CDT) Saturday August 11. For observers in North America overnight activity dropped to around 70-80 per hour. These numbers are what an observer would see under ideal dark skies with the radiant overhead. It’s known in the trade as the ZHR or zenithal hourly rate and determined by applying a mathematical formula to each individual’s meteor count.

Meteor shower watchers use the ZHR to standardize observations made by many different observers under different sky conditions. The actual number of meteors seen is nearly always lower, which is why you have to take meteor shower predictions with a grain of salt. By the way, you can still go out tonight to watch the shower. Numbers will be lower but the late-comers will still put on a show.

The moon and Venus, joined by Orion and Jupiter, will sparkle up the eastern sky tomorrow morning at the start of dawn. This map shows the sky facing east about 90 minutes before sunrise. Created with Stellarium

I finally turned in when the moon and Jupiter put a glow in the clouds to the east. Tomorrow morning if you’re willing to risk losing a bit of sleep, the moon and Venus will make a handsome couple at dawn. They’ll be joined by Orion – yes, Orion! – Aldebaran and the V-shaped Hyades star cluster next to Aldebaran. All the winter stars are on the move in the morning sky, itching to replace those of summer and fall. Watch out, snow will be here before we know it.

A part of the wall of Gale Crater north of the landing site shot with Curiosity’s high resolution camera. A network of valleys formed by water erosion long ago carved the rim. The main channel (labeled) looks like an arroyo or dirt road and is 11 miles away. Click to enlarge. Credit: NASA/JPL-Caltech/MSSS

Mission controllers have been uploading new software into Curiosity’s “brain” the past couple days to ready it for roving and geological exploration. On the first leg of its Mars journey, all it could “think about” was making a safe landing and shooting the first photos. Now that that’s been accomplished, it’s time for baby to walk.

One of the more interesting recent images from the rover shows a channel in the rocky rim of Gale Crater where water once flowed. According to NASA: “This is the first view scientists have had of a fluvial system – one relating to a river or stream — from the surface of Mars. Known and studied since the 1970s beginning with NASA’s Viking missions, such networks date from a period in Martian history when water flowed freely across the surface.”

We’ve seen these water-carved channels from orbit many times, but a ground level view makes it easier to imagine a Mars soaked with streams, lakes and maybe even an ocean.

12 Responses

  1. preciousgem

    Bob what about tonight or tomorrow night in southern California I thought tonight or Monday night was going to be the best nights to watch the meteor shower?.. like 60 per hour…your saying it’ll be slower and cloudiest tonight and tomorrow? And if we missed Saturday night and we want to go tonight or tomorrow what’s the best time my time you recommend???? The beach is fine place to watch? Thanks Bob and HAPPY BIRTHDAY!!! I’m a Leo too.. 🙂

    1. astrobob

      Early this morning was the predicted maximum but yes, there will still be meteors around tonight – just lower numbers. The best chance of seeing meteors is away from light pollution. A dark beach sounds ideal. You can go out anytime tonight to watch but later is better because the spot in the sky the meteors radiate from will be higher up. Try starting around 10 or 10:30 p.m. Oh yes – Happy Birthday!

  2. preciousgem

    Bob, this is some of information I’ve gathered as well from other sites, I wanted to share it with you and please I’m a little confused because I want to make sure I didn’t really missed this grand event I’ve been waiting for….please explain why other astronomers are saying this thanks Bob:

    On the nights of Saturday, Aug. 11 through Monday, Aug. 13, the best meteor shower of the year will fill predawn skies with hundreds of shooting stars. And that’s just for starters. The brightest planets in the solar system are lining up right in the middle of the display. The Perseid meteor shower peaks on the nights around Sunday, Aug. 12, as Earth passes through a stream of debris from Comet Swift-Tuttle. “We expect to see meteor rates as high as a hundred per hour,” said Bill Cooke of NASA’s Meteoroid Environment Office. “The Perseids always put on a good show.” Perseids can be seen any time after 10 p.m. to 11 p.m. The best time to look, however, is during the dark hours immediately before dawn.

    The alignment occurs in the eastern sky before sunrise on the three mornings of highest meteor activity. On Aug. 11, a 33 percent crescent Moon will glide by Jupiter, temporarily forming a bright pair directly above brilliant Venus. Red-giant star Aldebaran will be there, too, adding a splash of color to the gathering. On Aug. 12, the narrowing 24 percent crescent Moon will drop down between Jupiter and Venus. Together they make a bright three-point line in the sky, frequently bisected by shooting stars. On Aug. 13, with the shower just beginning to wane, the planets put on their best show yet: The 17 percent crescent moon will pass less than 3 degrees from Venus as Jupiter hovers overhead.

    1. astrobob

      As I explained in today’s blog those numbers are little “idealized”. One person looking up from a very dark sky under ideal condition might see 60 Perseids an hour at best. Most of us see closer to 30-40 per hour from say, suburban areas with far fewer visible from in or near a big city. Light pollution cuts the numbers down. I explained this in more detail in today’s blog. You missed the peak of the shower but there will still be Perseids out tonight – just a rough guess but you might see 10-15 per hour if your sky is fairly dark. And yes, the crescent moon will make a pretty sight near Venus tomorrow. Today’s blog has a map of what’s to see.

  3. Mike

    Counted 45 from Wisconsin Point. 12-130am was when we saw the most. It was great tempature wise but those clouds put a damper on things.

    1. astrobob

      Because there were many other things to report on today and I had planned that for tomorrow. The event happens in the mid to late afternoon for observers who’ll be able to see it. Stay tuned.

  4. Richard Hoops

    Bob — Great site! Can you create an RSS feed? It would be a great way for people to stay up-to-date on your site without clicking on it every day.


    1. astrobob

      Hi Rich – I’ve got one RSS feed to another site. I’ll check into another. Take a look at your e-mail – thanks for your note.

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