Shallow Thoughts : : astro

Monday night: Tau Herculid Meteor Shower, Possible Storm

There's some talk that a usually obscure meteor shower, the Tau Herculids, may this year become a meteor storm.

For details, see EarthSky News: Will the Tau Herculid meteors produce a storm?

The Tau Herculids come from periodic Comet 73P/Schwassmann-Wachmann, which in 1995, began to break up, creating lots of debris scattered across its orbit. It's hard to know exactly where the fragments ended up ... but comet experts like Don Machholz think there's a good chance that we'll be passing through an unusually dense clump of particles when we cross 73P's orbit this year.

I'm not a big meteor watcher — I find most meteor showers distinctly underwhelming. But in November 2002, I was lucky enough to view the Leonid meteor storm from Fremont Peak, near San Juan Bautista, CA.

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The Sun is Spectacular Today in H-Alpha

A couple of years ago, Dave and I acquired an H-alpha solar scope.

Neither of us had been much of a solar observer. We'd only had white-light filters: filters you put over the front of a regular telescope to block out most of the sun's light so you can see sunspots.

H-alpha filters are a whole different beast: you can see prominences, those huge arcs of fire that reach out into space for tens of thousands of miles, many times the size of the Earth. And you can also see all sorts of interesting flares and granulation on the surface of the sun, something only barely hinted at in white-light images.

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Fiddling with JavaScript Astronomy: ThreeWorlds

I have another PEEC Planetarium talk coming up in a few weeks, a talk on the summer solstice co-presenting with Chick Keller on Fri, Jun 18 at 7pm MDT.

I'm letting Chick do most of the talking about archaeoastronomy since he knows a lot more about it than I do, while I'll be talking about the celestial dynamics -- what is a solstice, what is the sun doing in our sky and why would you care, and some weirdnesses relating to sunrise and sunset times and the length of the day. And of course I'll be talking about the analemma, because just try to stop me talking about analemmas whenever the topic of the sun's motion comes up.

But besides the analemma, I need a lot of graphics of the earth showing the terminator, the dividing line between day and night.

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MarsMap: What Features of Mars are Visible?

I've been working on my upcoming PEEC talk, Observing Mars at Opposition on October 16.

Mars' closest approach was yesterday, October 6, and the actual opposition will be next Tuesday, October 13.

So, wait, we've already missed closest approach, and the opposition will be over before the actual talk happens? Then why bother?

Fortunately, opposition is actually an "opposition season", not a single date. And for most people, the best part is a little past opposition.

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S is for Starlink Satellites

Monday was the last night it's been clear enough to see Comet Neowise. I shot some photos with the Rebel, but I haven't quite figured out the alignment and stacking needed for decent astrophotos, so I don't have much to show. I can't even see the ion tail.

The interesting thing about Monday besides just getting to see the comet was the never-ending train of satellites.

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Comet C/2020 F3 NEOWISE in the evening sky

Comet C/2020 F3 NEOWISE continues to improve, and as of Tuesday night it has moved into the evening sky (while also still being visible in the morning for a few more days).

I caught it Tuesday night at 9:30 pm. The sky was still a bit bright, and although the comet was easy in binoculars, it was a struggle to see it with the unaided eye. However, over the next fifteen minutes the sky darkened, and it looked pretty good by 9:50, considering the partly cloudy sky. I didn't attempt a photograph; this photo is from Sunday morning, in twilight and with a bright moon.

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Comet C2020 F3 NEOWISE in the Morning (and eventually, the evening)

I've learned not to get excited when I read about a new comet. They're so often a disappointment. That goes double for comets in the morning sky: I need a darned good reason to get up before dawn.

But the chatter among astronomers about the current comet, C2020 F3 NEOWISE, has been different. So when I found myself awake at 4 am, I grabbed some binoculars and went out on the deck to look.

And I was glad I did. NEOWISE is by far the best comet I've seen since Hale-Bopp. Which is not to say it's in Hale-Bopp's class -- certainly not. But it's easily visible to the unaided eye, with a substantial several-degree-long tail. Even in dawn twilight. Even with a bright moon. It's beautiful!

Update: the morning after I wrote that, I did get a photo, though it's not nearly as good as Dbot3000's that's shown here.

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Solstice Sun Dagger

Today is the summer solstice. Happy solstice!

When I was in grade school -- probably some time around 7th grade -- I happened upon an article in Scientific American about the Anasazi Sun Dagger on Fajada Butte in Chaco Canyon. On the solstices and equinoxes, a thin dagger of light is positioned just right so that it moves across a spiral that's carved into the rock.

I was captivated. What an amazing sight it must be, I thought. I wondered if ordinary people were allowed to go see it.

Well, by the time I was old enough to do my own traveling, the answer was pretty much no. Too many people were visiting Fajada Butte ...

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