Category Archives: Astronomy

A Lovely Thing In The Sunset Sky Tonight

It was stunning – the pictures might have been a touch better if I had been able to grab a tripod, but given the last few days of panicking and packing, I’m not sure I could put my hands on a tripod in less than about an hour (or six) if my life depended on it. So holding my breath, being really still, bracing on the neighbor’s mailbox, and shooting a lot of pictures and hoping for one or two that didn’t suck will have to do for tonight.

The two-day old moon is on the left (370,557 km away), Venus on the right (225,892,785 km away).

The 6% crescent of the moon is illuminated by direct sunlight – the rest of the moon is illuminated enough by reflected Earthlight so you can see the dark mare areas.

With a better setup and a bit more magnification, you would see that both the moon and Venus are showing the same crescent shape and (to an excellent first approximation) the same percentage of illumination.

Angles! Geometry! Science! Math!

It’s also just very pretty, dangling up there in the twilight.



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ISS Pass, April 12th

Again there were some clouds, but having learned a couple of lessons yesterday…

Being later and darker, I went back to longer exposures. These are all five second shots, again combined with StarStaX 0.70. Part of the allure to tonight’s pass was the way it was going to be going right past Orion, which is clearly visible just to the left of center.

FYI, the stars aren’t misaligned or smeared because the tripod moved – they’re trailing because the planet moves! Over the course of these twenty-two exposures in 2:02 the tripod was reasonably still, the ISS rose in the lower right and headed toward the upper left, one of those 737s headed into Burbank crossed the upper right corner, and the planet I was standing on was rotating so that it appears that the western horizon in front of me is rising up to meet Orion. (Conversely we could think that we’re standing still and Orion is “setting” in the west, sinking down toward that horizon, but why be conventional?) If you blow the image way up, you’ll see that each of the bright start trails is also really 22 little lots in a line.

Having gone overhead up past Orion (and I notice that I once again bailed about three exposures too soon before moving the camera) I swung the camera off to the south and got in five more pictures before the ISS disappeared behind the coastal clouds.

Practice makes perfect. Now, if I just had some really dark skies I could try some really interesting stuff. I might have to leave Los Angeles behind to find those dark skies, though.


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ISS Pass, March 25th

It’s been a while since I did one of these, partially because the orbital mechanics haven’t lined up for evening ISS passes for a while over Southern California, partially because when they did it’s been cloudy, and partially because I haven’t had a whole lot of spare time available for any of this.

Tonight it was mostly clear, there was a nice pass, and I made time.

Again, using StarStax, a very nice freeware program, to combine multiple short exposures. I could do 30 to 60 second exposures, but with the light pollution they would be all washed out and way too bright to show the ISS trail. Instead, I take a whole series of much shorter exposures (these are all 3 seconds), firing the next shot off as soon as each one is done.

To track when an ISS pass is coming up (or other satellites) I use Heavens-Above, a wonderful website. (You should as well!) Here’s their map which you can match to the photos – rising in the west at the right, headed up toward the top left:


There she is! Coming up from the horizon in the west at the lower left, heading up through some passing clouds. Again, each “dash” is a three-second exposure.

One thing I need to work on is what the field of view is for the camera. These images could have fit into the previous field of view, but I thought that it might be moving out to the right, so I shifted the camera.

Another happy result from stacking the photos is the way it brings out the stars, even with the street lights and light pollution. The Pleiades cluster is just above the ISS’s track in the middle left, above the lens flare from the street light.

Of course, above LA there’s more than just the ISS moving overhead. Here the ISS was just above its apex and starting to sink back down toward the north-northeast. In the lower right of the photo you can see the distinctive “red-green-red-green-red-green-red-green-red-green-WHITE” pattern of an aircraft.

Moving almost due north, from our front yard we have another street light to deal with, and another plane way off to the north just starting to come up over the horizon.

And there she goes! Wave to the six astronauts and cosmonauts on board, Expedition 55! Check out the free available apps from NASA, ESA, and others, as well as sites like Heavens Above! Know when the ISS is coming over your area in the evening (or morning, if you’re one of those people) and see it for yourself!


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Someplace Special – March 13th

Southampton, England

“We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.” – Dr. Stephen Hawking

(People like me can understand how light diffracts through rain drops suspended in the air and can do the math to describe it. Well, I could at one point long ago. Stephen Hawking could understand how black holes warp the fabric of spacetime enough to radiate away energy and eventually evaporate – and do the math to prove it RIP, Dr. Hawking.)

(Read this thread to find out more about Hawking radiation in easy to understand terms.)

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I’ll be up late tonight, but not late enough to catch a little portion of the start of tonight’s “Supermoon Blue Moon Blood Moon” eclipse. For those of you on the North American west coast who are going to get up early – have fun….

I was out at the hanger on a late-night run earlier and did see this Pre-Clipse view as the moon was headed toward the Earth’s shadow (which would have been to the lower left of the moon I think, not that you could see it).

Those clouds might also be a good reason to not exactly hustle out of bed at 04:00. I’m thinking that not getting into bed until after 01:00 might be another excellent reason!

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Tiny Sliver Of A Moon At Sunset

It’s up there, about four days old. Just the tiniest sliver of a silver arc as the blues darken to black.

Which means that in about ten days, on January 31st, it will be full. And this full moon, not only will be a “blue moon” (i.e., the second full moon in a calendar month) but it will be a fully eclipsed moon! If you’re in western North America you’ll see it in the wee hours before dawn – in most of Asia and Australia you’ll see it after sunset. (Details here.)

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Full Moon & Christmas Lights

Okay, so the moon was only about 97% full. Close enough for government work!

It’s tough to find a balance…

..between the moon & the Christmas lights. The dynamic range is too large!

Up close and personal…

…it’s even worse. Overexpose the moon just enough so you can still see features, and you can barely tell there are Christmas lights to be seen here. But…

…pull in the Christmas lights and the moon is completely overexposed.

This is why composite photos are needed. Or you can get artsy-phartsy…

…and just go for something more abstract.

Time to post this before the electricity goes out. It is REALLY howling out there tonight, and it’s just a matter of time before the wind brings down a tree branch and we go dark!

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