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By Ben, on February 8th, 2010
5:17 a.m. Moon age 24d, 3h, 5m. Again had to boost the ISO to 400 to get enough exposure; images grainier than I’d like, but at least things are recognizable. Must explore webcam imaging.
The highlights of the moon at this stage are, from north to south, Philolaus, then la Condamine and Maupertuis, Sinus Iridum, Reinhold and Lansberg, Lubiniezky (the first time we’ve heard from him this entire month, showing what proximity to the terminator can do for an otherwise obscure crater!), Bullialdus, Campanus, Mercator, and Capuanus. The Palus Epidemiarum is right on the terminator, which makes this dark area stand out a little more than it does at other times of the mo-o-nth.
Enjoy!
By Ben, on February 7th, 2010
After several days in a row of getting up between 2 and 4 a.m. to get the moon as close to zenith as possible, I’m getting used to waking up at that hour. And that, ironically, makes it harder to get shots of the moon between last quarter and new, as it is now (Day 23 of the lunation). This morning my eyes flew open at 4:19 a.m. and, rather than risk going back to bed and sleeping through the better, later hour when the moon would be higher in the sky, I went outside and took a few shots.
The lower the moon is, the harder it is to get the exposure settings right; the fairly simple point and shoot exercise I’ve been indulging in over the last couple of weeks is gone. Every night until last night (that is, Day 22 and then this morning, Day 23) I had the camera set at ISO 64 (the slowest setting on the camera). This reduces the noise in the image as much as possible, so I can get the sharpest and clearest details. This morning, though, with the moon low in the sky (only 23° above the horizon!) and only 0.36 illuminated, I had to bump the ISO up all the way to 400 to get a decent exposure, even at the relatively slow shutter speed of of 1/30 sec. The slow shutter speed and the high ISO means that the image is noisier, which makes it look grainier.
But the resulting images were still good enough to have some fun with; this is the first time I’ve ever seen this phase of the moon, and it’s interesting getting acquainted with some old friends when the sun is coming at them from the sunset, rather than the sunrise, side.
Plato, in particular, looks dramatically different from any time I’ve ever seen it before. The center is entirely dark, with only the innermost edges of the eastern rim wall being lit up by the sun. I’m used to seeing this crater with the floor completely lit, playing the “count-the-craterlets” game. (I’d have to check my observing log for some years back, but I don’t think I’ve ever seen 5; seeing 4 (even 3) means you’ve got a pretty steady night that allows some good magnification, and most probably at least a 5″ scope. Not a single image of any of these over the past month has shown even one; a 60-mm scope with a point-and-shoot camera just can’t overcome the technical limitations. I might try adapting a webcam at some point and seeing if I can’t do better…)
Proceeding southward through the Mare Imbrium from Plato, we come to Timocharis and then Eratosthenes, both of which are illuminated similarly to Plato: dark floor, sunlit rim walls. Timocharis is slightly west of the sunset line, but Eratosthenes, like Plato, is right on the line.
Moving south from there, we come to the Mare Insularum, site of the Apollo 12 and 14 landings, with the submerged craters Parry and Guericke right near the sunset line; if you look closely you can make out Fra Mauro, a larger, even more submerged crater, just above and to the left of Parry.
Skipping over a few prominent craters, now, we come to the giant southern crater, Clavius, lit most dramatically right now, with the floor still in sunshine, but the two craters that impinge upon it in the east, Porter and Rutherfurd, in shadow.
I’m going to have to try to “sleep in” tomorrow morning. I’ll have to find that fine balance between letting the moon rise high enough to be visible and getting out early enough that I’m not shirking my duties as “morning dad” (morning mom being, in general, a sleeping mom)… The 5:30 a.m. moon will be at 24° elevation; I’ll have to hope that’s good enough. The boy’s almost always up by 6 a.m.
By Ben, on February 6th, 2010
This morning, after starting awake at 4:19 a.m. and staggering out to the backyard, I took what I think is the best picture of the moon I’ve made to date. And while I was out back rubbing the sleep out of my eyes, I discovered something that I had read about in books (and therefore “knew), but never really understood until it became part of my personal experience. (This happens to me a lot; book learning is great—says the Ph.D.—but nothing, I mean but nothing, makes book learning more real than actually having something you’ve read about in books happen to you.) This morning, I learned that the oft-repeated advice that “the seeing is better after midnight” is sometimes actually true. I was able to focus the digiscoping rig with ease, even though the moon was only 33° above the hypothetical horizon (I say hypothetical horizon because my actual horizon is probably around 25° thanks to the large ficus hedge in my neighbor’s backyard and the narrowness of my back yard).
This morning’s moon was about 10 hours past last quarter; yesterday’s cloudy moon was about 13 hours before last quarter. But today the sky was clear, and that made all the difference. (Well, not completely clear; I still had to wait about 20 minutes, taking frame after frame between clouds scudding by to get “the shot.”)
Tonight the craters of the southern hemisphere are arrayed along the terminator in almost an unbroken line. Starting roughly at the equator, there is Flammarion, Herschel, Ptolemaus, Alphonsus, Alpetragius, Arzachel, Thebit, Purbach, Regiomontanus, and Walter before the southern highlands get too crowded with small craters for the labeling to be legible. But it truly is an amazing slide from the equator down to 33°!
Making today’s moon map was a pleasure, today’s picture was so fun to navigate:
I’m still not confident I’ve got the craters in the north correct, which is why they’re not labeled on the map. Despite the fairly favorable libration, I just don’t have that area well enough imaged to be sure what’s where. Just one more of the mysteries of the moon for me; I hope to unravel it later.
By Ben, on February 5th, 2010
In an earlier post I went into the motions of the moon in some detail. Not the orbital mechanics, or even the libration; just the apparent position of the moon throughout the monthly cycle and throughout the year. If you recall, the first quarter moon near the March equinox is at maximum elevation above the horizon. Correspondingly, the last quarter moon near the March equinox is at minimum elevation above the horizon.
This morning we are about six weeks away from the March equinox. And at the time of the image below (3:50 a.m. EST), we were about 13 hours away from the time of official last quarter phase (6:49 p.m. EST tonight). So the moon was about 8 percent above the lowest it will get all year. Which means there is a LOT more of Earth’s atmosphere between us and it than there was two weeks ago, when the first quarter moon was about 8% below maximum elevation for the year, or last week, when the full moon was in about the same position.
See, that’s the funny thing about the lunar cycle: in some months, the full moon and first quarter moon (only 1 week distant in time) appear in hugely different parts of the sky. In October, for instance, the full moon is about halfway between mean and maximum elevation, while the first quarter moon is just about at minimum elevation. A graphic would be very helpful here, but I’m not skilled in computer graphics; there’s an excellent chart of all four major phases of the moon and their relative position above the horizon in Rükl’s Atlas of the Moon. There’s also a good explanation of lunar angles on the website of the Royal Astronomical Society of Canada. So until I figure out how to draw graphs on the computer, please use those resources.
[UPDATE: Today I learned how to plot graphs in Excel, export them to Illustrator, and create a .gif that, while not pretty, at least conveys a bit of the information I want you to see:
[End UPDATE]
Anyway, since the moon was so low above the horizon, that meant that I had to image through quite a bit of atmosphere to get this morning’s moon shot. Furthermore, there was a great deal of water vapor in that atmosphere, in the form of clouds. At no time did I get a good clear view, although the moon was technically “visible” for most of the time I was attempting to observe it. Saturn was also visible, by this bare definition, but not a single star could be seen.
The presence of all this moisture in the atmosphere had a bit of a scattering effect on the light; not only did I have to increase my exposure time to compensate for the lower light the moon gave off naturally (at only 0.57 illuminated), but I had to add time for its height above the horizon and the obscuring clouds. The results of which you can see below; I post the photo purely for the historical record:
I’m not even bothering to make a labeled map for this image; hopefully I’ll have better luck tomorrow. The reason I was excited to try today at all is that the moon is at maximum latitudinal libration for the month right now; its northern hemisphere is tilted toward us almost a full 7°, so I would have been able to see quite a bit of detail up there in that region. (The moon is also “fully tilted” in longitude, but since it’s the eastern limb, currently dark, that is tilted toward us, it’s rather less interesting to investigate.) Oh, well. Yesterday’s image is at roughly similar libration, so all is not lost.
Just for fun, I post below a completely unprocessed image (just rotated and cropped) so you can really see the effect of the clouds.
The exposure time was twice as long as for the “good” image, but details are still only barely visible, and the halo effect is quite intense.
Some days, it hardly pays to crawl out of bed early!
By Ben, on February 4th, 2010
The last week of the lunation is turning into a test of endurance. Waking at 3 a.m. to get moon shots is not ideal for those of us who have day jobs. On the plus side, though, I have upgraded to CS4 and am able to annotate the photos; I’m working on the backlog and will post updates as time permits.
This morning’s moon turned out fairly well, despite the vibrations from the passing train and the clouds I had to dodge now and then (fortunately it wasn’t the other way around; dodging trains is one thing, but vibrating clouds would really make we worry!):
This moon’s seas are rapidly disappearing. Crisium disappeared into darkness days ago; Mare Nectaris joins it in obscurity today, and Mare Tranquillitatis is so far gone (though still visible) that I didn’t even label it. You can still make out the eastern fringes of Mare Serenitatis, but you can tell that it’s next on the chopping block. A prominent system of wrinkle ridges (dorsa; singular dorsum) runs for nearly 500 km down the entire eastern side of Serenitatis. Formerly known (informally) as the Serpentine Ridge, this prominent feature of the third quarter moon has been subdivided and given individual names (who knew that real estate investors and lunar nomenclaturists had the same idea about subdivisions?). From south to north the components of the serpentine ridge are: Dorsum Nicol, after a Scottish physicist from the 18th Century, William Nicol (he invented the first device for obtaining plane-polarized light, the Nicol Prism); Dorsa Lister, after Martin Lister, the 17th-century British zoologist, and the first to propose a modern geologic survey; and the largest system of wrinkle ridges in the chain, Dorsa Smirnov, after a prominent naturalist from the former Soviet Union, Sergei S. Smirnov, about whom even Wikipedia knows very little.
One of the craters featured last night, Posidonius, is just barely visible today. Last night its eastern rim wall was shining in the sunset; today it’s the western wall that is being highlighed by the setting sun. At the southern end of Serenitatis, on the border with the Sea of Tranquility is the prominent crater Plinius, named after Pliny the Elder, author of the first-century encyclopedia Historia Naturalis.
Continuing south along the terminator we meet again with the prominent trio Theophilus, Cyrillus, and Catharina, and then the quartet Zagut, Lindenau, Rabbi Levi, and Riccius in the cratered highlands of the moon’s southern hemisphere. It’s easy for the astronomer at the eyepiece to get lost in this rugged terrain, which is part of the reason I’m taking the trouble to hand label each of these images. I figure after a month of this, I should be able to find my way around a little bit better!
By Ben, on February 3rd, 2010
The time between full moon and new moon really separates the careful, prepared astronomer from those like me. Anyone, given reasonable weather and a modest amount of time, can get images of the moon when it’s waxing; the waning moon requires much more effort and determination. Last night the moon didn’t rise until 11:06 p.m., when I am normally already asleep. Tonight, it’s not going to rise until after midnight (so technically, it’s not going to rise at all tonight!).
To be able to capture successful images of the waning moon requires not just patience, but preparation as well. I have 14 images taken this morning between 4:24 and 4:30 a.m., but because I went to bed last night without putting my SD card into my camera, I can’t get them off the thing until I find the special USB cable that Nikon cleverly provides with the P5100: smaller even than the “normal” small USB cable head, so no generic that you have lying around your office will work. And furthermore, when you have an SD card in the camera, you can’t read the internal memory of the camera, so you can’t transfer the photos from the camera to the card the way you’d expect to be able to.
Not only that, but if you put the SD card in before trying to read the camera’s internal memory, you’ll have a heartstopping few minutes confronting the message “Memory card contains no images,” and you’ll think all of this morning’s work with the 19-day-old moon will be lost! Fortunately, you’ll probably think to take the SD card out and check the playback feature again, and you’ll discover that you just have to find your d@^~ USB cable before you can see them on the big screen.
But they’ll be great. I promise!
[UPDATE]: RTFM! I just discovered that you don’t need to use the USB cable after all; all you have to do is transfer the pictures from internal memory to the SD card. In fact, the camera’s user manual specifies that for those users foolish enough to use Windows 2000 (which I am not)
To transfer pictures stored in the camera’s internal memory to the computer, the pictures must first be copied to a memory card using the camera.
Which implies, of course, that even if one is not a Windows 2000 user, one CAN copy the pictures to a memory card from the camera; you just have to find the pages in the manual that explain how to do this: 75, 115, and 119. (One of the most frequent complaints about the menus on Nikon’s P&S cameras is how difficult they are to navigate; most users simply find one or two settings they understand, and memorize the ridiculously complicated steps to get there, and forget about the rest of the camera. Suffice to say, I am like most users in this regard, and had no idea that it was possible to copy from internal memory to SD card until I’d read the manual trying to figure out how to do it.)
So, without further ado, here is this morning’s photo of the 19-day-old moon.
The Mare Nectaris is prominent in the southern portion of the moon, with the large crater Fracastorius beginning to take on some shadows. This is an interesting crater, the northern half of which appears to have been swallowed up by the lava flows that created the sea of nectar in the first place; the tops of the rim peaks can still be seen, but all their relief is “underwater,” so to speak. Obviously, then, the crater predates the mare here.
On the northwest edge of Nectaris is the large crater Theophilus; to its east is the small but prominent crater Mädler; continuing east-northeast from there we come to the pair of craters Isidorus and Capella before disappearing into the irregular shadows of the terminator. The terminator is not a clean sharp line here because the terrain is so mountainous; the sun is still poking through the crater rims and valleys to the west.
Jumping quite a ways north, we come to the Mare Serenitatis’s version of Fracastorius, the “ruined crater” le Monnier, which forms a small bay in that larger sea. Just north of le Monnier is the large prominent crater Posidonius, whose eastern rim wall is lit rather brightly by the setting sun, although the shadows behind it (to the east) indicate that the wall is not particularly high. Indeed, Posidonius appears to be mostly a sunken crater, although its eastern portion appears to be substantially more “above ground” than its western side.
One effect of the setting sun that I find quite striking in this photo is the brilliance of the eastern rim of the Mare Imbrium; the Appenine, Caucasus, and Alp ranges are lit up quite nicely with this sun angle, making sunset over this region at least as interesting as sunrise was. The small (only 33 km in diameter) crater Calippus stands out quite nicely in the area between Imbrium and Serenitatis, nestled in the middle of the Caucusus mountains, just to the east of the highest peaks of that range.
The brightest feature in the image is the extraordinary crater Aristarchus; even though it is “only” 40 km across, it is classified as a large crater. It is the brightest large crater on the moon by far, and just about the brightest feature at all; it is assumed to be one of the youngest visible features of the moon, older than Tycho, but, at 450 million years or so, still quite young, considering that the impacts that created most visible features of the moon STOPPED occurring at least 3 billion (that’s three thousand million) years ago!
By Ben, on February 2nd, 2010
Well, today I ran into the problem of how to name the moon. I had started off calling this series “January moon,” but that of course makes no sense now that we’re already two days into February and we’re only on Day 18. (Lunations run from new moon to new moon.)
I suppose this has to be considered the Winter Moon, since December’s second full moon (on December 31) was the Christmas moon, with the first full moon of December (on the second) being the so-often-wondered-about Blue moon.
So, here on February 2, 2010, is the Day 18 moon, waning gibbous phase, 0.86 illuminated:
The two most prominent craters from this morning’s image are Atlas (the larger one) and Hercules (the smaller one) near the advancing sunset line, just above center. Two maria, Serenitatis and Tranquillitatis appear at right, with the large crater Posidonius fairly prominent on the eastern edge of serenity. The prominent crater roughly at center right in this photo (which is not aligned correctly, as I am STILL waiting to get my photo editing tools installed correctly) is Macrobius.
Far to the south is the prominent grouping Janssen-Fabricius-Metus. Jansen is the largest crater, with a new, smaller crater (Janssen A) placed so that their northeast rims are almost contiguous in this photo, although seen in greater detail, the issue becomes fuzzier.
I consider the fact that I got any usable moon photo at all today, after 1.5 inches of rain last night and solid cloud cover most of the night, something of a triumph!
Just for comparison, here is the 11-day moon, which is also 0.86 illuminated:
As you can see, the terminator was advancing toward the western limb on day 11, bringing daylight to the western edges. In today’s image, though, the terminator line is encroaching on the visible face of the moon, spreading darkness from the eastern limb. In fact, the Mare Crisium is already dark. While today we’re watching sunset on Atlas, Hercules, and Macrobius, back on Day 11, it was all about sunrise on Herodotus and Aristarchus; Gassendi had already had its dawn and was becoming less and less prominent.
How far we’ve come in just seven days, with twelve more to go in this lunation!
By Ben, on January 31st, 2010
Tonight’s moon will not be visible from my location.
The clear sky clock (cleardarksky.com) is showing solid white (meaning cloud cover) until 1900 hours tomorrow night:
And weather.com is showing me just how serious the situation is:
I don’t think the cloud cover actually stops at Cuba; they just don’t have images from that far south in the data.
This is why astronomers build libraries: to have something to do on cloudy nights!
By Ben, on January 30th, 2010
Tonight the terminator starts sneaking across the face of the moon again, only this time the night side is advancing: the sun is setting over the features that we saw as a thin crescent two weeks ago.
There’s a bit of color in tonight’s image, because it was shot while the moon was still fairly low over our horizon. Normally I try to let it get as high as possible, so there’s the least possible amount of atmosphere between the telescope and the moon; while that doesn’t always ensure good seeing, it’s usually a good strategy. But since I’ve been playing peek-a-boo with the clouds over the last few days, I’ve decided to take my shots where I can get them, to extend the streak for as long as possible. I doubt I’ll be able to get images through all 27 visible days of this lunation, but at least while the shooting is easy, I’d like to try!
By Ben, on January 30th, 2010
Last night’s moon (actually this morning’s, since the best break in the clouds came at 2:30 a.m.) reached full at 1:18 a.m. EST. I wasn’t awake to take its picture, but I woke up soon after full and discovered that, contrary to all expectation, there was a break in the clouds wide enough to permit some lunar photography. So voilà! The first full moon of a lunation that began in 2010:
Lest anyone doubt that the full moon is much brighter than nearly full moons, this images was made at 1/125 second exposure time, f/3.5. The previous night’s image was 1/60; tonight’s image (see next post, please) was also made at 1/60 sec, f/3.5.
And this full moon is brighter than most, because full moon happens to coincide with perigee (moon’s closest approach to Earth) this time around. That doesn’t happen every time. According to Spaceweather.com, this moon was 14% bigger and 30% brighter than the remaining full moons of 2010 are going to be. This is not a particularly infrequent circumstance; a striking example of the difference in full moon size at apogee (farthest from Earth) and perigee was featured in NASA’s Astronomy Picture of the Day back in 2007.
I apologize for the fact that I was unable to orient the image with the polar axis running vertically through the frame; I am still without access to my photo editing software. Apple’s “Preview” only allows me to rotate in increments of 90°. Hopefully I’ll have the situation resolved soon; at least my MBP is back up and running after its run-in with the tile floor!
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