Isn't that a whole lot easier to say than "Supermoon"? But seriously, if you want to know what's happening with this Sunday morning's full moon, the best article I've seen in a while is over at Sky and Telescope's website. The moon will appear about 7% larger than the average full moon, because it's going to be—get this—7% closer to us. 357 061 km, instead of the "average" 384 402 km. It will appear more than 7% brighter, though, because brightness varies with the square of the distance. So, (384,4022 − 357,0612) / 384,4022 × 100 = 13% brighter. If the average lunar brightness at full moon is −12.74 magnitudes, then this Sunday's moon should be about −12.9. That's not a whole lot to write home about. If you want to do the math, go here. Another point to consider is that it's the start of summer, so we're near aphelion, when the earth is as far from the sun as it can get (the actual date of aphelion this year is July 5). That means that the light available for this June's perigee full moon to reflect back to Earth is slightly reduced from what it could be. On the other hand, when a supermoon (full moon at perigee) and perihelion (Earth at closest point to Sun) coincide, that's going to be one bright full moon! (Sort of. Actually, even a 30% difference in brightness is actually not all that noticeable to most people. Our eyes scale so quickly that such a relative difference is nearly imperceptible.) If you're curious, the next time these three events (full moon, perigee, perihelion) coincide will be January 1, 2018. That year the closest perigee full moon will occur on January 1, and Earth's perihelion occurs only two days later, on January 3, at 1 a.m.! So mark your calendar! In the meantime, I'll stay up late Saturday night with my camera, hoping for clear-ish skies to restart my full moon project, which got waylaid last October. Here's where it left off:
On the morning of the equinox, as I was fruitlessly attempting to capture an image of Mars near the waning crescent moon, I did manage to create a small mystery for myself with the digiscoped image of that crescent moon: Pythagoras and Babbage (the latter has sunken walls and a prominent crater overlying it to the 4 o'clock position), then the vast expanse of the northern Oceanus Procellarum, broken by the crater pair Herodotus and Aristarchus, with the fine wrinkled area called Vallis Schröteri between/above them. From there we continue south to the lonely Marius (lovely plurivocal name that; if you've not seen the Pagnol film, you really ought to, sometime, if you like old French movies), with an equally lonely Reiner to his lower left (SW). Reiner is situated near an interesting albedo feature (bright area) called Reiner Gamma, about which the moon master Chuck Wood has some interesting commentary. (In fact, after starting my research for this post, I noticed that the aforelinked LPOD photo mentions the very mystery feature I was looking up, so click the darn link!) At the bottom of the vast Oceanus Procellarum is the prominent crater Mersenius, which has a line of what look like mountains leading toward it from the northeast. These "mountains" are unnamed but appear to be part of the wall that surrounds the Mare Humorum, which is in shadow to the east (right). But what attracted my attention in this snapshot was how bright the left-hand side is. It's pretty hard to overexpose one part of the moon so much, while leaving the rest of it in relatively decent tonal values. When I zoomed in (click the photo; it's much better at larger sizes), I discovered that this overexposed region was a result of the bright ray system emanating from the western limb of the moon. I'd never noticed it before, and the feature responsible isn't really mentioned in the 1996 edition of the lunar observer's bible (Rükl's atlas), although it does appear in that book under the unassuming name Olbers A. Here is the portion of the Lunar and Planetary Laboratory's Quadrant map of the moon (1964) where the feature appears at far right (click the map for the full-size image, since the blog software helpfully "centers" the picture): It's a bit hard to see what I'm talking about from that shot, so here's a close-up of that close-up (again, click the image): The IAU, apparently in recognition of the prominent ray system visible under day 25–like illumination, decided in 1993 to give the crater a name of its own, rather than have it be "the closest crater to the already-named Olbers." The name they came up with was Glushko. Rükl's atlas from 1996 must have been prepared without updating to current nomenclature, because despite the fact that this name change dates back to 1993, this 1996 edition (published in 1990 in the author's native Czech Republic) continued to call it Olbers A. I'm happy to report that the 2004 edition of the Atlas updates the name with the current IAU designation, Glushko. This crater is rather small (43 km diameter), but it has a prominent sharp rim. You can see just how sharp, and how interesting this crater appears, in this radar image, taken with radar from the famous Arecibo dish in Puerto Rico, with accompanying commentary by Chuck Wood. The melt texture to the north of the crater in that linked photo is really interesting; it shows how dynamic the process of creating the moon's impact craters really was!
Having a five-week old in the house guarantees that if you need to be awake at night to do something, say, take pictures of the full moon, you've got a pretty good chance. Of being awake, that is. Staying awake long enough to put the baby to sleep, get downstairs and outside with your camera and spotting scope, well, that's another story. But Sunday night/Monday morning I was able to pull it off, and here is the result: Rükl atlas, which is apparently out of print again. But the main apps I use to enjoy the moon are even more old school than that: my brain, my eyes, and my telescope. With those, I can do just about anything; with a digital camera and these brave new world apps, I can add to the experience, but they don't replace me bringing my sensory and cognitive apparatus into direct contact with the moon's image in the eyepiece. It's my thoughts/perceptions/enjoyment of the spectacular nature in the night-time sky that I'm after; the technology is just a way of accessing and enhancing those thoughts, those perceptions, that enjoyment. No matter how good they are (and they're good--really, really good), nothing beats that immersive experience of Going Outside.
A rare celestial event occurred early this morning, so I thought I'd try my hand at capturing some images. I spent about an hour making sure my telescope mount was as close to polar aligned as I could make it. I balanced the heavy scope on the tube and aligned the spotting scope, the one through which I would be taking the images, with the main scope, so the computerized alignment would proceed smoothly. I took a few practice shots of the full moon about 5 hours before the event would occur: full moon during the September equinox earlier this year, so I've had some good luck already with shooting the moon while it's been in sync with the seasons. Still and all, a lunar eclipse is a pretty exciting event to witness, so it would be nice to have a personal record of it... Imagine my pleased surprise, then, when my eyes popped open at 3 a.m., and I was able to get dressed and get outside in time to see the first lunar eclipse on the solstice in 456 years. Without all the prep work, there would have been no chance to capture any images at all. As it is, I got two barely usable shots:
The moon goes by many different names. Here are the moon names for August according to MoonPhase, one of my favorite lunar apps for my iPod (and iPad, but I'm consulting the iPod version because Someone Who Shall Remain Nameless drained the battery last night and didn't plug it in so it's recharging from the wall charger):
- August (Calendar Month)
- Dog Days (in Colonial American parlance)
- Sturgeon (Algonquin, which was the basis for the Farmers' Almanac moon names)
- Grain (English)
- Dispute (Celtic)
- Wyrt (Medieval wiccan)
- Lightning (Neo pagan).
It's been said so often, and not just by those who dabble in astronomy, but perhaps especially often among those who do: patience is a virtue. After waiting up two hours past my normal bedtime for the summer moon to come out from behind the clouds, she finally did:
This morning at 2 a.m. it was still over 80 degrees outside, and, it being 2 a.m. and all, I found it hard to focus. Not just mentally. Literally. See the picture below if you doubt me.What we have here is a fuzzy shot of the Summer Moon, taken on a warm and sleepless night here in south Florida. I only took the shot because I couldn't get back to sleep after giving Eric his middle-night bottle (he's sick. again. and needs his comfort food), for fear that tonight's Summer Moon (9:35 p.m. EDT) would be clouded out or too low on the horizon for me to shoot while I'm still awake, etc. etc. So it's an insurance shot, with strong hopes for a do-over, although the clouds outside my window right now make me glad I've got this one in the image bank, so to speak. So, a warm and fuzzy summer moon to you all, and I'll hope for a sharper image tonight.
Friday night/Saturday morning, I decided to put my 2 a.m. wakeup call* to good use and get a shot of the moon at close to full. Backyard astronomy at its best! The house is nice and cool these days, thanks to the a/c man and my suddenly light bank account, and the contrast between the cool and dry indoors and the hot and muggy out of doors was intense, even at 2:25 a.m. I thought I'd entered a sauna just by opening the door to the Florida room! There was a deep mist in the air, but not too dense; a few stars were visible overhead. And, playing peekaboo with some higher fluffier clouds, so too was the moon, just five hours before full:
Moon 5 hours before full, June 26, 2010, 2:28 a.m. EDT. 100% illuminated. Moon age 13d, 19h, 12m.I'm quite pleased to have gotten any shot of the moon at all, given the cloudy conditions. The libration was about 5 degrees east (nearly maximal), and 6 degrees north (again, fairly high, but not maximal). You can see about as far around the eastern limb as possible; you can see both the Mare Marginis and Mare Symthii poking their heads around the side:
Maria Marginis and Smythii peeking around the eastern limb near maximal elongation, June 26, 2010, 2:28 a.m. EDT.Or, you can just enjoy the fuzzy pictures. If you want to know the names of the other maria in the picture, they are, from clockwise, Crisium (top center), Undarum (the little teeny patch of darkness just below and right of Crisium), Fecunditatis (with the bright smudge of the crater Langrenus at the right (eastern) side), and Tranquillitatis. Here's the gallery of all the full moons in this sequence; only the first full moon of the astronomical year (Winter 2010, which happened in December 2009) is missing. (For the explanation of how the second full moon in the month of December 2009 is actually part of the Winter 2010 moon sequence, and is NOT a blue moon, try this post.)
Here at long last is last month's shot of the near full moon. Time, weather, and energy permitting, I'm still committed to posting at least one shot of each month's full moon in 2010.
Just past full moon, May 29, 2010. 2:18 a.m. EDT. Moon age 15d, 5h, 12m.This shot was taken a little over a day after the full moon (which was on May 27 at 2307 UT), but it still looks pretty full. The moon was at about 4 degrees eastern libration, and a little over 3 north. That is, the northern and eastern limbs were tilted very slightly toward us. You can tell the moon was past full, because the upper right corner of the moon is starting to show some shadow. Interestingly, the shadow is much more prominent in that upper right corner; it seems to peter out shortly after you pass the equator heading south. I've not quite figured out the geometry of that, but it's a fun puzzle. Some of the effect might be due to an optical illusion; the Mare Humboldtianum is in that NE corner, and the shadow from its far wall might be deepening the shadows in that area, while the southern limb, lacking this large uniform feature, isn't thrown into such high shadow. Anyone else out there have a better idea?
Jet lag from a recent trip to India combined with a cloudy night to make the blurry shot below the best one I could get of the full moon closest to the March equinox. Oh, well. Here, for the record, is the full moon from March 30, 2010, at 2:52 a.m.: