The weather has finally improved just in time for the last long weekend of summer and wouldn’t you know it – it’s full moon! As all (cynical) amateur astronomers know – if it’s clear, there must be a full moon.
Here is a photo I took from York Blvd. near the high level bridge tonight of the full moon rising above our fair city.
1:12am Well, it’s 1:12am and there are no moons. I gotta say, it looks pretty strange.
I can clearly see both Europa’s shadow and Ganymede in front of Jupiter through my small but mightly 80mm scope, and a wealth of other detail on Jupiter. Still, pretty strange
1:25am I can’t see Europa itself, which is also crossing in front of Jupiter. I can only see Europa’s shadow, and Ganymede of course. Ganymede is so much bigger than Europa, so the limit of my telescope is somewhere between Ganymede and Europa. Europa also has a higher surface brightness, so it may be harder to pick out against the bright cloudtops of Jupiter.
2:05am I’m taking some photos through the eyepiece (afocal) just to show that there are no moons. I don’t really know how much good a photo is of something that isn’t there…
2:20am Wow! The photo actually shows the major bands and two little marks that are Ganymede and Europa’s shadow. I’m not saying it’s a great shot, but it’s something.
2:35am Yeah, it’s over. Io has popped out of the shadow and Jupiter again has a moon. I tried another photo and it barely shows Io. I suppose it is still partly shaded, and it is so much smaller than Ganymede. I just thought that since Ganymede showed up so well…
2:49am Exactly on schedule! Europa is coming off the limb of Jupiter. It is like a little pimple on the edge of the planet. Also, Ganymede’s shadow is now visible on the other side of Jupiter from Ganymede itself, and it looks huge in comparison to Europa’s shadow. It also appeared right on schedule. You could set your watch by this stuff (and people used to!) Don’t you just love Newtonian physics?!
3:02am Show’s over for this year. Well, for the next 10 years. Next time this happens it will be 2019. Right now, it’s time for bed.
Clear weather is coming just in time for an unusual and rare event for telescope observers. Jupiter’s four Galilean satellites are constantly orbiting around their giant parent planet, and always provide an interesting and entertaining show for observers. This Wednesday night the moons of Jupiter will again amaze us, but this time with their absence!
On the night of September 2nd (morning of September 3rd) starting at 12:45am, none of the moons will be visible for a period of nearly 2 hours. This type of occurence, when all four moons are invisible, occurs about 10 to 20 times per century. The last occurence was a mere 16 months ago, but we will not have another chance to see this for 10 more years, in 2019.
During the time when no moons are visible, Ganymede and Europa will be in front of Jupier (transiting), Callisto will be in Jupiter’s shadow (eclipsed) and Io will start out behid Jupiter (occulted) and then come from behid Jupiter but stay in its shadow.
Here’s the whole line-up of events for that night (from Sky and Telescope)
Wednesday, September 2, 2009
23:28 UT, Callisto enters occultation behind Jupiter.
Thursday, September 3, 2009
03:44 UT, Io enters occultation behind Jupiter.
04:00 UT, Europa begins transit of Jupiter.
04:46 UT, Ganymede begins transit of Jupiter. (NO MOONS VISIBLE)
04:56 UT, Europa’s shadow begins to cross Jupiter.
06:32 UT, Io exits eclipse by Jupiter’s shadow.(End of No Moon Period)
06:46 UT, Ganymede’s shadow begins to cross Jupiter.
06:50 UT, Europa ends transit of Jupiter.
07:50 UT, Europa’s shadow leaves Jupiter’s disk.
08:24 UT, Ganymede ends transit of Jupiter.
08:44 UT, Callisto exits eclipse by Jupiter’s shadow.
10:24 UT, Ganymede’s shadow leaves Jupiter’s disk.
After posting a couple of blog entries encouraging you to go out and observe the ever-changing parade of Jovian satellites, I now hope you enjoy this chance to not see any of Jupiter’s moons!
Well, they were imaged by the LRO, but it’s still impressive.
These images are about 4 feet per pixel. There’s 5 landing sites shown.
I guess they did not get Apollo 12 yet.
http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/apollosites.html
Check them out!
As the evening started, Callisto and Io were on one side of Jupter while Ganymede and Europa were on the other side. Within a span of a few hours Ganymede moved in front of Jupiter, followed by Europa, then Ganymede’s shadow appeared and Europa’s too. Io then moved behind Jupiter, and just after the clouds rolled in Europa and Io would have both emerged into view again, within minutes of each other, but on opposite sides of the planet. Phew! That’s a lot, but it is what we observed tonight. Even better, it is also the kind of action that goes on every night and can be seen in even the smallest telescope.
Tonight, I used my Burgess 5″ achromat refractor and a variety of eyepieces. The best view came through a borrowed binoviewer, which really works well on bright objects like Jupiter. The globular cluster M13 was disappointing through the binoviewer, and M17, the Swan Nebula, was really neither better nor worse. Double stars and open clusters were very nice though.
Returning to Jupiter, it appeared as an apparent 3 dimensional disk, rich in detail. The seeing started out poor, but as Jupiter rose higher in the sky the image became rock steady, and we were able to follow not just the shadows, but the moons themselves across Jupiter’s face. Ganymede appeared as a large disk in front of the white equatorial zone, while Europa was visible, but barely. The shadows appeared inky black and showed considerable difference in size. Notice that although Europa was the second moon to move in front of Jupiter it was the first to move off. That is because it is closer to Jupiter than Ganymede, and moves much quicker in its orbit. While in front of Jupiter, Europa actually passed by Ganymede, like a race car on an inner track.
Every night it’s something different. What will if be tomorrow? Go out and see this spectacle for yourself, now showing in the sky above you!
(All right, I’m going to give you this one rather than make you look it up yourself. On Friday night (Saturday morning) at 2:30am, Io is going to graze Europa. From our perspective here on Earth the disks will appear to actually touch! Use the highest magnification that your scope and the atmospheric seeing conditions will allow, and enjoy!)
I look forward to reading your reports here on the blog, or email them to me ( observing@amateurastronomy.org )and I will be happy to share them.
Today’s APOD is Kerry-Ann’s winning photo from Starfest.
Once again she has shown us what can be done with with equipment many of us have handy.
I am so proud of our members’ abilities and the awards they have received.
Well done, Kerry-Ann!
http://antwrp.gsfc.nasa.gov/apod/ap090826.html
I will be going out to the alt. site on Tyneside rd. tonight. If you would like to join me please come along. I am planing to arive there about 8:30 pm. Make sure you have bug juice as the mosguitos were very bad the last time I was there.
Today, August 25th, marks the 20th anniversary of the arrival of Voyager 2 at Neptune. In 1989 this automated probe completed a 12 year voyage to our solar system’s most distant planet, after visiting Jupiter, Saturn and Uranus. It passed less than 5,000 km above Neptune’s north pole, and a few hours later passed the large moon Triton. The images that were returned gave us our first detailed look at this giant planet and its satellite system.
Today, Voyager 2 and its companion Voyager 1 are both still operating well and are 13 and 16 billion km away, respectively. They are in communication with Earth on a weekly basis, with radio signals taking over a day to travel the great distance. In the twenty years that have passed since Voyager’s visit to Neptune, no other probe has been to the planet. Voyager 2 remains our sole emissary to Neptune.
Meanwhile……… a small contingent of HAA members made the trek to Cherry Springs for their Second Annual Astronomy Festival. Like at ?Twisterfest? the inclement weather played its part at Cherry Springs as well.
Although attendance was not as anticipated the weather didn’t dampen the spirits or the comradery of the astronomers who attended.
It was great to meet and spend time with Dave and Guy, members from the Aurora Astronomical Society based in Ohio. Dave had his new handmade 13 inch Dob at the ready. Dave said it was a labour of love that took him all last winter. Its a beautifully crafted scope and gave some really nice views. Guy set up his two Dobs and kept everyone laughing with all his adventures.
By late Saturday afternoon the public starting arriving for some planned activites at the pavillion. The most popular by far was the bottle rocket launch. The shrieks and laughter could be heard throughout the park. Onlookers gathered to cheer them on.
As darkness fell the clouds started to roll in, but there was still plenty of opportunity for a sky tour through the sucker holes.
Optimism had led to setting up the scopes. Although sporadic, several opportunities presented itself to view the outstanding night skies Cherry Springs is known to provide. At the close of the park activites passerbyes stopped for a Galileo Moment or two.
Bino observing of the Milky Way gave stellar views.
It was great to see Maxine Harrison as she made the rounds as usual, to say hello, have a visit and give us an update on park news.
As all things must come to an end, Sunday afternoon arrived. With that, a reluctant departure, knowing in our hearts the absolute best clear sky of the weekend would be…….Sunday night………why is that?
I have to admit that it was the most exciting Starfest we’ve ever attended! Thursday afternoon the field was rocked by a frightening storm that shredded trailer awnings, blasted shelters to pieces, snapped tent poles and destroyed at least one tent. In spite of all the damage, we were lucky. In nearby Durham, an F2 tornado killed a child and mangled many buildings. Even through the driving rains, we could see the black clouds passing north of us that apparently spawned that deadly twister. We had almost 2 inches of rain in less than 45 minutes. Thank goodness there is sand and gravel beneath River Place campground – the water drained quickly after the storm, leaving just a few puddles here and there.
There have been some significant changes to the campground this year. The “hill” that many of our members have camped on is gone. It has been bulldozed flat and a new road runs from the main road along behind where the hill used to be. Some new trailer sites have been added along this road, next to the tree line. Some of these trailer sites are ridiculously sloped and all but useless to anyone except perhaps a family of mountain goats. (Stay away from trailer sites #458, 459 and 460!!! ) The camp has a new, heated swimming pool which seems slightly larger than the old one. (Or maybe it just seemed larger because there were very few people in it.)
Thursday and Friday nights brought breathtaking views of the Milky Way that lasted for maybe an hour or two and then reappeared unexpectedly later in the night. This was a pleasant surprise especially considering the weather forecast! (Which essentially promised: rain, thunderstorms, drizzle and Armaggedon.)
The door prizes were spectacular – everything from cash to a new Celestron 8″SE telescope ! Steve Germann won a small telescope that will make an adorable companion to his huge 16″ Lightbridge. Skye Hepburn won a Williams Optics star diagonal and stole our hearts as she gleefully accepted her prize. (What a cutie!!!!) Everyone will be relieved to know that
neither we or Bruce & Margaret won anything this year. It seems our lucky streak has ended.
We met up with old friends and made some new ones. We bought some new astro-toys. The talks were entertaining and interesting. All in all, another successful Starfest.
Cheers,
Ann Tekatch
