Archive for the ‘Multiple stars’ Category

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Observing Reports: two perfect imperfect nights at the Salton Sea

November 23, 2015

Apex 127 ready for stars 2015-11-14

The Saturday before last, November 14, I was at the Salton Sea with Terry Nakazono.

Terry Nakazono with Meade Polaris 114 2015-11-14

Terry was rolling with a new scope – a Meade Polaris 114. It’s an f/8.8 reflector – the 1000mm focal length makes it a bit longer than the 900mm, f/7.9 Orion XT4.5 (which London has). UPDATE Nov. 29: Terry writes, “It’s a standard 900mm FL, not 1000mm. A lot of the retailer ads have it wrong and says its 1000mm. I myself was intrigued when I first read about it, but later found out from looking at the PDF manual and those who bought it is that it is an F/7.9 of 900mm focal length.” So it’s not longer than London’s XT4.5, it’s essentially the same OTA.

This Meade is a pretty amazing deal. A lot of small intro reflectors have a short dovetail bar bolted to the side of the tube (like my old scope Shorty Fats), but this one has real tube rings and an EQ-2 mount. The three MA (Modified Achromat) eyepieces it comes with are nothing to write home about, but the focal lengths of 26mm, 9mm, and 6.3mm are at least useful and non-overlapping when doubled with the included Barlow. Terry shared a few views with me and I can confirm that it serves up a sharp, contrasty image, as you’d expect for a scope of this focal ratio. It would be a good deal at the list price of $170, but Amazon has it for $135 as of this writing, and according to Terry it can be found for even less if you look around.

Matt aligning finder on Apex 127

I brought the Apex 127/SV50 combo – I’m sighting on the moon here, to align the finder with the scope – and the C80ED.

Matt digiscoping moon

Here I am digiscoping the moon with the C80ED. I used the Apex 127 for tracking down some planetary nebulae and double stars, and the C80ED for photography and just messing around. It’s a crazy fun little scope. Unfortunately, none of my moon shots worked out this time.

The forecast called for clear skies most of the night, but clouds between 10:00 PM and 2:00 AM. We got set up before the sun set at 4:45, and pushed through until 10:40. Then it got too hazy to observe, so Terry and I sat and jawed about scopes, atlases, and observing projects until the sky cleared a bit at midnight. We got in about half an hour more before the sky clouded over completely about 12:40. We talked a bit more then turned in.

Jupiter and moons 0530 PST 2015-11-15

I got up at 4:00 AM to catch the morning planets – Jupiter, Mars, and Venus. I cannot get the iPhone to take a fast enough picture to capture any detail on Jupiter – it always comes out as a blank circle of light (with some glare from the iPhone, not the scope). But the moons show up nicely. I really need to get a better camera control app.

Clouds at dawn 2015-11-15

I was clouded out again at 5:15, and Terry and I sat up until 5:45 watching the approaching dawn. Then it started sprinkling! Weather Underground, the Clear Sky Chart, and my other weather app all missed that. We packed up quickly and drove out at 6:30. A hearty breakfast at the Coco’s in Indio put a cap on the expedition. Although the skies were less than perfect, we had a good time catching up, and we did see some nice things.

Waxing gibbous moon 2015-11-22

Back Again

As luck would have it, I was back at the sea just eight nights later. London and I hadn’t been to the Salton Sea since last November, and he has all this week off from school, so we went last night. He took his XT4.5, and I took my C80ED. The waxing gibbous moon was only three days short of full, so the skyglow was pretty bad. But the seeing was excellent, easily 8 or 9 out of 10. I could split the four main stars of Orion’s Trapezium wide open at 25x, and fleetingly at 19x with the 32mm Plossl.

I could have held that split more easily with a better low-power eyepiece. I had not noticed it before last night, but my trusty Orion Sirius 32mm Plossl, my go-to widefield and finder eyepiece for many years, has some astigmatism. Not a lot – it was only noticeable immediately after switching from my 24mm ES 68. I tried both eyepieces with and without eyeglasses to confirm that the aberration was in the Plossl and not elsewhere in the optical train, my eyeballs included (I tried both). Another case of getting spoiled by premium eyepieces. It’s fine, though – since the 24mm ES 68 gives the same field of view, I only pull out the 32mm Plossl when I want to drop the magnification even lower, or when I’m doing outreach.

Sigma Orionis sketch 2015-11-22

I spent a lot of time cruising the central part of Orion at 120x with the 5mm Meade MWA, which is now my preferred high-power eyepiece. Just three weeks ago I saw and sketched the multiple star Sigma Orionis for the first time. It’s funny – I’d been observing Orion regularly for eight years before that and I’d never seen it, but now I stop there every night I have a scope out. Even London’s little 60mm Meade refractor split the six main components wide open. But last night I saw a faint, seventh member that I’d previously missed.

I turned in relatively early, around midnight, figuring that I’d get up after the moon set and do a quick morning Messier hunt. And the sky was truly phenomenal after moonset. I was waking up about once an hour and having a quick look around, and it was a spectacularly clear, dark night. But the flesh was weak, and I overslept, only dragging myself out of my sleeping bag at 5:00. By that time the first glimmerings of dawn were lighting the eastern horizon, so I skipped the Messiers and went to Jupiter.

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That planet above the scope is Venus, not Jupiter.

The view was jaw-dropping. The seeing was rock solid and I was able to Barlow the 5mm MWA up to 240x without the image breaking down. At that magnification I could detect at least three delicate brown belts north of the North Equatorial Belt, and the Galilean moons were little spheres, not just points of light. I tried taking some pictures but didn’t get any better results than I had the last time out, so I put the camera away and just stared. I must have spent 45 minutes just watching Jupiter drift across the field of view, mostly at 240x.

Last night I was definitely in aesthetic observing mode. I spent a little over two and a half hours at the eyepiece, entirely on four objects – the moon, Orion nebula and Trapezium, Sigma Orionis, and Jupiter. I had half-formed plans to look at other things, but I kept getting seduced into long sessions of fully immersed stargazing. And I’d do it again in a heartbeat.

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So, neither night had perfect observing conditions. It was hazy the first night, and the moon was out during the convenient observing hours last night. But I had a great time both nights, saw some cool things, learned a little more about my gear, and enjoyed the good company of Terry and London. Couldn’t really ask for more.

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Observing Report: All-Arizona Star Party 2014

October 30, 2014

 

AASP 2014 - loaded for bear

If it’s late October or early November, it must be time for the All-Arizona Star Party. London and I headed out for it this past Saturday, Oct. 25. As in 2012, we were joined by the indefatigable Terry Nakazono. Here Terry and London pose for the obligatory “look how much crap we crammed into the car!” photo.

We arrived at the site about an hour before sunset, plenty of time to set up camp and chat with the neighbors. As usual, we set up not far from Darrell Spencer and AJ Crayon, but irritatingly I failed to get a picture with Darrell, my first such lapse.

AASP 2014 - setting up in the shade

When we arrived the sun was still well above the horizon and temperatures were in the mid-90s. London and I set up our scopes on the east side of the car so we could sit in the shade. Here London is tinkering with his AstroMedia 40mm “plumber’s telescope”, which we just built last week. More about that scope in a future post. The scope behind London was another AASP newcomer.

C80ED newly arrived 1600

This is my new Celestron C80ED. This scope originally retailed for about $500. Celestron donated all of the remaining stock of the spotting scope version to Astronomers Without Borders, and AWB sells it for $350 with free shipping. Vicki got me one for our anniversary last week (and I got her some leather boots–in both cases, the choice of gift was, ahem, heavily influenced by the recipient). The package arrived on Thursday about half an hour before the partial solar eclipse was to start, so I just had time to take this photo before I ran out the door to London’s school.

I got this scope because it filled a hole in my lineup. My Maks have sharp optics but can’t do wide fields. The TravelScope 70 can do wide fields but still has limitations, even after its tune-up. And the C102 is a wonderful scope but not exactly small, and although its chromatic aberration is minimal it is still there. I figured a small ED scope could be a grab-n-go that could deliver wide fields like the TS70, take magnification on planets and double stars like the Maks, in a more convenient and false-color-free package than the C102. Plus I’d just always wanted to try an ED scope. I was going to get an AstroTech AT72ED but they are out of stock and have been for ages. The C80ED offered a small but significant aperture boost for less dough, so I bit–or rather, encouraged Vicki to do so.

I was going to bring both the C102 and the C80ED, but as the date got closer I decided that what I really wanted to do was put the C80ED through its paces under those dark Arizona skies, and another scope would just be a distraction. I had briefly set up the C80ED on Friday night to make sure the scope didn’t have anything seriously wrong. It didn’t–in fact, it star-tests as well as any scope I’ve ever owned.

AASP 2014 - refractor city

Turns out we were all rolling with small refractors. From left to right they are the C80ED, London’s 60mm Meade refractor, Terry’s Orion Short-Tube 80, and London’s 20×50 Orion spotting scope (reviewed here). Terry had been going to bring a 4.5-inch reflector but the Clear Sky Chart said that conditions were iffy. Also, like me he had been interested to see how deep he could push a small refractor under dark skies.

Incidentally, after bringing my XT10 to the AASP in 2010 and 2012, I brought the Apex 127 last year and now an 80mm refractor this year. At this rate, in a couple more years I’ll be down to bringing just a finderscope. (I jest, but I have had a longstanding interest in going to a dark site with only the SV50 or GalileoScope to see how many things I could see with a small scope under dark skies–so far, greed for photons has always won out, so this project remains unattempted).

AASP 2014 - moon in C80ED

Our first target of the evening was the waxing crescent moon. I got a few shots with the iPhone shooting through the C80ED. Here’s the best one. All I did was crop it and flip it left to right–other than the orientation change, the actual pixels have not been tinkered with at all. Note the absence of false color. I also put the scope on Vega early in the evening and could not detect any false color–very impressive.

On the drive out, Terry asked me if I had any plans or goals for the evening. I did have a few:

  • above all, spend some time observing with London;
  • look at some familiar objects to get a feel for the scope;
  • track down some southern objects, since I’d be at a dark site with a clear and dark southern horizon;
  • to the extent that I could, test the scope on challenging targets like globular clusters and close double stars.

And that is more or less what I actually did.

A word about the sky conditions before I get into actual observations: they were not fantastic. Seeing was lousy the whole night, with the stars twinkling visibly all over the sky. Transparency was good in the early evening but around 9 or 10 a very light haze set in across the whole sky. It wasn’t ghastly, but it noticeably knocked down the contrast–where the Milky Way had blazed overhead at 8:00, by 10:00 it was just sort of there, visible but not nearly as prominent. In my notebook, I rated the seeing at 2 out of 5 and the transparency at 3 out of 5.

I only used four eyepieces for most of the night:

  • 24mm ES68, which in the C80ED gives a magnification of 25x and a true field of 2.7 degrees
  • 14mm ES82 (43x, 1.9*)
  • 8.8mm ES82 (68x, 1.2*)
  • 6mm Expanse (100x, 0.67*)

I did use a 32mm Plossl to drop the power down to 18.75x to see if Polaris could still be split (it couldn’t, but read on), and I used a Barlow once. Other than that, it was just these four, and out of these four, I used the 24mm and 8.8mm EPs significantly more than the other two. I had planned to use the 8-24mm Celestron zoom, but in testing the scope Friday night, I could tell that the Explore Scientific eyepieces were noticeably sharper. Good heavens, I think I’m turning into a refractor weenie and an eyepiece snob.

After the moon we visited Mars, but it was tiny and featureless and fairly burning in the bad seeing. Then I swung next door to Sagittarius and got my first surprise of the evening: the big glob, M22, was partially resolved even at 25x with the ES68! I love globs–they are one of my chief joys in observing with the XT10, and I expected them to be dim, featureless cottonballs in the C80ED. That I was getting partial resolution on one in a small scope at low power was pretty arresting. I had a quick look at M28, M8, and M24, and then helped London get his 60mm on target on M22, M28, and M8. London was interested in seeing a double star so we wheeled the scopes around and had a look at Mizar and Alcor. Then we looked at M13, M57, the Pleiades, the Double Cluster, and Stock 2 in his 60mm.

AASP 2014 - our camp

Highlights of the Evening: M13, M57, M27

After all that, London went to lie in the lounge chair and watch for shooting stars–he got 17 before he went to sleep around 10:30. I went on to M13, the Great Globular Cluster in Hercules, and had my socks knocked off. Like M22, it was partially resolved even at 25x, and much better at 68x and 100x. It wasn’t fully resolved, of course, and the XT10 will blow away the C80 on this or any other glob, but it was at least a ball of many, many stars and not just a fuzzy blob. Here’s one of the nice things about widefield eyepieces and short focal length scopes: you get huge fields even at reasonable magnifications. At 68x in the 8.8mm ES82, I could park M13 comfortably inside the field stop and watch it drift across the field of view for more than four minutes. Even at 100x in the 6mm Expanse, I could watch the cluster drift across the center of the field for a bit over two minutes. I commented to Terry that if I hadn’t had other things I wanted to see, I could have kept watching M13 all evening and been very happy.

Lyra was still pretty high overhead so I went there next. Epsilon Lyrae was shimmering in the bad seeing. It was elongated at 68x and almost split at 100x, but I had to Barlow it up to 200x to get a clean split. You may recall that under better conditions, the TravelScope 70 split the Double-Double at 133x, and I know that it is often split at well under 100x by high quality small refractors. So the high magnification required for the split here reflects more on the quality of the seeing than on the quality of the telescope. I’m looking forward to seeing how the C80ED performs on Epsilon Lyrae on a better night.

M13 was probably my favorite view of the night, but a close runner-up was M57, the Ring Nebula. It was clearly ring-like at 68x, but I liked it even better at 25x–the expansive 2.7-degree field of the ES68 showed the nebula nicely framed between Beta and Gamma Lyrae (the stars that mark the south end of the constellation stick-figure) and their attendant stars. It reminded me of the view of the Ring at 12.5x in the TravelScope 70 back in 2012, which is what got me into refractors in the first place.

After that I spent a few pleasant minutes rocking through the Lyra-Cygnus-Sagitta axis, observing M56, Albireo, Brocchi’s Coathanger (Cr 399), M71, and M27. Interestingly, the view of the M27 was very similar to the one I had through the C102 at the Salton Sea last year: I could not only see the “apple core” extensions, but also some of the “football” nebulosity between those extensions. That is a lot of nebulosity to pick up in an 80mm scope. I wonder what I could see on a night with better transparency.

By now it was about 8:50 and I knocked off the serious observing for a while. First I went to hang out with London, and while he watched for shooting stars, I used the 15×70 bins to sweep up many of the same summer showpieces I’d just seen in the telescope: M57, M56, Albireo, Cr 399, M71, M27, M13, the Double Cluster, some of the nice NGC open clusters in Cassiopeia. Then some folks from the other end of camp stopped by and we chatted for a while. Darrell came over and had a look at M13, and London and I went down to the center of camp to get some hot chocolate. When we got back, London sacked out. I had a quick look at M11 before it set, and tracked down the asterism DeLano 1 just to make sure it was still there. Then, at Terry’s suggestion, I tried M15, the big glob off the nose of Pegasus. Here are my unedited notes:

M15 – tough nut to crack. Starting to look grainy at 100x. Also pretty grainy at 68x in 8.8mm ES82. Even though it only gives about 2/3 the magnification of the 6mm Expanse, I think the 8.8mm ES82 shows almost as much. It’s just a superior piece of glass. Another ES82 or 68 in the 3-5mm range should be priority.

Now, this idea that the 6mm Expanse is maybe not 100% awesome–hold onto that thought, we’ll revisit it at the end of the evening.

IMG_2140

Go South, Young Man

Ever since my incredible Salton Sea run with David DeLano last fall, I have been painfully aware of how much I’ve neglected the southern sky. So from 10:45 to 12:30, that’s where I went. My first southern target was NGC 7293, the Helix Nebula. It was dead easy to see once I got there, but it took me an unusual amount of faffing about to get on target. I was using the 6×30 straight-through correct-image finder that came with the C80ED. I’m normally a RACI man so using a straight-through finder took some getting used to. But I kinda like it, now that I have the hang of it.

After that it was onto some galaxies and planetaries: NGCs 55, 300, 288, 253, 247, 246, 720, and 779. NGC 288 and NGC 253 were nicely framed in the same field. NGC 288 is a globular cluster circling our own Milky Way galaxy, about 29,000 light years away, whereas NGC 253, the Silver Coin galaxy, is 11.4 million light years away, almost 400 times farther, and rivals our own Milky Way in size. So that pair has a bit of the M97/M108 ‘odd couple’ thing going on.

The not-quite-edge-on galaxies NGC 720 and NGC 779 were my only new objects for the evening. Both of them are on the Herschel 400 list, and bring my H400 tally to 175. I am starting to wonder if I will ever finish the Herschels–the only new ones I’ve notched in the past couple of years have been bagged at the All-Arizona Star Party. I gotta get out in the spring more. I’ve just about exhausted the fall Herschels, but there are hundreds of spring galaxies to observe in Ursa Major and the Virgo-Coma Cluster.

C80ED AASP 2014 2000

Orion and Points North

After almost two hours of faint fuzzies, I was ready for a change of pace. I turned east, toward Orion. The view was pretty great–the Trapezium was split into four components at only 25x, and the nebulosity seemed to go on forever. And yet, the subtle gradations in the nebulosity did not seem as pronounced as I had observed on other nights. Terry noticed the same thing observing Orion through his ST80. He thinks that the poor transparency was leaching some of the contrast out of the view, and I am inclined to agree.

Without a doubt, the strangest observation of the night was of NGC 1980, the field of nebulosity around Iota Orionis. When I looked right at the nebula, it was steady, but when I looked back at M42/M43, NGC 1980 would flicker in my averted vision like a bad fluorescent bulb. At first I thought maybe it was just my eyes, but I called Terry over and he reported seeing the same effect.

Now, I don’t think that the nebula was actually flickering. I suspect that through some quirk of eye/visual system physiology, it only seemed to flicker in averted vision.

Just to rule out the obvious distractors: we were parked on the very east end of the airstrip so there was probably no-one between us and Phoenix. Neither of us were using flashlights or any electrical gear at all while we were observing in Orion. Our nearest neighbors were about 50 yards to the NW and SW, and they’d all turned in for the night. So I’m about as certain as I can be that it wasn’t some terrestrial source that just happened to be shining into the eyepiece or objective lens. Also, we only noticed the flickering on NGC 1980, and not on the extended “wings” of nebulosity from M42, which were of similar brightness at their extremities.

Has anyone else seen anything like this, either for NGC 1980 or other DSOs? If so, I’d love to hear about it–the comment thread is open.

After Orion’s Sword I bounced around a few northern Messiers–M78, M1, M35 with NGC 2158 just starting to resolve behind it, M81 and M82 in the same field, and M97 and M108 in their own field. Midway through that tour I stopped to split Polaris. It was continuously split at 24x in the 24mm ES82, not split at 18.75x in the 32mm Plossl. This illustrates just how seeing-dependent double star splitting is–Friday night from my driveway, the seeing was even worse, and that evening Polaris was not continuously split at 25x, but it was a 43x in the 14mm ES82, and even at 28.5x in the 21mm Stratus. As indicated above, the seeing out in Arizona Saturday night was not awesome. One of my quests with the C80ED is to see how low I can go, magnification-wise, and still get clean splits on some of the classic double stars. Watch this space.

M97 and M108 were my last DSOs of the evening. After that I turned to Jupiter, and even at 68x I could see at least 4 belts. The Galilean moons were spaced about evenly, two on each side of the planet. Terry and I compared views of the planet through the C80ED and his ST80. We could get similar magnifications with our favorite short eyepieces: the 8.8mm ES82 gave 68x in the C80ED (FL = 600mm), and the 6mm Expanse gave 67x in the ST80 (FL = 400mm). So how did the scopes compare? Well, obviously the ST80 was throwing up a lot of false color, but I could detect the same four belts that I could in the C80ED, albeit not quite as crisply. More informative was the comparison of eyepieces. Terry had a 6mm Expanse clone from AgenaAstro.com. While were swapping all of these eyepieces between the two scopes–the 8.8 ES82, the 6mm Expanse, and the 6mm Expanse clone–I noticed something I had never spotted before: the 6mm Expanse threw up a huge circle of glare around Jupiter. Perfectly circular, like a lens flare, centered on Jupiter, and spanning out to the outermost moon on each side. The glare circle was there in the 6mm Expanse in both scopes. It was not there in either scope in the ES82, nor in the AgenaAstro Expanse clone. These are the Agena Enhanced Wide Angle (EWA) 6mm, which goes for $45 (you can find it here), and the 6mm Orion Expanse, list price $68, street about $59. So if you’re in the market for a 66-degree EP, you can save about 25% and get noticeably better performance from the Agena version. I’m tempted to get one myself, and hock the Orion EP. Until now, the 6mm Expanse has been one of my most-used EPs, but now that I can see its faults…like I said, eyepiece snobbery is taking hold.

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Settling Up

After one last look at Jupiter in the ES82 at 3:00 AM, I shut down and went to bed. The next morning, London and I went on our customary “bone hike”, and we did find several bones, including a couple of cow limb bones, and the jackrabbit lower jaw shown in the photo. More exciting were the Western diamondback rattlesnake and the horned lizard that we found.

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My final tally for the evening was 45 telescopic objects:

  • 2 planets (Mars and Jupiter)
  • 22 Messiers
  • 13 other NGCs
  • 2 asterisms (Brocchi’s Coathanger, DeLano 1)
  • 1 other catalogued DSO (Stock 2)
  • 5 double/multiple stars (Mizar/Alcor, Albireo, Epsilon Lyrae, Trapezium, Polaris)

…plus a couple of meteors.

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Irritatingly, I realized later that I had completely missed out on some real gems. I never once pointed the scope at the Andromeda galaxy or its satellites–detail in M31 would have been a good test of the C80’s optics. And I skipped the nice open clusters in Auriga–M36, M37, and M38–which maybe more than any other set of clusters give that “diamonds on black velvet” feeling in a sharp telescope. We set up early enough that I could have rocked through all of the Sagittarius Messiers instead of the handful I actually saw, but I deliberately traded that time away to help London find some things, so I don’t feel bad about that particular omission. The others are a bit galling.

Even with those omissions, I still met all of the goals that I had set for myself: I got in some good observing time with London, I had fun touring the southern skies, even if most of the things I saw there were revisits, and I both got a feel for how the scope performed on average targets, and got to push it on some challenging ones. The biggest revelation to me was that an 80mm scope would start to crack open some of the bigger globs. M13 and M22 didn’t just look good, they looked stunning. I wish I was observing them right now.

In sum, a great night of stargazing, and a pretty thorough field test for the C80ED. I think I am going to have a LOT of fun with this scope.

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Mission 20: Beta Monocerotis, a triple star

April 18, 2011

Mission Objective: Multiple star

Equipment: Telescope

Required Time: 10 minutes

Related Missions: Ring of Fire

Map to Beta Monocerotis, modified from the Monoceros constellation diagram on Wikipedia.

Hey look, I finally posted a new mission.

I’ve been slowly working away at the Astronomical League’s Double Star Club, and I just discovered this gem last week. It’s not the world’s easiest star to find. As a naked-eye subject, the constellation Monoceros, the Unicorn, is fairly dim and unimpressive. Beta Monocerotis is prominent in the western part of the constellation, just east of Orion and north of Canis Major, making a wide triangle between Sirius and Kappa Orionis (also known as Saiph, which is Arabic for “sword of giant”). I could just make it out with the naked eye from Claremont, hovering in the light dome over Los Angeles.

To fully appreciate this star’s charms, you’re going to want a telescope, but it doesn’t have to be a big one. I made my observation with my 80mm refractor, which has a focal length of 900mm (f/11). Using a 32mm Plossl eyepiece (28x), it was clearly a double star but not cleanly split (seeing was lousy). With the 12mm Plossl (75x) it was clearly split into a nice pair of equally bright gems. I decided to go up to 150x with a 6mm Orion Expanse, my favorite high-power eyepiece. So glad I did–at 150x, the southern member of the “equal pair” turned out to be a double itself, also of equally matched components! It was a nice surprise and a breathtaking sight, the three stars twinkling away at 150x.

I looked at dozens of photos, sketches, and eyepiece simulations of Beta Monocerotis while writing this post, and the image that come closest to capturing what I saw at the eyepiece is this sketch by Jeremy Perez, who kindly gave me permission to include it here. Jeremy is one of the authors of Astronomical Sketching: A Step by Step Introduction, and his website, Belt of Venus, has beautiful and evocative sketches of just about everything in the sky, from the moon and planets to deep sky objects and double stars. It’s definitely worth checking out, both to marvel at his work, and to get ideas for your observing wish list.

A poster on Cloudy Nights had this to say, “I just looked at Beta Mon last night in good seeing. What a neat thing. It reminds me of one of those antique mechanical solar system models.” I couldn’t agree more–it conveys exactly the same sense of mechanical precision and aesthetic appeal as an old-fashioned orrery.

If you’re going to catch Beta Monocerotis, you’ll need to do it soon after dark, because Monoceros is following Orion to the western horizon fairly early these days. Go have fun!

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Cosmic triple play: the moon, Jupiter, and Uranus tonight

December 12, 2010

The not-quite first quarter moon will zip past Jupiter and Uranus tonight (that is, Monday night, Dec. 13). Here’s the view in Stellarium at about 6:00 PM, Pacific time, looking high in the south:

The moon and Jupiter are the easiest naked-eye objects in the skies right now. Grab some binoculars–any binoculars–to see moon craters, the moons of Jupiter, and Uranus, which will appear as a bright star just above and left of Jupiter (or north and east, if you prefer). It’s not the only reasonably bright ‘star’ in the field, so here’s a more printer-friendly map to take along:

Note the nearby stars K and 9 Piscium (so named because they are in the constellation Pisces, the fish). They make a visual double but not a gravitational one, which means that they are accidentally aligned as seen from Earth. K is brighter mostly because it is closer, only 162 light years away compared to 9’s 400-plus.

All of those are easy binocular targets. In a small telescope, the view only gets better: hundreds or thousands of craters and other lunar features are visible, as well as cloud belts on Jupiter, and Uranus may show up as a small blue-green disc instead of a mere point if you crank the magnification.

But it will be worth taking a moment to see even if all you observe with are a couple of Mark 1 eyeballs. Go have fun!

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Mission 4: The Big Dipper

August 22, 2009

Mission Objectives: Constellation, Bright Stars, Multiple Stars

Equipment: Naked eye, Binoculars

Required Time: 3 minutes

Instructions: Get to a place with a clear northern horizon, look to the northwest, and find the Big Dipper. Seriously, it’s just that easy. Here, you can practice with this:

The view to the northwest right after sunset in the southern US, in Stellarium.

The view to the northwest right after sunset in the southern US, in Stellarium.

Note the little red W and N in the corners of the picture; at this time of year, the Dipper is exactly halfway between those cardinal points. If you can’t find it, make sure that it’s just after dark, see that your view isn’t blocked by clouds, trees, or mountains, and double check that you are, in fact, in the Northern Hemisphere.

The Big Dipper as a guidepost to the northern sky.

The Big Dipper as a guidepost to the northern sky.

If you can find the Dipper, you can find at least two more bright stars and have an edge on identifying their constellations. The path that is most widely known is that the two stars that make up the front end of the “pan” point unfailingly to Polaris, the North Star, around which everything else in the heavens appears to rotate. Also, you can follow the handle of the Dipper and arc to Arcturus, the brightest star in the constellation Bootes.

Like Lyra, Ursa Major has a double star treat for naked eyes and binoculars. The middle star in the handle is in fact two, Mizar and Alcor, the horse and rider. Your eyes don’t have to be particularly sharp to see that the brighter of the two, Mizar, has a dim companion. This is also a dead easy split with binoculars. A telescope working at even low magnifications of 40-50x will reveal that Mizar has another, even fainter companion, called Mizar B. Mizar was probably the first telescopic binary discovered, possibly as early as 1617, less than a decade after Galileo first aimed a telescope at the heavens. As if all of that weren’t enough, Mizar A and B are themselves both binary, although the components are too close to be separated by telescopes and can only be detected through spectroscopy.  So Mizar is a four-star system, another “double double”, all by itself.

The Big Dipper is just the rear end and oddly long tail of the constellation Ursa Major, the Great Bear. Polaris is at the end of the tail of Ursa Minor, the Little Bear. There are lots of stories about how these bears came to have such long tails–see what you can find. Because Ursa Major is so close to the celestial North Pole,  it is visible for most of the year and only dips below the horizon briefly at mid-northern latitudes. If you go far enough north, the Great Bear is visible all the time. The Greek word for bear is ‘arctos’. And so we call those far northern regions, under the eternal reign of the bear, the ‘arctic’.

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Mission 3: Waxing Lyrical

August 20, 2009

Mission Objectives: Constellation, Multiple stars

Equipment: Naked eye, Binoculars

Required Time: 3 minutes

Related Missions: Summer Triangle

Instructions: Ready for another constellation? This one is a piece of cake: nice and compact, all bright stars that show up easily even in the city, two simple shapes, high enough to be seen clearly throughout the Northern Hemisphere, and it even has a couple of nice Easter eggs for binoculars and small scopes. I’m talking about the constellation Lyra, the Lyre.

You remember how to find Vega, I’m sure (if you’ve forgotten, refresh your memory here). This time of year it is the brightest star overhead in the early evening; in fact, it is the fifth brightest star in the sky. It is so bright mainly because it is so close, only 25 light years away, not because it is big, although it is about twice the mass of the sun. Because it is heavier it is burning through its fusion fuel faster, and it will swell into a red giant in perhaps half a billion years. By comparison, the sun is only about halfway through its 10 billion year lifespan.

The constellation Lyra (red lines), and the Double Double (white arrow), from Stellarium.

The constellation Lyra (red lines), and the Double Double (white arrow), from Stellarium.

You already know that Vega is at the apex of the Summer Triangle. Even with the naked eye and under city lights, you should be able to see that Vega is also one point of a much smaller triangle, and that the smaller triangle has a parallelogram hanging off its southeast corner. That’s it, the constellation Lyra. If you can find the triangle and the parallelogram, you’re done.

But wait–there’s more! If you’re very sharp-eyed–or your corrective lens prescription is up-to-date–you may be able to see that the star at the “free” corner of the triangle is not one point of light, but two close together. This is Epsilon Lyrae, the famous “Double Double” star. It’s called the Double Double because both of the two stars that make up the naked-eye binary are themselves binary; so, two pairs of binary stars, circling each other. As if that wasn’t enough, spectrometry shows that the system includes a fifth star that is too dim for even telescopes to see.

If you can’t split Epsilon Lyrae into two components with the naked eye, grab your binoculars–any binoculars. Binoculars will show the wide separation between the two pairs, but to split the four visible stars requires a telescope with good optics. At 96x in my 90mm Maksutov-Cassegrain scope, the two pairs look like a couple of 8s, one standing up and one laying on its side. For a much better view, check out this photo of the four stars by acclaimed astrophotographer Damian Peach.

And as long as you’ve got your binoculars out, you might as well have a look at the third “star” in the triangle, Zeta Lyrae (the one star shared by the triangle and the parallelogram). This one is a simple double, not a Double Double, and the two component stars are much closer together than the double-eights of Epsilon Lyrae. Using my 10×50 binoculars and bracing my arms on the top of my car, I just make out that Zeta Lyrae is indeed two points of light, but I can’t hold the binoculars steady enough freehand. About time for a post on mounting binoculars, methinks.