Archive for the ‘Naked eye’ 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: a semi-cloudy night at Joshua Tree

October 8, 2012

My scope at Joshua Tree Saturday night. Clockwise around the scope are the bright star Capella just in front, the constellation Perseus (12:00), the Pleiades (2:00), the Hyades (V-shaped arrow of stars directly oppose Capella), and Jupiter (4:00). Photo by Kevin Zhao.

Saturday evening I was at Joshua Tree. My summer anatomy students invited London and me along to the Indian Cove campground. I didn’t have room in the car for the big gun so I took my 5” Mak, which is what it’s for—times when I need a decent amount of aperture in a small package. That was no loss: the sky was striped with high, thin clouds all night and never really cleared out. We got decent views of a few things, but the 10” would have been wasted. We used the Mak to look at the Double Cluster and Jupiter. In moments of steady seeing there were quite a few cloud belts showing, and all four Galilean moons were lined up on one side of the planet, which was pretty cool. London brought along his AstroScan and we used it to look at extended objects like the Pleiades and the Andromeda galaxy.

iPhone panorama by Chad Claus. Click for the big version!

The clouds might have made for lousy telescopic views but they made for gorgeous naked-eye skywatching. At sunset the whole sky was striped with light from one horizon to the other.

Here’s another view, actually taken by me for a change. This is the unprocessed raw image, direct from my Coolpix 4500.

Moon halo photo by Kevin Zhao. Jupiter is inside the ring at 1:00, and the Pleiades are outside at about the same angle.

When the moon rose around 11:30, it was surrounded by a ring of faint light. I thought it was a moonbow, but that’s something different. The ring we saw around the moon is called a 22-degree halo and apparently has no other or more poetic name. That’s a shame. In the early morning, when the moon had gotten well above the horizon, it was surrounded by a complete circular halo with radiating clouds on either side. That was worth the clouds. I’ve been under wonderfully clear desert skies many times, but I’ve never seen a moon halo quite like that. For once, I think the clouds were worth it.

Update: There wasn’t just a moon halo, there was also a sun halo Saturday afternoon. Agnes Kwon captured it in pixels. Witness:

Many thanks to Agnes, Chad, and Kevin for letting me illustrate my post with their awesome photos!

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The conjunction last Sunday morning

July 18, 2012

In the latest Mount Baldy observing report I described an awesome predawn conjunction of the moon, Venus, Jupiter, and the bright star Aldebaran. What made it so great was not just the close appearance of four bright objects in the eastern sky, but the almost perfect symmetry of their arrangement: not only did they form an almost perfect arrowhead shape, but the arrowhead pointed straight up toward the Pleiades. All in all, just about the most beautiful celestial sight I’ve seen with my naked eyes.

Just as the kite was flying up over the hill to the east of our observing site, a nice couple drove up and set up a camera. They were Robert and Elizabeth Preston, and they kindly send this photo with permission to post. Trust me, you’re going to want to click through to the big version.

Here’s a closeup of the four conjunction objects from a photo by Terry Nakazono. The moon, Jupiter (top), and Venus (bottom) are all unmodified. I had to crop out the area around Aldebaran (right) and boost the contrast to bring out the star.

I can’t imagine a better end to an observing run.

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Don’t miss the moon and planets at sunset this weekend

February 25, 2012

From bottom to top: the moon, Venus, and Jupiter, on Feb. 24, 2012.

Venus and Jupiter are both high in the evening sky at sunset right now. Just look west right when it gets dark and they’ll be the two brightest stars in the west. Venus is the brighter and lower of the two.

For the next couple of nights they’ll be joined by the waxing crescent moon. Tonight the moon was just below Venus, so the three bodies were stacked up the sky from lowest and brightest to highest and dimmest.

Early next week the moon will pull away from the planets as it continues on its monthly eastward trek around the sky, but Venus and Jupiter will still be there and looking good.

A close-up of the moon at the same time as the photo at top.

Venus is slightly gibbous right now (between 4 and 5 in the diagram below). On March 26 it will achieve its greatest eastern elongation from the sun, 46 degrees, meaning that at sunset it will be halfway between the horizon and the zenith. At that point it will be half-lit as seen from Earth (5). From then on into April and May, Venus will get lower and larger as it goes into its crescent phase (6) and gets ready to pass between the Sun and the Earth. Venus makes that passage all the time as it transitions from being the evening star (east of the sun as seen from Earth = above the western horizon at sunset, 6 in the diagram) to the morning star (west of the sun as seen from Earth = above the eastern horizon at sunrise, 1 in the diagram).

Phases of Venus as seen from Earth

Because the orbits of Earth and Venus are not precisely in the same plane, Venus does not usually pass directly between the sun and the Earth but passes above or below the sun as seen from Earth. This time will be different; as happens only a couple of times per century at most, the orbits are lined up just so and Venus will pass across the face of the sun as seen from Earth. That’s the transit of Venus I’ve been so het up about. Stay tuned for more on that, and keep looking up at sunset for the next few weeks to see Jupiter and Venus continue their tango.

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W00t!, W00t!, and Gaaaah!

May 15, 2011

No time for a real post, so here are a few things of note. Two good, one bad, as the title says.

W00t! #1: Want to have your mind blown? Check out this photographic sky survey “meant to reveal the entire night sky as if it rivaled the brightness of day.” Link.

W00t! #2: Want to see a star blow up? No a simulation, but a real-life supernova? You have two choices: be very patient, or use a telescope. The last 5 naked-eye supernovae in our galaxy were observed in the years 1006, 1054, 1181, 1572, and 1604, although supernova 1987a in the Large Magellanic Cloud, a satellite galaxy of the Milky Way, was also naked-eye visible. Anyway, the point is that if you want to see the light of an exploding star with your own eyes, the best place to observe from is the eyepiece of a telescope. It’s not uncommon for a supernova to briefly outshine its host galaxy–that fact is worth pondering for a moment–and there are literally thousands of galaxies within reach of amateur telescopes, so even a modest telescope will show you supernovae in other galaxies on a semi-regular basis. A good site for keeping track of potentially observable supernovae is this one, which lists them by their visual magnitude (you may also find this limiting magnitude chart and this calculator useful to determine which supernovae are within reach of your instrument).

I bring this up because right now supernova 2011by is at magnitude 12.5 and may get brighter still. It has already been sighted in a 6in telescope (according to a post on Cloudy Nights) and is theoretically observable with even a 3- or 4-inch instrument under very good skies. It’s in the galaxy NGC 3972, which you can find using Stellarium, Cartes du Ciel, or any of a number of other free programs. Right now isn’t the best time to see it, thanks to the nearly-full moon, but hopefully it will still be reasonably bright at new-moon time near the end of the month.

Gaaaah!: Sorry to end on a bummer. The state of California is planning to close 70 state parks for budgetary reasons, and the Salton Sea State Recreation Area is one of those on the chopping block (story here). The Salton Sea is one of my favorite spots for camping and stargazing, and I’m seriously bummed that they’re going to shut down the park. I don’t know who to write to in order to fight this, and even if I did, I doubt if enough people would write to make a difference. One reason I go to the Salton Sea is that it’s a really nice campground that is never empty but never overflowing, either. So it’s a bit of a catch-22: the low traffic that draws me there in the first place pretty well ensures that the park will have few advocates. And I’m not even sure if fighting this would be a good thing. I know that the state can’t afford to keep all of the parks open, and maybe it’s better to shut down a low-traffic place like the Salton Sea park and let the property rest undisturbed*, than to shut down a high-traffic place and drive those folks to the Salton Sea and thereby increase the human footprint. I’ll think about it some more, and look around and see if there is anything to be done. In the meantime, I’m just sad.

*Normally, I’d worry that this was Step 1 in some nefarious plan to sell the land for commercial development, but the Salton Sea is such a commercial black hole that I doubt if such a plan could be put into place even if someone strongly desired it, and there’s no evidence that anyone does. It’s a lonely spot, and that’s the point–I like to get out and enjoy the emptiness.

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Globe at Night 2010

March 2, 2010

We’ve all seen this map. This is why if you’re reading this, chances are better than even that you can’t see the Milky Way at night. For the entirety of human history, everyone everywhere could see more than a thousand stars on a clear dark night. That’s wrecked now, for most of the developed world, thanks to light pollution. And it only took us a couple of generations to do it.

But it would be very easy to unwreck. Our natural heritage in the sky is being washed out by wasted light. Fighting light pollution isn’t about doing away with artificial lighting, it’s about doing away with stupid artificial lighting. Full cutoff bulbs that illuminate roads, sidewalks, parking lots, and front porches contribute very little to light pollution. The problem is unshielded bulbs, which send 50% of their photons up into space. All they’re doing is lighting up the bottoms of birds, bats, airplanes, and satellites. And, not coincidentally, washing out our starscapes.

The bottom line is that unshielded bulbs are wasteful; that’s an awful lot of kilowatt hours we’re sending out into space. Putting a full-cutoff hood on a light doesn’t make it use less energy, but it at least directs all the energy where it’s needed. Or you could use a reflective hood and a bulb that eats half as much power and still achieve the same illumination.

If you want to help fight pollution, there is a very cool project going on now called Globe at Night 2010. All you have to do is go outside, find the constellation Orion, compare your naked-eye view with the GaN magnitude charts, and report your observation using their online form. You can also compare your result with those of thousands of people around the world. If you’re an amateur astronomer, just using the magnitude charts should give you a better idea of how to assess the naked-eye limiting magnitude at your observing site.

Globe at Night 2010 is running from March 3-16, so even if it’s the rainy season where you are, you will hopefully get at least one clear night. It’s fun, it’s easy, you help the human endeavor, and you learn a little something. Go to it!

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Mission 15: Ring of Fire

January 16, 2010

Mission Objectives: Bright Stars, Constellations

Equipment: Naked eye

Required Time: 2 minutes

Related Missions: Three Astronomical Treats for Naked Eyes, Binoculars, and Telescopes

Introduction: It’s a new mission for a new year. New stars are in the skies, and it’s the perfect time to start exploring the heavens–for the first time if you’re new to this, or exploring it again if you’re an old hand. This mission requires no prior knowledge, experience, or equipment; it’s just about getting out and getting acquainted with the night sky.

Instructions: Go outside after dark, face southeast, and find three stars in a straight, vertical line. These are the stars of Orion’s belt. They are flanked on either side by twin bright stars of roughly equal brightness but different color. On the left is Betelgeuse, an enormous red giant that appears yellow to the naked eye. On the right is Rigel, a blue-white supergiant.

Follow the line made by the belt stars down to even brighter Sirius. Sirius is the brightest star in Earthly skies, but it’s a not a giant or supergiant like Betelgeuse and Rigel. In fact, Sirius is a main-sequence star, a little less than twice the diameter of the sun, but about 26 times as bright. By comparison, Rigel is about 40,000 times as bright as the sun. But Rigel is 773 light years away, whereas Sirius is only 8.6 light years from us–the fifth closest stellar system to our own. Sirius, the Dog Star, is the chief star in the constellation Canis Major.

From Sirius, hang a right-angle left turn and head on to Procyon, “before the dog”, so named because it rises just a few minutes before Sirius from mid-northern latitudes. The small and otherwise dim constellation Canis Minor has little else to recommend it, and Procyon serves mainly as a celestial landmark.

Farther left still, and farther up in the sky, are the twins, Castor and Pollux, at the head of the constellation Gemini. If you have trouble keeping them straight, remember that “Castor is close to Capella, but Pollux is in proximity to Procyon”.

Speaking of Capella, it’s the very bright star directly toward the zenith from Castor and Pollux. It’s a brilliant gem in a ring of prominent stars that mark out the constellation Auriga, the Charioteer (this is not the big ring marked in red on the diagram above, but the much smaller blue-white ring on the upper left).

To the right of Capella is Aldebaran, the burning red eye of Taurus, the Bull. Aldebaran means “the follower”, because this star rises after the Pleiades, which it appears to chase from horizon to horizon (to trace that line, see the previous mission). Aldebaran is an orange giant, meaning that it has exhausted the hydrogen in its core and moved off the main sequence. Without the outward pressure of radiation from hydrogen fusion to prop it up, the core of the star is compacting under gravity and heating up. When it gets hot and dense enough to start fusing helium, Aldebaran will bloat into an immense red giant, like its neighbor, Betelgeuse.

And speaking of Betelgeuse, it lies in the middle of the great circle described by Rigel, Sirius, Procyon, Castor and Pollux, Capella, and Aldebaran. I call it the Ring of Fire–nowhere else in the northern sky is there an equal concentration of bright stars.

Below and to the left (east and north) of the Ring of Fire is Mars, which will be at opposition–opposite the sun, and at its closest approach to Earth–in a couple of weeks. The orbit of Mars is more elliptical than that of Earth, and this will not be one of the better oppositions, but it’s still the best look at the red planet that we’ll get for another two years.

What’s next? This mission was just a lightning run through the bright stars of winter. Their respective constellations are packed full of beautiful targets for binoculars and telescopes, and we’ll look at some of those in future missions. If you’re impatient to get started, download this month’s The Evening Sky Map, haul out your optics, and happy hunting!