Archive for the ‘Big telescopes’ Category

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Small, medium, large – observing near and far in the last two weeks

June 4, 2016

Matt at Delicate Arch IMG_2984

Preface – Running with the Red Queen

I’ve just finished maybe the busiest spring of my life. January and February were largely sunk into day-job work – time-consuming, but necessary, interesting, and in fact rewarding. Then the last three months have been taken up with travel and public lectures.

  • In March I went to Oklahoma for 10 days of paleontological research in field and lab, and I gave a talk at the Oklahoma Museum of Natural History titled, “Dinosaurs versus whales: what is the largest animal of all time, and how do we know?”
  • In April I did a two-day trip to Mesa, Arizona, for more paleo work. No talk on that trip, but I did participate in the “Beer and Bones” outreach at the Arizona Museum of Natural History.
  • In early May I was in Utah for another 10 days of paleo research, and I gave a talk at the Prehistoric Museum in Price on, “Why elephants are so small”. My colleague Mike Taylor and I took one day off from dashing through museums to tour Arches National Park, which is where Mike took the photo at the top of the post.
  • Last weekend I was up at RTMC, where I gave a Beginner’s Corner talk on, “The scale of the cosmos”.

I’m not complaining – far from it. It’s been exhilarating, and the collaborative work I have rolling in Oklahoma and Utah will hopefully be paying off for years. And planning and executing all of the work has been satisfying. Particularly the RTMC talk, which deserves a whole post of its own. And ultimately this is all stuff that I chose to do, and if I could do it all over again, I would.

BUT there have been consequences. Most frustratingly, I haven’t had enough uninterrupted time to get anything written up for publication – not the sizable backlog of old projects I need to get finished up, and not the immense pile of new things I’ve learned this year. I haven’t gotten out to observe as much as I’d like, and I’ve barely blogged at all.

And it’s not over. In two weeks I leave for a week of paleo fieldwork in Oklahoma, then I’m back for a week, then I’m off to Utah for about 10 more days of digging up dinosaurs. In between I’ll teaching in the summer human anatomy course at WesternU.

But I’ve had a nice little pulse of observing in the last couple of weeks – two weekends ago up at Arroyo Grande, near San Luis Obispo, last weekend at RTMC above Big Bear, and this week at Santa Cruz Island off the coast. No time for separate observing reports, so I’m combining them all into one.

Observing Report 1 (Medium): The Planets and Moon from Arroyo Grande

I was fortunate to be part of a great, tightly-knit cohort of grad students at Berkeley. Of the people I was closest to, some are still in and around the Bay Area and some of us have been sucked into the gravity well of the LA metro area. Occasionally we get together somewhere halfway in between, either up in the Sierras or near the coast. I usually take a telescope, because almost everywhere is darker than where I live, and when I’m traveling by car there’s simply no reason not to.

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This year we met up for a couple of days and nights in Arroyo Grande. We hiked in the hills, went down to Morro Bay to watch ocean wildlife and buy seafood, played poker, and generally got caught up on work, family, hobbies, and life. Our first night was wonderfully clear. I had along the trusty C80ED, which has become my most-used scope. It’s mechanically rugged, optically damn near perfect, and compact enough to not require much time or thought when it comes to transportation and setup. On Saturday, May 21, we spent some time with Jupiter, Mars, and Saturn. Jupiter and Saturn were as they always are: beautiful and surprising in their immanence. I cannot look through the telescope at either of them without being forcefully reminded that they are as real as I am, that as I go about my days full of busyness and drama, they are always out there, hundreds of millions of miles away, go about their own business whether I or anyone else pay them any attention or not. One of my friends had never seen the rings of Saturn with his own eyes, so that was an added bonus.

Mars was the real treat. Using the Meade 5mm 100-degree EP and a Barlow I was able to crank up the magnification to 240x. The dark dagger of Syrtis Major and the white gleam of the north polar cap were both obvious. It is always arresting to see details on this world that has loomed so large in the human imagination, from ancient mythology to science fiction to current and future exploration.

The next night we sat out on the patio, eating oysters and watching the sun set. I didn’t have any of my own binoculars along, but a friend had brought a couple, and after it got dark we watched the still-mostly-full moon rise through the trees on the ridgeline to the east.

It was all shallow sky stuff (solar system, that is), but it was all spectacular, and I’m glad we did it.

Observing Report 2 (Large): Going Deep at RTMC

Last weekend I was up at RTMC, finally. I’ve been wanting to go since I got to SoCal, but in the past it’s fallen on the same week as our university graduation and I’ve been too wiped out. I didn’t make it up for the whole weekend. We went up as a family to stay Saturday and Sunday nights. I went up to RTMC early Sunday morning to look around, give my talk, and hang out. Ron Hoekwater, Laura Jaoui, Jim Bridgewater, Ludd Trozpek, and Alex McConahay of the PVAA were all there and we spent some time catching talks and jawing about skies and scopes. I also chatted with some folks from farther afield, including Arizona and NorCal.

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I took off in the afternoon to spend time with London and Vicki, then went back up after dinner. All I had along were my Celestron 10x50s (yes, those), but Ron had his 25-inch Obsession dob, and he was content to use it as the centerpiece of a group observing session. We looked at the planets, or at least Jim Bridgewater and I did – Ron had checked them out the previous night and didn’t want to blow out his dark adaptation. That was a smart call, as the Obsession gathers a LOT of light and the planets were almost blown out. We could have put in a filter, but ehh, we had other things to be getting on with.

We started with globular clusters. M3, M5, M53, NGC 3053, and one or two other distant NGC globs. The close ones were explosions of stars that filled the eyepiece. The distant ones shimmered out of the black like the lights of distant cities. Then we moved on to galaxies. M81 and M82 were bigger, brighter, and more detailed than I had ever seen them. M51 was just stunning – the spiral arms were so well-defined that it looked like Lord Rosse’s sketch.

M51 sketch by Lord Rosse

As nice as those were, the Virgo galaxy cluster was better. There were so many galaxies that identifying them was a pain – there were so many little NGCs in between the familiar Messier galaxies that my usual identification strategies kept getting derailed. It was kind of embarrassing, actually – I did just write an article about this stuff. But also incredible. NGC 4435 and 4438 – the pair of galaxies known as “The Eyes” – were so big, bright, and widely separated that I didn’t realize I was looking at them until the third or fourth pass.

We finished up on planetary nebulae. The seeing was good but not perfect – the central star in the Ring Nebula was visible about a quarter of the time. The Cat’s Eye, NGC 6543, was a fat green S with a prominent central star – it looked like it had been carved out of jade.

An evening under dark skies with a giant scope is both a blessing and a curse. A blessing because you get to see so many unfamiliar objects, and so many details in familiar objects, that are beyond the reach of smaller scopes. A curse because by the end of the session you may find yourself thinking, “Sheesh, why do I even bother with my little 3-, 5-, and 10-inch scopes?”

Fortunately another observing experience, one that would remind me of the joys of small-aperture observing, was right around the corner.

Observing Report 3 (Small): A Binocular Tour of the Spring Sky

My son, London, is finishing up fifth grade at Oakmont Outdoor School, one of the half-dozen or so different elementary schools in the Claremont Unified School District. We were fortunate when we moved to Claremont to land just a couple of blocks from Oakmont – we would have been happy to land within walking distance of any of the schools, but if we’d had our choice we would have picked Oakmont anyway, since we wanted to raise London with as much exposure to the outdoors as we could.

Oakmont’s slogan is, “Learning in the world’s biomes”. The major activities of each grade are organized around a particular biome, and so is the end-of-year field trip. In third grade, the kids went to Sea World. Last year it was the desert by Palm Springs for a 2-day, 1-night trip. This year it was Santa Cruz Island, in Channel Islands National Park, for a 3-day, 2-night trip. Parent chaperones are needed and I’ve been fortunate to get to go every year.

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The island was amazing. We saw dolphins, sea lions, and petrels on the boat ride out – I took the photo above from the prow of the ship – more sea lions, seals, pelicans, cormorants, gulls, and red pelagic crabs at the shore, and dwarf island foxes, ravens, and the occasional hawk inland. On the final evening, June 2, we hiked up to the top of the cliffs to watch the sun set over the Pacific, which was one of the most beautiful things I have ever seen in my life. I didn’t know it at the time, but I’d see something even more beautiful just a few hours later.

I had binoculars along – Bushnell 10×40 roofs that I got specifically for daytime use, and which I had used a lot on the trip already to watch wildlife. When we got back to camp, a few of the teachers and hung back and started talking about the planets, bright stars, and constellations. I started pointing out a few of the brighter targets and passing around the binoculars, and we ended up having an impromptu binocular star party. (The kids and a fair number of the adults were all exhausted from a full day of hiking, and sensibly went to bed.)

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What followed was one of the best and most memorable observing sessions of my life. The only permanent residents of Santa Cruz Island are a couple of National Park employees, and they turn their lights off after dark. We got a little light pollution on the eastern horizon from Ventura and Oxnard, some 20 miles distant, but for the most part the sky was darkAfton Canyon dark, Hovatter Road dark – what I typically refer to as stupid dark.

We roamed all over the sky, looking at targets large and small, near and far, bright and dim. I didn’t keep track as we were going, but I wrote down a list yesterday morning on the boat ride back to the mainland (we went through a fog bank and only saw a handful of dolphins, so I had plenty of time).

In the northern sky:

  • Polaris and the Engagement Ring asterism
  • Mizar and Alcor
  • M51 – yes, it was visible in the 10×40 bins
  • The 3 Leaps of the Gazelle

In the western sky:

  • M44, the Beehive – easily visible to the naked eye, and just stunning in the binos
  • Leo
  • Coma Berenices star cluster
  • Virgo/Coma galaxies – identifications were tough, but a few were visible

In the eastern sky, Lyra had just cleared the trees when we started observing (at 9:15 or so), and all of Cygnus was above the trees when we finally shut down at 12:45 AM. In addition to tracing out the constellations, along the way we looked at:

  • Epsilon Lyrae, the Double-Double star
  • Albireo
  • Alpha Vulpeculae (the subject of my Binocular Highlight column in the ### issue of Sky & Telescope)
  • Brocchi’s Coathanger (Collinder 399)
  • Sagitta (just traced the constellation)
  • M27, the Dumbbell Nebula
  • Sadr and its surrounding ring of stars in the heart of Cygnus
  • NGC 7000, the North American Nebula – this and the Northern Coalsack were easily visible to the naked eye once Cygnus has risen out of the near-horizon LP

…and we just cruised the Milky Way from Cygnus to Cepheus, not singling out individual objects but just taking in the rich star fields.

But the southern sky was the best. Looking south from Santa Cruz Island, there’s only open ocean, broken here and there by other, distant islands and ultimately by Antarctica. It reminded me of looking south from Punta del Este in Uruguay, only I was in a valley instead of on a beach. The ridgeline to the south did cut off a bit of the sky, but we were still able to see all of Scorpio, including the False Comet, made up of NGC 6231 and Trumpler 24, which was one of the highlights.

It was trippy watching the Milky Way rise. I usually look at the summer Milky Way when it is higher overhead. I usually have to do that, because the objects aren’t visible in the near-horizon haze. But from Santa Cruz Island, things were not only bright but obvious as soon as they cleared the ridgeline to the south. It’s almost pointless to list them – we saw every Messier object in the “steam from the teapot”, from M7 and M6 in the south to M11 in the north, plus a lot of NGCs, plus star clouds and dark nebulae almost beyond counting. They were all great through the binoculars – M7 was a special treat, like a globular cluster on a diet – but honestly the best views of the night were naked-eye.

I realized that I am just never out observing the Milky Way at this time of year. My regular desert observing spots are all too hot in the summer, and when I do go there is often at least some light pollution to the south (El Centro from the Salton Sea, Barstow from Owl Canyon, etc.). I do most of my deep and dark observing in October and November, when the southern Milky Way is setting, not rising.

So I was completely unprepared for how much detail would be visible to the naked eye. When the Milky Way rose, it didn’t look like a band of light, it looked like a galaxy. I searched through a lot of photographs of the rising Milky Way to find one that approximated the naked-eye view, and this is the closest I got:

I am not exaggerating – the bright and dark areas were that defined. The Great Rift was visible from Cygnus to the horizon, and its southern border was notched by distinct deep sky objects from Aquila onward. The Scutum Star Cloud, M16, M17, M24, M23, M8, M6, M7, NGC 6281, and the False Comet were all easily visible to the naked eye as a chain of luminous patches against the dark dust lane of our own galaxy. In fact, I noted NGC 6281 with my naked eyes first, thought, “What the heck is that?”, and had to look it up. We also caught M4, M22, M23, and M25 in the bins, plus a bundle of dark nebulae that I’d never noted before and didn’t bother keeping track of.

Longtime S&T contributor Tony Flanders (now retired but still writing occasionally) is active on Cloudy Nights, and his sig file reads:

First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.

Until fairly recently I would have listed my own preferences in reverse order, from telescopes to binos to naked eye. That may sound odd for a “bino guy”, which I guess I am since all of my ‘professional’ astro-writing has been binocular-based. But it’s true – as much as I love binoculars, I would have picked a telescope first. But I am – gradually, belatedly – waking up. In some ways, it would have been great to have a scope, any scope, along on the island trip. I’m sure that even the C80ED would have taken us crazy deep, considering what we could see with a pair of low-end 40mm roof-prism bins. But it would also have come between us and the sky, and I would have spent more time futzing with eyepieces and less time just looking up.

This was a surprising and welcome realization, coming so shortly on the heels of a frankly astonishing session with Ron’s 25-inch dob at RTMC. I was worried that big-telescope observing might spoil me, but that fear turned out to be unfounded. All I need to be happy is a dark sky. If I have some people to share it with, even better. Anything more is just cake at the end of an already long buffet.

Let’s eat.

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A tour of Big Bear Solar Observatory

October 13, 2015

BBSO from up high

The gleaming white domes of the Big Bear Solar Observatory sit at the end of a causeway that projects from the north shore of Big Bear Lake – they draw the eye from almost any point in Big Bear Valley. And as I mentioned in my last post, the Pomona Valley Amateur Astronomers got to visit the BBSO on Friday, October 9.

BBSO causeway

We were greeted at the gate by Claude Plymate, Chief Observer and Telescope Engineer at BBSO, and Teresa Bippert-Plymate, who is not only a professional solar astronomer but also the president of the Big Bear Valley Astronomical Society. As pros who are also enthusiastic amateur observers, Claude and Teresa did a great job of pitching the tour with just the right balance of necessary background, technical detail, and the hands-on practicality of managing big scopes and the complicated hardware and software necessary to run them.

BBSO GONG scope

The first thing you come to on the causeway is a big white storage container with a coelostat (sun-tracking mirror) – this is one of the six Global Oscillations Network Group (GONG) installations spaced roughly equally around the world. The GONG telescopes track the sun around the clock for helioseismology research, mapping the acoustic pressure waves that propagate around and through the sun.

PVAA group outside BBSO domes

The smaller dome just short of the end of the causeway holds two telescopes on a common mount. One is a 10cm full-disc hydrogen-alpha solar telescope, the other is a second smallish refractor for Project Earthshine, which tracks the Earth’s albedo by measuring the intensity of the earthshine that falls on the moon’s unlit side.

London with BBSO New Solar Telescope

The observatory’s ‘big gun’ is the 1.6-meter New Solar Telescope, an off-axis Gregorian. One-point-six meters is 63 inches, which means this scope has a slightly larger aperture than the famous 60-inch reflector on Mount Wilson (which I’ve been fortunate to visit – see here and here). Here’s the light path of the NST (an unmodified version of this image is at the bottom of the post):

BBSO New Solar Telescope light path

And here’s a view on the right side of the scope showing the mask that rejects the light from most of the sun (which bounces onto the back wall of the dome, landing at about the same intensity as natural sunlight). The mask has a small hole which allows light from a small part of the sun to pass through to the chain of lenses and mirrors that bounce the beam to the research instruments on the next floor down.

BBSO New Solar Telescope right side optics

It took me a while to wrap my head around how this works. If the mask rejects most of the sun’s light, doesn’t that mean that most of the telescope’s 1.6-meter aperture is wasted? The answer is no – the mask functions as a field stop, not an aperture stop. If I put a mask across the front of my 10″ Dob and let only a 4″ beam of light through, that’s an aperture stop – it effectively turns a 10″ f/4.7 obstructed system into a 4″ f/12 unobstructed system (which may be desirable for sharp planetary and lunar views, where light-gathering is not so important). But imagine I left the front of the scope uncovered and instead masked down the field stop at the bottom of one of my eyepieces, so that I could only see a tiny hole in the center. If I put the scope on Jupiter, I’d see Jupiter in the center of the field but nothing else – I’d be getting the full benefit of the 10″ mirror’s light-gathering and resolution on Jupiter, but rejecting the light from the surrounding starfield, which would reflect off the mask at the bottom of the eyepiece. That’s more or less what happens with the New Solar Telescope, only “the rest of the field” is the rest of the sun, and the small area that the scope focuses on is not a planet but a small patch of the sun’s surface. But that patch can be imaged with the full benefit of the 1.6-meter primary mirror’s angular resolution.

BBSO burnt light shield

Now, a 1.6-meter mirror focusing the light from the full disc of the sun onto an area about 3cm across is a hell of a lot of energy. That beam could fry electronics, melt metal, and start fires if it got off-course. There are multiple redundant systems to prevent that from happening – the dome can close, the primary mirror has a cover that can activate quickly, and if all else fails a 1/16″ steel plate slides into position in front of the field stop. A few years ago – before Claude’s tenure as Chief Observer! – there were not so many safeguards in place. The software that allows the telescope to track the sun briefly got confused by some passing clouds, and the scope stopped tracking properly. That allowed the concentrated beam of sunlight to slide off-target. The steel plate did its job and slid into place, and the scope melted two holes in it in the space of about 30 seconds. The folks at the observatory keep the melted metal plate as a visible reminder that they are in a very real sense playing with fire.

BBSO sunspot image

This sunspot is a bit larger than our planet.

Our last stop on the tour was the telescope control room, where another professional astronomer was driving the scope and taking data. There was a minor mechanical hiccup at one point and Claude had to swing into action, running back and forth from the control room to the instrument room to get everything back on track. It was amazing to see live images coming in in real time. I’ve been fortunate to tour a lot of observatories but never while they were working. At one point Claude and the other astronomer put the scope on a sunspot group which was just swimming in atmospheric distortion. Once the computer had enough data to engage the adaptive optics, they switched on the AO and the view instantly settled down to nearly rock-solid, like it was painted on the monitor.

BBSO New Solar Telescope

The NST is currently the largest, best-equipped solar telescope in the history of humankind, and it is producing the sharpest images of the sun ever taken. BBSO joins Mount Wilson and Palomar in continuing the long, proud history of world-class astronomy in southern California. And it’s 65 miles from my house. Many thanks to Claude and Teresa for being such gracious hosts and letting us see their beautiful machines in action.

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Observing Report: Afton Canyon, again

April 26, 2015

Afton Canyon April 2015 1 - Wedel camp

I’m now posting observing reports in reverse order. The last post was about the PVAA star party on April 18, this one is about an informal gathering at Afton Canyon the week before. I got an email from Ron Hoekwater saying that he, Laura Jaoui, and Craig Matthews would be heading out to Afton on Saturday, April 11. London and I were already planning on camping somewhere that weekend, and the high desert promised to be cooler and darker overnight than the Salton Sea or points south, so we jumped.

Afton Canyon April 2015 3 - waiting for dinner

I was excited to get back. The only other time I’d been to Afton, in the fall of 2010, I had one of the most memorable nights of stargazing of my life. That time the road down to the campsite was in horrible shape so we camped up on the rim. This time the road was passable and we got a campsite right across from Ron, Laura, and Craig. Craig had his 12-inch Meade Lightbridge dob, and London and I brought our XT dobs and a couple of smaller scopes.

Afton Canyon April 2015 6 - Ron's Obsession

Ron brought his new 25-inch Obsession. More about that in a bit.

The early evening was fairly miserable. We were camped only a little over 100 yards from the Mojave River and the mosquitoes were ghastly. I had a ThermaCell on, but for once it seemed to do no good. Possibly because of the breeze – there was a very light breeze, not enough to keep the bugs off, but possibly enough to disrupt any benefit from the ThermaCell, even though I tried to keep it upwind. Fortunately, Craig had some DEET wipes to share, and the wind came up after dark, just enough to keep us mostly bug-free for the rest of the evening.

Afton Canyon April 2015 4 - campfire sparks

London and I set up camp and cooked dinner (hot dogs and brauts) and then started picking out some of the best and brightest things in the sky. I didn’t do much dedicated observing of my own – too busy helping London and sneaking peeks through Ron’s 25-inch. After London sacked out, I abandoned my scope entirely, and spend the next three hours observing with Ron. He was very generous with the scope and even let me drive it to new objects a couple of times. It was the first time I’d gotten to actually use such a big scope for more than quick peeks at star parties.

It was pretty freaking spectacular. We looked at M81, M82, M51 and NGC 5195, M104, M97, M108, M5, M13, M57, M4, NGC 6144, NGC 4565, NGC 4559, an Abell galaxy cluster in or near Serpens Caput (I’ve forgotten the designation, but there were a LOT of galaxies in the field), NGC 4361, and Epsilon Lyrae. We caught the outer spiral arms of M81, the bridge of gas between M51 and NGC 5195, to-the-core resolution on the big globular clusters…amazing things. Unfortunately, the lousy seeing kept us from resolving the central star in the Ring Nebula. The Owl Nebula actually looked like an owl. My favorite view of the night was of M51 – the spiral arms weren’t just there, they were sharp and detailed, like a slightly fuzzy photo of the galaxy. Wonderful night.

Peggy Sue's Diner-saurs - London with sauropod

On the way home the next day, London and I saw dinosaurs, but you’ll have to head over to SV-POW! for the rest of that story.

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PVAA outreach at Oakmont Elementary School

March 26, 2015

Oakmont astronomy outreach - London with telescopes

Our local club, the Pomona Valley Amateur Astronomers, had a public outreach at London’s elementary school this evening. London brought his 60mm Meade refractor, and I brought my C80ED.

Jeff Schroder and his 11-inch refractor

Our little scopes were quite literally overshadowed by Jeff Schroder’s 11-inch refractor, which is mounted to the top of his car. Jeff built this scope by hand, even ground the lenses himself. It’s entirely fitting that he’s the outreach coordinator for the PVAA – not only does he have the coolest scope, he was one of the founding members of the club back in the day.

First quarter moon - C80ED and iPhone 5 - 2015-03-26

Jeff also had a 10-inch Dob along, and Ron Hoekwater brought his Skywatcher 10-inch collapsible Dob. We showed people the moon, Jupiter, Venus, and the Orion Nebula. I got this moon shot with my iPhone with much less futzing around than usual. I don’t really understand how that happened, but I’m not complaining.

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A visit to the Griffith Observatory

November 2, 2014

2014-11-01 Griffith Park 1 - the observatory

Yesterday London and I went to the Griffith Observatory for the first time in a while. We used to go fairly frequently between 2010 and 2012, but this was our first visit in 2014 and might have been our first visit since 2012.

2014-11-01 Griffith Park 3 - moon over the observatory

It had been rainy earlier in the day but the skies opened up nicely in the late afternoon, and the waxing gibbous moon was bright overhead.

2014-11-01 Griffith Park sunset 2 - snapseed

Happily there were still some clouds to the west and north, which made for a fantastic sunset.

2014-11-01 Griffith Park 5 - London with Galileo telescope

One of my favorite displays is the replica of Galileo’s ‘Old Discoverer’ in the Hall of the Eye. It is still amazing to me that Galileo saw and learned so much with a 1-inch objective mounted in a paper tube. London is blocking the objective end here, but I had to pose him there for a reason.

2009-11-01 Griffith Park - London with Galileo telescope

Here’s the same shot, five years earlier. London was not quite five years old, and he was very excited about being at the “Griffick Ugzerbatory”. I didn’t realize until I checked the dates on the photos that that first visit was not approximately five years earlier, it was exactly five years earlier, on the first of November, 2009.

2014-11-01 Griffith Park 4 - observatory model

Farther down the same hall, there is this miniature architectural model of the observatory. The three domes all house different things. The one on the west end of the roof, nearest the camera in this shot, holds the triple beam coelostat for live viewing of the sun. The huge middle dome holds the planetarium, and the dome on the east end holds the big 12-inch Zeiss refractor–you can even see a translucent miniature version of the scope in the model dome.

2014-11-01 Griffith Park Zeiss refractor 1

And here’s the 12-inch Zeiss itself. There are actually five scopes on the mount currently: the big Zeiss, f/16.7, at the center, a 9.5-inch f/14.8 Zeiss refractor piggybacked on top, a 2- or 3-inch finderscope on the lower left, and two 8-inch Celestron SCTs on either side.

Originally the mount only held the 12-inch and the finderscope–you can see photos of it mounted that way on this page, which has a very interesting history of the scope and its uses. The 9.5-inch was added in 1955. The double refractors allowed one scope to be used for visual observation while the image from the second was sent to a closed-circuit TV. That job is now farmed out to one of the Celestron SCTs, which are much more recent additions.

2014-11-01 Griffith Park Zeiss refractor 2

Here’s another view. The total moving mass of the rig is 9000 lbs, or 4.5 tons.

We have gotten to look through the big Zeiss a couple of times, but we didn’t do so last night. There is usually a line with a wait time of about an hour. The way to beat the system is to be on the roof and near the east end at the moment that they open the dome and the line first forms–we have been lucky to be in that position once before. But last night we were in the middle of a planetarium show when the dome opened at 7:00, and we didn’t fancy standing around in the cold for an hour. Especially because there was a public star party on the lawn in front of the observatory, with about half a dozen scopes set up. There were long lines for the big scopes, but one guy had a 90mm Mak on an EQ mount that everyone seemed to be ignoring. London and I got razor-sharp views of the moon through that little scope with no waiting at all.

2014-11-01 waxing gibbous moon - raw

At home I hauled out the C80ED and the 8-24x zoom eyepiece for a quick look myself, and to make another photographic attempt with the iPhone. The two biggest challenges are getting the camera the right distance from the eyepiece, and getting the sensor fully illuminated without being overexposed. Through much trial and error I found that if I left the eyepiece cup up and stripped off only the outer layer of my 3-layer Otterbox phone case, I could rest the second layer of the phone case on the rubber eyepiece cup and have the phone at just the right distance. But that only worked perfectly with the zoom set to 18mm (33x), which is how I took this shot. There is some CA, but I’m pretty sure that was mostly from the eyepiece. If it’s clear tonight, I’ll try again with the ES eyepieces to see if I can isolate the cause of the CA.

One thing I desperately need to do is get one of the iPhone apps that lets you control the ISO and shutter speed of the camera. As it is, I’m just using the camera as-is, so I’m constantly fighting with its auto-exposure and auto-shutter. There’s a delicate balance–if I don’t magnify the moon (or the filtered sun) enough, all I get is a featureless white spot. But if I magnify the subject enough to spread out the light and give the camera’s internal processes some detail to bite on, then it’s hard to get the object fully illuminated–I get vignetting, or kidney-bean blackouts, or both at once. Eric Teske has a nice list of iPhone astro apps on his (ridiculously entertaining) blog–past time I started using them.

2014-11-01 waxing gibbous moon - snapseed

Still, for a shot through an 80mm refractor with the came-bundled camera driver on my phone, I’m pretty happy. One thing I really like about the iPhone is the number and utility of photo-editing apps. The first moon image here is the raw shot, only reversed left-to-right to match the moon’s orientation in the sky. The one immediately above I processed in Snapseed: sharpened, contrast enhanced (using the ‘Ambiance’ tool), and desaturated to take out the CA. Given the relatively small number of GIMP features that I actually use, Snapseed is a fast and easy alternative. I’m going to keep messing with it and see how far I can go.

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A birthday observing run at the Webb Schools Hefner Observatory

June 16, 2014
Spiral galaxy M81

Spiral galaxy M81

My birthday was June 3. That evening, fellow PVAA member Steve Sittig invited me up to the Hefner Observatory at the Webb Schools in north Claremont. Steve teaches science at the Webb Schools, and he has a particular interest in physics and astronomy. The dome at the Hefner Observatory houses an orange-tube C14 Schmidt-Cassegrain. Observing with us were two other Webb faculty members, Andy Farke (paleontologist, blogger) and science teacher Andrew Hamilton. Andrew Hamilton had brought along his DLSR, a Sony Alpha33—this would turn out to be important.

Starburst galaxy M82

Starburst galaxy M82

We got started a little after 9:00 PM with a look at Jupiter, which was low in the west. We noticed right away that the seeing was pretty darned good. We went on to the waxing crescent moon and then Mars and Saturn. After that we turned to the deep sky. M81 and M82 looked great, so we hooked up Andrew’s DSLR and attempted some photography. We didn’t have a remote shutter or computer control, so we were using only the camera’s native controls, and assessing the results on the LCD screen.

Planetary nebula M57, the Ring Nebula

Planetary nebula M57, the Ring Nebula

After the galaxies, we went on to the Ring Nebula, M57, and then the Great Globular Cluster in Hercules, M13. Even with the 30-second exposures that the camera was natively limited to, we were getting very respectable images. I am including a few here.

M13, the Great Globular Cluster in Hercules

M13, the Great Globular Cluster in Hercules

Our results were pretty primitive compared to what people can do with dedicated astro cameras and post-processing, but we still had a grand time, and the process was sufficiently rewarding that we stayed out until almost two in the morning. All in all, a pretty darned good birthday present. Hopefully we’ll be able to reconvene and shoot some more this summer. I’ll keep you posted.

Many thanks to Andrew Hamilton for permission to post these photos.

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Guest post: The “First” Great Telescope: the Great Dorpat Refractor in Tartu’s Old Observatory

October 1, 2012

Here’s another guest post by Terry Nakazono (his first is here). Enjoy!

(All pictures, except for the image of F.G.W. Struve, were taken by the author)

In a few posts (and one Cloudy Nights article), Matt made mention of getting his start in observational astronomy after a visit to Lick Observatory in San Jose, California and looking through the Great Lick Refractor.

The term “Great Refractor” refers to an achromatic refracting refractor that is the largest in a region, or in the world. When it was completed in 1888, the Lick refractor was the biggest (36-inch lens) in the world. Hence the term the “Great Lick Refractor”.Earlier in April this year, I made a visit to the Old Tartu Observatory in Tartu (Estonia), built between the years 1808-1810 and now a museum.

This observatory houses the first “Great Refractor” – the Great Dorpat Refractor (Dorpat is the old German name for Tartu), built by the noted German optician Joseph Fraunhofer in 1824 (also known as the Fraunhofer Refractor). This telescope was the forerunner of the Lick and other large refractors built in the 19th and 20th centuries.

This 9.6 inch (24cm) achromat with a focal ratio of 16.6 was the largest and best refractor in the world for many years. The lens had a light-gathering capacity equal to a reflector of that era having twice the aperture of this refractor. This was also the first telescope to use a German equatorial mount, with a precision clock drive that allowed objects to be tracked automatically.

The man who ordered this telescope from Fraunhofer was Friedrich Georg Wilhelm Struve, the director of the observatory from 1820-1839.

His most famous observations with this refractor included a massive survey of double stars (whereby he published two double star catalogs), the measurement of the parallax of Vega in 1837, measurements of the diameters of Jupiter’s 4 largest satellites in 1826 (which turned out to be the most accurate for the next century), and Halley’s comet in 1835, where he measured the dimensions of the tail and was able to see the nucleus of the comet. On the observatory grounds is a monument to Struve.

On display at the observatory are many other instruments used by Struve and others. One is the Dollond transit instrument (purchased in 1807), used to determine exact astronomical coordinates.

Another instrument used to measure the position of stars was the Reichenback-Ertel Meridian Circle (purchased in 1822).

The Troughton telescope (purchased in 1807) was a 3.5 inch achromat that was Struve’s main observational instrument before the Fraunhofer refractor.

But the most fascinating item on display (besides the Fraunhofer scope) is the Herschel 7-foot refractor, bought in 1806. Herschel made 200 of these 7-foot scopes between 1778 and 1820, out of which only 21 have survived today. It was with one of these scopes that he discovered Uranus in 1781. The aperture of the Herschel 7-foot scope was 160mm, or 6.3 inches. Reflectors of that era were made of speculum metal, which tarnished easily and reflected only 66% of the light that hit it. During the pre-Fraunhofer refractor days, it was easier for Struve to use the Troughton 3.5 inch refractor as his main observing scope, since it was much more portable and probably matched, if not exceeded, the light-gathering capability of the Herschel reflector. Consequently, the Herschel scope was used mainly for observing the occultation of stars by the Moon.

There were two Tartu University students working in the observatory (one worked the front desk and the other was letting visitors in and out of rooms]. Unfortunately, they were neither astronomy nor science majors and could not answer any of my questions regarding the Fraunhofer and other instruments.

Here is a picture of the dome of the observatory at night – you can see the moon and Venus next to it.

This next picture shows my Galileoscope 2-inch achromat refractor in front of the entrance to the observatory.

Looking forward to visiting other historic observatories, including the ones closer to home (e.g. Lick, Mt. Wilson, Palomar).