Ad Astra Observatory

I have been meaning to write about my trip to the observatory, but we’ve had a bit of a time getting phone time this week (end of the month and all (: ).

I called on Saturday, after verifying that it was a free public night. They set me up for Monday night at 9pm.

Monday was pretty cloudy all day, and I was worried that I’d have to skip the voyage. But, miraculously, it cleared up just as the sun was setting, so I decided to head out.

The address of the Observatory is “Observatory Way” (no number), so the taxi driver was having spasms about finding it. Also, although it’s in the village of Hojbjerg (pronounced “Hoybyur”), the same village as the Moesgard museum, it’s not nearly as far out into the sticks — it’s quite nearly walking distance into town from the observatory, where the museum was 5 miles or so out of town.

Anyway, so we pull up, and I’m not sure this is the place; I mean, it’s an observatory, but the website went off about how it’s called Ole Romer Observatory, and this place is called University of Aarhus Observatory.

shrug.

So there’s a female grad-student type sitting on the steps and I ask her if this is the place, and she says it is, so I hop out of the cab and head inside.

So Anna (the female grad student) turns out to be a 4th-year PhD candidate in Astrophysics/Cosmology (her thesis is something about cosmic background radiation or something like that), and she tells me I’m the only person to sign up for Monday night, and that she has a lecture prepared (so we can wait for it to get dark), but I tell her I’m an amateur astronomer, and I’d like to hear about the history of the observatory, but anything else, we can skip.

So the observatory was built in 1909 by a German guy (Ole Romer, I assume) who had a large telescope but nowhere to house it. So he made a deal with University of Aarhus; they build him a dome, he puts the telescope in it.

There was something of a controversy in the city government and populace because the guy was German, and it got worse when the guy’s son signed up (on Germany’s side, of course) for WWI a few years later. In any case, the building reverted to the University of Aarhus in the 1970s, and it has historical landmark status (because of the particular architectural style of the early 1900s; there is a very cool set of bas-relief carvings in the lobby of the Zodiac, and other “nice touch” type stuff that they never do anymore…).

There are 2 domes. The first houses a half-meter (20”) Classical Cassegrain telescope on a gigantic fork mount; the scope is about 10′ or 12′ long, and the scope and fork are painted robin’s egg blue. The forks are about as tall as I am, and about as thick as my torso. The gear for the Right Ascension drive is visible — it’s about 3” thick and about 6′ across! (The RA drive in ad Astra Observatory is about 1/2” thick and 6” across…). I’m not sure if this is Romer’s scope or not. It’s certainly “built to last”, an imposing looking mammoth. It has some kind of home-brewed CCD camera permanently mounted to it. I didn’t mess around with the half-meter scope, just looked it over and was suitably impressed.

The other dome houses a Paramount ME mount (probably the largest mount that could reasonably be called an “amateur” mount; some amateurs own them, and they advertise in S&T, but it’s really a commercially-built observatory-class mount; its list price is $16,000), a very impressive and large chunk of beautifully milled aluminum, anodized red. Atop this monster are twin Celestron 11” Schmidt-Cassegrain telescopes (these are owned by lots of amateurs; it’s the first “big” scope that a lot of people buy, and known for having sharp optics; they’re about $1500 apiece used on Astromart); that’s an impressive amount of hardware, both in size and in cost, but somehow the scale of the whole thing (if you can imagine a mount about 3 times the size of the one in our observatory, with two scopes mounted on it like robot eyes, each scope half again the diameter of Veronica, you can start to get the idea of what I’m talking about — it’s a big object) … anyway, the scale of the whole thing is absolutely dwarfed by the size of the dome itself. This dome feels like it could easily house a telescope 20′ long or more, and the Paramount (while huge) and twin SCTs (also huge) feel a little lost in the middle of it all.

So, although it’s still a little light out, we decide to fire the system up and start looking for stuff.

Monday was still a day before 1st quarter moon, so the moon was pretty bright and over near Saturn, and Venus is still pretty high, so those targets (visible in twilight) were the first ones. Venus was bright, but just sort of blobby; I believe it’s in a gibbous (as opposed to crescent) phase, so all you’re really going to get is “bright” and “not round” and “not crescent”. ho hum. Off to the moon, which was spectacular in both scopes. The moon provided a chance to make sure the scopes were focused properly, and also to check out the field of view. With a 30mm eyepiece in one scope, and a 8-24mm “clickstop” variable “zoom” eyepiece in the other, the moon would fit entirely in the 30mm, but was just barely too big for the 24mm. Nice craters along the terminator, the Caucasus and Appennine mountain ranges were in stark relief. The Appennines are where Apollo 17 landed (”they have grandeur”). After the moon, I slewed over to Saturn.

This is where the “zoom” eyepiece came in handy. It was fun to see the extra detail on Saturn pop out just by twisting the zoom eyepiece. If I was anything of a visual astronomer and didn’t already have a big ticket purchase on the horizon, I’d look into one of those…

By now, it’s getting dark…ish… so off to find deep sky objects. M31 was way too low in the west to find. Ditto The Pleiades. M81 and M82 were there, but faint; M82 (the little, cigar-shaped one) was definitely brighter, because edge-on galaxies mean you’re looking at the combined light of more stars than face-on ones. Every time the scope slewed to a significantly different part of the sky, the dome had to be moved, too (I really like the roll-off design better and better…), so I decided to set up a trip that covered as much stuff as I could think of, but with minimal dome movements. So there was a lot of looking out at the sky, seeing what vertical slice of sky was visible, and then thinking of all the junk that was in that area, before moving on (and not a lot of jumping back and forth).

Aarhus is a pretty small city (250,000 people or so) and for a town that size, it’s still pretty dark at night, but there was still some light pollution, and because the telescope was computer controlled, my night vision never really got very good, because I’d start to see detail in the object, and then go look at the computer screen and my dark adaptation was shot again… Anyway, I decided that galaxies are on the tough side for these conditions, so I decided to check out some star clusters instead. There are a bunch in Gemini and Auriga, which always takes me back to my first days of astronomy, sitting on the balcony at the Camden apt., trying to find stuff with binoculars. So I hit M44, then M35, M37, and M38, four old friends in that area (I don’t have pictures of them, because while clusters are interesting visually, I think that nebulae and galaxies are more interesting photographically…). As I suspected, the field of view was too small to do M44 any justice (this is one of your and my favorite clusters, Praesepe or The Beehive, in Cancer); M44 is just too big, at about 1 degree across (note that the FOV at 30mm is right around half of that; the moon is 30 arcminutes = 1/2 degree, in diameter). It’s very pretty in binoculars, or the ED80, as you know. But in the 11” (focal length = 2800mm, compared to ED80’s 600mm, almost 5x more magnification), it was marginal. I mean, lots of stars, but too big. The other clusters, M35 etc were much better. Nice, compact, and showed up very well. Things made of stars show up better than things made of clouds, when you’re doing visual under light pollution. M38 (I think) has a nifty “question mark” asterism that I’d never noticed before; I’ll have to go look for it once I’m back in CA. Of course, Auriga is headed for the horizon these days; I think the only reason it was still up here is because being farther north, you can see stuff that’s below the pole that is seasonal in CA, but is up all year here. Weird.

For some reason, I found myself chasing the sky West all night (normally I start in the west, and progressively move the scope further and further east as things rise), so, in the strange order of things, from Auriga, it was off to Lyra for a peek at M57 (the Ring Nebula, no photos yet; it’s *way* too small for my photo rig to do justice), the Double Double (Epsilon Lyrae is a pair of stars, each of which has a faint companion), and Delta Lyrae, a very pretty binary star in which one is red/orange, and the other is green. From there, it was off to M13, probably the highlight of the night. M13 is gorgeous in any size of telescope, from binoculars right on up, and the more telescope you throw at it, the prettier it gets. It simply filled the eyepiece at 24mm, and zooming in really changed it from “a puffy fuzz with some stars” into “salt scattered on velvet”. What a sight. Absolutely stunning. M3 (I need a better photo of it) was also quite nice, although nothing compared to M13. Then, in a fit of confidence, I pointed at M51 which was disappointing after the string of bright star clusters, but both galaxy cores were visible, and if I stayed and stared a little, I could believe that I could see fuzzy cloudyness that must have been the spiral arms of the larger galaxy. It was starting to get late, but I wanted to see the Virgo cluster of galaxies, so I skipped the other galaxies in The Big Dipper area, and off I went to M84 (no photos yet of this area; springtime is a tough time for astrophotography in CA), and again, the galaxies were visible. There are 3 bright galaxies in the region (here’s an amateur image of the area; M84 is one of the “eyes” of the “face” on the RHS… ); I could see both “eyes” and the “mouth”, but it was late and I didn’t have time to poke around much for other galaxies in the area.

At this point it was about midnight, so I helped to shut the scope down and get it all covered, etc. and then called a cab. While waiting for the cab, I discovered that public nights are held most weekdays, with a variety of grad students sharing the load of being “docent on-call”. I decided to try to find a T-ring for my camera so I could try to snap some shots of the sky next time I’m there. Despite my complete inability to find a T-ring, I may go back tonight (Friday night), and Martin and Willy want to go see the place on Monday night, so I may do that as well.

The cabbie had trouble finding the place, because all the lights were out, but I got that straightened out, and thus ended my trip to the Ole Romer Observatory.