I’m not sure if we’ve been especially unlucky or if this is the norm for observing trips, but we once again the weather is curtailing our telescope time. After a few hours of normal observing, clouds started to blow across the top of Mauna Kea, and now it’s raining outside the dome.
In the meantime, Becky and I shot a short video tour of the dome a couple days ago you can check out:
Tomorrow, we check out of Hale Pohaku and head down to Hilo for a night. Then I’m off to Chicago and Becky and Sandor are back to Oxford. Even with the bad weather, sleep deprivation, and static electricity, this trip has been a really great experience for me. I now know infinitely more about radio astronomy than I did before! I hope the people doing the real work were able to get all the data they needed.
A Few Notes:
After few good days of observations the wind has returned to ruin our fun. The CSO telescope is supposed to be closed when the wind is above 35mph. Curiously the telescope itself doesn’t have its own anemometer, so we have to rely on readings from the other telescopes on the mountain to decide if it is safe to open the telescope building.
Feeling this entire situation was quite unsatisfactory, I decided to build my own anemometer using a clipboard with a ruler and Becky’s boot, giving you the answer to Chris’s question from earlier tonight:
Using the above chart we tried to workout the wind speed. We had to do a bit of fudging. We decided the boot was a perfect cylinder (drag coefficient 0.82), and that it weighed about 300g. We also decided not to take into account lower air pressure. Finally when Sandor and I calculated it independently, we got wildly different results, so it was a futile exercise in the end. (Also CSO buy an anemometer)
Since then, we’ve been playing chicken with the wind. Sometimes having to close the dome. Sometimes thinking we can be open, only to have the telescope struggle to stay on target. Sometimes we hear Meg Schwamb‘s wind tracker say “Warning High Winds”. The conditions made us miss out on a second night of observing Comet Lovejoy, and everyone seemed pretty down for most of the night.
Around 1 or 2am the wind finally let up and we were able to start observing, so the night wasn’t a complete loss. Hopefully the weather tomorrow is better.
A Few Notes:
- It’s really hard to get enough sleep. Sleeping at altitude is hard anyway, and adding in trying to sleep during the day gives us all points for degree of difficulty. Everyone has lovely bags around their eyes.
- This is the last day Chris is with us. We’ll be all alone tomorrow night.
- Sandor is succumbing to the static curse now too.
- @GeertHub on Twitter wanted to me to post a screen shot of the telescope software:
- All the Sex & Drugs & Rock & Roll is helping us touch the sky.
(turns out they have swinging ropes in the control room, who knew?). Sandor and Becky did the actual observing work. Sandor running the telescope, and Becky doing the data reduction to produce a nice graph Chris tweeted:
In the last post, I talked about how the telescope deals with the background noise from the Earth’s atmosphere by ‘chopping’ or alternating reading from its target and a point slightly off the target, then combining the readings to produce a measurement of the target with atmospheric interference removed. This works well for the distant galaxies we are observing, but not with the comet. Chris realized that the comet was too close and large (in a relative sense) for chopping to work. The telescope would take its noise reading while still pointing at the comet.
Instead, we used another, albeit less effective, technique for handling noise. We tuned the telescope to the frequency we were looking for (Carbon Monoxide) took a measurement, and then tuned it to another frequency to measure the background noise. Subtracting the noise measurement from the measurement of our target frequency gives us a clean(-ish) signal.
After that the really exciting bit happened. I got to operate the telescope as we recalibrated it and got ready to point it at our first galaxy of the night. It was pretty easy, telescope operating. Even someone with a BS in Film, like me, can do it. The procedure for moving on our first source was to first pick a bright known object, aim the telescope at it, and have the telescope calibrate its positioning by taking five measurements around the source to figure out the source’s true location.
Once the positioning was calibrated, I ordered the telescope to ‘slew’ (using that new vocabulary) to the galaxy we’re observing, set the exposure time, and then had it ‘chop’. And then ‘chop’ again. And then ‘chop’ again. And again. And you get the idea. I’ve gotten to use a bunch of different cameras, but this was by far the coolest one I’ve operated.
A Few Notes:
- We ran into to computer glitch around 5 in the morning yesterday. Simon, the telescope manager, kindly helped us fix it.
- “Watts/Hertz or Watts*m^2/Hertz” I overheard Becky saying, triggering deeply repressed memories of doing unit conversion in High School chemistry.
- Sorry there haven’t been as many pictures recently. Stuff inside the control room doesn’t really seem to change that much from night to night.
- There was concern about our comet observation from a collaborator. It turns out the telescope was trying to compensate for the comet’s motion as though it were a distant galaxy, so the above graph still needs a few adjustments applied to it.
- We had some Comet Lovejoy themed music tonight . We didn’t even look at M83.
It occurred to me I haven’t talked much about the telescope itself. There haven’t been any pictures of it yet either. We’re at the Caltech Submillimeter Observatory which is basically a giant (10m) dish inside a sweet looking disco ball on top of a dormant volcano. It observes at wavelengths somewhere in between infrared and microwave.
We spend all of our time at the telescope in the control room with everyone hunched over a computer. I’ve learned a couple of the incantations they use to control the telescope. The first command ‘chop’ is what actually makes it record an observation. I wondered why it wasn’t called ‘listen’ or ‘observe’, but it turns out that ‘chop’ pretty accurately describes the motion of the telescope while it records.
The galaxies we’re observing are very distant and faint, and blend in to the background radiation in our atmosphere. To make up for this, the telescope will take a measurement of the source and then another slightly off the source. The controlling computer uses the second measurement to subtract the background noise from its measurement of the source galaxy.
The other command causes the telescope to move. It’s called ‘slew’. When I asked where that name came from, I was given a shrug by the so-called ‘experts’ in the room. So I turned to Google, and found the dictionary definition is to ‘turn or slide violently or uncontrollably in a particular direction’, which sounds like an accurate description of how the telescope’s movement feels from the control room. It’s also originally a nautical term which also feels appropriate.
A few notes from the second half of last evening and this:
- We had a small earthquake! It was exciting. It was shocking. It was only a 3.3! This is the second earthquake Chris, Sandor, and I have experienced and was Becky’s first. Pretty cool.
- Apparently the observations tonight have provided some confusing results. I tried to get Chris to explain what was odd about them. Mostly due to altitude (partly due to working on this), all I could grasp was that they wanted to compare their observations to a nice looking graph with a clear regression line, and the galaxies they are observing are way off in a corner instead of along the line.*
- Becky has a major problem with static electricity.
- Here are some of the songs we’ve been listening to tonight (presented without judgment).
- You can find more pictures of all the other telescopes at the top of Mauna Kea (post about all of them upcoming!) and other photos of the trip here.
* They misinterpreted the data and everything fits now!
(In which dismayed by forecasts of 100mph winds we go to beach and then end up observing anyway)
A brief update on last night, we were actually able to open the telescope in the wee hours of Thursday morning. Sandor and Becky got as far as pointing the telescope and starting to calibrate it when the wind picked back up and forced us to close.
On the bright-side we enjoyed a beautiful sunrise from the top the mountain.
We awoke late in the afternoon, to emails warning us that “Summit Conditions are Extremely Dangerous” and weather predictions of 100mph winds on the top of the mountain. Thinking it would be a lost night, Becky, Sandor, and I took off for Kona, hoping to checkout the ocean and maybe catch the sunset. Chris stayed behind to answer emails.
It was awesome. Definitely a good decision.
Back at Mauna Kea, the predicted extreme winds never materialized, and Chris and Meg Schwamb were able to open the CSO’s doors for a bit of remote observing, while the beach bums rushed back to Hale Pohaku to join. After a brief wind scare, we made the trip up the mountain to observe on site.
It turns that radio astronomy is pretty similar to computer programming (my normal Zooniverse occupation), in that it mostly seems to involve typing obscure commands into a shell prompt and then waiting for things to happen. Unlike programming, it also involves stomach churning shifts, as the entire building moves to track the source.
During the waiting periods, I’ve tried to learn more about how the telescope works after being mesmerized by Simon’s, the telescope’s manager, technospeak. One part of the telescope he seemed most eager to show us was the heterodyne receiver. After asking the real astronomers what is was, I was very disappointed to learn that it wasn’t a Terminator weapon. Instead, it’s part of the telescope’s processing pipeline that transforms the signal from the telescope to a frequency where detectors are cheap(er). Anyway it’s certainly a cool looking piece of equipment.
That’s about it for me tonight. We’ll just be up here listening to some sick jams and looking at distant galaxies. Remember you can find a bunch of pictures of trip (not many of people observing yet though) here.
(…more like Day 1.5. We arrived late last night in Hilo, HI after about 24 hours of traveling for the Oxford contingent and mere 14 hours of travel for myself).
Chris, Becky, Sandor, and I are at Mauna Kea to use the CSO telescope to look for blue elliptical galaxies. Or at least they are. I’m just here with my American driver’s license to be the chauffeur. As the non-astronomer in the group, I think it’d be fun to give an outsider’s perspective into what an observing trip is like.
We’re staying at Hale Pohaku, just downhill from the observatories. It’s name means ‘Stone House’, referring to the original structure built by the CCC during the 1930s. It lets visiting observers acclimatize to the high altitude of Mauna Kea. (As Zooniverse readers may know, altitude sickness is not fun.)
While the weather at Hale Pohaku has been beautiful, it is also amazingly windy. So amazingly windy that we weren’t able to start observing tonight when the sun set. Instead we’re reduced to sitting in the common room refreshing a page of anemometer readings hoping that it will drop down below the maximum 35 mph wind speed we can operate the telescope at.
We did get to drive up to the summit of Mauna Kea to visit CSO with its manager Simon Redford. Driving the road up the mountain was quite the trip. It’s 5 miles of winding back and forth dirt road that ascends from 9,000ft (2,740m) to 13,000ft (3,960m), but it did give us a spectacular view.
You can find more photos of the trip on our album. We’ll be adding to it throughout out stay. Hopefully tomorrow we’ll have some actual observing news to share.