Tag Archive | Observing

Here we go…

The continuing adventures of the Pea hunting trip to Chile

We’ve spent the afternoon finalising our target selection, preparing our observing strategy, and taking calibrations. The sun has now set and we’re already pointing in the right direction for our first target. In a few minutes time we will start our observations. We begin with a standard star, which will be used to calibrate the spectra of our main targets. The we are on to our first Pea candidate.

The SDSS Peas that Carrie studied were green in the SDSS colour images because they were bright in the r-band, actually the red region of the visible spectrum. On this occasion we are looking for similar object that are a bit further away, so we expect them to be very bright in the i-band (further into the red) ar the z-band (on the border between red and the near infrared). Tonight we are observing the i-bright objects, and hopefully we will get through about a dozen of them. The weather looks good, so fingers crossed.

Anyway, better concentrate on the observing.

On the mountain

The continuing adventures of the Pea hunting trip to Chile

An hour’s flight from Santiago to La Serena, followed by a 2 hour drive, and we arrived at La Silla in time for a tasty lunch (notable lack of peas, though). We then had a meeting with our support astronomer to check our plans for the upcoming observing run and make sure we had filled in all the necessary forms. He also kindly gave us a tour of the three biggest telescopes, including the NTT which we will be using. I’ve been here a couple of times before, but always using the NTT, so it was nice to see the other main telescopes, and get some great views from their dome catwalks.

View of the La Silla landscape from my room

View of the La Silla landscape from my room

The landscape around La Silla is red, arid and lumpy. Dry red soil strewn with small rocks, covering many hills of different sizes which appear to be piled on top of one another to form larger peaks. Although this is the edge of a desert, the landscape is dotted by small bushes, though many look more like collections of twigs than living plants.

La Silla observatory was set up in the early Sixties. Like other sites from the same era, such as La Palma, Kitt Peak and Siding Spring, it sports a collection of telescope enclosures of various shapes and sizes. Although the traditional dome is most common, it seems the discerning enclosure has an element of squareness, the degree of which varies with construction date like a fashion.

The telescopes here have apertures varying from half a metre to 3.6 metres. Although the atmospheric conditions at La Silla are very good, they weren’t considered exceptional enough to site the latest generation of 8 metre telescopes here. Instead ESO chose to develop a new observatory at Paranal. When you’re pushing technological and scientific limits, and spending the amount of money that requires, you need to be very careful choosing your site to maximise the quantity and quality of observations that are possible. As science has advanced and typical astronomical observations have become more challenging, the numerous small telescopes around the world are being used less and less. In fact, most of the domes on La Silla are either empty or contain telescopes that are no longer in routine service.

Visiting astronomers usually arrive on the mountain at least one night before their observations begin, to prepare final details and adjust to nocturnal working. We actually have two full days and nights here before we start using the telescope. That will give us plenty of time to review and refine our initial list of targets, although we will certainly still need to adapt our plans once we start taking data. We’ve now got our list of high priority targets organised, and tomorrow we’ll decide upon other interesting objects that it would be useful to observe, if everything else is going well.

Pea Hunting preamble

Greetings from the ESO Guest House, in Santiago de Chile! As I described in a blog post) a while ago, I am here on a mission to hunt for more distant counterparts to the ‘Peas’) which were first identified by Galaxy Zoo participants.

This is the first Galaxy Zoo initiated observing project to use an ESO telescope, so I thought I would take the opportunity to give you a bit more of an insight in to an ESO observing trip. ESO is the European Southern Observatory, which operates observatories in Chile in order to provide European astronomers with access to the Southern sky. These are among the most technologically advanced and scientifically productive observatories in the world. ESO’s premier facility is the, imaginatively named, Very Large Telescope (VLT), located at Paranal observatory in the middle of the Atacama desert. The VLT actually comprises four massive telescopes which are usually used separately, although their light can be combined for special observations.

For our observations we don’t need quite so much light-collecting power, so will be using the smaller, but still very capable, New Technology Telescope (NTT) at La Silla observatory, also in the Atacama, but in its slightly more hospitable Southern outskirts.

ESO Guesthouse

The ESO Guesthouse

I, and my observing colleague Seb Foucaud, arrived in Santiago earlier today after long journeys from the UK and Taiwan, respectively. ESO is an extremely well organised operation and really looks after visiting astronomers. We were met at the airport by an ESO representative and driven to the Guest House in the affluent Las Condes suburb of Santiago. The Guest House is renowned for its hospitality, friendly staff, good food and the traditional Pisco Sour cocktail before dinner. Most visiting astronomers stay here for one night before and after their observing run. Tomorrow morning we fly to North to La Serena and then drive to La Silla observatory to begin the preparations for our run, which starts on Thursday night. Right now I’d better get some much needed sleep. I’ll give you an update when we get to the observatory.

Supernova Zoo news

Thanks to all of you who participated in our second trial of the supernova hunt! As with our first trial in August, it was very successful, and kept our WHT observers, Jakob and Isobel, very busy – as you can see from their blogs! In the 3 days that we ran the trial, 2089 of you inspected over 2000 supernova candidates, answering more than 100,000 classification questions. The best of these were then passed to WHT for observation.

The first observing night had relatively poor observing conditions, but the second night was clear and plenty of zoo targets were observed. You can see a selection of the supernovae that you found and that were observed at WHT on the supernova zoo front page. Using the spectrograph on WHT, we were able to confirm these as supernovae and determine their types. We took spectra of more than 20 candidates identified by the zoo, and are now busy reducing and analysing that data.

Our plan now is to take the supernova hunt down for a short while, to make improvements to the tutorial and classification questions. Please do keep the feedback coming – the supernova zoo now has its own sub-forum where you can give us comments, and we will try to answer any questions that you might have. Our goal to have to supernova zoo support all of our Palomar Transient Factory supernova observing runs – and not just those at WHT – in the near future.

Thanks for all of your help!


Good morning

Almost all candidates on the list have been observed. Some were junk, but most were something real, like a supernova, an AGN, or a star. Now we only have to take some calibration data and burn the data to a dvd. I’m really looking forward to a few hours sleep. Good night!


The hunt goes on

The atmospheric conditions have degraded a bit, but we’re still collecting data.


Features of supernova spectra are very broad and therefore look like wiggles. Tonight we’re indeed lucky. All the spectra apears to have these wiggles in them. We’ve found a few type Ia supernova so far tonight. Apparently the selection of candidates via the supernova Zoo has been very effective.


Fantastic seeing

We’re lucky! Clear skies. The seeing is marvelous which means that we can obtain very good spectra.


Excellent conditions

The conditions are now excellent (seeing of 0.7 arcseconds). I hope it stays like this all night. This is really exciting!


Awaiting the sunset

We’re sitting in the control room of WHT awaiting the sunset. Before sunset we should take some calibration data and finalise the list of candidates. New candidates are sent to us by e-mail all the time. Tonight we’ll have a go at some candidates we didn’t observe yestereday or need to get an additional spectrum of. There are som very faint challenging targets we still haven’t decided whether to include or not. The wheather is much better to night. Almost no clouds at all. This is going to be an exciting night!