Here we go again…

I’m busy getting ready for my next trip to Hawaii and realise that I haven’t posted on here since the last trip. Observing is like that, there’s lots of sitting around at the summit so you can catch up with all the things you don’t usually have time for. This trip I’m planning to attack my large pile of unread journal articles, write a few outreach presentations that I’ve been meaning to do for over 6 months and also write some catch up posts for this blog.

The latest trip starts on Tuesday, when I’ll be catching the 10.35 flight from Heathrow to San Francisco, there’s then a connection to Honolulu, where I’ll be staying overnight. Then  on the morning of 22nd I fly over to Hilo, have my briefing at the Joint Astronomy Centre and drive up to Hale Pohaku, the astronomer residential centre, where we eat and sleep.  So watch this space for updates on my first year as a PhD student and my latest observing trip

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Observing at the James Clerk Maxwell Telescope (JCMT)

What I’m meant to be observing

I am meant to be observing for the Cosmology Legacy Survey (CLS) using the Submillimetre Common-User Bolometer Array (SCUBA). The CLS is a survey of high redshift galaxies at wavelengths of 450 and 850 microns. Unfortunately the CLS needs the best weather conditions, and we have pretty poor weather this week.

The way surveys work is that lots of astronomers help out taking the observations and the results are shared by the community. So I won’t necessarily be using the data that I obtain. The telescope is actually controlled by an experienced operator who works permanently at the site. The attending astronomers are just there to help make decisions about what to observe and also for safety reasons  – there must always be two people at the telescope. Typically visiting astronomers will observe for about 5 nights, although it varies. They then go home and the next visiting astronomer takes over. This system has the added advantage of giving students experience of working at a telescope.

Weather Conditions

There are a number of factors that effect our observing. We can’t observe if humidity is too high, 85% is a rough guide, or if there are strong winds. Assuming the humidity and wind speed are ok we then have to consider the optical depth. This is a measure of how much radiation is actually reaching the telescope. The sub millimetre wavelengths that we use are affected by the amount of water vapour in the atmosphere. The more water vapour, the poorer the optical depth and the poorer the quality of the observations. We measure optical depth using something called tau – this is defined as -ln(I/Io) where I is the observed intensity of the radiation and Io it the actual intensity of the radiation. So we are measuring how much of the radiation gets through the atmosphere. As we are taking the natural log of the ratio, the smaller tau the better.

For CLS we need a tau of 0.1 or less, but so far we haven’t had anything this low.

What we are actually observing

JCMT operates a queuing system. Time on the telescope is divided up between the major surveys (of which CLS is the biggest), but if conditions are not right for observing that survey we look at the queue to see what we can observe instead. This takes into account

a) the priority awarded to the project,
b) whether the target is visible (Most targets can only be observed at certain times of the year and of the night),
c) the recommended tau for the observation

Our best tau values this week have allowed us to take some observations for two other SCUBA2 surveys – The SCUBA-2 “All-Sky” Survey (SASSy) and The Nearby Galaxies Survey (NGS).

However, much of the time the tau has been too high for these projects too and so we have been observing with the heterodyne instruments –  HARP and Receiver A. These measure spectral lines.

Targets can often be observed for a short period in good weather or a long period in bad weather. The best weather is generally reserved for the high priority surveys and so one tactic is for smaller projects to request longer observations in poorer weather. This allows them to get telescope time when the tau is too high for the surveys.

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Arrival

I have arrived at the astronomers residential facility at Hale Pohaku (~2,900m). This is where we sleep when we aren’t observing. There is also a cafeteria, TV room, games room etc. It’s the middle of the night in Hawaii, but I am staying up as long as possible, to try and get my sleep pattern in line with the observing schedule. We spend about 24 hours at the facility to help our bodies acclimatise to the altitude.  We come down here to sleep each night as staying on the summit (~4,200m) would increase the risk of getting altitude sickness.

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My room

cafeteria
The cafeteria. There are three fixed meal times each day, but in between we can help ourselves to drinks and snacks. We can also request a packed lunch to take up to the summit with us.

entrance
The entrance hall. Notice all the flags. Many countries have telescopes on the mountain and use the residential facility.

mountain
View of Mauna Kea from my hotel in Hilo (where I stayed one night before driving up to the facility). Note the snow on the summit. The telescope domes are just about visible as white blobs on the top.

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Hawaii – the journey

For anyone who is interested, here is my itinerary for the next day or two.

Thursday 30 Jan:

6am   Taxi arrives to take me to Heathrow. Probably followed by a long wait and leisurely breakfast after going through security.

10.30   Board ~11 hour flight to LA. I have 6 novels on my kindle and a pile of astro papers to read.

9.50pm (1.50pm local time)  Arrive in LA

Friday 31 Jan

1.25am (Thurs 5.25pm local time)   Board flight to Hilo, Hawaii.

7.06am (Thurs 9.06pm local time)   Arrive Hilo, Hawaii and take taxi to my hotel. Where hopefully I will manage to sleep, followed by breakfast at Ken’s House of Pancakes (apparently compulsory for all visiting astronomers)

9pm (11am local time)   Arrive at the Joint Astronomy Centre in Hilo for a briefing.

Saturday 1 Feb

~1am (3pm Friday local time)   Travel up to the Astronomers Residential centre at about 2800m. Here I’ll spend about 24 hours acclimatising before my first observing session.

By which time I think my internal body clock is going to be very confused!

 

 

 

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Catch Up

It’s hard to believe I’m nearly at the end of my 4th month of my PhD. All my good intentions to do a weekly blog post were in vain. I’ve just been so buy. Anyway, here is a quick catch up and then hopefully I’ll start to blog more regularly.

Coffee

I seem to have spent a significant part of my PhD so far organising the coffee rota and making coffee. The first years provide coffee for three meetings a week and biscuits for two. I had the task of creating a rota and hence end up covering for anyone who doesn’t show up. The first coffee machine we had broke and had to be replaced, which led to endless jokes about how many astrophysicists it takes to make coffee. One of the things you quickly learn is that PhD life revolves around coffee and biscuits.

Hawaii

I’m off to Hawaii on Thursday, observing at the James Clarke Maxwell Telescope. I have 5 days on the telescope and then my boyfriend is flying out to join me and we have a week’s holiday. Organising this has been one of the biggest time sinks so far. I am told that there is lots of free time when at the telescope so I am planning to blog my trip as well as catch up on some reading.

We moved house

Yes, we finally moved into our new house in late November. Most of the next month was spent unpacking boxes; when I wasn’t having a forced break due to hurting my back. The house is now reasonably tidy, but we haven’t started on all the things that need fixing yet. Everything to do with the house is on hold until after Hawaii.

 Science

I have made a start on my project, but haven’t done nearly as much as I’d have hoped. So far I’ve taken some Hubble Telescope images of Lyman break galaxies and catagorised them on the basis of their morphology. Having done that I then had to write some code to automate the process which took a couple of weeks, despite getting lots of help. My coding has now improved, but I haven’t really moved the project forward. This is going to be my top priority when I get back from Hawaii.  More details to follow in a future post.

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The Beginning

I had my Master’s viva yesterday and am due to start my PhD next week. So this seems like a good moment to start a blog and share my experiences of studying for a PhD in astrophysics. I still have some minor amendments to make on my Master’s thesis, but it is more or less done. So I have a few days of limbo before PhD activities kick off. As I’m staying at the same University the change to PhD is marked by a change of supervisor and project rather than anything else.

As a mature student the switch to full time study has been a little complicated. For the duration of my Masters (9 months) I have been staying with my boyfriends sister during the week and going home at weekends. Now that I am to be based in Hatfield for 3.5 years we are in the process of selling our house in Wokingham and moving to St Albans. So most of my days of limbo will actually be spent packing the last of our stuff into boxes ready for the big move. Just to make life a little more interesting we expect to move out of our house before we have bought a new one and so I will be continuing my nomadic lifestyle for a little while longer. The weekends will be spent with my parents until we have somewhere of our own to live.

When not studying I volunteer with Berkshire Lowland Search and Rescue. I’m having to take a break from active searching due to the PhD, but will continue to help with accounting and fundraising. I’ve also been actively involved with UKSEDS (UK Students for the Exploration and Development of Space), although less so this year due to concentrating on my Masters.

So expect this blog to be full of galaxies, stars, statistics, plots, python, house moves, family chat, space exploration, science fiction references, zoo visits and other cool stuff.

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