Wednesday, October 31, 2018

A long overdue observing run


Figure 1: Diana and Clay.
Almost eight years after my first on-site observing experience (at the CTIO 1.0m), here I am, wrapping up my second observing run ever. This time, I've been trusted with a much larger telescope (Clay, see Figure 1) and a precious instrument (the Planet Finder Spectrograph - PFS).

Of course, I had to first get trained on PFS (thanks Johanna! thanks Steve!). It's been a learning curve. Here are the things I have done this past week that I had not done before:
- observed on site with a spectrograph;
- filled the instrument Dewar with liquid nitrogen (see Figure 2).
- drove an automatic car that is trying to be manual.






This observing run has certainly posed some challenges, both to the PFS team and to me personally. 


Figure 2: Filling up the PFS Dewar at 6:30am.
On my first night of training, we sent a command to move the iodine cell in the light path in order to complete calibrations and begin observing. However, the iodine cell would not move. Upon inspection, we discovered a glycol leak near the area where the PFS calibration lamps and CCD controller are. We suspect the glycol lubricated the iodine cell motor, disabling it from moving the iodine cell. The mountain crew rushed over and did a fantastic job cleaning up the leak. Following the cleanup, we were able to complete calibrations and start observing, but we did lose about 3 hours. 



I usually use space-based data or observations from robotic telescopes, which is why I do not go observing very often. Adjusting to the night schedule was a personal challenge for me, and it took me a couple of days to adapt. At first, in the morning at the end of observing, each of the last few steps before bedtime seems like an insurmountable challenge: getting the calibrations right, filling the Dewar with liquid nitrogen safely, driving back to the lodge.

In the end it was all worth it for the learning experience, but also for the wildlife (see Figures 3 - 8), scenery, and sense of escape (see Figure 9).


Figure 3: Burro.
As a "bonus", we had good weather and seeing (at least during the week I was there!), and we acquired numerous spectroscopic observations that will be used to measure the masses of newly-discovered exoplanets.
Figure 4: Vulture (thanks George!).






Figure 5: Vizcacha.
Figure 6: Guanaco (thanks George!).

Figure 7: Zorro.

Figure 8: Small owl.

Figure 9: Our galaxy.






Monday, July 2, 2018

Night 2... Let the observing begin!


So last night ended up as a total observing bust, but never fear there was still tons of fun to be had! We tried to wait out the high winds, somewhere between 50-60ish mph all night, we got to tweeting up a storm. We also decided to venture out to the catwalk, while the winds were at 60 mph, because when your advisor says,"You should go on the catwalk with the wind! It's fun. And a little scary. The moon will brighten you", you oblige.

And with that I bring you the greatest wind photoshoot.... The live photo really does the first one justice. I felt like if I let go of the railing that I would have literally blown away. Our collaborator said that we should fly a kite and I responded with "I in fact was a human kite."



On the catwalk between Baade and Clay
Post wind hairdo!


Night 2 started out much better with the winds dying down... but then the humidity struck! At one point we had all the weather problems we could have had at the time wind, clouds, and humidity. The text message anger was real on our collaborators end and the gifs he said definitely did it justice. Once the weather got better we could open and then we were on a run. 14 targets down and then dun dun dun the wind came back with a vengeance! And now we wait. Hoping for the wind to go away but you never know with the winter weather. Hopefully Victoria's post will have a happy ending for us and hopefully all of the fabulous additional targets!

Saturday, June 30, 2018

A Chile and Windy Winter Night

BDNYC in da House! This is my third trip to LCO, but my first time teaching someone else how to use the instruments on the Baade telescope. My partner-in-crime for this run is Victoria DiTomasso, who recently graduated from CUNY with her BA in physics this May. We have two nights and are planning to use FIRE, the NIR spectrograph, and Fourstar, a NIR imager, to observe some awesome brown dwarfs.

Victoria and I outside of El Pino




My journey to LCO started with a sad amount of sleep for me on the long flight from NYC, but no worries I immediately passed out on the SCL-LSC flight surrounded by a family with so many children. While I waited for the flight from SCL-LSC we found a few other astronomers that were going to Las Campanas as well, making our new group woman dominated- 4 female astronomers and one male astronomer. My adviser said we'd be the only women on the mountain, but ha we are not! I have never been the only woman on the mountain, since our research group runs deep in amazing women.






As stated by twitter, the IBMT or 
the itty-bitty Magellan Telescope



When we arrived in La Serena we had to wait a few hours before we could go up the mountain. While we waited we got to explore a little of El Pino and found a cool scale model of the GMT. After that we took a walk to get some empanadas and enjoyed the warm sun and fairly nice weather, the last to be seen of  until Monday when we come down (the weather of course, I am sooooo looking forward to empanada Sunday!).


The first night on the mountain was supposed to be the night I worked on switching over to the night schedule by staying up late.  But because I was so exhausted from the lack of sleep on my flight my plan of action changed. Instead of trying to stay up late, I went for trying to sleep in as late as possible. Sucess! I made it to 12 and a half hours of sleep! Yea for naptime!





The winds sometime at the start of the night. Gusts of 58 mph! Most of the day was like this, but slightly less windy.


The selection of teas. There is one made of a plant that I have
never heard of, which will definitely be my next cup!



After lunch on our first night of observing (today!) we went up to do calibrations and a telescope photoshoot. Check out Victoria's blog post for those photos! The photo that I really should have taken was one of me and the wind. No lie I was blowing away! I hoped for the wind to die down over the day not only for my safety as a tiny person, but for good observing. While I showed the telescopes to Victoria we could feel the wind pushing our tiny little blue car, so you get the picture.






Mars is keeping warm and staying hydrated 
while we wait out these winds!


As the sun set we knew that we would be in for a long night. The night so far has been observing the tea selection (oh so many!) while we wait for the high winds to die down.


Hoping the weather gets better but the TO said it looks bad for the next two days aka our entire run  :( Luckily, its still early on in the night. Updates to come tomorrow as we start night two of the run!



Thursday, May 24, 2018

The weather is good, but....

From left: Me (Juliette), Johanna Teske, Sharon Wang, and
Erin May in the Clay telescope dome. Erin and I are
observing on Baade this week, and Sharon and Johanna
are observing on Clay.
Hi! My name is Juliette Becker, and I'm a graduate student at the University of Michigan. This week is my first Magellan run, using IMACS to look at a white dwarf with a disintegrating planet and also at some transiting planets. I am observing alongside Erin May (a fellow UMich graduate student and IMACS pro!), and we have a four-day run this week. Johanna Teske and Sharon Wang are observing on Clay this week, so it's ladies' week at Magellan!

Erin has in the past had terrible luck with weather at Magellan; it seems to be cloudy or raining every time she comes to observe (the running joke is that she's "cursed"). We've been checking the forecast for the last few weeks, getting nervous when it looked like there might be clouds and getting happy when the forecast became more favorable. When we arrived here Sunday evening, the weather was pretty good, with just some scattered clouds. The forecast looked favorable!

Monday night, the weather got even better. We were able to get on sky on-time and observe both of our targets for the night! There were some scattered clouds, but it wasn't too bad. We reduced some preliminary data, and things were looking pretty good.
Pretty good weather, with only scattered clouds!
Come Tuesday, we were excited to get more data on our targets: it appeared that the "curse" was broken, because the weather was great! We did our calibrations Tuesday afternoon, headed back for dinner, and returned to the telescope before sunset.

When we arrived at the telescope, several of the local Magellan engineers and instrument specialists were in the control room, looking concerned. The guiding wasn't working, and they quickly determined (as Erin and I looked on in horror) that the reason for this was liquid on the camera. My first thought was "Liquid? How did that happen? It hasn't even been raining!", but things quickly got worse...

The engineers determined that a hose had a nick in it, resulting in glycol spilling everywhere. And it wasn't just a spill - it had spewed all over the instrument and the local area, resulting in a GIANT MESS:
Video of the aftermath of the spill, courtesy of Gabriel Prieto.
As the engineers worked hard to fix the spill and get the instrument functioning again, things were not looking good. It seemed like IMACS would not be functioning again for at least two nights, but one of the engineers mentioned that they could unplug IMACS and plug in another instrument. Erin and I scrambled to get backup targets that we could observe using another Baade instrument, so as not to waste valuable Magellan observing time!

As 11pm approached and the engineers continued to work, we had come up with a list of backup targets for FIRE, calibrators, and an observing plan. Even if IMACS wasn't working the next night, we would be able to observe on FIRE. At this point, I was totally convinced of the existence of Erin's observing "curse." Clearly, the curse hadn't been able to control the weather this time, so it had decided to take another approach...

But just as we almost reached the point at which we would not be able to observe our transit, the Magellan crew came back from the dome with good news: they had a temporary fix for IMACS, and we could get on sky after all! We finally got on sky ten minutes before the transit we were observing, thanks to the herculean efforts of the telescope operators, instrument specialists and engineers on site. The guiding system was out of commission, so our telescope operator Alberto had to focus the telescope manually all night. In the end, though, we were able to get data for our second target of the night.

The lesson I've taken away from this trip is that it takes more than good weather to have a successful observing run: you also need a talented crew of telescope operators, instrument specialists and engineers ready to save the day if something goes wrong!


Friday, April 27, 2018

Interview Cross-Post

I'm back at Las Campanas with the MagAO team! But tonight I'm just cross-posting an interview I did for the DTM website. Read the Interview

Tuesday, April 10, 2018

Using the tunable filter

One of the most difficult experiments we did in my undergrad physics class involved calibrating a finicky Fabry-Perot interferometer. The MMTF tunable filter on IMACS at Magellan works on the same principles, where you precisely calibrate the alignment and spacing of two parallel plates to allow only a small range of wavelengths to pass through. After talking with fellow Carnegie postdoc Rosalie, we had an idea for a possible project which would involve the tunable filter, and decided to go for it.

We allotted ourselves a big chunk of time in the first afternoon to get everything set up for the first time, and after some skype help from Ben Weiner, got our calibrations all set for the night. We were pretty happy about this, come sunset:

(Decker and Rosalie, after successful calibrations, trying not to think about the clouds in the background)


After some threatening clouds, things cleared up enough to start taking data, and we got on our science target:

(Science data with the MMTF!)

I'm super excited about what we're seeing in the quick-look of the data, and looking forward to seeing what happens after the full reduction!

Unfortunately, the clouds did end up rolling in halfway through the night:

(Clouds seen on the satellite image over the sad red dot which is us)

So, we'll have to try again tomorrow night and hope for clear skies.



Thursday, February 8, 2018

PFS Upgrades Series, Day 15: El Final

This is part of a series of posts about upgrading an instrument at Las Campanas Observatory. If you want to start at the beginning, it's here.

So....this happened last night.



As in, the entire night were were closed due to high humidity. Boo. But upon leaving the telescope around 5 am this morning, everything was damp and drippy, so I have no problem with the telescope operator's decision. It was just a bit of a fizzle end to our awesome two+ weeks here at LCO working on PFS. 

Per usual, I started with a focus test, to see if it had changed since the night before. Since the instrument was nearing its ideal temperature, I expected little change in the focus value, and actually found the best focus to be the same as the previous night. We took some images to use in a linearity test -- when does the relationship between incident light and recorded signal become non-linear and thus BAD? -- which Jeff started running through an old IRAF script used with the MIKE instrument. We also figured out that the images we took last night (like in the picture I showed, with the red on the screen) actually were *not* fully saturated, so we did the same test over again, changing the CCD voltages to make sure the saturation limit did not change much between the different voltage settings. It did not change enough to make us want to go back to the voltage setting with the wonky bias. I got a nice explanation from Steve about what A_HIGH and A_LOW mean -- basically they are the top and bottom voltage values of a "bucket" that moves electrons along the detector for readout. Steve drew a diagram almost exactly like the "clocking diagram" here. I learned about this in graduate school, but hadn't really applied it to real life measurements/data until now. Knowledge! 

Then the rest of the night was mostly spent watching for the humidity to drop, which it did a little, to something like 77.5%, but never low enough to open to dome. Sigh. I did take the time to read all about the new TRAPPIST-1 results, though! I also sent all the data to Paul Butler, who replied this morning that he'd received it and would work on a reduction soon. We will eagerly await those results.

After getting a few hours of sleep, I got up this afternoon to tour the Giant Magellan Telescope site, which is one peak over from LCO. Funny enough, that peak is actually Las Campanas peak. The GMT site is leveled off and has chalk designating where the dome and mirror base will go -- GMT will be made of seven 8.4m mirrors, built at my grad school alma mater the University of Arizona -- as well as the auxiliary building where mirror coating will happen and an extra mirror will be stored. We also got a tour of the "casino" (kitchen and dining hall) and recreation facilities for the folks living and working at the site now. It's still hard for me to picture everything coming together, but I still got excited visiting the site. 



Each of those circles represents the footprint of a 8.4m mirror. 
LCO from GMT site. Iiiiiity bitty telescopes.
Above: Mosaic in the recreation area at GMT.

Below: Leon ringing the "las campanas", some of the ground-breaking rocks from the GMT site.


But for now, I'm perfectly delighted to work at LCO and use the telescopes here. Part of me is ready to go home, but part of me could stay here forever. Tomorrow Jeff and I go back to the US, while Christoph and Steve are staying a few more nights to observe with MIKE, another high resolution spectrograph that Steve built. Jeff and Steve will be back here in March to install a new dewar in PFS and hopefully something to control the icicle formation and melting that has been happening in the tube were we fill the dewar with nitrogen. At some point we'll install fibers and a pupil slicer, I hope by the 2018B semester. I won't be back until May for more PFS observing, when, I realized, it will be my 10 year anniversary of coming to Magellan! My first visit was right after I graduated college in 2008, when I was finishing up an internship at Carnegie DTM with Alycia Weinberger, who continues to be a great mentor and friend. So many good memories here! 

I'll sign off with some pretty pictures. :)

Hawk friends saying goodnight last night. 
I always think of the Stairs of Cirith Ungol when I go up and down these. I don't know why, they are happy stairs, not scary stairs!
The previous photo was look down the stairs after climbing them, this photo is what you see when you reach the top. See, happy stairs! From left to right, Clay Telescope (Magellan II), auxiliary building, Baade Telescope (Magellan I).
Looks like a good night tonight! I will be spending it sleeping, but hopefully the humidity stays low for the observers.