PFS Upgrade Series, Day 3: Optical Alignment

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.

One of the best parts of my job is learning new things. I like puzzles and intellectual challenges (as well as some physical ones), and very often that's what my work comes down to -- solving challenging puzzles. This process often consists of a lot of trial and error, and can sometimes be frustrating, but it makes solving the puzzles even more rewarding. Today was a day of puzzles. 

We want to make sure that the light inside our instrument will go where we want it to, namely straight through the lenses, off the grating and through the prism and back to the right spot on our detector, so it can record the light and we can detect planets. To make the light go where we want it to, we have to change the positions of the different components in our instrument so they guide the light path correctly. This is one of the three "upgrades" to PFS we have planned -- a precise (as possible) optical alignment of the lenses inside the instrument. 

To accomplish this optical alignment, we want to use our fancy-shmancy Shack-Hartmann wavefront sensor. It produces a beam of light that we can (eventually) use to shine down all of the lenses in the instrument and make sure the light is reflected off the grating and comes right back to the sensor in the same spot. Then we know the same thing will happen when we replace the sensor with our CCD.

We ended yesterday and started today somewhat confused about how to use it; the manual was originally written in French and translated to English, but unfortunately not very well, so it was a challenge to even know where to start. After several hours of just playing around -- turning knobs, watching how the wavefront changed (using the computer software that came with the sensor), turning knobs again, putting in a pinhole, taking it out, etc. We first wanted to make sure that the wavefront sensor itself was producing a beam perfectly perpendicular to our optical bench, parallel with the desire optical axis inside the instrument. Steve developed his own method for doing this wavefront sensor calibration, but we determined this morning that the method recommended by the sensor manual (as best we could tell) worked just as well, and was easier to replicate. Check.

Next, we needed to make sure the light beam from the sensor would hit the grating in the right spot and come back towards the sensor. Instead of using the grating from the start, we are using a large mirror in its place for now. We kind of got stuck at this part -- how could we make sure the light was leaving the sensor and coming back to the same place, and hitting the mirror on the other side of the instrument? It sounds trivial but it was not. Steve had a great breakthrough after lunch, though, when he rigged up a small aperture in front of the sensor, got the light beam adjusted to go through that aperture, and then we adjusted the sensor so that the light beam that fell on the mirror's surface reflected back nearly perfectly through the same aperture. 

The photos above show Steve's set-up for verifying that the light beam from the sensor was properly aligned with the optical axis of the instrument. The yellow arrows in the top photo represent the (ideal) path of light, except really it's all in one line, not two lines on top of each other  The bottom left photo shows the metal beam that Jeff made, originally to hold a lens or mirror, but here without anything in the holder. The blue thing you see through the holder is Steve's homemade "work of art" aperture (paper, blue tape, and a metal washer), which is in front of the wavefront sensor. The wires going across the holder mark the center of the aperture (my photo wasn't perfectly aligned). In the bottom right photo, the reflective mirror at the other end of the instrument is shown (reflecting some tubing!). There is blue tape on each side of the mirror, holding thin wires to mark the exact same spot in space as the wires in front of Steve's aperture (except translated down the length of the instrument) on the surface of the mirror. 

And it worked! Below is a not-great photo of the screen of the computer, showing what the wavefront sensor was detecting when we had Steve's set-up aligned. The green cross in the center marks the true  center of the image, and we were trying to line up our circular image so its center matched that green cross. Actually, first we just had to get the circular image, then make fine adjustments to center it. We did pretty good! (I think there might have been one more iteration of the adjustments after this photo was taken.)

So, step 2 of the puzzle is solved, at least we think so. :) Tomorrow we will start on step 3, which is adding in the lenses that actually go in the instrument and trying to recreate that light beam path that goes out through a pin hole, through the lenses, off the mirror, back through the lenses, and back through the pinhole. This is probably the hardest task we have to do during this trip, or at least the one with the most uncertainty. But that's what makes puzzles fun, right? If you went in knowing the answer it would be boring. Onward towards discovery! 

Sunrise at LCO this morning. How many telescopes can you spot?

PFS Upgrade Series: Day 2, Taking Apart the Puzzle and Putting (Some of) It Back Together

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.

I wanted to focus my post yesterday about moving PFS, but that was really only the first half of the day. During the rest of the day, Jeff, Steve, and I worked to disassemble the instrument into its component parts, beginning with taking off two of the sides and the top. I didn't get many pictures of that work because we were pretty focused, but today I snapped some photos of the parts we took out, as well as the new things we installed (mostly today). 

Above: PFS stopped of almost all component parts! Eeeps! Below: Old dewar, holding old CCD. 

Above: New dewar holding new CCD. So shiny and big (10kx10k!) Below: Pre-slit assembly, which holds the calibration units and our precious iodine cell (here we're looking at it face on, it's on the right inside the enclosure). The pre-slit assembly actually hangs outside the temperature-controlled enclosure (the big white box) of the instrument.

Above: Prism/grating mount, and hoist (see top of photo) we used to move it out of the instrument. That was also really nerve-wracking. Below: White side panel of instrument (insulation), and collimater/camera assembly (lenses and rods).

Above: New pre-slit assembly anchor, which goes inside the instrument/insulation. You can't tell from this photo but the left-most hole (three holes make a triangle) changed its shape in the new design to accommodate a new cable from the new detector. Below: New CCD camera mount, installed on optical table. In this photo, you can better see that left-most hole I mentioned. We don't have the CCD installed here, but a stand for a fancy-shmancy wavefront sensor instead. 

Above: Fancy-shmancy HASO wavefront sensor, now on its mount. We will be using this to optically align the camera assembly. Below: Pre-slit assembly re-installed on side of instrument (top black box). We also installed a new power supply unit (bottom, smaller black box). I tried to rivet one of the holes on the side of the enclosure to mount the new power supply, but my hand strength wasn't up to snuff. Instead I held things and handed them to Jeff.

Steve (left) and Jeff (right), working on setting up our optical alignment software and hardware. More on that tomorrow...

I am really starting to feel the physical effects of instrumentation work, at least this type. I'm not used to being on my feet all day! Good thing I like the people I'm working with (and they are so patient with me), and the food the chefs here cook for us is so yummy. :) 

PFS Upgrade Series: Day 1, Nerve-wracking Moving Day

Hi! This is Johanna, I'm finally back at Las Campanas and ready for new experiences and adventures. On this trip, I will be observing again with the Planet Finder Spectrograph (PFS), searching for new planets around near-by stars via the radial velocity method (read all about it in my previous post and post). More on that later. But first, I will be helping the people who built PFS, Steve Shectman and Jeff Crane, to make some upgrades to the instrument. We hope that these upgrades will help improve PFS' performance and planet-finding power! I'll be documenting different parts of the upgrade process on this blog for the next few weeks. 

Today was Moving Day, when we transferred PFS from the auxiliary building between the two Magellan telescopes down the hill to a semi-clean room, where we will be gutting, fixing up, and reassembling PFS before we observe with it in February. PFS has only ever been moved such a far distance once before -- when it first arrived on the mountain -- so we were all nervous. The instrument is special because of its high-precision observing capabilities, which stem from its stability. Like any astronomical instrument, there are a lot of very fragile and *expensive* parts inside PFS, so we were worried about them surviving the trip on the flatbed. 

Before I forget, I have to give a HUGE shout-out to the day crew that helped move PFS and keep it safe. They were super careful but worked efficiently, and we couldn't have asked for better. Thank you!

Above: PFS being rolled out of the auxiliary building, its home when not on the telescope, in preparation for a little trip down the hill. Below: Aaaaand it's on the lift! Step 1 complete, many steps to go.

Hopefully you can see in the video above that PFS was chained from the back to the platform, and then rolled slightly downwards onto the bed of a truck. As you can imagine, this part went very slowly and carefully.

Then the day crew strapped PFS in from multiple angles, focusing on the heaviest/most stable parts of the instrument to tie down, and we were off! Oh, actually, before that, we locked the wheels with some pins that I didn't even know where there. Props to Jeff Crane for thinking of everything. 

Locked and ready to *not* roll!

The journey down the road was nerve-wracking for sure. We had multiple people walking alongside or in front of the truck (so, it was only driving as fast as we could walk), and a drive that usually takes a minute took more like ten. It was all worth it, though, to get PFS safely into the anti-chamber of the clean room in one piece. Tomorrow I'll try to show some photos of the PFS dis-assembly and what we're testing and changing inside the instrument. 

PFS comes off the truck and on to another platform outside the antechamber of the clean room. We weren't sure it would clear the roof, but by moving it onto the platform and then lowering the platform, we just made it. Another score for Jeff Crane's design skills!

Home sweet home for a few weeks! 

What instrument are you using (now)? .... And zen observing

I am open to whatever my fate may be this run…. So far, that is a very good mentality to have, since no plans have stayed relevant, or constant, for long.

Months ago, I heard that the instrument I wanted to use, the near-infrared echelle spectrograph FIRE on the Baade telescope, was broken.  However, people said, the principal investigator, or PI, is working on it, maybe it will be available in time, so don’t change your plans.

Earlier this month, I checked in with the PI, who also said, I think it will be fixed, but wait until after our run at the beginning of December and check back.  Lo and behold, FIRE was fixed!  Victory!

As I am getting on my first of three airplane rides down to Chile, psyched for my first Magellan run but stuck with a head cold, I get the email of doom: FIRE is broken!  I should look into other instruments and resubmit an instrument setup.  NO!  Shoot!  

Well, darn.  At the Dallas airport, I download the instrument manuals for IMACS, the all-purpose optical imager and spectrograph, and MagE, the optical echelle spectrograph.  I spend the flights thinking about the capabilities of the two instruments and let my internal debate rage.  Of course, brain power is beginning to hit a local minimum since airplanes are not conducive to sleep.

On the beautiful drive up to the telescope, in between naps, I chat with fellow astronomers about instrument considerations. Of course, since I was planning to observe in the infrared, I have entirely forgotten that it is pretty much full moon; my faint galaxies are going to pretty challenging to observe with all that background light. Shoot.

We arrive in time for a quick nap before dinner, and then I learn - they are trying to fix FIRE!  Maybe not all hope is lost?  But, they also say, there is no guarantee that the instrument will be cool enough to observe, or that the software will start up successfully.  So, my debate is whether to continue planning for optical observations, plan for unlikely infrared observations, or … just zen out and wait. Picking option three is hard, but all my planning has not helped so far. And I am so happy to be at the observatory for the first time, just seeing it and talking with everyone; watching the sunset helps!

My time is during the second half of the night, so the waiting game continues for the entire evening.  The instrument should be cool enough (yay!), but will the software start successfully? Will it break?  

At switchover, FIRE is not working, but with half an hour of restarted servers, traced paths, and general pandemonium… the instrument is running!  VICTORY!!!

I had a great night observing my target as planned (and replanned and replanned and…), and my data looks marvelous.  As astronomers, we like to plan and control everything about our observing runs, but this time it was eye opening to sit back and resolve not to panic.  I will be trying to practice zen observing more in the future. 

Happy New Year from the Baade!  And may all your all-sky cameras contain owls!

First Time Observing at Magellan

Baade and Clay at sunset

I'm Decker French, a new postdoc at Carnegie Observatories. I was recently observing at Magellan over four nights. This was my first time at Las Campanas and using IMACS and MagE, two instruments on Baade (the telescope on the left above!) which have the ability to get optical wavelength spectroscopy. 

Observing with the Magellan telescopes is traditional or "classical" observing in that the observer still physically goes to the telescope. The upside of this, is that the observer gets to go on a trip to a beautiful and remote mountaintop halfway around the world. The site is gorgeous,

The view of the mountains

and the sunsets are amazing, though you always hope for a boring cloud-less sunset.

Sunset

The Las Campanas staff also take exceptionally good care of the observers. Observing is stressful, and having a steady supply of good food and comfy accommodations helps.

View from the telescopes of the lodging area and cafeteria

A downside of this mode of observing, is that telescope time is scheduled months in advance. I was observing galaxies, whose starlight properties don't change on month to month timescales, but I also work on tidal disruption events, which vary more rapidly. For people who study supernovae, tidal disruption events, and other "transient" objects, fitting into a classical observing schedule can be difficult.

The Baade control room

For this upcoming year, I've joined a collaboration working on upgrading the Swope telescope (which you may have heard about earlier this year!) for more efficient observations of time varying sources, among other uses.

The Swope, DuPont, and OGLE telescopes down the ridge from Magellan

I hope to be back at Las Campanas soon, but in the meantime, I was fortunate that the weather cooperated, and I have a lot of data to reduce!

Me, waiting for the sun to set in front of the Magellan telescopes

Being an Ally.

One of our Las Campanas Belles is hurting.
I have been serving as her ally for the past few weeks trying to help her thrive during a grueling Title IX investigation over sexual harassment she has endured. I can't tell you anything about her except that she is a Belle that I believe her and that she is a wonderful and talented individual that deserves the world, but who has suffered in the past and continues to suffer.  My thoughts often wander to her and to what she has faced and to how utterly powerless I feel to help her.

For a long time I have wanted to write a post on the blog, but for various reasons, it always falls low in the queue of everything else that needs to be done -- including taking much-needed breaks from my ever-present laptop! Indeed, there are drafts scattered about my desktop to share my experiences on the mountain -- about working on instruments, making new instruments (!!), talking astronomy at the Obama White House, and the weirdness of realizing how often I am the only Belle on the mountain. The topic of this post -- what it means to be an ally, however, rises to the top of my queue over and over again -- I have to express the topic of this post somewhere and the Belles community seems a like good a place to start.

Being an Astronomy Ally (http://www.astronomyallies.com/) is a tough job, but not for the reasons you might think. Hearing the stories of the victims of harassment is painful and their stories stick with you -- swimming out of the chaos of your thoughts in the most unpredictable times. But this I can handle -- it is why I am an Ally. I also am filled with anger. Anger at the harasser, anger at the system that offers so little support to the victims, and anger at the practices in our community that permit so many to suffer in silence for so long. But this I can handle -- it is why I am an Ally.

What I struggle with is how little I can really do. What I struggle with are the feeling of hopeless that overtakes me when I consider this in depth.

All I can offer are my words and my tears and my thoughts and my deepest belief that we can make Astronomy the safe place it should be. I can tell them about my #MeToo story and talk about my own struggle to conquer it. These are not trivial things to give -- it means a lot to validate the experiences of harassment victims with your words and your emotions. It means a lot to carry their story. It means a lot to show them that while it feels like the world is against them, I, at least, am for them. It means a lot to stand for them in all the ways that Allies choose to do.

But what I want to do for this Belle is to stop time and let her have back the moments she has lost to her pain and her fear. What I want to do for this Belle is to disentangle this struggle from her experiences in astronomy and give her back that love of this science. What I want to do for this Belle is tell her that all of this is 100% conquerable and that it will not impact her career goals and her dreams. What I want to do for this Belle is to whisk her forward in time to the safe community we are striving to build.

But I can't do any of that.

Reconciling these strong desires with what I can do is tough. It is the hardest part of being an Ally.

What I can do is listen to stories and learn from them. What I can do is train my students to be allies. What I can do is demonstrate that I can be talked to about difficult situations and that I will listen. What I can do is influence my peers to build supportive environments. What I can do is talk to my superiors about how they can change our community. What I can do is work to be a superior one day that can enable change -- and be the type of superior that can be approached by others to discuss it. What I can do is design safe meetings and teleconferences that are equitable and inclusive, give a voice to the individuals that need it, embrace and enforce good work-life balance among my colleagues, and do my very best to lend my support everywhere that I can. All of these are important things that I do and things that I force myself to double check that I am doing to the best of my ability for all marginalized populations in our community.

But all of these things seem like quiet moves during a time when I honestly feel that the best course of action might to be to burn academia down and start over. I don't really rationally think this thought, but in the irrational frustration of my helpless feelings, it does seem like it would be really satisfying and direct. I told this Belle that and she laughed -- the kind of honest and heartfelt laughter that makes me know that she is on her way to being okay.

So, I have decided to be a little more vocal and try to express all of the things I that I want to do but that I just can't do. I will tweet about the time I spend being an Ally and how important it is to me. I will talk about how the experiences shape me and fortify my resolve that Allies are integral to our community. I will talk about these difficulties in the most anonymous ways possible to gather support for this Belle -- support she may never be able to acknowledge, but support that is so very very meaningful to her struggle. I will show with my words and my actions how much these stories impact our entire community. I will talk about how it is a privilege to not have experienced harassment in any form and one that we all must internalize when we talk about achievement and progress and struggle. I will use this hopelessness I feel as the motivation to keep fighting.

Crosspost: MagAO Team Takes a Field Trip!

Welcome to LCO to Jhen Lumbres, a graduate student in Optical Sciences at University of Arizona She wrote her first MagAO blog today on the fitting theme of ringing the rocks on Cerro Las Campanas.