Blog

We've started an observing block for the LEECH survey this week. It's been a rocky beginning. We learned on Sunday of a coolant problem with the left secondary. The mirror has now been removed, leaving us with a monocular telescope for the run. This would be a showstopper for interferometry, but the LEECH observations can continue with one aperture, although at a reduced sensitivity.

We have now had four straight nights of high winds and poor seeing. Sometimes the wind has been bad enough that we have been unalbe to open the shutters (safety concerns). Sometimes it's just bad enough that the seeing is really poor. Last night the seeing varied between 2-4 arcseconds. We were thrilled at the end of the night when it settled down to 1.4 arcseconds.

So, it's been challenging conditions, but we have made progress. We have tested coordinated AO offsetting. This routine allows the observer to pause the AO, move the star and resume AO correction with a single command. The approach has increased our offsetting efficiency by roughly a factor of 4, for a 5 arcsecond move.

We have also begun observing the LEECH targets. The AO still creates reasonable images for seeing of less than 2 arcseconds.

And the weather looks to be improving. I had a nice view during my breakfast this afternoon of calm blue skies.

We're gearing up for a big LEECH run in a couple of weeks. In the mean time, read all about the project on our new webpage leech.as.arizona.edu.

Matt showed off his iphone photosynth app while the LBT was opening.

Here's a click-and-zoom version.

We've had a productive night at the LBT observing some wide, low-mass companions in the mid-infrared. Luckily the conditions are very dry, which is great for our sensitivity in bands affected by precipitable water vapor. When possible, we try to prioritize our observations based on the different weather conditions they require, and the nearby SMT has a nice Tau-meter that measures the water content of the atmosphere.

Currently, the Tau-meter is reading 0.06, which corresponds to ~1.5 mm precipitable water vapor, an excellent value for Mount Graham.

We're visiting from Leiden in the Netherlands for two half nights to use the APP coronagraphs and look for a planet. We thought everyone was joking about needing a four wheel drive car to get up to the telescope, but as we drove up above 8000 feet, we hit the deeper patches of snow still in the shadow of the mountain and we were especially grateful that we did get a big SUV to make it up here in one piece.

After a rocky start with one of the LBT doors getting jammed, we then got over one hour of on-sky data with subarcsecond seeing - a wonderful sight to see! The control room is fairly quiet despite being filled with engineers and astronomers, everyone looking at their laptops and computers and working on getting the two separate AO systems to work together. The APP coronagraph helps us look for faint companions within 1 arcsecond of the target star. It has a 180 degree area of increased sensitivity, and to get coverage all around the star, we use two sets of APP plates over the course of two nights. This is also the first time we are taking very deep image sets with these coronagraphs on the LBT, so it's partially an engineering run as well as an observing run.

Now it's the second night on LBTI for us, and it's amazing to see the two AO systems in action again tonight. Thanks to Phil, Andy, TJ and Denis we have a great team of people working to get us data from the two 8.4m telescope system. Here's hoping the seeing stays low for the rest of the run and that we all get clear skies!

Josh Eisner and Stephanie Sallum joined us today to do some observations with the non-redundant mask. The non-redundant mask turns the LBT into a bunch of little interferometers that can be analyzed independently in order to look for structure very close to a bright star. The image below shows the LBT pupil with 12 little holes, which make the non-redundant mask.

Rafael Milan-Gabet also joined us after having to turn back while driving up during yesterday's snow-storm. Expect a blog post from Rafael about his exciting night in Safford.

Woke up yesterday afternoon to cloudy skies and some light snowfall. By midafternoon that had turned into windy conditions and heavy snowfall. The storm was over by 8 pm or so, but the accumulated snow, wind, and high humidity kept us closed for the night.

We spent the evening characterizing NMOIC, our mid-infrared camera on LBTI. The measured read noise on the camera is roughly 300 e- in its installed configuration. The sky and telscope background was measured to be approximately 12 Megaphotons/s/pixel in the 10-12.5 um filter we will typically use for dust disk detection. This will put the photon noise at approximately the read noise for an 8 ms exposure. Longer exposures will be dominated by the background noise, as any well-designed instrument should be.

We also troubleshot some motor movements on LMIRCam. Filter wheel #3 is occasionally skipping steps. We confirmed it was the feedthrough shaft into the croystat. This needs to be looked at during the next warmup of NIC. FW#2 may be having similar problems, but is not skipping.

It was our first LBTI night of 2013, last night. The goal was to do phase sensing engineering the first half and exoplanet hunting (LEECH) the second half.

We opened at sunset and closed the right side AO. Left side was causing more problems, but finally fixed the alignment to get it closed. We scanned for fringes and found them quickly. However, seeing was 1.5-2". The phase sensor was aligned and run at 400-500 Hz. However, fringes were not detectable in the poor seeing.

Switched over to LMIRCam at 12:30, only to have first the winds come up and then the humidity, requiring us to close for the rest of the night.

Minor type-o correction... PK-50 Blocker was reinstalled in LMIRCam FW#4 Pos2, another Revision History slide was added.

Attached is the latest revision of the NWP file. Changes were made to LMIRCam FW#3 and PhaseCam Optics Wheel. See Slide 5 for details.

I have revised the file to show the latest changes to LMIRCam FW3&4. FE II and H2 on and off were added to FW3. PAH1 and Std L' were switched from FW3 to FW4. The AGPM detail was added to the LMIRCam Field Stop Wheel and an exploded view of the installation hardware for the AGPM was added. The newly AR coated NOMIC grism was re-installed in NOMIC FW1 with some mylar tape on the edges of the mount to prevent light leaks.

I have revised Slide 28 LMIRCam Field Stop Wheel to include the slit length in the description. Also, I increased the size of the cartoon of the square slit aperture held by four (4) clips inside the larger square aperture of the wheel. This shows a better approximation of relative size.

We were on sky for our first of five nights in September commissioning,and carrying out early science with LBTI. The system was taken almost completely apart over the summer for alignment and improvements. We aligned the interferometer and were on the sky by the end of twilight. Object acquisition went smoothly. Both AO systems were operational after significant software upgrades. We identified a motor failure in NIC which has prevented mode changes between nulling and Fizeau. The nulling channel looks reasonably well aligned.

The automated control of AO on the left side was the main priority of tonight. By mid-morning, Vidhya, with Alfio's remote help had demonstrated a completely working AOS (the automated top-level software). This takes the system from having a star on the acquisition camera to closed loop, with three button clicks and minimal user expertise. This should be dramatically helpful in improving our efficiency and reducing the operators required for LBTI.

The nulling channel was overlapped and Phasecam images were taken for the first time in both pupil imaging and star imaging mode.

Automated filter control and scripting on LMIRCam was tested in parallel with the AO testing.

It was a bumpy first night with some significant steps forward. Weather looks good, so we hope to continue!

Attached is the revised file of NIC_Wheel_Positions_v4.0 containing the latest changes to the various wheels and mechanisms. Please let me know if there are any errors/type-o's.

These are some images with both sides of the LBT AO system in operation.

We also took some initial data with the apodizing phase plates.

Big step. We closed both AO loops last night, and found fringes. The tight images allowed us to see the three-lobe characteristic PSF at both 4.0 and 10.6 microns. Images are below.

The image above has a pixel scale of 11 mas. The short exposure image (0.087 s) was taken at 4 microns using the LMIRcam system within LBTI. Both AO systems were locked in mediocre seeing (~1.6").

The image above has a pixel scale of 18 mas. This is a short exposure image (0.029 s) taken at 10.6 microns. The two images above were taken essentially simultaneously (slight tweaking was done for a focus shift between the cameras). This illustrates the potential of LBTI to acquire simultaneous images from 2-25 microns.

The evening started out with a promise of clear skies.

We opened at 6:30 pm and started acquisition of a bright star for alignment, AO checkout, and focus. The winds were between 15 & 18 m/s.

Within moments the humidity was on the rise. Apparently a very moist airmass was passing overhead. Even though there were few clouds the humidity quickly reached 95% and we were again forced to close the dome. You could smell the moisture in the air if you stepped outside. The moisture was also very evedent on the all-sky camera which completely fogged over.

We were back open in about an hour. In the mean time we had the opportunity to sing HAPPY BIRTHDAY to Phil and enjoy cupcakes.

Seeing was terrible after we opened back up. However we did accomplish quite a bit:

SX AO System

√ Acquire star

√ Close loop (10 modes)

DX AO System

√ Acquire star

√ Close loop (200 modes)

NOMIC

√ Acquire both SX and DX stars

√ Focus

LMIRCam

√ Acquire DX & SX star

√ Focus

√ Phase

PhaseCam

√ First Light

√ Acquire fast frame data (phasing)

√ Acquire full frame data (acquisition)

Late Afternoon:

Arrived at the LBTO at 6pm with the night's activities in full swing. The dome was open and the observing team were finishing the fine alignment of the science camera. It is always impressive to be in the dome with the shutter doors open.

We spent a productive if not frustrating first part of the evening checking out the cameras, hunting for holes in the clouds, and debugging the AO operations. We had assistance from Doug Miller in Tucson, who with the help of Armando Richardi was able to get the SX side working. There were issues that were identified and our colleagues at Arcetri were just arriving at work to help out with the issues.

Unfortunately we were forced to closed the dome at 1:30 am due to high winds. The protocol is more than one gust over 22m/s in a 6 minute time window. The baseline wind speed was ~18m/s so I think that we were lucky to stay open as long as we did. It was a productive, but short night.