Category: MagAO-C

Yesterday our SPIE paper pre-prints were announced on the astro-ph ArXiv. In case you missed it, here’s a run-down:

Into the Blue: AO Science with MagAO in the Visible (Invited Talk)
Laird M. Close, Jared R. Males, Katherine B. Follette, Phil Hinz, Katie M. Morzinski, Ya-Lin Wu, Derek Kopon, Armando Riccardi, Simone Esposito, Alfio Puglisi, Enrico Pinna, Marco Xompero, Runa Briguglio, Fernando Quiros-Pacheco

We review astronomical results in the visible ({\lambda}<1{\mu}m) with adaptive optics. Other than a brief period in the early 1990s, there has been little astronomical science done in the visible with AO until recently. The most productive visible AO system to date is our 6.5m Magellan telescope AO system (MagAO). MagAO is an advanced Adaptive Secondary system at the Magellan 6.5m in Chile. This secondary has 585 actuators with < 1 msec response times (0.7 ms typically). We use a pyramid wavefront sensor. The relatively small actuator pitch (~23 cm/subap) allows moderate Strehls to be obtained in the visible (0.63-1.05 microns). We use a CCD AO science camera called "VisAO". On-sky long exposures (60s) achieve <30mas resolutions, 30% Strehls at 0.62 microns (r') with the VisAO camera in 0.5" seeing with bright R < 8 mag stars. These relatively high visible wavelength Strehls are made possible by our powerful combination of a next generation ASM and a Pyramid WFS with 378 controlled modes and 1000 Hz loop frequency. We'll review the key steps to having good performance in the visible and review the exciting new AO visible science opportunities and refereed publications in both broad-band (r,i,z,Y) and at Halpha for exoplanets, protoplanetary disks, young stars, and emission line jets. These examples highlight the power of visible AO to probe circumstellar regions/spatial resolutions that would otherwise require much larger diameter telescopes with classical infrared AO cameras. MagAO: Status and on-sky performance of the Magellan adaptive optics system
Katie M. Morzinski, Laird M. Close, Jared R. Males, Derek Kopon, Phil M. Hinz, Simone Esposito, Armando Riccardi, Alfio Puglisi, Enrico Pinna, Runa Briguglio, Marco Xompero, Fernando Quirós-Pacheco, Vanessa Bailey, Katherine B. Follette, T. J. Rodigas, Ya-Lin Wu, Carmelo Arcidiacono, Javier Argomedo, Lorenzo Busoni, Tyson Hare, Alan Uomoto, Alycia Weinberger

MagAO is the new adaptive optics system with visible-light and infrared science cameras, located on the 6.5-m Magellan “Clay” telescope at Las Campanas Observatory, Chile. The instrument locks on natural guide stars (NGS) from 0th to 16th R-band magnitude, measures turbulence with a modulating pyramid wavefront sensor binnable from 28×28 to 7×7 subapertures, and uses a 585-actuator adaptive secondary mirror (ASM) to provide flat wavefronts to the two science cameras. MagAO is a mutated clone of the similar AO systems at the Large Binocular Telescope (LBT) at Mt. Graham, Arizona. The high-level AO loop controls up to 378 modes and operates at frame rates up to 1000 Hz. The instrument has two science cameras: VisAO operating from 0.5-1 μm and Clio2 operating from 1-5 μm. MagAO was installed in 2012 and successfully completed two commissioning runs in 2012-2013. In April 2014 we had our first science run that was open to the general Magellan community. Observers from Arizona, Carnegie, Australia, Harvard, MIT, Michigan, and Chile took observations in collaboration with the MagAO instrument team. Here we describe the MagAO instrument, describe our on-sky performance, and report our status as of summer 2014.

Direct imaging of exoplanets in the habitable zone with adaptive optics (Invited Talk)
Jared R. Males, Laird M. Close, Olivier Guyon, Katie M. Morzinski, Alfio Puglisi, Philip Hinz, Katherine B. Follette, John D. Monnier, Volker Tolls, Timothy J. Rodigas, Alycia Weinberger, Alan Boss, Derek Kopon, Ya-lin Wu, Simone Esposito, Armando Riccardi, Marco Xompero, Runa Briguglio, Enrico Pinna

One of the primary goals of exoplanet science is to find and characterize habitable planets, and direct imaging will play a key role in this effort. Though imaging a true Earth analog is likely out of reach from the ground, the coming generation of giant telescopes will find and characterize many planets in and near the habitable zones (HZs) of nearby stars. Radial velocity and transit searches indicate that such planets are common, but imaging them will require achieving extreme contrasts at very small angular separations, posing many challenges for adaptive optics (AO) system design. Giant planets in the HZ may even be within reach with the latest generation of high-contrast imagers for a handful of very nearby stars. Here we will review the definition of the HZ, and the characteristics of detectable planets there. We then review some of the ways that direct imaging in the HZ will be different from the typical exoplanet imaging survey today. Finally, we present preliminary results from our observations of the HZ of {\alpha} Centauri A with the Magellan AO system’s VisAO and Clio2 cameras.

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And here are some pictures from the conference, which was the SPIE Astronomical Telescopes and Instrumentation conference in Montreal in June. You can check out #SPIEastro to find out more about the general topics covered at the conference.

I’m on Mauna Kea visiting Olivier Guyon and the Subaru Coronagraphic Extreme AO (SCExAO) system. At 13,800 feet I’m pretty sure this is the highest altitude pyramid AO system in the world. Despite having a pyramid wavefront sensor, SCExAO is a pretty different AO system from MagAO. For one thing, there isn’t an adaptive secondary. Instead, the deformable mirror is on an optical bench off to the side. SCExAO is also not the only AO system – before light gets to SCExAO it has been corrected by the AO188 system, which is the AO workhorse of the Subaru telescope.

SCExAO hosts several science cameras, including VAMPIRES and FIRST which are being engineered on this run. I’ve also seen some impressive demonstrations of low-order wavefront sensing, focal plane wavefront sensing, and speckle nulling. SCExAO has some really exciting high contrast imaging capabilities.

As you can see, the SCExAO team is very creative with their camera displays. They consider Chuck Norris to be their spiritual leader, though somebody seems to like My Little Ponies.

Mauna Kea is high, and the air is thin up here.

We stay at Hale Pohaku (HP), which is at a more comfortable 9000 feet.

One thing that I learned during this visit is that if Olivier ever asks you to go for a walk, you say NO. What he considers a “walk”, most people would consider “rock climbing in the dark”.

The view is amazing from up here.

Being back in Hawaii reminds me of old times. The song of the day describes one of life’s enduring mysteries, which I still have little insight into.

Hi MagAO fans, you’ll never guess where I am…

We spent almost the entire month of April in Chile for MagAO’s first science run, and we were very happy with how well it went. So what better thing to do than get on a plane back to Chile to work on my other high-contrast AO project? I’ve been at the Gemini South Telescope at Cerro Pachon this week, helping with the 3rd commissioning run for the Gemini Planet Imager (GPI). When I was in grad school, I worked in the lab on the MEMS deformable mirror for the GPI AO system, advised by PI Bruce Macintosh. And now that GPI is on the telescope, I was very happy to get a chance to come and see the instrument on sky!

On this commissioning run, we’ve been running lots of tests, because GPI is a complicated instrument with stringent top-level requirements for its international user base. But today I’ll focus a set of data we took to calibrate the astrometry of GPI.

Astrometric calibration is critical for GPI as well as MagAO: When we see a faint dot near a star, the best way to check whether it is a planet orbiting that star, versus whether it is a background star along the same line-of-sight, is to compare the astrometry at a later date. Astrometry means measuring the stars — measuring the exact position in arcseconds and angle from North. But to figure out the size of our pixels on the sky, and the orientation of our camera and which way is North, we have to observe known groups of stars and measure their separations and angles. Then we compare our measurements to those from other instruments and tie that back to basic calibrations done in the lab with pinhole masks to create a common reference frame. This is how we calibrate astrometry.

But the field of view of GPI is very small, and it is hard to find a group of stars that are very close together, that also have a bright enough guide star for the AO system. Fortunately, MagAO observed an 8th-magnitude star in Baade’s Window at Magellan during our science run in April 2014, and we decided to try it with GPI. (Baade’s window is a clear window through to the galactic plane, so it’s full of stars that are thousands of parsecs away.)

We have to give credit to Laird for finding this field — it wins for the most stars (six!) visible in GPI’s field of view so far! Here is the GPI image compared to the MagAO/Clio image — both in H-band:

We have also sent the field along to our friends at VLT/SPHERE, who are currently on their first-light run, because someday we will all be trying to compare our observations of the same planets, and that will be much easier if we can also compare our astrometric calibrations.

Although GPI’s field of view is small, MagAO/Clio’s is a bit larger and so we can bootstrap our astrometry from some of the stars seen wider out in the field. Here is the zoomed-out Clio H-band image:

Finally, here are the zoomed out images from both VisAO and Clio, where we have plenty of stars for boot-strapping:

This is a great example of what we gain with cooperation and synergy between complementary instruments and our scientific friendships!

This post is cross-posted at the GPI blog. Over here you get a song of the day: