SDSS Tweep of the Week: John Parejko

This week the SDSS is preparing for our telescope at Apache Point Observatory to come out of its usual 4 week summer vacation shutdown and get back to observing.

This period of shutdown is a very busy one for SDSS operations when a lot of essential maintenance happens. For example this year the primary mirror of the telescope has been given a new reflective coating. The timing of the shut down is set to coincide with the monsoon season in the South West of the USA – a period when the weather is often not good for observing anyway.

As part of the process of re-opening, SDSS Operations Software Guru John Parejko (who is usually based at Yale University in New Haven, CT) will travel out to APO. John has agreed to tweet what’s going on for us as our “Tweep of the week” while the telescope gets ready to start observing again.

John Parejko in front of the Sloan 2.5m Telescope at Apache Point Observatory.

John Parejko in front of the Sloan 2.5m Telescope at Apache Point Observatory.

John got his PhD in physics in 2010 from Drexel University where he used SDSS data to study the topic of Low Luminosity Active Galaxies (ie. how supermassive black holes which are only accreting a little bit work). Following this he was a postdoc at Yale University working on the BOSS (Baryon Acoustic Oscillation Spectrosopice Survey) data, before taking over responsibility for the SDSS telescope operations software two years ago.

John’s an example of someone whose been in the SDSS family for a while!

SDSS Collaboration Meetings in Park City, Utah, USA

Over 150 scientists from institutions in 13 countries in Europe, Asia, North America and South America recently traveled to Park City, Utah for the SDSS Collaboration meetings. First SDSS-IV got underway. The start of SDSS-IV observations on July 1, 2014 meant that this meeting was much less anticipatory and much more participatory than the SDSS-IV meeting last year. For the second half of the week, the SDSS-III collaboration, data all taken, was focused on the interesting science results coming out of this very successful 6-year survey. The overlap between the membership of the SDSS-IV and SDSS-III collaborations is quite large, so expect to see many of the faces in the photo from the SDSS-III half of the meeting in the future as well! Our enthusiastic thanks to the University of Utah for playing host to such a fabulous set of meetings.

SDSS-III collaboration meeting picture from the wonderful setting of Park City, Utah

SDSS-III collaboration meeting picture from the wonderful setting of Park City, Utah


SDSS Tweep of the Week – Karen Masters

This week is the 2014 SDSS Collaboration Meeting which is happening in Park City, Utah. The @SDSSurveys twitter account will be “taken over” this week by Dr. Karen Masters from the Institute of Cosmology and Gravitation at the University of Portsmouth.

Karen is the first ever “SDSS Tweep of the Week” – a new idea to give the SDSS Twitter account over to collaboration members for week long stints. We don’t expect to fill every week this way, but look out on the blog for introductions to future “Tweeps” from the more than 200 scientists involved in SDSS from all over the world.

As our SDSS Director of Education and Public Engagement, Karen is the ideal guinea pig for this plan. Karen is also a science team member of the @MangaSurvey part of SDSS so expect to hear a lot from MaNGA parallel sessions during this week.

Dr. Karen Masters

Dr. Karen Masters – SDSS Director of EPO and a member of the MaNGA Science Team

If you’re a SDSS Collaboration Member reading this and interested to sign up for a week please visit the Twitter Schedule on the Wiki (password protected site).

Sloan Research Fellowships Open for Nominations

The Alfred P. Sloan Foundation is now accepting nominations for Sloan Research Fellowships in eight fields: chemistry, computational and evolutionary molecular biology, computer science, economics, mathematics, neuroscience, ocean sciences, and physics. These two-year, $50,000 fellowships are awarded annually to 126 early-career faculty in recognition of their distinguished performance and exceptional potential as researchers. Candidates must be nominated by a department head or other senior researcher. For more information, please visit this site:

The Sloan Digital Sky Survey Expands Its Reach

With the start of SDSS-IV this July, the Sloan Digital Sky Survey is entering a new and exciting phase of exploring the Universe. We’ve imaged 1/3 of the sky and taken over 3 million spectra, but we haven’t explored beyond the centers of nearby galaxies, haven’t mapped the Universe between 3 and 7 billion years after the Big Bang, and haven’t studied the part of the Milky Way that is only visible from the Southern Hemisphere. Well, that all changes starting now! We have a press release today featuring the science of SDSS-IV and including a fantastic video by John Parejko illustrating how SDSS takes all that data (hint: it starts with a lot of work in the daytime and continues with a lot of work in the nighttime).


Revamp of

As part of the transition from SDSS-III to SDSS-IV we have just launched a revamped version of the website.

The site is redesigned to represent the entire SDSS, from the beginning through today. We hope that it provides a good balance between presenting our amazing results so far and our exciting future.

The original SDSS website is still available at, and the SDSS-III website is still available at

Congratulations to the web team on the successful transition of the sites.

Passing the Baton – SDSS-III to SDSS-IV

Tonight marks the official start of the fourth phase of the Sloan Digital Sky Surveys (SDSS-IV), and the end of SDSS-III.  


SDSS-III ran from 2008-2014 and made a major upgrade of the SDSS spectrographs. SDSS-III contained four interweaved surveys: BOSS focussed on mapping the clustering of galaxies and intergalactic gas in the distant universe;  SEGUE-2 and APOGEE surveyed the dynamics and chemical evolution of the Milky Way; and MARVELS observed the population of extra-solar giant planets. Over the full survey, SDSS-III took more than 2 million spectra, all of which will be released in a final SDSS-III Data Release (DR12 for the SDSS) in January 2015. 


SDSS-IV will run from 2014-2020, comprising three surveys, eBOSS, APOGEE-2 and MaNGA. eBOSS will work to extend precision cosmological measurements to a critical early phase of cosmic history; APOGEE-2 will expand the survey of the Galaxy across both the northern and southern hemispheres, and MaNGA will for the first time using the Sloan spectrographs to make spatially resolved maps of individual galaxies. 

We’d like to take this chance to congratulate the SDSS-III collaboration on a successful set of surveys, and wish SDSS-IV all the best for the future.

The 2014 Shaw Prize in Astronomy Recognizes Key Measurements of Cosmic Structure by 2dF and SDSS

The 2014 Shaw Prize in Astronomy has been awarded to Daniel Eisenstein, John Peacock, and Shaun Cole “for their contributions to the measurements of features in the large-scale structure of galaxies used to constrain the cosmological model including baryon acoustic oscillations and redshift-space distortions.” For more details on the Shaw Prize see

Daniel Eisenstein, the director of SDSS-III, remarks that “although this is a tremendously gratifying personal recognition, it is also a wonderful recognition of the SDSS/BOSS and 2dFGRS collaborations that have created these exquisite surveys and pushed forward the science of large-scale structure. It is a great honor for our field and our teams!”

Shaun Cole and John Peacock were key members of the 2dF Galaxy Redshift Survey (2dFGRS) which together with the work of Daniel Eisenstein and his SDSS collaborators made the first detections of the baryon acoustic oscillation pattern in the distribution of galaxies in the Universe. Baryon acoustic oscillations are an imprint from fluctuations of matter and light in the early Universe. By measuring the apparent size of this pattern at different cosmic eras, astronomers are studying the nature and amount of dark matter and dark energy that govern our expanding Universe.

SDSS congratulates all of the winners of this year’s Shaw Prize in Astronomy!

Miembros del SDSS Chileno Visitan APO – Chilean SDSS Members Visit APO

A post by Garrett Ebelke, Telescope Operation Specialist and APOGEE Hardware Development and Training Coordinator at Apache Point Observatory. Translated into Spanish by Loreto Barcos and Guillermo Damke (University of Virginia), with help from Veronica Motta (Universidad de Valparaíso, Chile).

Publicado por Garret Ebelke, Especialista de Operaciones del Telescopio y Coordinador de Desarrollo y Entrenamiento del Instrumento de APOGEE del Observatorio Apache Point. Traducido al Español por Loreto Barcos-Muñoz y Guillermo Damke (Universidad de Virginia, con ayuda de Veronica Motta (Universidad de Valparaíso, Chile).

Durante la segunda mitad de Abril, los ingenieros Daniel Garrido y Mario Cáceres viajaron desde Chile al Observatorio Apache Point (APO, por sus siglas en inglés), en Nuevo México, como parte del proyecto QUIMAL de la Universidad de La Serena. El objetivo de su viaje fue conocer en profundidad la infraestructura del instrumento de APOGEE para adquirir un conocimiento más acabado de sus numerosos subsistemas. Estos serán replicados en el proyecto APOGEE-2 e instalados en el telescopio du Pont de 2.5 m ubicado en el Observatorio Las Campanas (LCO, por sus siglas en inglés).

During the second half of April, Daniel Garrido and Mario Caceres, both engineers from Chile, travelled to Apache Point Observatory in New Mexico as part of the QUIMAL project at the Universidad de La Serena. The purpose of their trip was to delve deep into the APOGEE infrastructure hardware to gain a better understanding of the numerous hardware sub-systems. These systems will be replicated for the APOGEE-2 project and installed at the du Pont 100-inch Telescope at Las Campanas Observatory.

[For more on the plans for APOGEE observing at Las Campanas see this blog post.]


Daniel Garrido (left), Mario Caceres (right) at APO

Daniel Garrido (left), Mario Caceres (right) at APODaniel Garrido (a la izquierda) y Mario Cáceres (a la derecha) en APO.

While at APO, they were introduced to the daily task of plugging fiber optics into spectrographic plug plates, all contained within cartridges. They became very familiar with mounting these cartridges to the telescope, and how much care must be taken when handling the cartridges. A similar cartridge design will be used at LCO and Daniel will be heavily involved in assembling and populating the cartridges with fiber optics. Daniel was very eager to explore the internal configuration of the cartridges and quickly got his hands dirty once we opened a cartridge.

Durante su visita a APO, se les inició en la tarea diaria de conectar fibras ópticas a placas espectrográficas, cada una contenida en distintos cartuchos. Daniel y Mario también aprendieron a montar estos cartuchos en el telescopio y entendieron la delicadeza de este proceso. Los cartuchos que se utilizarán en el LCO tendrán un diseño similar. Daniel además estará involucrado en el montaje e instalación de las fibras ópticas en los cartuchos en el LCO. Daniel mostró mucho entusiasmo en explorar la configuración interna de los cartuchos y no tuvo inconvenientes en “ensuciarse las manos” para estudiarlos por sí mismo.

Mario and Daniel plugging fiber optics into a spectrograph plug plate

Mario y Daniel conectando las fibras ópticas en una placa espectrográfica. Mario and Daniel plugging fiber optics into a spectrograph plug plate.

Daniel pushes a cartridge to the telescope

Daniel pushes a cartridge to the telescope. Daniel empuja un cartucho hacia el telescopio.

Daniel (left), Mario (right) explore the internal configuration of an APOGEE fiber optic cartridge

Daniel (a la izquierda) y Mario (a la derecha) exploran la configuración interna de un cartucho de APOGEE. Daniel (left), Mario (right) explore the internal configuration of an APOGEE fiber optic cartridge.

No pudimos dejarlos marcharse de APO sin antes llevarlos a disfrutar del lado oscuro de las operaciones, donde pasaron varias noches familiarizándose con las operaciones nocturnas. Una parte importante de las observaciones es el aprendizaje del software usado para controlar el telescopio y el instrumento de APOGEE.

We couldn’t let them leave APO without letting them join the dark side of operations, where they spent several nights being introduced to nightly operations. A major part of observing is learning the software used to interface with the telescope and the APOGEE instrument.

Moses Marchante (SDSS Telescope Operations Specialist) introduces Daniel and Mario to the interface software used to control the telescope and the APOGEE instrument.

Moses Marchante (SDSS Telescope Operations Specialist) introduces Daniel and Mario to the interface software used to control the telescope and the APOGEE instrument. Moses Marchante, Especialista de Operaciones del Telescopio Sloan Digital Sky Survey (Relevamiento Digital del Cielo Sloan, SDSS por sus siglas en inglés), les enseña a Daniel y Mario el software de la interface usada para controlar el telescopio y el instrumento APOGEE.

This was an excellent start to incorporating some Chilean participants to the APOGEE-2 project, the hardware designs, operational processes and forge an excellent working relationship that will last throughout the entire project.

Esta fue una gran oportunidad para comenzar a incorporar participantes chilenos al proyecto APOGEE-2, al diseño del instrumento, los procesos operacionales, y para forjar una excelente relación de trabajo que durará a lo largo de todo el proyecto.

Daniel and Mario in front of the APOGEE instrument

Daniel y Mario frente al instrumento APOGEE. Daniel and Mario in front of the APOGEE instrument.

All photos were taken using Daniel Garrido’s camera, there are many more photos at Mario’s web gallery

MaNGA’s First Galaxies

A post by Anne-Marie Weijmans, the MaNGA Lead Observer: 

Last month MaNGA (Mapping Nearby Galaxies at APO) had its first commissioning run at Apache Point Observatory, with its first installed cartridge. MaNGA is part of SDSS-IV and scheduled to start observing in July of this year, but it now already has its first galaxies in hand!

MaNGA is an integral-field spectroscopy survey, which will map the motions and properties of stars and gas in 10,000 galaxies. By grouping fibers together into integral-field units, MaNGA obtains spectra not just of the centre of the galaxy, but also its outskirts, covering the whole galaxy. This means that we can measure properties of stars, such as age and metallicity, over a large surface area in the galaxy, and based on that, figure out how these galaxies were assembled. We also are able to measure the velocities of the stars, which in turn tells us about the structure of the galaxy, and how much dark matter is present. From the gas, we learn about the radiation present in the galaxy: is the gas energized by young stars (indicating that there is on-going star formation), by an active black hole, or both? Combining all these different sets of information, we form a picture of how different galaxies form, and evolve over time.

Niv and Nick installing the cartridge

MaNGA chief engineer Nick MacDonald (UW) and instrument scientist Niv Drory (UT at Austin) inspecting the first MaNGA cartridge, before mounting it to the telescope (credit: A. Weijmans).

MaNGA instrument scientist Niv Drory (UT at Austin) and chief engineer Nick MacDonald (UW) prepared the cartridge, carefully adding the MaNGA integral-field units and making sure that the surfaces of the fibers were clean to optimize their light throughput. The observers at APO, together with MaNGA lead observer Anne-Marie Weijmans and several other members of the MaNGA team took various test-observations of sky and stars, before turning their attention to galaxies. MaNGA can observe 17 galaxies in one go, and with two plates completed this resulted in 34 galaxies.

MaNGA Observing Team

The MaNGA observing team at APO. From left to right: David Law (Toronto), John Parejko (Yale), Niv Drory (UT at Austin), Nick MacDonald (UW), PI Kevin Bundy (IPMU), Anne-Marie Weijmans (St Andrews), Renbin Yan (Kentucky), Brian Cherinka (Toronto), José Sánchez-Gallego (Kentucky) and Hai Fu (Iowa). (credit: D.R. Law).

Right now, two more cartridges are being prepared for MaNGA to start observing this summer, and in the Fall, three more cartridges will follow. And at the same time, MaNGA lead data scientist David Law (Toronto) and survey scientist Renbin Yan (Kentucky) with many other members of the MaNGA team are working hard to analyze the results of these first 34 galaxies. Only 9,966 more to go!

MaNGA First Galaxies

One plate full of galaxies. These galaxies are the very first ones observed by the final MaNGA instrument. Some galaxies have been off-set from the centre of the IFU to allow inclusion of foreground stars, to test our measurement precisions. (credit: K. Bundy).

To keep in touch with MaNGA and see what we are up to, follow us on Twitter @MaNGASurvey.

A few more pictures:



MaNGA plate

MaNGA galaxy plate, showing the holes for the MaNGA IFUs and sky fibers (credit: D.R. Law)

Anne-Marie plugging a MaNGA plate

Attempt at plugging a MaNGA plate by lead observer Anne-Marie Weijmans (St Andrews), (credit N. Drory).


MaNGA observers watching the stars (credit: D.R. Law).


SDSS-III Director Elected to National Academy of Sciences

It is a great pleasure to share the news that the Director of SDSS-III, and long time member of SDSS, Daniel Eisenstein (Harvard University) has been elected to the National Academy of Sciences!


Daniel Eisenstein

The SDSS is delighted, and feel this is a well a deserved recognition testament to Daniel’s scientific accomplishments and leadership.  

Daniel wants to emphasize that he feels this recognition is also a recognition of the impressive scientific scope of the Sloan Digital Sky Survey, in all its iterations, which has been the context for key aspects of Daniel’s scientific and leadership accomplishments.  

So congratulations to the SDSS-III Director and also to all those who have helped make all phases and surveys of the SDSS a success over the past decades.

The other three NAS electees this year in astronomy are Fiona Harrison, Steve Schectman, and Joseph Silk.

Please join us in congratulating all four astronomers on this honor and accomplishment!

BOSS Completes its Main Survey of Distant Galaxies and Quasars!

The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) has completed its main survey of galaxies and quasars. With 1.35 million luminous red galaxies and 230,000 quasars across 10,200 square degrees of the sky, BOSS has exceeded the number of objects and sky area goals from the original SDSS-III proposal.

Reaching this milestone involved the hard work and efforts of many people. In particular, the mountain and observing staff at Apache Point Observatory have been worked hard and efficiently to observe 2,300 plates with the new BOSS spectrograph in 4.5 years of dark time.


The coverage map of the completed BOSS main survey in equatorial coordinates with (RA, Dec)=(90,0) in the center of the image. Completed areas are shown in light blue and yellow. The red area is a 10,500 deg^2 region from which observations were selected. The project goal was to observe the 10,000 deg^2 footprint above declination -3 deg. A 200 deg^2 region was added between declinations of -3 deg to -7 deg to provide overlap with the Dark Energy Survey.

For the remaining 3 months of SDSS-III, the BOSS spectrograph continues to observe new interesting classes of objects as part of a set of ancillary proposals that were internally competed within the SDSS-III collaboration.

All of SDSS-I, SDSS-II, and SDSS-III/SEGUE observed 1.84 million survey-quality spectra with the original SDSS spectrograph during the timeframe 1999-2009. SDSS-III DR12 will be released publicly in 2014 December and the final BOSS data in DR12 is expected to exceed 2.7 million survey-quality spectra, including calibration targets, stars, repeated observations, and ancillary programs.

The Most Precise Measurement Yet of the Expanding Universe

More exciting news from the SDSS! A worldwide team of SDSS astronomers has completed the most precise measurement of the expanding universe ever. The result was announced just hours ago at the meeting of the American Physical Society in Savannah, Georgia.

Click on the illustration below to go to the SDSS press release describing this exciting news!


Yellow lines showing light paths pass through circles of increasing size. Each              circle shows in purple the structure of galaxies in the universe at some point in the past.

An illustration of how astronomers used quasar light to trace the expansion of the universe.

APOGEE2 Engineering Run at Las Campanas Observatory, Chile

The APOGEE-2 survey of SDSS-IV plans to run observations both at the Sloan 2.5m telescope at Apache Point Observatory, New Mexico, and at the du Pont 2.5m telescope at Las Campanas Observatory in Chile. This will enable observations from both hemispheres, allowing APOGEE-2 to efficiently obtain spectra of stars from all regions of our own Galaxy. Observations from Chile are due to start in 2016.

Last month, several members of the APOGEE-2 Team had three engineering nights kindly provided by the Carnegie Institution on the du Pont 100-inch Telescope. This time was needed for engineering work in preparation for use of the telescope with APOGEE. Paul Harding (Case Western), John Wilson (UVa), French Leger (UW), Garrett Ebelke (APO) and Fred Hearty (PSU) made nighttime measurements in the visual and near-infrared wavelengths to help determine the optimal focal plane location and radius of curvature for wide-field telescope use (ie. the best places to put the tips of the APOGEE fibers so they capture as much of the light from target stars as possible).

du Pont 2.5m

The 3-segment wide-field baffle system on the du Pont 2.5m telescope

Before the run the Las Campanas Observatory staff installed the 3-segment wide-field baffle system so the team could measure vignetting as a function of field location using both traditional and pinhole imaging. The 3-segment wide-field baffle system uses three different blackened, conical, tubes mounted between the telescope mirrors to ensure that only light from the direction the telescope is aimed reaches the focal plane. This was the first time the 3-segment baffle system had been installed in about 15 years.

French Leger

French Leger and the mechanical assembly he designed which allowed precise camera positioning in three dimensions at various locations behind the telescope.


Installation of the assembly

Installation of the assembly. In the foreground are Paul Harding (left) and Oscar Duhalde (right, a member of the Observatory Staff).

This run was an excellent first start to learning the wide-field capabilities of the du Pont telescope and how best to position the hundreds of fibers in the focal plane.  Another run is planned for late this year to make further measurements.