APOGEE and Amateur Spectroscopy

Drew Chojnowski, APOGEE plate designer and lead of the emission-line stars science group, discusses SDSS and Be stars observed with the APOGEE instrument.

This weekend, APOGEEans David Whelan and Drew Chojnowski attended the Sacramento Mountains Spectroscopy Workshop. The workshop’s goal? To get amateur astronomers interested in pursuing spectroscopy. With a mix of amateurs and professionals in the room, the expertise was readily available, and the excitement was palatable.

On Friday, David Whelan lead a discussion on spectral classification of intermediate- and high-mass stars. This is a science effort that is essential to both APOGEE’s emission-line stars group and high-mass stars studies more generally. Perhaps some knowledgeable amateurs can begin to contribute?

Then on Saturday, Drew introduced the group to observing with the Sloan Telescope. Below, he is shown with one of SDSS’s APOGEE plates.

Drew and an APOGEE plate – teaching people how the SDSS is done.

These kinds of workshops break down the barrier between the amateur and the professional, and opens both groups to new possibilities. With special thanks to the organizers Ken Hudson and Joe Daglen, as well as François Cochard from Shelyak Instruments, we very much look forward to pursuing the science generated by this workshop.

The attendants of the Sacramento Mountains Spectroscopy Workshop. David and Drew are on the far right.

Amateur astronomer Joe Daglen, center, tells workshop attendants about the equipment that he uses to teach undergraduate students about imaging and spectroscopy.

Job Opening at The Sunspot Astronomy Visitor Center

The Sunspot Astronomy Visitor Center includes content related to the science and observations of the Sloan Digital Sky Surveys. They are seeking a new Program Co-ordinator for Education and Public Outreach. The below is reposted


New Mexico State University is seeking a program coordinator to manage the education and public outreach program at the Sunspot Astronomy Visitor’s Center.

Duties include: Oversees operations of public access to exhibits and daily tours around Sunspot Observatories. Initiates and provides local tours, plans and operates star parties: Coordinates visits from local schools and interested groups; Ensures visitor center facility is staffed during operational periods for visitors and tours as needed;  Develops a  business plan to ensure visitor center solvency; Manages gift shop including stock ordering, pricing and design and/or selection of gift shop merchandise; Manages exhibits including coordination of repairs and updates as needed; Responsible for fiscal management of Visitor’s Center;  and may require grant writing and cooperative agreements with other local tourist attractions and of state and federal agencies.  Manage staff as required.

A bachelor’s degree and/or a strong background in and knowledge of astronomy is preferred.

Job Closing Date: 08/31/2017

Targeted Start Date: 10/01/2017

Please visit to https://jobs.nmsu.edu/hr to apply

SDSS Summer Interns Apply SDSS Science to Small Telescopes

By Kate Meredith.  Kate is the Director of Education Outreach at the University of Chicago Yerkes Observatory.  Kate began working with SDSS data while still a high school science teacher and continued that work in her role with SDSS as lead educator for formal education.  She is the primary developer of the SDSS Voyages website.  In her first year as Education Director at Yerkes, Kate launched a summer intern program.  In this post, Kate describes one of the projects interns lead during the summer of 2016.  

Rebecca Chen and Lindsay Berkhout are sophomore physics majors at the University of Chicago. Both chose the astronomy specialization, and both spent the summer of 2016 as interns at Yerkes Observatory . They were two of the 12 undergraduates that helped launch the first ever Yerkes Education Outreach internship program.  Their goal was to take precise photometric measurements of targets (how bright objects are) with instruments including the 24-inch telescope at Yerkes, as well as Stone Edge Observatory’s 20-inch telescope, located in Sonoma, California.

Rebecca Chen positioning new SDSS filters for use with the 24 inch reflecting telescope at Yerkes Observatory.

“We both came in, and we didn’t know anything,” Berkhout laughs. But they soon got up to speed, and ended the summer with a tested methodology that allows not only them, but students following in their footsteps, to use the telescopes to measure the brightness of objects to within 5% the value obtained by the venerable Sloan Digital Sky Survey (SDSS).

The long-term goal on Yerkes’ side is to be able to extend SDSS catalog to bright stars. The survey, designed to measure many faint targets, has gaps when it comes to measuring the brightest stars. But the Yerkes and Stone Edge telescopes—large for small observatories, but tiny compared to SDSS’ 100-inch mirror—can tackle the bright stars with ease. The trick is being able to compare data using the very different instruments of SDSS and the observatory telescopes.Chen and Berkhout were interested in more dramatic events; they wanted to measure the lightcurves of recent supernovae. But both projects rely on being able to precisely measure the brightness of targets. And figuring out how to reliably attain such precision with the Stone Edge and Yerkes telescopes became the students’ summer objective.

Richard Kron, a professor at the University of Chicago and former director of Yerkes Observatory, worked closely with the students. But he says he was mostly there to answer their technical questions, and let them guide the direction of the work themselves—something Chen and Berkhout handled with aplomb, though he notes that other students might desire a more hands-on approach to mentoring.

He introduced the pair to software packages—Aperture Photometry Tool and Topcat—to help them in their work, and advised on details such as calculating uncertainty in their measurements. He admits that his first instinct is often to push through and rush to big results. And students likewise often want to do something novel and exciting—like observing supernovae.

Intern Lindsay Berkhout installs SDSS filters in CCD camera at Yerkes Observatory.

But Kron says it’s important to remember how much time new students take to assimilate the big concepts at play: operating the telescopes, learning new software routines, finding and measuring the targets, understanding uncertainty. “Make sure the student feels really in command,” he suggests. “It’s okay if you don’t cover quite as much as your original dreams had suggested.”

“There’s still a lot of work to do,” Berkhout acknowledges. Steep learning curves, but also telescope downtime, contributed to the sometimes slow pace. “The next step is actually taking data and using this methodology to get results,” she says, something they ran out of time for in the short summer.  “I think that if someone else takes the project they could go wherever they want with it, whether it’s bright stars or variable stars, or supernovae.”
Berkhout and Chen left behind a detailed guide of the work they did, summarizing the technical details of how to take observations, run them through the software, measure sources’ photometry, and compare it to SDSS values. They also left suggestions for ways future interns might improve from 5% down to within 2% of the SDSS values. And they took with them many more lessons in how to plan and tackle such a project.

“I felt like it was a really nice internship for summer after first year,” Berkhout says. “It was a good way to get involved in a research project that taught us a lot so now we can go to other people and be able to say that we’ve done something. That we learned a lot and we’re competent and can be involved in bigger research projects in the future.”

Chen reflects that, “While we were working it was frustrating, because at times it felt like we weren’t getting anywhere. But at the end of the summer, looking back on all the things we had done, I was like, ‘Oh that’s pretty cool. That’s a project. We did a real project.’”


Rebecca Chen and Yerkes Director of Education and SDSS EPO Specialist, Kate Meredith, celebrate the first successful night of observing with the new SDSS filters and several hundred mosquitos at Yerkes Observatory.

A plug plate for the South Downs Planetarium and Science Centre

Yesterday I had the pleasure of giving an SDSS Plug Plate to the South Downs Planetarium and Science Centre, in Chichester, West Sussex. This facility has been run by a team of volunteers and astronomy enthusiasts since 2002. It boasts a 100 seater planetarium, running 8-9public planetarium shows each month, as well as being available for schools bookings. I was visiting the planetarium with a group of First Year Physics students from the University of Portsmouth.


John Mason takes delivery of SDSS plate 3955 from SDSS-IV Spokesperson, Karen Masters.


The organization plan to put the SDSS plate on display, along with their other astronomy displays which include a waxwork model of famous UK amateur astronomer, Sir Patrick Moore and memorabilia from British Astronaut Tim Peake who went to school in the nearby Chichester High School. In addition they discussed plans to show the sky location the plate was designed for in future planetarium shows.

If you’d like to explore the data from this plate, which is in the direction of the constellation “Serpens”, see Plate 3955 in our Skyserver Navigate interface.


Certificate of Ownership for Plate 3955.

The South Downs Planetarium and Science Centre now joins museums and science centres from all over the world who display SDSS plates.

SDSS Collaboration Meeting 2016: Madison, Wisconsin, USA

At the end of June 2016, over 150 members of the SDSS collaboration met for workshops, talks, discussions, and fun by the lake at the University of Wisconsin, Madison. The week began with a two-day APOGEE workshop on Saturday and Sunday. On Sunday, the APOGEEans were joined in Madison by the FAST/REU bootcamp and the Plate workshop for teachers and scientists.

2016 SDSS collaboration meeting photograph. The happy attendees gathered by the beautiful lake. If you were there and not in this picture, you were probably getting coffee.

2016 SDSS collaboration meeting photograph. The happy attendees gathered by the beautiful lake. If you were there and not in this picture, you were probably getting coffee.

The FAST/REU students were getting up to speed really quickly on how to work with our data. The REU students are undergraduates who will be working on a science project over the summer, while the FAST students are graduate students in longer term teams with SDSS as we seek to help raise the participation of under-represented minorities.

On Monday-Wednesday, the meeting focused on discussions of SDSS-IV science, including many exciting results from the MaNGA survey, which is releasing its first data in Data Release 13. The APOGEE-2 survey present maps of the composition of stars across the Galaxy, characterizing the trends with position. The eBOSS survey showed the first results for large-scale structure of the Universe based on the 2014-2016 observations (very fast turn-around!). Quasars were also a big topic of conversation, as SDSS is now studying their evolution in detail. We are interested both in how they change over a few years time and mapping how they “grow” the supermassive black holes over billions of years. Results discussed that have been highlighted by SDSS in press releases/blog posts include the shutting off of star formation in galaxies by Edmond Cheng , additional examples of “changing look quasars” by Jessie Runnoe and the discovery that brown dwarfs could be quite common around certain types of stars by Nick Troup.

Poster for Daniel Eisenstein's public talk

Poster for Daniel Eisenstein’s public talk

We saw ways that other galaxies could “quench” their star formation in the presentation by Francesco Belfiore and could study the history of star formation in our Galaxy thanks to age maps by Melissa Ness. Apparently our galaxy has some similarities to other spiral galaxies! We tweeted a whole bunch about about the science results and will Storify some of our most popular tweets soon.

On Tuesday night, we had the collaboration meeting banquet, where we honored Dan Long, longtime Sloanie who worked at Apache Point Observatory for over 20 years, including as Chief Telescope Engineer for the Sloan Foundation Telescope. He is retiring next year and, as the email from Jim Gunn put it, “we will miss him more than I can say.” In addition to spoken tributes, we also showed of a movie of some of Dan’s greatest hits and well-wishes from the many other Sloanies. We will be posting that to youtube soon, so stay tuned.

The SDSS collaboration is big and includes people from many career stages, institutions, and cultures. We take the opportunity of these meetings to discuss how the collaboration is working and what we can do better. There was a thoughtful and thought-provoking discussion of how to improve the climate in SDSS and how to establish a “Code of Conduct” that will work to ensure that all are treated with respect.

This meeting also featured our first public talk by Daniel Eisenstein, talking about using the disturbances that sound waves left in the gas of the early Universe to trace the shape, past, and future of the Universe. He’s been working with SDSS data on this subject for over 10 years, so is a leading expert in this amazing result. The April 2016 edition of Sky and Telescope featured the article “Mapping the Universe’s Ancient Sound Waves” written by Daniel. The “Beyond the Pages” addition by the editors is also wonderful.

We had our most ambitious meeting ever for education and public outreach. The Plate Workshop on how to use an SDSS plate to introduce your class to the science of SDSS had a number of educators from across the US attending, looking pretty happy when they got their picture taken.

Educators from the Plate Workshop, organized by Kate Meredith (bottom right) and Karen Masters (who is probably taking the picture)

Educators from the Plate Workshop, organized by Kate Meredith (bottom right) and Karen Masters (who is probably taking the picture)

The Sunday workshop was followed on Monday and Tuesday by educators attending science talks, working with SDSS scientists on education and public outreach ideas, and doing an “EPO Hack Day” to create new activities for Voyages, SDSS’s website for how to use our data for education for K-12 students.

Thanks to the University of Wisconsin, especially the head of the Local Organizing Committee, Christy Tremonti, for hosting such a lovely meeting and we look forward to seeing everyone at the next meeting next summer.

Letter from the New Editor in Chief

Dear Readers of the SDSS Blog,

I am Zheng Zheng, a SDSS-IV postdoctoral research fellow at the National Astronomical Observatories, Chinese Academy of Sciences (NAOC). I will be your new Editor in Chief for the SDSS Blog for the next 6 months and I will try my best to work with other bloggers to make the blog posts more interesting and smooth.

I got my PhD at Johns Hopkins University and now I am a postdoctoral researcher working at the NAOC and partially at the Institute of Cosmology and Gravity (ICG) at the University of Portsmouth in the U.K. I am currently studying extra-galactic galaxies using the SDSS-IV MaNGA data. I am also interested/involved in MaNGA stellar library, APOGEE and eBOSS projects.

As you may have known, the SDSS is an internationally collaborated survey project and the member institutes come from all over the world. In the future, we will introduce more interesting SDSS related sciences/events from all over the world, including the U.S., Europe, East Asia, and South America. We are aiming to a post frequency of about 1 ‘long’ post (like the ones introducing science projects) per 1-2 weeks. We will also have ‘short’ posts reporting SDSS related events and/or short news.

Please do not hesitate to make comments and let us know your ideas about the blog posts. Your feedback is highly appreciated and we will try our best to post more articles according to your interests.


Zheng Zheng


Zheng observing at Palomar

IYL2015 Post: SDSS Plates (in Retirement!)

As part of Dresdner Lichtjahr 2015 [Dresden Year of Light 2015], you can now see a previously-used SDSS plate on display at Technische Sammlungen der Stadt Dresden, a museum located in a former Dresden factory. The exhibit will run through June of 2016, and has some really awesome demonstrations of how light propagates, and how much today’s technology depends on light.  Technische_SammlungenThe SDSS plate (below, designated plate 4385) is suspended above a table illustrating principles of how light propagates, what we can do with light of different wavelengths, and a demonstration of fiber optics. If you’re curious why our telescope might need need a metal plate, read this previous post.

Technische_Sammlungen2Used SDSS plates are available for educational purposes by schools, museums, astronomy clubs, and other educational & community organizations. Just contact someone at your nearest SDSS member institution to get started!

Technische_Sammlungen3Elsewhere in the exhibit and the museum, you can find a working infrared camera (selfie-compatible!), a very challenging puzzle involving prisms and laser light, and other neat activities suitable for children of all ages.

While you’re in Dresden, make sure to also stop by the Mathematische-Physikalische Salon [Royal Cabinet of Mathematical and Physical Instruments], at the Zwinger Palace in the center of Dresden, to have a look at old telescopes, clocks, and surveying tools. Of special interest to telescope enthusiasts are two very early reflector telescopes (i.e., telescopes that use a mirror to focus the incoming light, rather than lenses). You can also see them online in a panoramic view (upstairs in “Instruments of Enlightenment”).


This post is part of the SDSS Celebration of the International Year of Light 2015, in which we aim to post an article a month in support of the celebration of light. 

SDSS at the 29th General Assembly of the International Astronomical Union

The 29th General Assembly of the International Astronomical Union is due to start on Monday 3rd August 2015 in Honululu, Hawaii. These meetings happen every 3 years and are the biggest single conference in astronomy. This is your guide to all things SDSS related at IAU2015.

Thanks to generous support from the central project office, SDSS Education will be particularly well represented at IAU2015. SDSS Educational Consultant (Kate Meredith) and Director of EPO (Karen Masters) will be attending to run workshops on how to use SDSS data for education.

Screen Shot 2015-07-31 at 14.44.32

This half day splinter session on Monday 10th August will give astronomers and educators (including, but very definitely not limited to members of the SDSS collaboration) a chance to participate in a hands on workshop exploring voyages.sdss.org, a new educator focused resource designed to enable the use of real data from the Sloan Digital Sky Surveys in the classroom. Participants will have the opportunity to contribute their own experiences using data in the classroom into new guided journeys through Voyages for specific educational levels and/or suggest new content based on exploration of SDSS data. The schedule of the workshop is as follows:

Workshop Schedule (Drop-in Welcome), Monday 10th August 2015 in Room 327, Hawaii Convention Center.

  • 8.30am: Welcome
  • 8.40am: Mapping the Universe with SDSS (Karen Masters)
  • 9.15am: Introduction to SDSS Voyages (Kate Meredith)
  • 10.00am: COFFEE BREAK
  • 10.30am: Matching content to a curriculum (Kate Meredith)
  • 10.50am: Hands on exploration of voyages.sdss.org
  • 12.00pm: Lunch/work time
  • 1.00pm: SDSS Plates and how to get one (Karen Masters)
  • 1.30pm: SDSS Plate resources online (Kate Meredith)
  • 2.00pm: END

The SDSS EPO group will run a similar workshop, but this time especially for High School Teachers as part of the Galileo Teacher Training Program, happening at the IfA, Honululu on 8th/9th August. One lucky Hawaii based teacher attending this training will be able to take an SDSS Plug Plate back to their school for use in lessons.

The SDSS EPO group will be active participants in Focus Meeting 19: Communicating Astronomy with the Public in the Big Data Era. As part of that, SDSS Director of EPO, Karen Masters will lead a discussion on what Researchers would like to Improve in Communication Initiatives. The outcome of this meeting is intended to be a Playbook on Communicating Astronomy with the Public in the Big Data Era.

There are also of course numerous science results from SDSS data being presented at the meeting. Thanks to the open data policy of SDSS many of these results are from scientists who have never been part of the SDSS Collaboration. Here is a summary of all the posters and talks at IA2015 which can obviously linked to SDSS data or projects.

Week 1 Posters:

FM16p.13. White dwarf+main sequence binaries identified from SDSS DR10, Lifang Li

FM19p.16. Galaxy Zoo: Science and Public Engagement Hand in Hand
Karen Masters; Chris Lintott; Julie Feldt; Bill Keel; Ramin Skibba

FM19p.17. SDSS Plate Packets – From Artifact to Teaching Tool
Kate K. Meredith; Karen Masters; Britt Lundgren; Oliver Fraser; Nick MacDonald

FM19p.18. SkyServer Voyages Website – Using Big Data to Explore Astronomy Concepts in Formal Education Settings
Kate K. Meredith; Karen Masters; Jordan Raddick; Britt Lundgren

S315p.193. High Resolution Molecular Gas and Star Formation in the Strongly Lensed z~2 Galaxy SDSS J0901+1814
Chelsea Sharon; Andrew Baker; Amitpal Tagore; Jesus Rivera; Charles Keeton; Dieter Lutz; Linda Tacconi; David Wilner; Alice Shapley

S315p.235. Detecting HII Regions in Z=0.1 Galaxies with Multi-Band SDSS Data
Chris Richardson; Anthony Crider; Benjamin Kaiser

Week 2 Posters:

DJp.2.15. Extreme Red Quasars in SDSS-BOSS
Fred Hamann; Nadia Zakamska; Isabelle Paris; Hanna Herbst; Carolin Villforth; Rachael Alexandroff; Nicholas Ross; Jenny Greene; Michael Strauss

DJp.2.19. Environmental dependence of AGN activity in the SDSS main galaxy sample
Minbae Kim; Youn-Young Choi; Sungsoo S. Kim

DJp.2.24. Exploring large-scale environment of SDSS DR7 quasars at 0.46Hyunmi Song; Changbom Park

FM14p.06. The link between galaxy mergers and single/double AGN: a statistical prospective from the SDSS
Xin Liu

P2.096. An efficient collaborative approach to quasars’ photometric redshift estimation based on SDSS and UKIDSS databases
Bo Han; Yanxia Zhang; Yongheng Zhao

S319p.01. SDSS J012247.34+121624, one of the most dramatic BALQSOs at redshift of 4.75 discovered by the Lijiang 2.4m Telescope
Weimin Yi

S320p.10. White dwarf + main sequence binaries identified from the data release of the Sloan Digital Sky Survey (SDSS)
Lifang Li
FM7p.06. Stellar mass of elliptical galaxies in the Sloan Digital Sky Survey
Chen-Hung Chen; Chung-Ming Ko

S319p.05. Variability of 188 broad absorption lines QSOs from the Sloan Digital Sky Survey
Weihao Bian

S319p.251. Redshift-Space Enhancement of Line-of-Sight Baryon Acoustic Oscillations in the Sloan Digital Sky Survey Main-Galaxy Sample
Haijun Tian; Mark C. Neyrinck; Tamas Budavari; AlEXANDER SZALAY



Wed 5th
12.00pm: FM4.1.05 Hot evolved stars in massive galaxies
Claire Le Cras

Mon 10th
Voyage to Education with the Sloan Digital Sky Survey
Organizer(s): Karen Masters (University of Portsmouth), Kate Meredith (Yerkes)
8:30 AM – 2:00 PM; Room 327, Hawaii Convention Center

Thurs 13th
11.35am: FM7.5.05 Age derivation from UV absorption indices and the effect of the UV upturn.
Claire Le Cras

Mon 10th
Voyage to Education with the Sloan Digital Sky Survey
Organizer(s): Karen Masters (University of Portsmouth), Kate Meredith (Yerkes)
8:30 AM – 2:00 PM; Room 327, Hawaii Convention Center

2.30pm: S319.10.03. Extreme Red Quasars in SDSS-BOSS
Fred Hamann; Nadia Zakamska; Isabelle Paris; Hanna Herbst; Carolin Villforth; Rachael Alexandroff; Nicholas Ross; Jenny Greene; Michael Strauss

Fri 14th
10.55am FM17.7.02. Synergies of CoRoT asteroseismology and APOGEE spectroscopy — Applications to Galactic Archaeology
Friedrich Anders; Cristina Chiappini; Thaíse S. Rodrigues; Andrea Miglio; Josefina Montalbàn; Benoit Mosser; Leo Girardi; Marica Valentini; Matthias Steinmetz

12.00pm S319.12.06. Redshift evolution of massive galaxies from SDSS-III/BOSS
Daniel Thomas


If you are attending the IAU2015 we hope you have a great time, and we’ll see you on Social Media Karen Masters will be tweeting as @sdssurveys on #iau2015.

How SDSS Splits Light into a Rainbow for Science

All of the Sloan Digital Sky Surveys currently active (APOGEE, eBOSS, MaNGA, Spider and TDSS) are spectroscopic surveys. A spectroscope is a scientific instrument, which splits light into a rainbow (or spectrum) in order to make precise measurements of the amount of light of different colours (or wavelengths). To date the SDSS collaborations have used three different spectroscopes (the SDSS, BOSS and APOGEE instruments) to measure the rainbow of light from millions of stars and galaxies in our mission to map the Universe. Below is an image of one of these spectrographs.



The BOSS Spectrograph. In centre the instrument is shown with optical fibres plugged into it. The diagrams at the side show the path of the light through the instrument after it passes down the fibre. Different parts are labelled.This instrument you have made has many similarities to the BOSS spectroscope shown above.

It is possible to make your own spectroscope using simple household materials and use it to measure the spectra of common light sources.  Here are instructions to build an SDSS CD Spectropscope. This instrument you can make has many similarities to the BOSS spectroscope shown above. For example:

  1. You will construct a slit through which the light will pass. In the diagram of the BOSS spectroscope this is labeled “slit-head”, and the light from the optical fibres is collected, “collimated” (i.e. lined up) and passes though it.
  2. You will use an old CD to make a grating (the BOSS spectroscope has 4 gratings; 2 on each side, and sandwiched between prisms to make a “grism”). A typical CD is made with 625 lines per mm. The the BOSS spectrograph has 520 and 400 lines/mm for the blue and red sides respectively.

Your spectroscope will be sensitive to all visible light. In the BOSS spectroscope a “dichroic” is used to split the light into red and blue before passing it through the gratings. A dichroic has a special property that it is reflective to blue light, while red light passes through it. This means the light can be spread out more, and special cameras can be used to detect light from near ultraviolet, right across the visible rainbow to the near infrared.

Instead of a camera you will use your eye (or you could try using a camera lined up with the viewing window). In the BOSS spectroscope there are four cameras (two for blue and two for red light) each kept specially cold in a “dewer”.

When the light passes through the slit it gets spread out a little bit, and then when it passes through the CD, the very fine slits in it (the diffraction grating) spread it out more. Different colours are spread out (or “dispersed”) by different amounts. The angle of dispersion is set by both the wavelength (colour) of the light, and the line spacing on the diffraction grating. The below image illustrates this (compared to refraction which can also create spectra; this is the physics which creates natural rainbows from refraction in raindrops). The diffraction angle increases with wavelength (and decreases with the line spacing).

Comparison of the spectra obtained from a diffraction grating by diffraction (1), and a prism by refraction (2). Longer wavelengths (red) are diffracted more, but refracted less than shorter wavelengths (violet).Credit: Wikimedia

Comparison of the spectra obtained from a diffraction grating by diffraction (1), and a prism by refraction (2). Longer wavelengths (red) are diffracted more, but refracted less than shorter wavelengths (violet).Credit: Wikimedia

Here are some examples of the kind of spectra you should be able to take with your CD spectroscope.

Example spectra through a CD spectroscope. Credit: CoolStuff Newsletter

Example spectra through a CD spectroscope. Credit: CoolStuff Newsletter

To make precise measurements we don’t tend to look at a pretty image of a rainbow, but instead make a graph which shows the brightness as a function of the wavelength (colour). An example of this is shown below which is a typical spectrum of a galaxy shown at five different distances (or redshifts).


The spectrum of a galaxy shown at five different distances (or redshifts), z=(0.0, 0.05, 0.10, 0.15, 0.20) corresponding to distances of (6, 12, 18 and 21 hundred million light years). Credit: SDSS Skyserver

If you do make an SDSS CD Spectroscope please take a picture (either of it or through it) and share it with us on Twitter or Facebook.


This post is part of the SDSS Celebration of the International Year of Light 2015, in which we aim to post an article a month about how SDSS uses light in our mission to study the Universe. 

SDSS Plates as Art in Nashville, Tennessee

Check out these cool art pieces made from SDSS spectroscopic plates!  Nashville based artist, Adrienne Outlaw, designed and built them and they will be exhibited in various locations at Vanderbilt University over the next year. The pictures show their first installation, just in time for the Inclusive Astronomy meeting that started yesterday. The concept design was done by Adrienne Outlaw in collaboration with Vanderbilt astronomers David Weintraub and Billy Teets, and the project was funded by Vanderbilt University’s Curb Creative Campus program.

If you want to learn more about what these plates are, and see them in other art installations please see this previous post on SDSS plates.

We love seeing images of SDSS plates around the world. Please send any you find to us via social media (you can find us on Facebook, Twitter and Google+), or email to outreach ‘at’ sdss.org.



SDSS at the New York Hall of Science

A few months ago (at the end of March), SDSS Members spent a Saturday taking part in the Big Data Fest at the New York Hall of Science, in Queens, NY.

This event was aimed at helping people find out how data is relevant to their lives and featured interactive experiences focused on data literacy and data gathering and visualization.

2014-03-08 10.51.19

Chang Hahn and Yuqian Liu from NYU ready to go with the SDSS booth

Seven SDSS members in total helped out – six from NYU (Chang Hahn, Yuqian Liu, Nitya Mandyam Doddamane, Kilian Walsh, Ben Weaver, and Mike Blanton), along with Guang Yang who travelled up from Penn State University (PSU). This group ran one of about a dozen booths spread throughout the Hall of Science buildings in between the regular exhibits.

The SDSS booth contained an SDSS plate, along with a large-scale printout of the imaging for the part of the sky it was designed for. There was also a set of flash cards with images of galaxies on them, next to an invitation to try classifying them. Visitors were invited to take a card home with them if they wished. There were laptops running both Galaxy Zoo and the SDSS SkyServer. The SkyServer demo was set up to allow visitors to explore the data taken with the plate on display. Finally a monitor displayed a loop of videos about SDSS from the SDSS YouTube Channel.

Galaxy flashcards ready for classifying.

Galaxy flashcards ready for classifying.

The audience were made up of a mixture of children, teenagers and adults (including some who were very scientifically literate). The location in Queens meant that it was mostly NY area residents – with fewer tourists than Manhatten based museums attract.

Nitya Mandyam Doddamane and Yuqian Liu talks about SDSS with some visitors, while Chang Hahn is running a demo of Skyserver.

Nitya Mandyam Doddamane and Yuqian Liu talks about SDSS with some visitors, while Chang Hahn is running a demo of Skyserver.

This event at the NY Hall of Science is just one example of SDSS scientists around the world working to engage members of the public with our data. If you are running a similar event and might be interested in seeing if SDSS would be able to participate, please contact outreach ‘at’ sdss.org and we will try to connect you with your nearest SDSS institution.

SDSS Plates for Education

Here at SDSS we’re working on a new educational initiative, where teachers and informal educators will be able to take back to their classroom their very own piece of SDSS history – an actual SDSS plate which was used to map a small patch of the night sky.

We have been developing a “Plate packet” to distribute to teachers and educators. This packet contains an SDSS plate, along with a custom made poster showing the SDSS image of the region of sky the plate was designed for, as well as some selected educational materials, and links to specially designed activities on SDSS Voyages.

Certificate handed out with each plate.

Certificate handed out with each plate.

On Saturday 30th May 2015, SDSS Members from the University of Washington handed out the first plates to a group of  teachers representing high schools from around the western Washington, USA. These teachers spent the day at the in Seattle discussing ideas for using the plates in their classrooms, as well as getting a tour of the machine shop, where all the SDSS plates are manufactured.


“Hard at Work”: SDSS Member Oliver Fraser (pink shirt) shows some educators how to find the data from their plates and use it for classroom investigations. A plate poster can be seen on the board in back. Credit: Danielle Skinner

Photo May 30, 2 41 54 PM

“Yay Plates!”: some happy educators (and SDSS Member, Danielle Skinner in black) excited to be taking their very own SDSS plates back to their schools. Credit: Oliver Fraser.

The University of Washington is already planning more such workshops, and we look forward to expanding this program to other SDSS Member Institutions.

If you’re a teacher or educator reading this and interested to know how you can get your own SDSS plate, please contact the outreach representative at your nearest SDSS Institution, or email outreach ‘at’ sdss.org for assistance doing that. SDSS members interested in getting involved in this programme should join the EPO mailing list (details on the password protected collaboration wiki). 

SDSS Plates

The SDSS has used thousands of plug plates in its fourteen year history. These are large aluminium plates into which tiny holes are drilled. Each hole has an optical fibre plugged into it (by hand by our plate pluggers). Each hole corresponds to the sky location where there is an object (a star or a galaxy) which SDSS wants to measure a spectrum for.

During SDSS spectroscopic observations, between six and nine of these are used every night. Each plate is custom drilled for a special part of the sky (about the size of your palm stretched out at arms length), and once all the data is collected for the astronomical objects in that plate, it becomes surplus to requirements.

All SDSS Collaboration members can request that used plates be sent to them (contact your Collaboration Council Representative for assistance with this). This has resulted in some interesting uses for the leftover plates across our diverse collaboration.

You might like to mount your plates on the wall for display.

A wall mounted plate at the Institute of Cosmology and Gravitation, Portsmouth, UK.

A wall mounted plate at the Institute of Cosmology and Gravitation, Portsmouth, UK. Image credit: Karen Masters

SDSS plates on display at CCAPP (Center for Cosmology and Astrophysics), Ohio State University. Image credit: Qingqing Mao.

SDSS plates on display at CCAPP (Center for Cosmology and Astrophysics), Ohio State University. Image credit: Qingqing Mao.

If doing this, it is helpful to have a good description as a guide. This is especially helpful if you are donating a plate to a local science museum or other location away from SDSS collaboration members who know what it is. The example below was made for a display of plate 825 by Jordan Raddick from Johns Hopkins University in Baltimore.


To make a version of Jordan’s information sheet tailored for your own plate you can find the sky co-ordinates of your plate in this List of plate observation dates and centres. Then visit the Skyserver Navigate Tool to find an image at this location. You will likely want to invert the images, zoom out to the second largest scale, and overlay the plate location (all under “Drawing Options” to the right of the screen). You can then use Google sky to work out roughly which constellation this plate is in (unless you happen to know!), and the constellation maps are available from the IAU. To convert the MJD of observation to something understandable you might like this MJD converter.

We have a second example of plate display information from David Kirkby at UC Irvine. Here David has made an overlay of the SDSS imaging and coloured marks corresponding to the holes in BOSS plate 6640 (green for galaxies and purple for quasars), as well as an 3D representation of the distances to these objects (based on their SDSS measured redshifts).

An overlay for Plate 6640 showing both SDSS imaging and the location of drilled holes (green = galaxies; purple = quasars). Image credit: David Kirkby.

An overlay for Plate 6640 showing both SDSS imaging and the location of drilled holes (green = galaxies; purple = quasars). Image credit: David Kirkby.

A visualisation of the 3D structure behind BOSS plate 6640 based on redshifts measured by SDSS. Image credit: David Kirkby.

A visualisation of the 3D structure behind BOSS plate 6640 based on redshifts measured by SDSS. Image credit: David Kirkby.

It’s possible to back light wall mounted plates in some circumstances, to really nice effect. The below example was made by Mark Klaene at Apache Point Observatory.


Mounted in the corner of Mark Klaene’s office at APO. It is spray painted black with a fluorescent desk lamp back light.

If you’re lucky you might find a natural source of light for this effect, as in this example where Stephen Bailey from LBL has mounted a plate in the window in his office door.


SDSS Plate in an Office Door (the hole was there already).

Several collaboration members have used plates to make special coffee tables, or coffee table covers.

The most basic version of this is just placing a plate on top of a round coffee table of similar diameter.


Coffee table topper by Bob Nichol, ICG Portsmouth.

This second one uses a 36″ round glass top table topped with a plate. Bumpers have been added to the plate and the normal glass top placed on top of it. The lighting shown below is from a single puck from a modular LED lighting system.


Coffee table with under lighting by Brian Lee from SDSS-II.

At JHU they have made two coffee tables with the SDSS plates. The base is a hollow box made from scratch of four wood pieces and there is a lamp inside so at night you can see the light shining through the slits.


Custom coffee table at JHU. Credit: Ting-Wen Lan, Murdock Hart, Guangtun Zhu and Brice Ménard. Photo courtesy of Zheng (Jared) Zheng.

SDSS Plug Plate Coffee Tables in use at JHU. Image credit: Gail Zasowski

SDSS Plug Plate Coffee Tables in use at JHU. Image credit: Gail Zasowski

Plates have also been used to make lab demos. The below is an example set up which LBL has to give quick demos.


SDSS Plate Demo at LBL.

SDSS plates have also been used to make works of art. The most well know is work by Josiah McElheny in collaboration with David Weinberg (also described here and in this NYTimes Article).

Sculpture by Josiah McElheny using SDSS plug plate. Image provided by David Weinberg.

Sculpture by Josiah McElheny using SDSS plug plate. Image provided by David Weinberg.sdss


Sarah Ruether, an artist from Seattle and London based artist Xavier Poultney have also made artwork using plates.

Public art by Sarah Ruether made from SDSS-II plug plates

Public art by Sarah Ruether made from SDSS-II plug plates

Plate Artwork by Xavier Poultney as part of his Transient Objects exhibit.

Plate Artwork by Xavier Poultney as part of his Transient Objects exhibit.

If you have other examples of interesting uses of SDSS plates please let us know about them by commenting below, or emailing outreach@sdss.org.

See how the plates are drilled at the SDSS Plate Drilling Labs at the University of Washington in Seattle:
[youtube https://www.youtube.com/watch?v=iYyO7pGaJNw]

See how the optical fibres are plugged into a BOSS plate by our awesome SDSS plate pluggers (at Apache Point Observatory): [youtube https://www.youtube.com/watch?v=i6ZOUDWRwtg]