About Pandora's Spectrometer System

Pandora Spectrometer System

The Pandora Instrument uses spectroscopy over a specific range of wavelengths to analyze trace gas densities in the atmosphere. Spectroscopy is used to measure specific wavelength ranges and analyze atmospheric trace gases and particles. To learn more about the science behind the project, please head to the Science page. To learn more about the technical aspects of the instrument, head to our The Instrument page.

Technical Specifications

Pandora uses a tracker system to follow the Sun and Moon in order to observe their light through Earth’s atmosphere. This light data is channeled through the sensor head from a fiber optic cable and into a spectrometer. Depending on the amount of spectrometers available, Pandora is able to detect finite differences in light absorption between wavelengths 291nm-532nm. Based on the differential absorption of light (often referred to as DOAS- Differential Optical Absorption Spectroscopy) the Pandora can derive atmospheric total column amounts of certain components such as ozone, nitrogen dioxide, sulfur dioxide, and formaldehyde.

Significance of Pandora

Pandora provides an opportunity to establish a global network of atmospheric detection systems for trace gases and particles. Pandora is a research-grade spectrometer system able to be deployed from a portable platform for use in a variety of applications and installations. Pandora data can be used for air quality monitoring, satellite algorithm refinement, interpixel variability, and in the developing understanding of the Earth’s climate. For more on the Pandora System, go the the Science tab.

History of Pandora

The NASA Pandora Project began in 2005 and was the collective idea of Jay Herman and Nader Abuhassan.

The Pandora system got its name from its first deployment in 2007 in Thessaloniki, Greece. Jay Herman, a co-founder of Pandora, noticed a thin brown haze above the city, indicative of the pollutant NO2.

This made Thessaloniki an ideal location to site a newly developed instrument for air quality measurements. Initially, the entirety of the original system (pictured here) was housed in a single box. When they would run into issues with the original system, researchers in the field would lament, often referring to troubleshooting as having to open Pandora's box.

History of Pandoras in Field Campaigns

Download the Latest Instrument Operation Guide.



  • Robert J. Swap | Principal Investigator | NASA GSFC

    Bob came onboard in April 2017 with NASA GSFC after having served several years as a NASA HQ Program Officer with the Radiation Sciences Program. As an environmental scientist, Bob has spent much of his academic research career focusing on understanding coupled human-natural systems primarily through the study of land-atmosphere interactions. He has held a range of academic and leadership positions for a number of international, interdisciplinary research and education initiatives in emerging regions, most notably in subequatorial Africa and Brazil: NASA’s GTE ABLE-2B, STARE/TRACE-A/SAFARI-92 and SAFARI 2000. He has also supported the EVS ORACLES program as Project Scientist and as a U.S. Embassy Science Fellow with the U.S. Embassy in Windhoek Namibia in 2016.

  • Alexander Cede | Pandora Co-Founder | GESTAR/NASA GSFC/Pandonia Liaison/Luftblick | Kreith, Austria

    Alexander Cede has been working with atmospheric radiation since 1994. Since 2002, Dr. Cede has been part of the Laboratory for Atmospheric Chemistry and Dynamics at NASA Goddard Space Flight Center. His specialty is design, calibration, operation, and algorithm development of remote sensing instrumentation. He is currently part of the NASA Pandora project, PI of the ESA Pandonia project and PI of the NASA project for EPIC Level 1 calibration.

  • Nader Abuhassan | Pandora Co-Founder, Engineer | JCET-UMBC/NASA GSFC

    Dr. Abuhassan participated in the design and development of multiple world recognized sensors such as the Cimel sun photometers, Solar Viewing Interferometer and the Pandora Spectrometer. He participated in multiple national and international satellite validation and ground based instruments inter comparison campaigns. For the past 20 years, Dr. Abuhassan has been working on NASA-funded initiatives to validate ground based, aircraft and satellite measurements. He is in charge of designing and building sensors capable of automatically measuring a wide range of atmospheric pollutants and real-time monitoring of greenhouse gases. In 2011 Dr. Abuhassan received an outstanding performance award for his latest design of the Pandora. Dr Abuhassan is heavily involved with several national and international NASA’s validation field campaigns. More than 35 of NASA’s Pandora systems were deployed to supports field campaigns such as DISCOVER_AQ, KORUS_AQ for observations relevant to air quality as well instruments inter comparisons campaigns such as CINDI.

  • Jay R. Herman | Pandora Co-Founder, Scientist | JCET-UMBC/NASA GSFC

    At present, Dr. Herman is the Pandora instrument scientist, and has been responsible for its development since 2005. He is also the instrument scientist for the EPIC instrument on the DSCOVR spacecraft. Dr. Herman has a PhD in Physics from Penn State University (1965) and has published about 175 refereed papers on a wide variety of topics. He has published 5 papers on Pandora and recently submitted 3 more Pandora papers.

  • Alexander Dimov | Technician | SSAI/NASA GSFC

    Alex Dimov has worked for on Pandora for just a year and a half maintaining and building instruments for field deployment. Dimov constructs many of the components for Pandora such as building a variety of cables, wiring the temperature controls and power supplies, populating electronics boards, mounting spectrometers and data loggers. He deploys the instruments at Goddard on a science platform for testing and continuous measurements to verify that they remain in working order and identify and troubleshoot any issues that may arise. Additionally, he trains local operators in the operation of the instruments.

  • Joe Robinson | Research Analyst | JCET-UMBC/NASA GSFC

    Joe is a recent May 2017 graduate from Virginia Commonwealth University with a B.S. in Biology and Environmental Science. Outside of NASA, his interests include hiking and backpacking through America’s National Parks and travelling. His research interests include weather and climate as well as atmospheric composition and chemistry. He currently acts as a Research Analyst for the Pandora Project, aiding in data processing and analysis and working closely with scientists from other teams to provide context to Pandora and ancillary observations. He intends to pursue a graduate degree in the atmospheric sciences and continue to research the Earth system.

  • Lena Shalaby | Research Analyst | JCET-UMBC/NASA GSFC

    Lena graduated in May 2017 with a B.S. in Mechanical Engineering from the University of Maryland, Baltimore County. Since June of 2017, she has acted as the Network Operator for the GSFC-based Pandora Project, which includes the calibration of each instrument, maintenance of instrument hardware and software, and observation of operational data. Her role ensures the network of Pandora instruments in the United States and around the world operates smoothly and collects meaningful data. Ultimately, she intends to pursue a graduate degree and to position herself to one day fully manage an instrument network. Her interests outside of NASA include cheering on Baltimore sports as well as fitness.

  • Mischa Grünberg | Research Analyst | ESSIC-UMD/NASA GSFC

    Mischa is currently finishing a degree in Information Science at the University of Maryland and has recently finished a program in Astronomy. He has been working at GSFC since January of 2017 doing data analysis and programming with the mini-LHR. Mischa joined the Pandora team in the Spring of 2017 and has worked together with Joe Robinson on programming and website development. In his free time, he enjoys playing soccer, competing in judo, and playing piano and guitar.

  • Stephanie Whitridge | Student Research Programmer | ESSIC-UMD/NASA GSFC

    Stephanie is currently pursuing a degree in Information Science at the University of Maryland. She has been working at GSFC, with the Pandora team, since February of 2018. She is currently doing website development as well as data analysis. Outside of NASA, her interests include being outdoors as well as travelling.

  • Collaborators

    Elena Spinei | Collaborator | Virginia Polytechnic Institute

    Elena Spinei has been part of the Pandora project and Laboratory for Atmospheric Chemistry and Dynamics at NASA Goddard Space Flight Center since 2012. Dr. Spinei's research experience lies in design, calibration and deployment of UV-VIS spectroscopic ground-based remote sensing instruments for ozone, formaldehyde, nitrogen dioxide, sulfur dioxide and bromine monoxide measurements; radiative transfer modeling of solar radiation propagation in atmosphere using VLIDORT; and algorithm development for remote sensing data interpretation (e.g. optimal estimation methods). Prior to joining Pandora project Dr. Spinei did her post doc (2010-2012) at Washington State University working on a research-grade MFDOAS instrument for OMI validation.
  • 2018 Intern Team

  • Alison Reynolds | NASA GSFC

    Alison Reynolds is a rising sophomore at the College of William and Mary pursuing a degree in applied mathematics. Her research interests involve executing statistical tests and creating models to evaluate how systems evolve over time. As a summer intern with the NASA Pandora Project she runs inter-comparisons between co-located Pandora systems to assess their differences. She uses this information in combination with ancillary instrumentation to provide a complete picture of Pandora performance. In her free time she enjoys biking, reading, baking, and watching baseball.

  • Felipe Rivera | NASA GSFC

    Felipe is currently an undergraduate student in the Chemistry Department at the University of Puerto Rico-Rio Piedras Campus. Since 2016 he has worked at the Atmospheric Chemistry and Aerosol Research (ACAR) laboratory at UPR-RP studying the impact of long-range transported African Dust on the solar energy budget at “El Yunque” National Rainforest and monitoring air quality over the San Juan Metro Area following Hurricane Maria. He is currently working on mastering the building, monitoring, and deployment of the Pandora system as well as understanding the atmospheric composition data it provides. In his free time, he enjoys playing beach volleyball and billiards.

  • Gabriela M. Aviles-Pineiro | NASA GSFC

    Gabriela is currently finishing her undergraduate studies in Environmental Science at the University of Puerto Rico, Rio Piedras Campus. She is a research assistant at the Atmospheric Chemistry and Aerosol Research Lab studying the air quality impacts of African Dust transport to Puerto Rico. This research will help understand how dust affects climate, ecosystems and human health. With the skills gained during her NASA summer internship, she will be deploying a Pandora system in Puerto Rico to begin long-term observations in support of the expanding Pandonia Global Network. Outside of NASA she enjoys traveling and caring for sheltered animals.

  • Jeremy Schroeder | NASA GSFC

    Jeremy is a graduate student who has completed his B.S. in Biology from Bellarmine University in Louisville, KY. He is currently completing his M.A in Geography and Planning from the University of Toledo and will be pursuing a PhD in Atmospheric Science from the University of Houston in Fall 2018. After the exposure to field work during OWLETS-1 as an intern at NASA Langley in the summer of 2017, he is now participating in an internship with the Pandora Project at GSFC during the OWLETS-2 campaign in 2018. During this experience, his goals are to become familiar with the Pandora system to prepare him for his research at the University of Houston. For leisure, he enjoys being in the outdoors and participating in activities such as camping, hiking, biking, climbing, kayaking, and white-water rafting.

  • Weston Millar | NASA GSFC

    Weston graduated in May 2018 from American University with a B.S. in physics. Back with the Pandora Network for a second summer internship, his work in 2017 covered instrument construction, deployment, and maintenance, in addition to fieldwork at Wallops Flight Facility for the OWLETS campaign. This summer, he’ll be working on field of view characterization and stray light mitigation for the spectrometers within the Pandora systems. His career aspirations lie in experimental optics, fostered by elective courses and a senior capstone project on the subject which included outfitting a new university optics lab. His hobbies beyond physics are building and flying model aircraft, gardening, and playing video games with his older sister.

  • Interested in future internship opportunities with Pandora? Contact Robert Swap.

    2017 Intern Team

  • Amanda Engel | NASA GSFC

    Amanda earned her B.A. in Broadcast Journalism 2017 with an astronomy minor from the University of Maryland, College Park. She was brought onto the Pandora team to work on videos and messaging for the project. Her professional interests include local TV news producing and her personal interests include stellar evolution and the history of the universe.

  • Faran Haider | NASA GSFC

    Faran earned his B.S. in Mechanical Engineering and joined the Pandora Project in order to gain professional development, work on an exciting project, and to apply the knowledge he gained through his internship in the classroom. During his time with the project he worked on building 3D models of the spectrometers as well as helped improve the insulation of the instruments. In his free time, Faran enjoys Design, Energy, Mechanics, EV, Management, Traveling, and Skiing.

  • Fayzan Saleem | NASA GSFC

    Fayzan earned his B.S. in Computer Sciencee from the University of Maryland, College Park. He joined the Pandora Project in order to gain more hands-on experience and work with a new instrument. His main responsibilities were to work with Raspberry Pi setup/installation, callibrate lab enhancements, and to act as a liaison between GSFC and Virginia Tech.

  • Hakeem Bisyir | NASA GSFC

    Hakeen earned his B.S. in Electrical Engineering from Virginia Tech. He joined the Pandora Project in order to work with Raspbeery Pi's. His main responsibilities were to do instrument callibration, produce documents and graphics, and to create a dashboard for the instruments.

  • Joe Robinson | NASA GSFC

    Joe earned his B.S. in Biology from VCU. He joined the Pandora Project in order to work on data analysis. His main responsibilities were to act as the VCU Rice Center Pandora Project liaison and to coordinate with members of other ground-based teams.

  • Julio Roman | NASA GSFC

    Julio earned his B.S. in Computer Engineering from UMBC. Julio joined the Pandora team so that he could learn new technical skills and gain more hands on experience in the industry. His main responsibilities were to help with the deployment of ceilometers, provide logistical support, and to do data collection/processing.

  • Lena Shalaby | NASA GSFC

    Julio earned his B.S. in Mechanical Engineering from UMBC. Her responsibilities included spectrometer calibration and assessment, instrument installation and operation, insulation improvement, and working to improve S.O.P.’s.

  • Sahil Bandyopadhyay | NASA GSFC

    Julio earned his B.S. in Chemistry from the University of Maryland, College Park. His responsibilities centered around Logistics. He organized expensive components by instrument to prepare for increased production.

  • Weston Millar | NASA GSFC

    Julio earned his B.S. in Physics from Ameican University. His responsibilities included building instruments, cataloguing parts, and assisting with the set-up/installation of these instruments. Weston also acted as the technical liaison to Pandonia.

    Interested in future internship opportunities with Pandora? Contact Robert Swap.

  • Tutorial

    Here you can find tutorial videos for setting up and troubleshooting the Pandora instrument.

    The Instrument

    Pandora spectrometer instrument spectroscopy is used to measure columnar amounts of trace gases in the atmosphere. These gases (O3, NO2, CH2O) absorb specific wavelengths of light from the sun in the ultraviolet-visible spectrum. Using the theoretical solar spectrum as a reference, Pandora determines trace gas amounts using differential optical absorption spectroscopy (DOAS). This principle attributes differences in spectra measured by Pandora to the presence of trace gases within the atmosphere (i.e. the difference between the theoretical solar spectrum and measured spectrum is caused by absorption of trace gas species). Using DOAS, Pandora is able to retrieve data with a temporal resolution of 80 seconds.

    The Pandonia Global Network is used to monitor trace gas values worldwide. With a multitude of instruments collecting data daily, the Pandora team is able to obtain information about the behaviors these gases have in the atmospheric column. The raw data collected enters a vigorous filtering and processing cycle which produces the final data product with very high accuracy. Used synonymously with other instruments, Pandora is able to validate collected data and extend the range of data collected on gases in the atmosphere. Today, Pandora instruments are distributed at over 50 locations worldwide and is a continually growing project.

    Spectrometer Specifications

    Detailed Technical Specifications

    The Pandora spectrometer system uses a temperature stabilized (1OC) symmetric Czerny-Turner system from Avantes over the range 280 - 530 nm (0.6 nm resolution with 4.5x oversampling) with a 2048 x 64 backthinned Hamamatsu CCD, 50 micron entrance slit, 1200 lines per mm grating, and fed light by a 400 micron core diameter fiber optic cable. The fiber optic cable obtains light from the sun, moon, or sky from front-end optics with a 2.2 degree field of view (FOV) for direct-sun observations using a diffuser and 1.6O FOV for sky observations without a diffuser. The optical head uses a double filter wheel containing 4 neutral density filters, a UV340 filter, ground fused silica diffusers, and a blocked position. When combined with the variable exposure time (4 - 4000 ms), Pandora has a dynamic range of 107 to 1, which is sufficient for viewing both direct sun and sky, and for measuring the dark current in between each measurement.

    Wavelength calibration is performed at several spectrometer temperatures using a variety of narrow line emission lamps that cover most of the spectral range 280 - 530 nm. From the laboratory data, a polynomial is fitted to the results as a function of pixel column number 1 - 2048. Wavelength calibration was validated using comparisons with the slit function convolved high resolution Kurucz spectrum's solar Fraunhofer lines. Based on laboratory measurements, the Avantes spectrometers are corrected for response nonlinearity to the incoming signal, which can amount to 3% at high counts and is negligible at low counts. The exposure times to sun or sky photons are adjusted so that the readout pixel with the highest intensity is never in excess of 80% of the CCD readout well depth of 200,000 electrons. This means that each pixel in the 64 rows for each wavelength is limited to less than 2500 electrons.

    The laboratory calibrated Pandora TCO retrieval algorithm uses an external solar reference spectrum derived from a combination of the Kurucz spectrum (wavelength resolution λ/Δλ = 500,000) radiometrically normalized to the lower resolution shuttle Atlas-3 SUSIM spectrum (Van Hoosier, 1996; Bernhard et al., 2004). Ozone absorption cross sections (BDM) are from Brion et al. (1993; 1998) and Malicet et al. (1995). The use of a well calibrated top of the atmosphere TOA spectrum convolved with the laboratory measured spectrometer slit function derived for each pixel permits derivation of ozone amounts without resorting to either a Langley calibration approach or calibration transfer from a standard instrument. The core slit function is known to within 1%, which propagates into an ozone error of less than 1%.

    To read the guidelines for submitting grant proposals, please email Robert J. Swap