Ten Websites for Spectroscopic Research – by Albert Lim

Based on my research on the Internet, the 10 sites I think worthwhile for research in spectroscopy are listed below. This list is not intended to be comprehensive nor complete. Each site is given a site number not in order of merit and is presented in a standardised format. The address of each site is stated along with an appropriate title. The next 3 paragraphs describe briefly what the site is about, what was or are still being done and why that particular site is beneficial to research in spectroscopy.

Site No. 1
Site Address                    :          http://speclab.cr.usgs.gov

Site Title                         :          USGS Spectroscopy Lab

About USGS Spectroscopy Lab site :         

This  website belongs  to the Spectroscopy Lab of the US Geological Survey located in Denver, USA. USGS is a bureau of the U.S. Department of the Interior. This site receives over half a million hits in 1998 from all over the world, many to access their papers and their spectral library. The researchers here study and apply methods for identifying and mapping materials through spectroscopic remote sensing (imaging spectroscopy) for the Earth and throughout the solar system. They maintain a large database of their material maps and spectra libraries. The lab maintains specialised facilities required to map material, calibrate spectroscopic data, measure reference samples and verify results.

What USGS Spectroscopy Lab did ?   :

They employ a new tool called imaging spectroscopy that can be used to map specific materials by detecting specific chemical bonds. It is a technique  applying reflectance/emittance spectroscopy to every pixel in a spatial image and can be used to detect individual absorption features due to specific chemical bonds. Current missions involving USGS lab personnel and utilising their imaging spectrometers are for example the Visual and Infrared Mapping Spectrometer (VMIS - 0.35 - 5.1 microns ) on the Cassini Mission to Saturn, the Thermal Emission Spectrometer (TES - 6.25 to 50 microns ) on the Mars Global Surveyor and the Near Infrared Mapping Spectrometer (NMIS - 0.7 to 5.2 microns) on Galileo, now orbiting Jupiter.

Why is USGS Spectroscopy Lab's site beneficial for research purposes ?         

Remote Sensing Imaging Spectroscopy relies on detection of chemical bonds and are very efficient for detecting solids in crystalline ( i.e. minerals ) or amorphous solids. The technique can also be employed to liquids and gases. Every material on a planet's surface is formed by chemical bonds and has the potential for detection. It has powerful applications for Earth and planetary astronomy areas such as assessment of abandoned mine lands on Earth and surface mineralogy of planets. Spectroscopic mineral mapping can also be used to map lithology which closely follows geologic formations.
                                                 
Site No. 2
Site Address  :          http://orpheus.nascom.nasa.gov/serts/frmain.htm

Site Title       :          Solar Extreme-Ultraviolet Rocket Telescope and
                               Spectrograph ( SERTS )

About SERTS site           :

This site belongs to NASA's SERTS - Solar Sounding Rockets Program. This site also contains educational material about sounding rockets and their instrumentation as well as a page that describes basic solar spectroscopy and how SERTS spectra are used to obtain valuable information about the Sun's atmosphere. SERTS instrumentation was conceived in the late 1970s as a follow-on to the Skylab SO-82A spectroheliograph. Most of the integration work for these sounding rockets are done at NASA’s White Sands test facilities, New Mexico, USA. SERTS instrumentation includes a telescope and special spectrograph as payload on board a sounding rocket. The page
http://orpheus.nascom.nasa.gov/serts/science.htm also highlight a dozen very significant SERTS scientific discoveries and accomplishments. Among them is the calibrated line list - a major calibrated emission catalog obtained from the cumulating of SERTS data.

What SERTS did ?          :
         
SERTS employ a special dumbell shaped slit - two relatively wide lobes, one on either end of a central narrow slit - for it's spectrograph specially for detailed study of the solar atmosphere  in  extreme UV. These produce a unique spectra of high resolution adjacent to 2 spectroheliogram images ( with only slight spectra overlapping ) of 2 solar areas. The telescope and spectrograph are flown in sounding rockets to high altitudes in the Earth's atmosphere and targeted at the sun.  The SERTS team have and are continuing to make significant contributions to the developments of new spectroscopic instrumentation in the EUV for space applications because sounding rockets provide a relatively inexpensive means of  demonstrating their performance in space. Areas of most significant developments are :

a) Intensified CCD Detector development
b) Telescope Development
c) Diffraction Grating Improvement Program
d) Improved Entrance Slits Fabrication

Why is the SERTS's site beneficial to research purposes ?

SERTS is beneficial because spectra obtained from high altitude are of the very high quality. In fact SERTS provided the highest resolution ever obtained in the 170 - 450 Angstrom wavelength range. Because of its unique slit design, SERTS also provides high quality spectroheliograms over a wide range  of  extreme  UV  wavelengths,  characteristic  of  temperatures  between 5 x 10^4 to 3 x 10^7 K. Another strength of SERTS data stems from the fact that this spectra range is rich in emission lines ( over 240 lines from 57 different ions ! ) Multiple lines in Fe IX to Fe XVII are observable for all ionisation states and provide for extremely accurate calibration. SERTS thus allow study of temperature and coronal features using multiple line ratios from several ions of similar elements. This provides extreme consistency and minimise greatly calibration or atomic physics errors. As a result, SERTS data is now the standard for the wavelength for 170 - 450 Angstroms for both the active and quiet sun.

Site No. 3
Site Address  :   http://physics.nist.gov/PhysRefData/platinum/forward.html

Site Title       :   Reference Spectra and Energy Levels for Neutral and
                        Singly-Ionised Platinum

About NIST site            :

This site is run by the National Institute of Standards and Technology (NIST). The above site address refers to Vol. 97, Number 1, Jan - Feb 1992 Journal of the National Institute of Standards and Technology. The site is essentially a full report on the NIST measurements in the form of a complete and detailed atlas of reference spectra  and energy  levels for  the  spectrum  of  Platinum / Neon (Pt/Ne ). The investigation work is partly supported by NASA and undertaken at the suggestion of William C. Martin. William C. Martin is also the group leader of Atomic Spectroscopy in the Atomic Physics Division of NIST. The above site address refers to a forward by him in regards to the importance of this atlas.     

What the NIST team did ?

The NIST team conducted both photographic well as photoelectric scans of the Pt/Ne lamp with their 10.7 m vacuum spectrograph. To determine the relative intensities of the lines emitted by the Pt/Ne lamp and to observe lines weaker than those recorded on their photographic plates, the NIST team recorded the spectrum by translating a 0.050 mm exit slit and a photomultiplier tube along the focal tube of the spectrograph. Richard Deslattes assisted by suggesting photon counting techniques which were applied very successfully to produce this atlas. The atlas provide a very comprehensive description of the spectrum of  Pt/Ne hollow-cathode lamp in the region from 1128 to 4333 Angstroms. The atlas was produced by scanning in overlapping 650 Angstroms segments with each segment or scan lasting 20 hours and corresponding to a different rotational setting of the grating. The raw data from each scan was adjusted to produce a consistent set of values over the whole spectral region.

Why is NIST's site beneficial to research purposes ?

Prior to work to complete this reference atlas in 1992 by NIST, test carried out in NIST in 1983 indicated that the best available wavelengths for Pt had errors ranging to about 0.015 Angstrom. With the launch of Hubble Space Telescope ( HST ) in 1990, the full potential of the Goddard High Resolution Spectrograph ( GHRS ) then cannot be realised because of a lack of accurate reference spectra of  Pt / Ne. The observation range of GHRS is 1100 - 3200 Angstrom and in its echelle mode can be used to determine doppler velocities to about 1 km/s. This however requires Pt/Ne calibration wavelengths to be accurate to 0.002 Angstrom - much more accurate than available then. The 1992 reference atlas achieves an uncertainty of 0.001 Angstrom for some wavelengths while virtually all are less than 0.002 Angstrom meaning this is the best atlas/source currently available that provide such a dense and complete coverage of this spectral region with spectral lines suitable for use as reference wavelengths. This atlas not only enable GHRS to realise its full resolution and potential but is also an extremely valuable for astronomical spectroscopy as a whole. It is now also being used for calibration of general laboratory spectra.

Site No. 4

Site Address               :          http://www.aao.gov.au/2df

Site Title                    :          2 Degree Field - Anglo Australian Observatory

About AAO - 2dF site          :

This 2dF site is maintained by the Anglo Australian Observatory. This site explains the 2dF instrument and its complete operation. The Two Degree  Field ( abbreviated 2dF ) is one of the world's most complex astronomical instrument. It is designed to allow acquisition of up to 400 simultaneous spectra of objects within a two degree field in the sky - hence its name 2dF. It consist of a wide field corrector, an atmospheric compensator and a robotic ganty which can currently accurately position 400 object optical fibres plus 2 spectrographs. A tumbling mechanism also allows the next field to be configured while observation is in progress with an existing field. The entire system control, user interfaces and data acquisition is run on Sparcstation systems running Sun's version of UNIX called Solaris. The site also provide useful information for observers intending to use the unique 2dF facility. It also provides information and progress on the 2 unique 2dF Galaxy and QSO Redshift Surveys.

What the AAO - 2dF team did ?          :

Dr. Keith Taylor is 2dF Project Scientist and Visionary. He and his AAO team spent 6.5 years to date helping to develop the incredible 2dF system - probably AAO's greatest achievement to date. The robotic arm for example can rearrange 400 prisms in under 30 minutes while achieving positional object such as galaxies with accuracies of within 5 microns on the steel plate.
AAO is currently involved with a very major UK-Australian redshift survey which plans to take full advantage of the unique capabilities of the 2dF facility built by AAO. Called the 2dF Galaxy Redshift Survey, their goal is to secure high quality spectra and redshifts of 250,000 galaxies brighter than bj  = 19.5  (extinction-corrected) with deeper extension to R = 21 making use of best conditions. The survey project involves 250,000 galaxies selected from the APM Galaxy catalog and is currently on-line. There is also a 2dF QSO (Quasi-Stellar Object ) Redshift Survey integrated in parallel to save precious observing nights. The 2df QSO Redshift Survey aims to take spectra of some 30,000 QSOs.

Why is AAO-2dF's site beneficial to research purposes ?

The above 2dF surveys are extremely beneficial ( possible only because of the 2dF facility built by AAO ) because it might tell us for the first time if our ideas of cosmology are wrong. Accurate measurements of spectra energies of galaxy clusters on such a large scale will enable astronomers for the first time ever to make direct comparison of the microwave background anisotropy measurements of fluctuations on the same spatial scales. These measurements will have many other implications such as better defining the cosmological density parameter and understanding dark matter distribution and provide insights into galactic evolution, galactic cluster dynamics and clustering amplitude and star formation rates up to a redshift of z = 0.5.  The surveys when complete should also provide a comprehensive inventory of galaxy types as a function of spatial position for the first time. The novel techniques used to classify the uniform sample of 250,000 galaxies should also be a most useful database for future researchers.

Site No. 5

Site Address                    :          http://www.stsci.edu/top.html

Site Title                         :          Space Telescope Science Institute

About STScI site          :

The Space Telescope Science Institute ( STScI ) is the astronomical research centre responsible for operating the Hubble Space Telescope as an international observatory. It is located at the Steven Muller Building on The John Hopkins Homewood campus. The staff comprises astronomers, computer scientist, technicians and administrative personnel from AURA, ( Association of Universities for Research in Astronomy ) ,the European Space Agency and
NASA. Staff strength is 500 of which about 100 are Ph.D. astronomers and scientist. The Hubble Space Telescope is a co-operative program of the European Space Agency ( ESA ) and NASA. This site also has many link pages to a tremendous wealth of information on the Hubble Space Telescope, its extensive database. In particular, it provides full details on how astronomers world-wide can submit proposals for HST observation time and how they can retrieve data from the extremely extensive HST data archive.

What STScI do ?          :

STScI operates the low Earth orbiting Hubble Space Telescope as a major observatory for the world-wide astronomical community. The institute is established by NASA on the recommendation by the National Academy of Sciences. STScI is also responsible for data processing, calibration, editing, maintenance and distribution of HST data to the scientific community world-wide. STScI also allocates HST observing time but competition is very keen and only one in every ten proposals are accepted. 

Why is STScI's site beneficial to research purposes ?

STScI site is beneficial to research purposes not only in that researchers world-wide may submit proposals for HST use but more importantly because researches may access very high resolution HST data. The HST data handbook available on line provide a very comprehensive list of thousands of objects observed by HST in the past. These HST data are archived and listed appropriately by the instruments that acquired them. Many contain spectroscopic data beneficial to researchers from current instruments such as NICMOS ( Near Infrared Camera and Multi Object Spectrometer ) and STIS     ( Space Telescope Imaging Spectrograph ). Data base from former generation instruments such as GHRS ( Goddard High Resolution Spectrograph ) and FOS ( Faint Object Spectrograph ) are also accessible by researchers. Data collected by many other unique instruments are also available. In addition, future generations instruments such as the COS (Cosmic Origins Spectrograph) should be even more beneficial to researchers when they come on line.

Site No. 6

Site Address       :        http://www-space.arc.nasa.gov/~sloan/index.html

Site Title            :        Gregory S. Sloan - NASA Ames Space Science
                                  Division

About Gregory C. Sloan site          :

This is the site for Gregory C. Sloan and maintained by NASA Ames Space Science Division. He has worked at US Air Force Philips lab where he did a thesis on the Air Force's long-slit spectrometer and also at NASA Ames Research Centre. Dr. Gregory C. Sloan is currently a National Science Foundation Research Fellow at the Australian Defence Force Academy. His current work in Australia is funded by the U.S. National Science Foundation USA. The site has links to his research projects, abstract and paper library and his personal life. It also has a link to his Australian pages.

What Gregory C Sloan did ?          :

Dr. Gregory C. Sloan is currently collaborating with Craig Smith in Australia studying how dying stars eject their envelopes before they form planetary nebulae or supernovae. While at US Air Force Philips lab, he did his thesis work on the Air Force's long-slit spectrometer where he was responsible for the complete replacement of the electronics used to read the array and process the data. He also improved techniques developed for long-slit spectroscopy. He also did a second project which eventually led to the classification of infrared spectral emission from dust shells around evolved stars and the discovery of the silicate dust sequence. Between 1994 - 1997, while at NASA Ames Research Centre, he studied spectra emission from organic molecules in the interstellar medium called Polycyclic Aromatic Hydrocarbons or PAH. On this Dr. Gregory C. Sloan collaborated with Jesse Bregman utilising a combination of narrow-band imaging and long-slit spectroscopy in the near and mid infrared to study  the spatial and spectra behaviour of PAH emission in extended sources.

 Why is Gregory C. Sloan's site beneficial to research purposes ?

Because Dr. Gregory C. Sloan and Jesse Bregman were the first to have made direct, unambiguous identification of ionised PAHs in the interstellar medium. PAHs are the largest organic molecules detected in space so far and could represent the initial stages in the formation of exotic molecules like amino acids. PAHs are known to produce well-known emission features at 3.3, 3.4, 6.2, 7.7, 8.6, 11.2 and 12.7 mm but work by Hudgins and Allamandola shows that ionised PAHs provide a much better spectra fit to what was observed. There are still doubts in the astronomical community as to whether PAHs would actually be ionised in astrophysical environments and if so whether they survive long enough to be detected. The results of Dr. Gregory C. Sloan and Jesse Bergman should eliminate these doubts. Understanding PAH emissions would also enable astronomers to use them as probes of the interstellar medium in a wide range of physical conditions. The research papers and abstracts in this site should greatly benefit researchers in these fields.

Site No. 7
Site Address              :      http://www-astro.phast.umass.edu

Site Title               :    Herbig-Bell Catalog - Five Colleges Astronomy Department         

About Five Colleges site          :

The site address hosted on The University of Massachusetts server but is run and maintained by the Five Colleges Astronomy Department. Five Colleges, Incorporated  is a consortium comprising Amherst, Hampshire, Mount Holyoke, Smith Colleges and the University of Massachusetts Amherst. The Data and Publications link contains the Herbig-Bell Catalog prepared for HTML by Karen Strom. It is the original work of G.H. Herbig and K. Robin Bell done at Lick Observatory under the Board of Studies in Astronomy and Astrophysics, University of California. Karen M. Strom have published a number of papers on astrophysics and is currently involved in research focused on issues concerning the formation and evolution of low and moderate mass stars. There is also a Spectra of Standards in the Publications and Data link which appears to be still in the process of update.

What Five Colleges Astronomy Department did ?          :

Through the efforts of Karen M. Strom, they have put up a digital version site containing the new and improved Herbig-Bell Catalog ( HBC ).This work is partially supported by the National Science Foundation under a recent grant under Grant NSF AST82-03115. They divided the HBC into 4 sections due to the length of the files. This HBC list 735 pre-main sequence, members of the Orion Population, that has been observed with slit spectrographs or at equivalent resolution. This HBC version is intended to replace the Second Catalog of Herbig and Rao ( 1972 ) and it is hence called the Third Catalog of Emission-Line Stars of the Orion Population. 

Why is this Five Colleges site beneficial to research purposes ?

By listing this third catalog on the site, Five Colleges have made an extensive amount of useful data and information from this site available to world-wide researchers. This third catalog contains more stars ( 735 ) compared to the initial Herbig catalog in 1962 ( 126 ) and the second Herbig-Rao 1972 catalog  ( 323 ). Improvements added into the 3rd catalog are inclusions of v sin i's, radial velocities, X-ray and radio frequency data due to improvements of spectroscopic instrumentation. The new catalog also has a modified classification scheme for pre-main sequence stars as a result of improved observational information.

Site No. 8
Site Address       :    http://khobs.kyunghee.ac.kr

Site Title            :    Ultraviolet and Visible Spectroscopic Database (UVSD)

About this site          :

This site features the Kyunghee Observatory and belongs to Kyunghee University in South Korea. It has a link under Space Data Centre titled  "Ultraviolet and Visible Spectroscopic Database". It is essentially a spectroscopic database project submitted by Dr. Sang J. Kim from the Department of Astronomy & Space Science at KyungHee University, Korea to the Journal of the Korean Astronomical Society on the 30th of December  1994.
Kyunghee Astronomical Observatory is equipped with a 30 inch RC telescope on a half fork equatorial mount and a spectroscope with 600/g, 1800/g grating.

What Dr. Sang J. Kim did ?          :
         
He developed an Ultra Violet and Visible Spectroscopic Database ( UVSD ) for atoms and molecules which are found in interstellar medium, stars galaxies and in the atmospheres of the Earth, planets, satellites and comets. He has systematically consolidated widely scattered important data from laboratories and institution and is attempting to standardise the currently heterogeneous data for possible future network. His current  UV and Visible Spectroscopic Database ( UVSD ) listed on this site consist of 3 different sub-databases as follows :
a) atomic and molecular line listings from laboratory
b) absorption spectra measured in laboratories observations or theoretical studies
c) solar UV, visible, and infrared spectra atlases

Why is this UVSD site beneficial to research purposes ?

Firstly, while there are currently satisfactory database for infrared and microwave, there is currently no such well organised spectroscopic databases for the  UV and the visible ranges. Dr. Sang J. Kim's compilation is a first step to making such information available for world-wide researchers. Astronomers need an information base on the UV and visible spectra of molecules and atoms in celestial objects in order to properly analyse visible data from many important instruments from spacecraft and ground-based telescopes. Moreover, these compiled data are arrange so as to make searching these important data faster and easier for researchers.

Site No. 9
Site Address :    http://www.eso.org

Site Title      :   Optical and UV Spectroscopic standards stars catalog - ESO

About ESO site          :         

This is the site of the European Southern Observatory. ESO is an intergovernmental, European organisation for astronomical research. It has 8 member countries comprising Belgium, Denmark, France, Germany, Italy, the Netherlands, Sweden and Switzerland. ESO operates at 2 sites - the La Silla Observatories in the Atacama desert, Chile and the Very Large Telescope on Paranal which is still under construction. ESO's headquarters is located in Garching, near Munich, Germany. This ESO site also maintains Catalogs and Databases - among which is the Optical and UV spectroscopic standard stars catalog.

What ESO did ?          :

ESO makes available this Optical and UV spectroscopic standards stars catalog from data for standard stars from 4 sources :

1) HST UV spectroscopic standards - this has of data for 23 stars based in IUE and optical spectra and calibrated by the primary WD standards. Also data on 6 more stars with IUE and model spectra.

2) Optical spectroscopic standards from Oke ( 1990 ) - this has data for 25 stars ( 7 to 16 mag.) from 3200 to 10200 Angstroms based on Hale 5m observations.

3) Optical spectrophotometric standards from Hamuy ( 1992, 1994 ) - this has data for 10 bright secondary standards and 19 fainter ( 10 - 14 mag. ) tertiary standards over the wavelength range 3300 to about 10300 Angstroms, mostly in the Southern hemisphere, taken with CITO telescopes.

4) White Dwarf primary spectrophotometric standards - this has data for 4 stars ( 11 to 13 mag. ) from 10 Angstroms to 3 microns based on the White Dwarf model atmospheres and HST FOS observations, from the CALSPEC data base at STScI.
          

Why is ESO's Optical and UV spectroscopic standard stars catalog beneficial to research purposes ?

Because ESO have provided a tool for easily finding the suitable optical and ultra-violet standard stars on the sky most appropriate to the reduction of astronomical spectroscopic observations. This resource consist of a set of www pages each devoted to a single spectroscopic standard star and containing positional information, magnitude, a finding chart and plots of the magnitude and flux against wavelength. Access is also very straightforward via an RA ordered list or via an RA-DEC skymap with star positions. The finding charts also have conventional orientation - i.e. North at the top and East to the left. Image dimensions are also indicated. This allows researchers to find quickly the closest standard star to their observed source.

Site No. 10
Site Address               :          http://nssdc.gsfc.nasa.gov

Site Title                    :          National Space Science Data Centre ( NSSDC )

About NSSDC site           :

This is the site of NSSDC ( National Space Science Data Centre ). NSSDC is located at NASA Goddard Space Flight Centre and provides access to a very wide variety of astrophysics, space physics, lunar and planetary data from NASA space flight missions. NSSDC also has in addition other selected data and some models and software. It also has links to non-NASA data. NSSDC also holds the Master Catalog database. The Master Catalog for planetary science for example contains information on all NASA data on Mercury, Venus, Earth, the Moon, Asteroids, Jupiter, Saturn, Uranus, Neptune and Pluto from missions including Ranger, Mariner, Surveyor, Lunar Orbiter, Apollo, Pioneer, Viking, Voyager, Magellan and Galileo. Future NASA missions are also listed. Similar catalogs exist for space physics etc. making this a complete virtual source of all available NASA mission data.

What NSSDC do ?          :

NSSDC archived all of NASA's data as described above and organised them into distinct categories such as astronomy, planetary science, space physics etc. for distribution to researchers world-wide. NSSDC's CD-Rom catalogs for example, archived over 500 CD-Roms for distribution to researchers for a nominally US$ 10.00 fee each. NSSDC Master catalog under planetary science for example currently holds 43 titles and 870 unique volumes and is neatly categorised into Apollo 8 - Apollo 17, each with its distinctive link similar for Marina 2 to 10, Lunar Orbiter 2 - 5 and Surveyor 1 to 7 etc. among a comprehensive list of NASA planetary missions. Data on every NASA spacecraft such as COBE, Einstein, ROSAT, IRAS etc are being updated and archived for distribution at this centre. With the exception of Earth science data, originally part of NSSDC until 1994,  which is now in transition of migrating to a separate site.

Why is NSSDC site beneficial to research purposes ?

NSSDC is beneficial because the organisation has done an excellent job organising this massive amount of all available NASA data into a orderly and easy to find system. NDAD which stands for NSSDC Data Archival and Distribution System and WISARDS ( Web Interface for Searching Archival Research Data ) makes locating specific spectroscopic information from any source very easy. WISARDS in particular is a multi-wavelength ( X-Ray, UV, Optical and IR ), multi-mission interface to the astrophysics data archive and is focused primarily on NASA-supported missions and data sets. Because NSSDC also tap into Astronomical Data Centre ( ADC ) and many other resource, the sheer amount of data and information such as the valued NIMS Spectral Image Cubes from Galileo and literally thousands of other available data makes NSSDC probably the most comprehensive source of space borne spectroscopic data and information for researchers. NSSDC also holds a large number of data sets on-line for download via FTP.