Catalina Sky Survey (CSS; List of observatory codes, obs. code: IAU code#703, 703) is an astronomical survey to discover comets and asteroids. It is conducted at the Steward Observatory's Catalina Station, located near Tucson, Arizona, in the United States. CSS focuses on the search for near-Earth objects, in particular on any potentially hazardous asteroid that may pose a threat of Impact event, impact. Its counterpart in the southern hemisphere was the Siding Spring Survey (SSS), closed in 2013 due to loss of funding. CSS supersedes the photographic Bigelow Sky Survey.


The NEO Observations Program is a result of a United States 1998 congressional directive to NASA to begin a program to identify 1 kilometre (0.62 mile) or larger objects to around 90 percent confidence level or better. The Catalina Sky Survey, located at the Mount Lemmon Observatory in the Catalina Mountains north of Tucson, carries out searches for near-earth objects, NEOs, contributing to the Congressionally mandated goal. In addition to identifying impact risks, the project also obtains other scientific information, including: improving the known population distribution in the main belt, finding the cometary distribution at larger perihelion distances, determining the distribution of NEOs as a product of collisional history and transport to the inner Solar System, and identifying potential targets for flight projects.


The Catalina Sky Survey (CSS) uses three telescopes, a 1.5 meter (60 inch) f/1.6 telescope on the peak of Mount Lemmon (MPC code G96), a 68 cm (27 inch) f/ 1.7 Schmidt camera, Schmidt telescope near Mount Bigelow (Arizona), Mount Bigelow (MPC code 703), and a 1-meter (40 inch) f/2.6 follow-up telescope also on Mount Lemmon (MPC code I52). The three telescopes are located in the Santa Catalina Mountains near Tucson, Arizona. The CSS southern hemisphere counterpart, the Siding Spring Survey (SSS), used a 0.5 meter (20 inch) f/3 Uppsala Southern Schmidt Telescope, Uppsala Schmidt telescope at Siding Spring Observatory in Australia. The 1.5 meter and 68 cm survey telescopes use identical, Thermoelectric cooling, thermo-electrically cooled cameras and common software written by the CSS team. The cameras are cooled to approximately −100 °C (−148 °F) so their Dark current (physics), dark current is about 1 electron per hour. These 10,560 x 10,560 pixel cameras provide a field of view of 5 square degrees with the 1.5-m telescope and nearly 20 square degrees with the Catalina Schmidt. Nominal Exposure (photography), exposures are 30 seconds and the 1.5-m can reach objects fainter than 21.5 UBV photometric system, V in that time. The 1 meter follow-up telescope uses a 2k x 2k CCD detector which provides a field of view of 0.3 square degrees. Starting 2019, CSS started using the 1.54 meter (61 inch) Kuiper telescope situated on Mt. Bigelow for targeted follow-up for 7-12 nights per lunation. CSS typically operates every clear night with the exception of a few nights centered on the full moon. The southern hemispheres' SSS in Australia ended in 2013 after funding was discontinued.


In 2005, CSS became the most prolific NEO survey surpassing Lincoln Near-Earth Asteroid Research (LINEAR) in total number of NEOs and potentially hazardous asteroids discovered each year since. As of 2020, the Catalina Sky Survey is responsible for the discovery of 47% of the total known NEO population. CSS discovered 310 NEOs in 2005, 396 in 2006, 466 in 2007, 564 in 2008, 573 in 2009, 607 in 2010, 572 in 2011, 626 in 2012, 600 in 2013, 616 in 2014, 576 in 2015, 929 in 2016, 989 in 2017, 1054 in 2018, and in 2019, 1067 NEOs were found.

Notable discoveries

List of discovered minor planets

For a complete listing of all minor planets discovered by the Catalina Sky Survey, ''see the LOMP, index section in list of minor planets''.

CSS/SSS team

The CSS team is headed by Eric Christensen of the Lunar and Planetary Laboratory of the University of Arizona. The full CSS team is: * Eric J. Christensen (principal investigator) * Gregory Farneth * Stephen M. Larson * Alex R. Gibbs * Albert D. Grauer * Richard E. Hill (Retired) * Richard A. Kowalski * Hannes Gröller * Frank Shelly * David Rankin * D. Carson Fuls * Gregory J. Leonard * Rob Seaman * Theodore Pruyne * Kacper Wierzchos


* Robert H. McNaught * Gordon J. Garradd

Educational outreach

The CSS has helped with Astronomy Camp showing campers how they detect NEOs. They even played a role in an astrophotography exercise with the 2006 Adult Astronomy Camp ending up with a picture that was featured on Astronomy Picture of the Day.

Catalina Outer Solar System Survey

The Zooniverse project Catalina Outer Solar System Survey is a citizen science project and it is listed as a NASA citizen science project. In this project, the volunteers search for trans-Neptunian objects (TNOs) in pre-processed images of the Catalina Sky Survey. Computers can detect the motion of TNOs, but humans have to check if this motion is real. Upon agreement with the volunteers, they will be cited as "measurers" in the submission of the astrometry to the Minor Planet Center. The project already found previously known TNOs, including 47171 Lempo, , and .

See also

* Asteroid Zoo * Astronomical survey * Large Synoptic Survey Telescope * Minor Planet Center (MPC) * Planetary Data System (PDS) * Spaceguard * Asteroid Terrestrial-impact Last Alert System * List of near-Earth object observation projects


External links

Catalina Sky Survey Website

Overview and history
{{Planetary defense Astronomical surveys Discoverers of asteroids Near-Earth object tracking