Catalina Sky Survey
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OVERVIEW & HISTORY

The "Catalina Sky Survey" currently consists of a consortium of 2 cooperating surveys: the original Catalina Sky Survey (CSS) and the Mt. Lemmon Survey (MLS). These are also known by their MPC codes of 703 and G96 respectively. Though united by the common mission of meeting the Congressionally mandated goal in obtaining an inventory of better than 90% of the 140-meter or larger Near Earth Objects (NEOs) they have separate development histories and facilities. In late 2013 a 1-meter robotic telescope (MPC code I52) will be added to this team to handle follow up and arc-extension work, relieving the burden on CSS and MLS freeing up more of thier time for discovery.

The Catalina Sky Survey

The CSS Schmidt telescope is located on Mt. Bigelow in the Catalina Mountains just north of Tucson, Arizona, (longitude -110deg. 43.9min. West and latitude +32deg 25min North, 2510 meters above sea level). The site is owned and operated by Steward Observatory of the University of Arizona.

The Catalina Sky Survey began operation in April 1998 with the installation of a single-channel, thermoelectrically cooled, thick 4K x 4K CCD to the modified 0.4-/0.6-m Catalina Schmidt telescope. Automated detection software was added in September 1999 and operated until April 2000 (Larson, et al. 1999). During those seven months, 175,000 astrometric measurements were reported to the MPC, and 46 new NEOs were discovered. Both the hardware and software were prototypes designed to demonstrate that the facility could contribute significantly to the goal of discovering new NEOs.

After a comprehensive upgrade and overhaul of virtually every telescope/detector subsystem, the Catalina Sky Survey resumed routine observations in early November of 2003 with 68/76 cm f/1.9 classical Schmidt optics making it the second largest schmidt-type telescope in the United States. From that time through May 30, 2004, the Catalina Sky Survey submitted 324,128 astrometric observations to the Minor Planet Center (MPC) resulting in a number of new discoveries.

At present, CSS typically covers over 800 square degrees of sky in a single night of observing. In the course of accumulating these observations during the first half of 2004, CSS surveyed a total of 62,425 square degrees (four "visits" each) and detected 182 known NEOs and 19,350 main belt asteroids.



The Siding Spring Survey

The Siding Spring Survey is our sister survey at Longitude 149.1 East, Latitude 31.3 South, Altitude 1150m, at Australia's Siding Spring Observatory near Coonabarabran, NSW. In partnership with the Research School of Astronomy of the Australian National University, and with support from a previously independent grant from the NASA NEOO program, we have outfitted the Uppsala 0.5-m Schmidt with a camera and computing system identical to that to the CSS Schmidt.

Routine observing at the SSS began in April of 2004. Despite the fact that commissioning a new instrument is often hindered by steep learning curves and engineering issues, the first two months of operations with only two observers have yielded more than 22,400 astrometric observations. A total of 6 new NEOs, 1 PHA, and 1 comet discovered.

The SSS relies heavily on the developments of software and hardware technologies developed first for the CSS. This has resulted in significant savings over the costs of operating two independent surveys. Future operations of the SSS are predicated on the ongoing maintenance and enhancement of these technologies by our University of Arizona team.

The Siding Spring 1-m Telescope - Astrometric Follow-up from the Southern Hemisphere

The ANU 1.0-m telescope has been an integral part of the SSS program since 1999 and it deserves special mention. Observing about 5 nights per month, we routinely use the 1.0-m for follow-up of NEOs. Through careful selection of objects, critical arc extensions have been achieved through this effort. Many of the follow-up observations of new discoveries by other surveys are credited to observations made with this instrument (Appendix D). Astrometric observations from this site are of very high quality, with typical accuracy of ~0.1 arc second for V ~18 objects or brighter. Astrometry for objects down to V ~21.5 is rarely less accurate than 0.5 arc seconds.



The Mt. Lemmon Survey (MLS)

The 60" Cassegrain reflector operated by the Steward Observatory of The University of Arizona lies at an elevation of nearly 2800 m (Longitude: 110 47' 20" West, Latitude: +32 26' 36" N, Elevation: 2790 m = 9154 ft.) at the summit of Mount Lemmon in the Catalina Mountains north of Tucson. As used by the survey, it consists of an f/2 parabolic primary mirror with a CCD-mosaic camera at prime focus that provides images with about a 1-wide field-of-view down to magnitude 22. This camera is used routinely to discover and do follow up observations of near-earth asteroids and minor planets in the solar system. Potentially Hazardous Asteroids or PHAs are usually identified within 48 hours of discovery, but observing geometry (proximity to the sun, speed of recession from Earth, etc.) can severely limit the observing window. It is desirable to obtain physical observations close to the discovery epoch when objects are usually at their brightest for ground-based telescopes. Responding to such observing opportunities requires access to larger telescopes on short notice - a luxury that most ongoing characterization programs do not have. We have developed such a rapid response capability with the Mt. Lemmon 1.5-m telescope. Later in 2004 we will use the Mt. Lemmon 1.5-m telescope to obtain physical data of objects that will help complete our understanding of the threat posed by newly-discovered and multiple-return NEOs.

The Mt. Lemmon facility will have a threefold mission of:

1. Discovery and follow-up astrometry (from discovery epoch, data mining of pre-discovery images and subsequent oppositions) to quantify impact probability and impact velocity.

2. Accurate time series photometry to determine or constrain size, shape, and spin vector. (Density can also be constrained using photometry to obtain orbital characteristics of secondary satellites in binary systems.)

3. Spectrophotometry to determine composition and inferred albedo from which one can estimate density.


Images and further details on the individual survey sites.



Catalina Sky Survey

Click on images below for larger view.


The dome from the west.

The Location

The CSS Schmidt telescope is located on Mt. Bigelow in the Catalina Mountains just north of Tucson, Arizona, (longitude -110deg. 43.9min. West and latitude +32deg 25min North, 2510 meters above sea level). The site is owned and operated by Steward Observatory of the University of Arizona.


Pictures of schmidt telescope


The Telescope

The telescope is a 68/76 cm f/1.9 classical Schmidt design . A quartz field flattening lens is used for the CCD dewar window just in front of the CCD . The mount is a bent yoke providing access to high declinations and excellent rigidity. A 20 cm refractor mounted on the main tube is used for acquisition and guiding. With a full-aperture corrector, we gain a factor of 4 in effective light-gathering power for the center of the field. Telescope motion is controlled through Dave Harvey's (Steward Observatory) ComSoft PC-TCS software along with many other telescope functions and interfaces.



Image of 4K CCD Image of 4K CCD

The CCD Camera


Spectral Instruments Inc. (Tucson, AZ) built the camera head, controller and power supply. The CCD has 4-channel readout and is cooled with a Cryo-Tiger to -90oC.





CSS Fields

CSS Fields

Some CSS Fields on the Sky
(click on image for larger view)

This demonstrates the CSS field coverage for a small portion of the sky. CSS has demonstrated throughput of over 800 square degrees of sky in a single, long night of observing. At present, we use a survey strategy that capitalizes on our ability to cover large areas of sky each lunation, and exploit areas that promise to yield the greatest number of PHAs. Our favored approach includes areas surrounding the ecliptic, with an emphasis on areas around 70 degrees elongation from the sun.




Siding Springs Sky Survey

Image of 4K CCD Image of 4K CCD

The Siding Spring Survey is our sister survey at 32 degrees South, at Australia's Siding Spring Observatory near Coonabarabran, NSW. In partnership with the Research School of Astronomy of the Australian National University, and with support from a previously independent grant from the NASA NEOO program, we have outfitted the Uppsala 0.5-m Schmidt with a camera and computing system identical to that to the CSS Schmidt.

Routine observing at the SSS began in April of 2004. Despite the fact that commissioning a new instrument is often hindered by steep learning curves and engineering issues, the first two months of operations with only two observers have yielded more than 22,400 astrometric observations. A total of 6 new NEOs, 1 PHA, and 1 comet discovered.

The SSS relies heavily on the developments of software and hardware technologies developed first for the CSS. This has resulted in significant savings over the costs of operating two independent surveys. Future operations of the SSS are predicated on the ongoing maintenance and enhancement of these technologies by our University of Arizona team.

Image of 4K CCD
The Siding Spring 1-m Telescope

Astrometric Follow-up from the Southern Hemisphere The ANU 1.0-m telescope has been an integral part of the SSS program since 1999 and it deserves special mention. Observing about 5 nights per month, we routinely use the 1.0-m for follow-up of NEOs. Through careful selection of objects, critical arc extensions have been achieved through this effort. Many of the follow-up observations of new discoveries by other surveys are credited to observations made with this instrument (Appendix D). Astrometric observations from this site are of very high quality, with typical accuracy of ~0.1 arc second for V ~18 objects or brighter. Astrometry for objects down to V ~21.5 is rarely less accurate than 0.5 arc seconds.


Mt. Lemmon Survey

Image of 4K CCD

With funds from a previous NEOO grant, we have completed upgrades to the Mt. Lemmon 1.5-m reflector needed to support deeper survey, follow-up, and physical characterization programs. Its f/2 parabolic primary was refigured to produce sub-arcsecond images and it was outfitted with a new, opto-isolated control system interface. Modifications to the RA drive system and installation of a declination drive has greatly improved pointing and tracking performance. An existing top-end ring was modified to accept a prime focus camera that consists of correcting optics, filter slide, shutter, focusing mechanism, and camera mount. The anti-reflection-coated three-element field corrector feeds a thinned, back- illuminated 4K x 4K CCD camera to produce a 1.2 square-degree field at f/2 with one arcsecond pixels. The ImagerLabs four-channel CCD, thinned at the Steward Observatory Imaging Technology Lab, has a peak DQE of 92% and very low readout noise. This configuration is well suited for survey work to about magnitude 22.0 and faint, second-return follow-up of NEOs with large orbital uncertainties. The camera is also very well suited for time-series photometry of moving asteroids since the same reference stars can be used for several hours without the usual hand-off problems required with smaller fields. First results indicate the ability to achieve 1% photometry of R=19.5 objects with 180 sec integration.

As an example of the capabilities of this system, the large CSS binary PHA 2003 YT1 was observed during close approach in early May of 2004, demonstrating the utility of obtaining a suite of data that included light curves and ECAS colors. Preliminary results from those measurements are presented in Appendix A.