Timeline and Milestones

2010 Jun 15 - Spacewatch observed an object recovered by WISE which shows a well-developed tail. 237P/2010 L2 (LINEAR) = 2002 LN13 was re-discovered/recovered by the orbiting WISE satellite. At initial discovery, it was the apparently asteroidal object 2002 LN13 (discovered then by LINEAR). R. S. McMillan used the Spacewatch 1.8-m telescope on 2010 Jun 15 to comfirm the cometary nature of the object as indicated by WISE. The composite image here was assembled by J. V. Scotti. The shifted and co-added comet image has 418 seconds effective exposure, and the stars have 139 seconds exposure. The narrow tail can be seen to extend almost 3 arc minutes toward the WSW. In the image, North is at the top, and East to the left. Once displayed, click on the image to reverse the view from negative to positive, and vice versa.

2010 Feb 8 - Spacewatch observed the first comet discovered by the WISE spacecraft, P/2010 B2. The images were taken by J. V. Scotti on 2010 Feb 8 at 11:14:00, 11:19:41, and 11:25:02 UTC with the Spacewatch 1.8-m telescope on Kitt Peak (in these negative views, the comet is the fuzzy object near the center of each frame).

Each pass has a FOV of 3.27 arcmin N-S and 3.08 arcmin E-W. East is up and North is to the right due to the way we scroll drift scans on the screen.

Effective exposure time of the drift scanning at this declination is 141 sec. As the drift scanning is synchronized to the sidereal rate, the stars are round and the comet is trailed slightly.

2010 Feb 1 - Spacewatch observers T. H. Bressi and J. V. Scotti carried out successful ground-based targeted followup observations of Potentially Hazardous Apollo Asteroid 2010 CO1, the first PHA discovered by the WISE Spacecraft.

2010 Jan 8 - Spacewatch observes main-belt Comet C2010 A2 (LINEAR), and finds it remarkably free of a central condensation. The object may be a comet that has had an outburst, or it could be a rare instance of an asteroid that has undergone an impact recently, with impact debris and dust still traveling along with it and forming a tail in its path. Stacked and shifted exposures made by J. V. Scotti at the Spacewatch 1.8-m telescope on 2010 Jan 8 are here shown as a composite by Scotti, and show the cometary aspect as well as the puzzling lack of nucleus.

2009 Dec 14 - present: Collaboration with the WISE Mission: R. S. McMillan is a co-investigator in the Wide-field Infrared Survey Explorer (WISE) spacecraft mission. The URL of WISE, which was launched on 2009 Dec 14, is:

http://www.astro.ucla.edu/~wright/WISE/

Spacewatch will recover and follow interesting solar system objects discovered by WISE. On 2010 Jan 12-15 UT Spacewatch made the first ground-based recoveries of three asteroids discovered by WISE by observing them with the Spacewatch 1.8-meter telescope. Our recoveries made it possible for the Minor Planet Center to designate them W00016c = ts579 = 2010 AX58, W000e2t = ts582 = 2010 BD, and W000prw = ts580 = 2010 AO61, all main belt asteroids. Followup of WISE discoveries will continue throughout the mission and afterwards as conditions permit.

2009 - Several papers and presentations of Spacewatch results, Spacewatch collaborations with the WISE spacecraft mission, and with NEO surveys, have been published.

Haskell, H, and J. Larsen. 2009. "The Size Distribution of the Small Near Earth Asteroids from Spacewatch". AAS Meeting #213, #401.11; poster abstract.

McMillan, R. S., A. K. Mainzer, R. G. Walker, E. L. Wright, P. R. Eisenhardt, R. M. Cutri, T. Grav, and the WISE Science Team. 2009. "NEOWISE: Proposed Discovery of Near-Earth Objects in the Infrared by the WISE Mission". AAS Meeting #213, #459.06.; abstract, and poster.

McMillan, R. S. 2009. "Spacewatch Support of Deep Wide-Field NEO Surveys"; White Paper submitted to NRC Committee to Review Near-Earth Object Surveys and Hazard Mitigation Strategies, and PDF format Powerpoint slide series to accompany presentation to the Committee on 2009 April 20.

McMillan, R. S., et al. 2009. Abstract of Talk for 214th Meeting of the American Astronomical Society, 2009 June 9, Presentation No. 217.02, and slides.

2009 June 19 - IAU Circular 9053 announces that (136617) 1994 CC, a Spacewatch PHA discovered on 1994 Feb. 3 by Jim Scotti with the 0.9-m telescope, is a triple system, consisting of a 650 m diameter primary, and two satellites of at least 50 m and 100 m diameters. The satellites were discovered with Goldstone and Arecibo planetary radars, and optical photometry by the PROMPT telescopes on 2009 June 3 shows an eclipse/occultation event.

2009 May 26 - Large Amor asteroid 2009 KM7 discovered with Spacewatch 0.9-m Mosaic telescope by Jim Scotti, and followed up by Terry Bressi with the Spacewatch 1.8-m telescope. This object, with H magnitude 17.9, is between 0.7 - 1.6 km in diameter.

2009 Jan 2 - Recovery of large, highly eccentric, steeply inclined Apollo Asteroid 2000 YJ29 (as 2009 AO), with Spacewatch 0.9-m Mosaic telescope by Jim Scotti. The object, with H magnitude 17.9, is between 0.7 - 1.6 km in diameter.

2008 Sep 4 - Large Amor asteroid 2008 RJ1 discovered with Spacewatch 0.9-m Mosaic telescope. The object is between 0.7 - 1.6 km in diameter.

2008 Jan 30 - Unusual object 2008 BN18 discovered with Spacewatch 0.9-m Mosaic telescope. When observable again after emerging from the Sun's glare in 2008 Nov., this object may show itself to be cometary, as hinted at by its eccentric orbit over 0.92, and semi-major axis over 34 AU.

2007 Nov 1 - Comet C/2007 VO53 (Spacewatch) discovered with Spacewatch 0.9-m Mosaic telescope, due for perihelion in 2010 (about Apr 27); inclination of the comet's orbit is 87 degrees.

2006 Dec 27 UT: Conversion of Spacewatch astrometry to the U. S. Naval Observatory's B1.0 reference star catalog has improved astrometric residuals on reference stars from 0.3 to 0.2 arcseconds.

2006 Apr 7 - Retrograde Outer Solar System Object discovered by Spacewatch 0.9-m Mosaic telescope: a Comet!

Bressi, T. H., and T. Gehrels. 2006. Discovery and Followup Observations of Retrograde Outer Solar System Object 2006 GZ2. This turned out to be a comet (P/2006 GZ2 (Spacewatch); IAUC 8703), as its orbit suggested. In MPEC 2006-G38.

2006 March 4 UT: Dual-scope operations: Automation has made it possible for the 0.9-meter telescope to run unattended and monitored by the observer at the 1.8-meter. This mode of solo observer operation of both telescopes was first used on 2006 January 8 UT and has been standard practice since 2006 March 4 UT.

2006 Jan 7 - First Discovery of a Large Transneptunian Object with our Collaborators at the U. S. Naval Academy in archived Spacewatch data.

Larsen, J. A., E. A. Roe, J. V. Scotti, A. F. Tubbiolo, M. Block, A. S. Descour, R. S. McMillan, M. T. Read, T. H. Bressi. 2006. Discovery, Prediscovery, and Incidental Followup Observations of Large Trans-Neptunian Object 2003 MW12, the first discovery of a Kuiper-Belt Object by the search at the United States Naval Academy. In MPEC 2006-A28.

2005 Dec 28 - Discovery of small Apollo asteroid with 59 close approaches in 70 upcoming years.

McMillan, R. S., and J. V. Scotti. 2005. Discovery and Followup Observations of Small Apollo Asteroid 2005 YU55. This object, while not initially labeled a PHA by the MPC, turned out to have 59 potential encounters with Earth between 2036 and 2105. In MPEC 2005-Y47.

2005 Oct 29 - Spacewatch discovers a Main-Belt Comet.

Read, M. T., M. Block, T. H. Bressi, T. Gehrels, J. V. Scotti. 2005. Discovery and Followup Observations of Comet P/2005 U1 (Read). In MPEC 2005-U74.

This is one of only a few comets with orbits similar to those of main-belt asteroids. See story at "Space.com".

2005 Oct 12 - Spacewatch Discovers a small, fast-moving Aten "VI" with 24 close approaches in 64 upcoming years.

Block, M., R. Gorelli, and T. H. Bressi. 2005. Discovery and Followup Observations of Small, Fast-Moving Aten Asteroid 2005 TH50. This H=28.0 Virtual Impactor (VI) has 24 potential encounters with Earth between 2031 and 2094. In MPEC 2005-T85.

2005 Oct 12 - Spacewatch Discovers a small, fast-moving Apollo with 3 close approaches in 74 upcoming years.

Bressi, T. H., J. J. Gomez, M. Block. 2005. Discovery and Followup Observations of Small, Fast, Closely-approaching Apollo Asteroid 2005 TK50. This H=29.1 VI has 3 potential encounters with Earth between 2027 and 2100. In MPEC 2005-T87.

2005 Jul 11 - Discovery of Apollo PHA with 85 close approaches in 92 upcoming years.

Block, M., and E. P. Majden. 2005. Discovery and Followup Observations of Potentially Hazardous, Fast-moving Apollo Asteroid 2005 NX55. This H=21.9 VI has 85 potential encounters with Earth between 2011 and 2102. In MPEC 2005-N64.

2005 July 5 - Spacewatch images of 9P/Tempel 1

2005 July 4	2005 July 5

Copyright 2005 by the Arizona Board of Regents.

The image on the left was obtained on July 4, 2005 by James V. Scotti using the Spacewatch 1.8-m telescope in drift scan mode in the hours before the impact of the Deep Impact Spacecraft. Five images were coadded giving an effective exposure time of about 694 seconds. The comet has not changed significantly since the previous night. North is to the right and west at the bottom and the field of view is about 12.6 arcminutes N-S and 11.2 arcminutes E-W.

The image on the right was obtained on July 5, 2005 by Miwa Block using the Spacewatch 1.8-m telescope in drift scan mode. Three images were coaded by James V. Scotti, giving an effective exposure time of about 416 seconds. Superimposed on the fan shaped coma and towards the west is an arc or shell of material that exploded from the Deep Impact spacecraft impact crater. North is to the right and west at the bottom and the field of view is about 12.6 arcminutes N-S and 11.2 arcminutes E-W. Here is a median combined version of the same three images.

Recovery of Large, Potentially Hazardous Apollo Asteroid 1990 SM which allowed linkage to 1987 SB4. This H=16.2 PHA was uncertain by 90 degrees of arc after not being observed for 15 years, but the search pattern and strategy developed by M. Block, A. S. Descour, and J. V. Scotti found the object seven degrees from the nominal ephemeris prediction. The object was running early in its orbit by 90 days. In MPEC 2005-C25.

2004 Dec 27 - Possibility of an Earth Impact in 2029 Ruled Out for Asteroid 2004 MN4:

URL: http://neo.jpl.nasa.gov/news/news148.html

Animation

Pass1 Pass2 Pass3

Copyright 2004 by the Arizona Board of Regents.

Three prediscovery images of the Potentially Hazardous Aten Asteroid 2004 MN4 made by the Spacewatch Project on 2004 March 15. The observer was Arianna E. Gleason; the images were found and measured by Anne S. Descour and Jeffrey A. Larsen. At the time of observation, the object's rate of motion produced trailing of 5 arcseconds during the 2 minute exposure times that were spaced approximately 40 minutes apart in time. This trailing, combined with variations in seeing and background noise, make these faint images less uniform and distinct than those of brighter stars in the same image. Field shown is 128x128 arcseconds with north at the top and east on the left.

Three positions within frame (short timeline)

Peter Lake of Melbourne, Australia submitted the above FMO candidate which is 2000 EV70, a PHA last seen 2000 April 23. The Spacewatch mosaic system, with its large field of view, was used for this deliberate recovery as 2000 EV70's position was highly uncertain. 2000 EV70 received an orbital adjustment in MPEC 2004-E11 based on our initial recovery measurements and followup measurements by another telescope.

Only 1 position within frame (regular timeline)

For more details, please see the press release.

                 

On Sept 22, Spacewatch object ts272 was given the official designation of 2003 SW130. A preliminary orbit calculated by the Minor Planet Center [MPC] suggested this Spacewatch object was only 0.005 astronomical units [AU] (750,000km) from the Earth at the time of discovery, or about twice the distance from the Earth to the Moon. 2003 SW₁₃₀'s closest approach actually occurred the night before, Sept. 19 when it flew by at a distance of only 162,000 km, or less than half the distance to the Moon!

As the smallest asteroid detected by Spacewatch and designated by the MPC, its estimated size is between 5 - 9 meters in diameter, calculated as a function its absolute magnitude (H = 29.2). An object of this size poses no threat to the Earth, despite its close proximity on Sept 19. If the orbit were ever perturbed, predicting an impact with the Earth, it would probably disintegrate in the Earth's upper-atmosphere appearing as 'shooting-stars'. Small pieces of the asteroid might also fall to the ground as meteorites. It has been roughly calculated that objects of this size (about 5 meters) impact somewhere on the Earth's surface once each month! These are the largest objects a person could expect to see as a brilliant shooting-star in a lifetime. Although the smaller objects such as 2003 SW₁₃₀ are not hazardous, the statistics of their population provide information about the processes of fragmentation and cohesion of asteroids due to their mutual collisions and gravitation, respectively.

On the second night of testing the CCD mosaic in bright moonlight, the focus and collimation were already so good that we decided to try some real observations. We detected the Potentially Hazardous Asteroid (PHA) 2002 TD₆₆. Software and engineering refinements continue.

On Oct. 10 we had First Light on the optical system, and now we have achieved First Light on our new science detector, the Mosaic of CCDs. Focus, tip, and tilt look good.

Installation of the new optical system for the mosaic of CCDs was completed, and images of star trails on a small engineering CCD showed good collimation and focus. Tracked "stare" images will be next, after the telescope is balanced with the science detector and the drive system set up again.

2002: The technically challenging conversion of the 36" telescope to the mosaic of CCDs is completed and observing on that telescope resumed. This conversion will increase the rate of detection of NEOs by seven times compared to the old detector system on the same telescope.  CCD mosaic of 37.7 million pixels. See the Photo Gallery detailing the conversion.

2002: Spacewatch was the first to detect the "lost" CONTOUR Spacecraft.

2001:  Full size CCD installed on 1.8-meter telescope. First astrometry with the 1.8-meter telescope. Spacewatch detects the WIND spacecraft. Minor Planet 2000 WR₁₀₆ is named (2000) Varuna by the IAU.

At 900 kilometers in diameter, Varuna is among the largest Trans-Neptunian objects after the planet Pluto and its satellite Charon. Click here for the images.

This NEO had a potential of colliding with the Earth in 2022. Click here for the images.

Spacewatch data leads to Science article estimating number of Near Earth Asteroids and their properties! Images and News Release of Spacewatch discovery of S/1999 J 1 , a new satellite of Jupiter.Spacewatch discovers new Minor Planet 2000 WR₁₀₆.

Spacewatch discovers first designated comet of the 2000s -- C/2000 A1 (Montani), due for perihelion on 2000 June 15 at a distance of 10 AU!)
Spacewatch discovers Near-Earth Asteroid 2000 BF₁₉.
Spacewatch finds the last, then-remaining, "lost" numbered asteroid, (719) Albert.

2000: New estimate of the number of NEOs larger than 1 km in diameter. First light with Spacewatch 1.8-meter telescope. Our first determination of the bright end of the cumulative luminosity function of TNOs. Rediscovery of minor planet (719) Albert. Discovery of the large TNO (20000) Varuna.

1999: Image Motion Package for Asteroids, Comets, and Transneptunians (IMPACT) in operation at the telescope. TNOs discovered in archival data. Found two objects in the outer solar system (1995 SN₅₅ and 1999 TD₁₀) with orbits that are intermediate between those of Centaurs and Scattered Disk Objects.

Spacewatch discovers its first Trans-Neptunian object! Berkeley supernova search found a Type Ia supernova at redshift 0.24 using Spacewatch data.

This NEO had the fastest rotation known for any asteroid at that time. Click above link for the images.

1998: Orbital and absolute magnitude distributions of main belt asteroids determined.  Rapidly rotating NEO 1998 KY₂₆ discovered.

This FMO was predicted to pass within 950,000 kilometers of Earth on 2028 October 26. Early predictions suggested an approach to within only 45,000 kilometers, but observations from 1990 were found which allowed improved estimates and a much more generous miss distance. Click above link for the images.

1997: Spacewatch 1.8-m telescope dedicated.  Estimate of the number of Centaurs from 1992-1995 observations.

As of 2002 July 28, this was the only NEO with a multiple-opposition orbit that had the orbital elements that are most favorable for frequent low deltaV (< 5 km/s) rendezvous by spacecraft (eccentricity less than 0.1, inclination less than 5 degrees, and synodic period less than 5 years).

This object was a FMO, which came close enough to be captured on video in real time at Kitt Peak.

1995: Coma corrector on 0.9-m telescope, scan regions repeated 3 times per month.  Discovered the S or C type asteroid with smallest q at the time(1995 CR; 0.120 AU).

This object was a VFMO. 1994 XM₁ came within 105,000 km of the earth - a record close approach.

1994: Scans of uniform length adopted.  Detected the closest approach of any asteroid to the Earth (105,000 km; 1994 XM₁).

This NEO passed within 150,000 km of the Earth.

1993: Detected the smallest known asteroid (1993 KA₂ with absolute magnitude H=29.2; 4-9 meters diameter). Discovered enhancement in numbers of asteroids smaller than 100 meters.

5145 Pholus (1992 AD) has a perihelion just inside Saturn's orbit and aphelion outside Neptune's. Pholus was the second of the Centaurs discovered and eight additional ones have been discovered since by Spacewatch. The second Centaur found by Spacewatch was numbered and named as (7066) Nessus (1993 HA₂). Centaur 1995 SN₅₅ is the intrinsically brightest Centaur yet discovered, brighter even than Chiron, the first Centaur ever discovered. The orbits of these bodies are unstable and easily perturbed while passing by the giant planets. Consequently the possibility exists for them to be either ejected from the solar system or nudged towards the inner planets in the future. They may be the direct progenitors of the short-period comets and must be fed from a source region such as the Edgeworth-Kuiper belt or the Oort Cloud.

1992: (5145) Pholus discovered, the second known Centaur. First automatic discovery of a comet (C/1992 J₁) with a CCD. Thinned 2Kx2K CCD installed.

It was recovered in April of the following year at a magnitude of 22 V. We define an Arjuna type asteroid as one with a nearly Earth-like orbit.

It was a 5-10 meter object which passed by the Earth with barely 170,000 km to spare. This occurred during the first Gulf War when an airburst of an incoming meteoroid could have appeared as a discharge of a nuclear weapon, possibly triggering a retaliatory strike by a combatant nation.

1991: Astrometry using HST Guide Star Catalog; first detection of a comet (1991x = 125P/1991 R₂) with a CCD.

1990: Moving Object Detection Program (MODP) in operation at the telescope.  First automatic detection of an NEO (1990 SS).

1989: 2Kx2K pixel CCD; first NEO (1989 UP) detected with a CCD.

1985: First version of software for automated detection of asteroids; first automatically detected asteroid.

1984: First production-mode astronomical use of TDI drift scanning. Began astrometry of asteroids and comets.

1983: 320x512 pixel RCA CCD in operation.

1982: 0.9-m Newtonian telescope of Steward Observatory made available.

1980: First proposals to survey the solar system using the name "Spacewatch".

Epochs of Spacewatch Equipment on 0.9-meter telescope:

Epochs of Spacewatch Equipment on 1.8-meter telescope:

CCDs:

Thin 320x512 = RCA SID 53612 CCD 320x512, 30 micron pixels, thinned and backside-illuminated.

Thick 2Kx2K = Tektronix 2048-SP 2048x2048, 27 micron pixels, thick and front illuminated.

Thin 2Kx2K = Tektronix TK2048EB-1 2048x2048, 24 micron pixels, thinned and backside-illuminated.

Thin 4CCD Mosaic = Four E2V Technologies, Model CCD42-90-I-941; 4608 x 2048 pixels each, thinned and backside illuminated.

FLI-2k = 2048x2048, 14.4 micron pixels, thinned and backside illuminated.

JVS = Image processing and astrometry software in Fortran by Jim Scotti, run on the Perkin-Elmer 3242 mainframe computer. SAO Catalog used at first, then AGK3 north of -2.5 degrees declination starting in 1987 October.

AGK3 = Astrometry by hand measurement of AGK3 stars.

MODP = Moving Object Detection Program by Dave Rabinowitz

OG-515 = Schott OG-515 filter transmitting wavelengths from 515 nm to the long wavelength cutoff of the CCD.

IMPACT = Image Motion Package for Asteroids, Comets, and Transneptunians by Jeff Larsen and Anne Descour

IMGPARS = Image Parameters by Jeff Larsen

MOSAF/MOSSUR = Mosaic Astrometry Finder / Mosaic Survey by Jeff Larsen.

SA1.0 = U. S. Naval Obs. astrometric star catalog SA1.0

SA2.0 = USNO SA2.0 catalog

A2.0 = USNO A2.0 catalog

B1.0 = USNO B1.0 catalog

JEF = Telescope drive by Jack E. Frecker

THB = Telescope drive by Terrence H. Bressi

Last Update: 2011 June 30