ATLAS Technical Specifications


Number of observatories/sites Initially 2, goal 6 or more
Location Mauna Loa and Haleakala in Hawaii. Additional planned in Chile and South Africa.
Site separation 100 miles (160 km)
Number of telescopes per observatory 1
Telescope design DFM custom Wright Schmidt
Telescope aperture 0.5m
Telescope focal length 1.0m (f/2.0)
Telescope field of view 7.4°
Telescope mount APM German equatorial mount
Detector STA-1600, 10.5x10.5k CCD
Pixel size 9µm
Pixel scale 1.86"
Effective PSF FWHM (assuming 1.5" seeing) 3.8"
CCD operation temperature -53C
Individual camera FOV 30 deg²
Total FOV 60 deg² for initial 2 sites
Nominal exposure time 30 sec
Expected readout time 6 sec
Filters and 5-sigma limiting AB magnitude per 30 sec exposure (stationary, solar spectrum, dark, SNR² average over FOV)
Filter name Bandpass
[nm]		 m1
[AB]		 sky
[AB/"²]		 m5σ
[AB]
'cyan' 420-650 22.8 21.2 19.7
'orange' 560-820 23.2 20.4 19.7
g 400-550 22.1 21.9 19.3
r 560-690 22.4 21.0 19.3
i 690-820 22.5 20.1 18.7
H-a 653-663 19.7 20.9 17.7
[OIII] 498-508 19.3 21.9 17.7
Photometric accuracy 0.01 mag @ r~16.0
0.02 mag @ r~17.2
0.04 mag @ r~18.
Saturation r ~ 12.5
Astrometric accuracy ~2"/SNR where 2.5*log(SNR) ~ 22-m
Auxiliary cameras Canon 5dm3, 135f/2 lens, 10x15 deg, mlim ~ 14
Survey coverage 20,000 deg² three times per night
Time between revisits each night About 10 minutes
Total number of images per night per site 1000
Total data rate per site 150GB/night
Number of asteroid detections/night Up to 75,000 (i.e. 25,000 asteroids detected 3x each)
Number of detected impactors/year 1
Impactor detection efficiency >60% for objects larger than about 50 meters diameter. Most of the remaining 40% are approaching from the direction of the Sun and can not be seen in the night sky.
Impact Warning Time About a week for 50 meter diameter impactor
About a month for a 140m diameter impactor
Maximum asteroid detection distance:
(assuming 0.1 albedo and face-on)

1 meter diameter:
~ 0.4 million km ~ 1 lunar distance
~ 0.003 AU ~ 5 hour

10 meter diameter:
~ 4 million km ~ 10 lunar distance
~ 0.03 AU ~ 2 day

100 meter diameter:
~ 40 million km ~ 100 lunar distance
~ 0.3 AU ~ 3 week
Development time for each additional observatory/site About 18 months