The document summarizes the history and operation of PROMPT, a telescope array for rapid follow-up of gamma-ray bursts (GRBs). It began in 2005 with six telescopes that simultaneously observe in multiple optical and near-infrared bands. PROMPT dedicates ~5% of time to GRB follow-up and shares the remaining time among collaborators and outreach. The document describes the current hardware of the telescopes and the Skynet/Terminator software that automates control of the array over a network.

1. History of PROMPT
• Operational since 2005
• Primary mission: rapid GRB response
• Six telescopes built initially
– Simultaneous observing in U,B,V,R,I,NIR
• GRB follow-up accounts for ~5% of time
• Remaining time shared among
collaborators and outreach programs

2. PROMPT Sites

4. PROMPT
UNC - CTIO, Chile

5. PROMPT
UNC - CTIO, Chile

6. PROMPT
UNC - CTIO, Chile

7. Current hardware (Prompt 1,3,4,5,6)
• Paramount ME
• RCOS 16” f/11.26 OTA
• Apogee U47 camera
– Backside illuminated
– 90% QE
– 10 arcmin FOV
– 1024 x 1024
• ACE filter wheel
– UBVRI
– Sloan ugriz
– RGB
• Astro-Haven 12ft dome

8. Current hardware (Prompt 2)
• Planewave A200HR
• RCOS 16” f/11.26 OTA
• Apogee U9 camera
– Frontside illuminated
– 60% QE
– 21x14 arcmin FOV
– 3072 x 2048
• Apogee filter wheel
• Astro-Haven 12ft dome

9. CTIO
• Weather:
– 75% - “Excellent” nights
– 15% - “Marginal” nights
– 10% - “Unusable” nights
– Wind typically blows from the north
– Some snow each year
– Worst weather is during Chilean winter
• Seeing:
– 0.5” – 1.0” often reported at top of mountain
– 1.2” – 1.8” typically seen at Prompt
• Problem: No available space for new structures

10. Skynet design
• Problem when building PROMPT:
– Operate multiple telescopes
– Simultaneous control
– Run over a network
– Shared among many users
– Controlling a variety of hardware
• Solution: Skynet and Terminator
– Software developed at UNC
• Opened possibility of expanding beyond PROMPT

11. Skynet Sites

12. Skynet
PROMPTTTT GORT
DSO-14 Morehead
Dolomiti PARI
REMO HSC
DSO-32

13. Telescope Automation
• Skynet
– One server running at UNC
– Discovers jobs submitted via website
– Dispatches jobs to telescopes running Terminator
• Terminator
– Runs at each telescope node
– Controls hardware subsystems: mount, camera, etc.
– Takes dark and flat calibrations
– Detects and reports hardware errors

14. Skynet
Website
Terminator
Telescope 1
Terminator
Telescope 2
Terminator
Telescope N
Mount Camera Focus Filter Dome Weather

15. System Flowchart
Web
Browser
Web
Server
MySQL
Database
Skynet
Terminator
(Prompt2)
Terminator
(Prompt1)
Terminator
(TTT)
Data
Manager
Reduction
Pipeline
…
GCN Alert
FUNGRB
User computer
At Telescope
Linux cluster
GCN
Machines

16. Terminator operation
• If no hardware errors:
– If weather is good:
• 0 < SunAlt < 20:
– Take darks
• Sun < -1:
– Open dome
• -3 < Sun < -7:
– Take twilight flats
• -12 < Sun < -18:
– Twilight exposures
• Sun < -18:
– Nighttime exposures
– If weather is bad or Sun > -1:
• Close dome, park telescope
• If hardware error:
– Send notification; stop everything