# Copyright (C) 2016-2025 tilepy developers
# (Monica Seglar-Arroyo, Halim Ashkar, Fabian Schussler, Mathieu de Bony)
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
#
##################################################################################################
# Default observatory definitions #
##################################################################################################
from astropy import units as u
from astropy.coordinates import EarthLocation
__all__ = [
"HESSObservatory",
"LST",
"CTASouthObservatory",
"CTANorthObservatory",
]
[docs]
class HESSObservatory:
r"""
Coordinates and basic information for the H.E.S.S. Observatory.
The **High Energy Stereoscopic System (H.E.S.S.)** is an array of five Imaging Atmospheric Cherenkov Telescopes (IACTs)
located in Namibia, dedicated to very high-energy gamma-ray astronomy. The array consists of four 12 m telescopes
arranged in a 120 m square for stereoscopic imaging, and a central 28 m telescope (operational since 2012).
H.E.S.S. has provided full service since 2022, enabling major discoveries of galactic and extragalactic sources
of gamma rays :footcite:`2018A&A...612A...1H`.
- **Latitude**: -23.271778°
- **Longitude**: 16.50022°
- **Altitude**: 1835 m
More information: `H.E.S.S. website <https://www.mpi-hd.mpg.de/HESS/>`_
References
----------
.. footbibliography::
"""
def __init__(self):
self.Name = "HESS"
self.Lat = -23.271778 * u.deg
self.Lon = 16.50022 * u.deg
self.Height = 1835 * u.m
self.location = EarthLocation(lat=self.Lat, lon=self.Lon, height=self.Height)
[docs]
class LST:
r"""
Coordinates and description for the Large-Sized Telescope (LST), CTAO.
The **Large-Sized Telescope (LST)** is the flagship instrument of the Cherenkov Telescope Array Observatory (CTAO),
optimized for the detection of gamma rays at the lowest energies accessible from the ground (20-150 GeV).
Each LST features a 23-meter segmented mirror (collecting area : 400 m :math:`^2`) and a field of view of 4.3°, allowing
high sensitivity to faint Cherenkov flashes :footcite:`2016APh....72...76A`. Four LSTs are being installed at the center of the CTAO northern site,
enabling rapid and sensitive follow-up of transient events. Thanks to their lightweight structure, LSTs can repoint in less than 20 seconds, which is
crucial for observing phenomena such as gamma-ray bursts.
Each LST is equipped with a high-speed camera containing 1855 photomultiplier tubes (PMTs), able to record fast
Cherenkov signals produced when gamma rays interact with the atmosphere. These data provide crucial insights
into extreme cosmic sources.
The LST, together with the Medium-Sized and Small-Sized Telescopes, forms the CTAO, offering broad energy
coverage from 20 GeV to 300 TeV :footcite:`2023arXiv230512888H`.
More information: `LST official page <https://www.ctao.org/emission-to-discovery/telescopes/lst/>`_
.. figure:: ../_static/LST.jpg
:alt: The Large-Sized Telescope (LST) at the CTAO site (Credit: Otger Ballester, IFAE).
:width: 80%
:align: center
The Large-Sized Telescope (LST) at the CTAO site (Credit: Otger Ballester, IFAE).
References
----------
.. footbibliography::
"""
def __init__(self):
self.Name = "LST"
self.Lat = 28.75 * u.deg
self.Lon = -17.5 * u.deg
self.Height = 2200 * u.m
self.location = EarthLocation(lat=self.Lat, lon=self.Lon, height=self.Height)
[docs]
class CTASouthObservatory:
r"""
Coordinates and site information for the CTAO-South Observatory.
The **CTAO-South Observatory** is located in the Atacama Desert in Chile, about 10 km southeast of the ESO Paranal Observatory.
This remote desert site is one of the driest places on Earth, providing excellent observing conditions for very high-energy gamma-ray astronomy.
- **Latitude**: -24.5°
- **Longitude**: -70.3°
- **Altitude**: 2653 m
The southern array is designed to detect gamma rays from 150 GeV up to 300 TeV, covering the highest energies accessible
from the ground and focusing mainly on Galactic sources .
The initial array, called the ``Alpha Configuration``, includes:
- 14 Medium-Sized Telescopes (MSTs), covering energies from 150 GeV to 5 TeV,
- 37 Small-Sized Telescopes (SSTs), which extend sensitivity above 5 TeV, and the full array covers about 3 km :math:`^{2}`.
`The SSTs <https://www.ctao.org/emission-to-discovery/telescopes/sst/>`_ use a dual-mirror design with silicon photomultiplier (SiPM) cameras
and a wide field of view (about 8.8 degrees). `The MSTs <https://www.ctao.org/emission-to-discovery/telescopes/mst/>`_ have 12 m mirrors and fast PMT-based cameras (FlashCam), with a field of view of about 8 degrees.
`The CTAO-South site <https://www.ctao.org/emission-to-discovery/array-sites/ctao-south/>`_ is built to explore some of the most powerful particle accelerators in our Galaxy,
such as supernova remnants, pulsar wind nebulae, and massive star clusters :footcite:`2019EPJWC.20901038C`.
There is no Large-Sized Telescopes (LSTs) are installed at CTAO-South for now, but the site is prepared for future LST additions.
.. figure:: ../_static/CTAO_south.jpg
:alt: An artistic illustration of the proposed CTA. Image credit: Gabriel Pérez Diaz, IAC / Marc-André Besel, CTAO.
:width: 80%
:align: center
An artistic illustration of the proposed CTA (credit: Gabriel Pérez Diaz, IAC / Marc-André Besel.
References
----------
.. footbibliography::
"""
def __init__(self):
self.Name = "South"
self.Lat = -24.5 * u.deg
self.Lon = -70.17 * u.deg
self.Height = 2635 * u.m
self.location = EarthLocation(lat=self.Lat, lon=self.Lon, height=self.Height)
[docs]
class CTANorthObservatory:
r"""
Coordinates and location for the CTA North Observatory.
The **CTAO-North Observatory** is located at the Roque de los Muchachos Observatory on La Palma (Canary Islands, Spain), at :math:`\approx 2200` m altitude.
This site is optimized for low- and mid-energy gamma rays (20 GeV to 5 TeV), with a layout focused on extragalactic sources :footcite:`2016APh....72...76A`.
- **Latitude**: 28.762°
- **Longitude**: -17.891°
The “Alpha Configuration” includes (covering about 0.5 km\ :math:`^2`):
- 4 Large-Sized Telescopes (LSTs)
- 9 Medium-Sized Telescopes (MSTs)
As of mid‑2025:
- **LST‑1**: installed in October 2018 and under commissioning
- **LST‑2 / LST‑3 / LST‑4**: under construction, expected to be in place before end 2026
- **9 MSTs**: being deployed on-site
CTAO–North is ideal for studying low-energy cosmic transients, distant active galactic nuclei, and extragalactic gamma-ray sources.
More information: `CTAO North site <https://www.ctao.org/emission-to-discovery/array-sites/ctao-north/>`_
References
----------
.. footbibliography::
"""
def __init__(self):
self.Name = "North"
self.Lat = 28.75 * u.deg
self.Lon = -17.5 * u.deg
self.Height = 2200 * u.m
self.location = EarthLocation(lat=self.Lat, lon=self.Lon, height=self.Height)