3D model of the STELLA observatory.

STELLA (abbreviation for STELLar Activity) is a long-term project for observing and monitoring activity tracers on cool stars with two robotic telescopes. STELLA is an observatory hosting two robotic telescopes (STELLA-I and STELLA-II) that operate in fully unattented mode. The building itself is automatic, and the telescopes decide about the best observing strategy on the fly. STELLA-I will host an optical CCD imager & photometer (WIFSIP) and an AO testbed, while STELLA-II fiberfeeds the STELLA echelle spectrograph.

STELLA is a project of the Leibniz-Institut für Astrophysik Potsdam (AIP) in collaboration with the Instituto de Astrofísica de Canarias (IAC) and is located at the Teide Observatory on the Canarian island of Tenerife, Spain. P.I. is Klaus G. Strassmeier.

	Automatic Telescope, 1.2m diameter, f/8, Alt/Az mount, Nasmyth focus, ø 24' field of view
	Stella Echelle Spectrograph (SES). Until STELLA-II is finished, the SES will be fed from this telescope.
	Wide Field Stella Imaging Photometer (WIFSIP) with emphasis on narrow band filters. A large-format CCD imager and photometer for STELLA-I. The useable FOV is 22'x22' at a scale of 0.32"/Pixel. The detector is a single 4096x4096 back-illuminated thinned CCD with 15um Pixels and a peak QE>90% from University of Arizona ITL. Available filters: Stromgren uvby, Halpha-narrow and wide, UBVRI, and the Sloan-filterset.

Automatic Telescope, 1.2m diameter, f/10, Alt/Az mount, Newton focus, ø 1.5' field of view

Stella Echelle Spectrograph (SES). A fiber-fed cross-dispersed echelle spectrograph for STELLA-I. The spectrograph has a fixed format to cover the wavelength range 380-860nm in a single exposure. The spectral resolution is 55,000 with a 50-micron fiber attached to a high-curvature microlens. In the final configuration with a 100-micron fibers sliced 3 times, it will achieve a resolutions of approximately 75,000. The current detector is a 2kx2k back-illuminated thinned CCD with 13.5um Pixels from E2V/Marconi. The current CCD controller is the Genneration-II controller from IJAF Kopenhagen. The final configuration will use a 4kx4k CCD with a Magellan CCD controller.

	AIP: Robotic building for both telescopes, automation software, weather stations, spectrograph (SES), imaging instrument (WIFSIP), AG-units for both telescopes, telescopes, operations- and data-center in Potsdam (MCC).
	IAC: infrastructure, attendance/services

The telescopes were built by Halfmann Teleskoptechnik in Neusäß (Augsburg).