LUCIFER1 is a NIR camera and spectrograph installed at the Large Binocular Telescope (LBT). Working in
the wavelength range of 0.9-2.5micron, the instrument is designed for direct imaging and spectroscopy with 3
different cameras. A set of longslit masks as well as up to 23 user defined (MOS) masks are available. The set
of user defined masks can be exchanged while the instrument is at operating temperature.
Extensive tests have been done on the electro-mechanical functions, image motion due to flexure, optical
quality, instrument software, calibration and especially on the multi-object spectroscopy. Also a detailed characterization
of the instrument's properties in the different observing modes has been carried out. Results are
presented and compared to the specifications.
The successful roll-out of the control software for a complex NIR imager/spectrograph with MOS calls for
flexible development strategies due to changing requirements during different phases of the project. A waterfall
strategy used in the beginning has to change to a more iterative and agile process in the later stages. The
choice of an appropriate program language as well as suitable software layout is crucial. For example the
software has to accomplish multiple demands of different user groups, including a high level of flexibility for
later changes and extensions. Different access levels to the instrument are mandatory to afford direct control
mechanisms for lab operations and inspections of the instrument as well as tools to accomplish efficient science
observations. Our hierarchical software structure with four layers of increasing abstract levels and the use of an
object oriented language ideally supports these requirements. Here we describe our software architecture, the
software development process, the different access levels and our commissioning experiences with LUCIFER 1.
LUCIFER 1 is the rst of two identical camera-spectrograph units installed at the LBT (Large Binocular Telescope)
on Mount Graham in Arizona. Its commissioning took place between September 2008 and November
2009 and has immediately been followed by science operations since December 2009.
LUCIFER has a 4x4 arcminute eld of view. It is equipped with a 2048x2048 pixel HAWAII-2 array, suitable
lters (broad-band z, J, H, K & Ks plus 12 medium and narrow band near-infrared lters) and three gratings for
spectroscopy for a resolution of up to 15000. LUCIFER has 3 cameras: two specic for seeing limited imaging
(the N3.75 camera, with 0.12"/pixel) and spectroscopy (the N1.8 camera, with 0.25"/pixel) and one for diraction
limited observations (the N30 camera). We report here about the completed seeing-limited commissioning, thus
using only two of the cameras.
LUCIFER is a NIR spectrograph and imager (wavelength range 0.9 to 2.5 micron) for the Large Binocular
Telescope (LBT) on Mt. Graham, Arizona, working at cryogenic temperatures of less than 70K. Two instruments
are built by a consortium of five German institutes and will be mounted at the bent Gregorian foci of the two
individual telescope mirrors. Three exchangable cameras are available for imaging and spectroscopy: two of
them are optimized for seeing-limited conditions, a third camera for the diffraction limited case will be used with
the LBT adaptive secondary mirror working. Up to 33 exchangeable masks are available for longslit or multi-object
spectroscopy (MOS) over the full field of view (FOV). Both MOS-units (LUCIFER 1 and LUCIFER
2) and the auxiliary cryostats together with the control electronics have been completed. The observational
software-package is in its final stage of preparation.
After the total integration of LUCIFER 1 extensive tests were done for all electro-mechanical functions and
the verification of the instrument started. The results of the tests are presented in detail and are compared with
LUCIFER (LBT NIR Spectrograph Utility with Camera and Integral-Field
Unit for Extragalactic Research) is a NIR spectrograph and imager for
the LBT (Large Binocular Telescope) working in the wavelength range from 0.9 to 2.5 microns. Two instruments are built by a consortium of
five German institutes (Landessternwarte Heidelberg (LSW), Max Planck
Institut for Astronomy (MPIA), Max Planck Institut for Extraterrestric Physics (MPE), Astronomical Institut of the Ruhr-University Bochum (AIRUB) and Fachhochschule for Technics and Design Mannheim (FHTG).
All major components for the first instrument have been manufactured or are in the final stage of procurement. While integration and testing of LUCIFER 1 started in spring 2006 at the MPIA in Heidelberg, the cryostat for LUCIFER 2 has been sent to the MPE in Garching for system integration tests of the MOS-unit and testing of the mask cabinet exchange. The control electronics for the basic instrument has been manufactured, the MOS control electronics has been integrated and is being debugged. The MOS control software is under development by AIRUB. Fabrication and integration of components for LUCIFER 2 have started.
We present the concept and design of the interaction between users and the LUCIFER Control Software Package.
The necessary functionality that must be provided to a user depends on and differs greatly for the different user
types (i.e., engineers and observers). While engineers want total control over every service provided by the
software system, observers are typically only interested in a fault tolerant and efficient user interface that helps
them to carry out their observations in the best possible way during the night. To provide the functionality
engineers need, direct access to a service is necessary. This may harbor a possible threat to the instrument in
the case of a faulty operation by the engineer, but is the only way to test every unit during integration and
commissioning of the instrument, and for service time later on. The observer on the other hand should only have
indirect access to the instrument, controlled by an instrument manager service that ensures the necessary safety
checks so that no harm can be done to the instrument.
Our design of the user interaction provides such an approach on a level that is transparent to any interaction
component regardless of interface type (i.e., textual or graphical). Using the interface and inheritance concepts
of the Java Programming Language and its tools to create graphical user interfaces, it is possible to provide the
necessary level of flexibility for the different user types on one side, while ensuring maximum reusability of code
on the other side.
Lucifer VR is a virtually realized instrument that was build in order to allow improved pre-integration software tests,
training of observers as well as providing educational access. Beside testing the instrument hardware in combination with
e.g. a telescope simulator, software tests need to be done. A virtual instrument closes the gap between regression tests
and testing the control software with the integrated instrument. Lucifer VR allows much earlier tests and reduces the
amount of time needed to combine the software with the hardware. By modeling the instrument in a simulator, motion
times can be calculated very easily and the position of all instrument units can be traced. Especially when using complex
mechanisms like a MOS unit a virtual instrument makes software development less time consuming. Lucifer VR consists
of three parts; one for handling the communication, another to simulate the hardware and finally a part to visualize the
whole instrument in three dimensions.
The LUCIFER instrument is a near infrared spectrograph/imager with MOS for the Large Binocular Telescope.
Here we present the final software design, the interrelation of the software packages and the used hardware
architecture. The software package is completely running under Java using intensively its Remote Method
Invocation (RMI) mechanisms in a distributed system environment. The use of Java helped us to cope with a
small amount of available manpower for the SW development, providing many native built-in Java methods and
classes, which speed up the development process a lot. The control software will be finally installed on a Solaris
OS, hosted on a Sun Fire V880 server, which results from a specific hardware constraint. For testing purposes a
standard Linux environment is used. This shows another big Java advantage, the platform independency. The
"First Light" of LUCIFER 1 is estimated for summer/fall 2007, following LUCIFER 2 one year later.
In this paper we present the software development process and history of the LUCIFER (LBT NIR spectroscopic Utility with Camera and Integral- Field Unit for Extragalactic Research) multi-mode near-infrared instrument, which is one of the first light instruments of the LBT on Mt. Graham, Arizona. The software is realised as a distributed system in Java using its remote method invocation service (RMI). We describe the current status of the software and give an overview of the planned computer hardware architecture.