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Adaptive optics laser guide star systems perform atmospheric correction of stellar wavefronts in two parts: stellar tip-tilt and high-spatial-order laser-correction. The requirement of a sufficiently bright guide star in the field-of-view to correct tip-tilt limits sky coverage. Here we show an improvement to effective seeing without the need for nearby bright stars, enabling full sky coverage by performing only laser-assisted wavefront correction. We used Robo-AO, the first robotic AO system, to comprehensively demonstrate this laser-only correction. We analyze observations from four years of efficient robotic operation covering 15,000 targets and 42,000 observations, each realizing different seeing conditions. Using an autoguider (or a post-processing software equivalent) and the laser to improve effective seeing independent of the brightness of a target, Robo-AO observations show a 39+/-19% improvement to effective FWHM, without any tip-tilt correction. We also demonstrate that 50% encircled-energy performance without tip-tilt correction remains comparable to diffraction-limited, standard Robo-AO performance. Faint-target science programs primarily limited by 50% encircled-energy (e.g. those employing integral field spectrographs placed behind the AO system) may see significant benefits to sky coverage from employing laser-only AO., Accepted for publication in The Astronomical Journal. 7 pages, 6 figures

The Echelle spectrograph operating at Vainu Bappu Telescope is a general purpose instrument designed for high-resolution spectroscopy. It is being considered for precision Doppler measurements without altering the existing design and basic usage. However, the design level limitations and environmental perturbations are a major source of instability and systematic errors. As a result, a small Doppler signal in the stellar spectra is completely swamped by the large and uncontrolled instrumental drift. We discuss some of the remedial measures we took to improve the radial velocity performance of the spectrograph. We show that an autoguider assembly has greatly reduced the mechanical jitter of the star image at the fiber input, making the illumination of the spectrograph slit at the other end stable. We have also installed an iodine absorption cell to track and eliminate the instrumental drifts to facilitate precision radial velocity observations. Furthermore, we have developed a generic algorithm that uses iodine exposures to extract the stellar radial velocities without the need for the complex forward modeling. Our algorithm is not accurate to the level of traditional iodine technique. However, it is convenient to use on a low-cost general-purpose spectrograph targeting a moderate radial velocity (RV) precision at a few 10 to 100 ms − 1 level. Finally, we have demonstrated the usefulness of our approach by measuring the RV signal of a well-known short-period, planet-hosting star.

The Carl Sagan Observatory is a new project for a remote observatory that will be built at the summit of Cerro Azul (a 2480 m mountain located near Magdalena. Sonora, México). It will include one 55 cm and four 14 cm telescopes. The 55 cm telescope will be dedicated to supernovae research. One of the 14 cm Maksutov telescopes will be used as an autoguider for the stellar observations. The other 14 cm telescopes will feature different narrow band filters that will be used for solar research. The observatory will be controlled from the campus of the Universidad de Sonora in Hermosillo, Sonora, México (~ 200 km from the site). A prototype of the observatory building has been built on campus and first light is expected by the end of May of 2001. We expect to have an operating mountain observatory by the end of 2002. Some of the unique technical aspects of this observatory, which we believe can be a model for future small telescope observatories are discussed in this work.

Measurement of stellar radial velocities (RV) is one acknowledged approach for planetary-search and asteroseismology programs. We study the incomplete scrambling action of a fiber feeding a spectrograph, which leaves RV errors at a level of few m/s. Observations realised with the ELODIE fiber-fed crossed-dispersion spectrograph at the 193-cm telescope of Observatoire de Haute-Provence (OHP) are presented. A fiber-locked autoguider (called FLAG) has been specifically built to reduce the stellar-beam geometrical fluctuations within the spectrograph. With FLAG, the fiber-input plays the role of guiding detector. Automatic focusing is also accomplished by the system. The design and performance characteristics of the instrument tested at the 152-cm telescope of OHP are reviewed here.

Spectronebulagraph, an automated observation system of tridimensional spectroscopy with a long slit spectrograph, is now in operation at the 188 cm telescope of the Okayama Astrophysical Observatory. This system is based on the local area net work of personal computers which control the telescope, the autoguider, the Cassegrain spectrograph and its CCD camera. Effects of variable atmospheric transmission during scans of target objects are removed by performing a set of two orthogonal scans and the data processing.A new spectrograph is now under development for the telescope. This instrument has multiple modes for tridimensional spectroscopy, i.e., the filter imagery mode, the imaging Fabry-Perot interferometer mode, a slit spectrograph mode for Spectronebulagraph, and the microlens array spectrograph (TIGER) mode. For the last mode, a dual preoptics to get simultaneously the sky background is introduced and achromatization of the microlenses is tried. This project is a part of development of a prototype instrument for the SUBARU telescope.

The "Photon Collider" uses a compact array of four off axis autoguider cameras positioned with independent filtering and focus. The photon collider is two way symmetric and robustly mounted with the off axis light crossing the science field which allows the compact single frame construction to have extremely small relative deflections between guide and science CCDs. The photon collider provides four independent guiding signals with a total of 15 square arc minutes of sky coverage. These signals allow for simultaneous altitude, azimuth, field rotation and focus guiding. Guide cameras read out without exposure overhead increasing the tracking cadence. The independent focus allows the photon collider to maintain in focus guide stars when the main science camera is taking defocused exposures as well as track for telescope focus changes. Independent filters allow auto guiding in the science camera wavelength bandpass. The four cameras are controlled with a custom web services interface from a single Linux based industrial PC, and the autoguider mechanism and telemetry is built around a uCLinux based Analog Devices BlackFin embedded microprocessor. Off axis light is corrected with a custom meniscus correcting lens. Guide CCDs are cooled with ethylene glycol with an advanced leak detection system. The photon collider was built for use on Las Cumbres Observatory's 2 meter Faulks telescopes and currently used to guide the alt-az mount.

In this paper we describe the hardware and software architecture of the Automatic Imaging Telescope (AIT), recently developed at the Perugia University Observatory. It is based on an existing 0.4 m telescope which was transformed into an automatic device. During the night, all the observatory functions are controlled by two PCs in an unattended mode. The system is equipped with an autoguider and the software was designed to allow the automatic reduction of the data at the end of the night. Since October 1994 the AIT has been collecting a large amount of BVRcIc data for about 30 blazars.

Spectro-nebula graph (SNG), a tridimensional-spectroscopic system, has been developed as a versatile observation system attached to the Cassegrain focus of the 1.88 m telescope at the Okayama Astrophysical Observatory. Tridimensional spectra, i.e., so-called data cubes, are obtained by sweeping the telescope in the direction perpendicular to the slit of a spectrograph step by step. From the data cube, various monochromatic images can be extracted by data processing. SNG consists of four devices, i.e., the telescope control system, the autoguider, the spectrograph, and the CCD camera, which are distributed on a personal computer network. The control software for SNG performs cooperative control of four devices in an automated fashion according to a programmed sequence of procedures. Some observational results taken with SNG are shown for 3C 120, NGC 4449, and NGC 3646.

A microprocessor-based telescope autoguider is described that uses the signal from an existing field acquisition TV camera to generate tracking-error information for an optical telescope. The guider can accept input from any black and white video camera conforming to NTSC (EIA RS-170) standards. This autoguider has been used for several years on the Shane 3-meter telescope at Lick Observatory.

The automatic offset guider at the prime focus of the AAT is described. A description of the guider and its organization in the telescope's computerized drive system is followed by the initial results obtained with it. Key words: autoguider - main-beam guidance - telescope instrumentation - computerized guidance

We present here some of the techniques used to automate many of the observing tasks on the 0.91-meter telescope of the Goethe Link Observatory. A description of the method used to calculate the dome position for a telescope which is mounted asymmetrically is included. We also give details of a novel autoguider. This autoguider uses a digitized television image of the star field to enable the microcomputer to generate error signals from a centroid calculation.