× 0. Palomar Observatory
M. Visitor Center (Museum)
H. Hale Dome

Hale Telescope Science and Instruments

The Hale Telescope is used every night for astronomical research thanks to a modern and evolving instrument suite. Hale Telescope instruments provide a wide range of imaging and spectroscopic capabilities in the optical and near-infrared parts of the electromagnetic spectrum. A significant fraction of Hale science activity is focused on spectroscopy—dividing starlight into its constituent colors. But Hale instrumentation also emphasizes adaptive optics capabilities that correct for distortions caused by Earth’s atmosphere—known as seeing, what makes stars twinkle—to deliver sharp images comparable to those produced by space telescopes from a ground-based facility.


The Hale Telescope uses a modern and evolving set of instruments at its multiple foci to enable a broad range of science investigations; while possible, very rarely do people directly look through the telescope at the night sky. Astronomers use the Hale and other large telescopes to study objects as close as other planets in our Solar System, to as far away as distant galaxies at vast—astronomers say cosmological—distances, and virtually everything in between.

Astronomers typically use the Hale to perform “spectroscopy”—dividing light into its constituent colors—using instruments at the Cassegrain focus below the telescope. There are two spectrometers—one at optical wavelengths similar to what our human eyes see (roughly 300 – 1000 nm wavelength), and one in the near infrared (from 1000 – 3500 nm wavelength). These spectrometers are typically used to infer the chemical makeup of individual nearby objects like planets and stars in the solar neighborhood, and to infer the distance to far-away objects through their “redshift” recession velocity. There are examples of both of these kinds of science results featured in the Visitor Center.

The Hale also has a so-called “adaptive optics” system that is mounted at the Cassegrain focus, and can measure and counteract distortions due to atmospheric turbulence. Children learn “twinkle, twinkle little star”; the Hale adaptive optics system suppresses that twinkle, and is used to produce images and spectra at the highest angular resolution the telescope is capable of providing. Such high angular resolution images can be used to study close binary stars, or even separately image the light from planets around other nearby stars.

Hale prime focus at the top of the telescope is where we typically place imaging cameras that can image wider fields. Prime focus cameras in optical and near-infrared wavelengths are often used to study ensembles of objects like star clusters, or to identify interesting sources in external galaxies. One novel prime focus camera can even generate video-like data, and is used to observe rapidly changing astronomical objects.

Observatory staff and astronomers operate and use the Hale Telescope from the data room here on the observing floor. Staff telescope operators support an observing program by operating the telescope at a control console, but also carefully monitor system conditions and weather that might represent a hazard to the telescope. Visiting astronomers (and those participating remotely through computer network connection) interact with the operators, and separately the instruments by computer control to make their observations. Staff support astronomers are experts on the Hale and its instruments, and often assist visiting observers in making the best use of the telescope and instrumentation.

Upcoming guided tour.