The Hamilton spectrograph is optimized for high resolution, broad spectral coverage, and high throughput. Its CCD detector takes advantage of the echelle format by simultaneously recording the multiple spectral orders produced.

The Hamilton's echelle grating is ruled for maximum efficiency at high blaze angles. Most of the light energy is concentrated in high (and highly dispersed) spectral orders. The orders, which overlap one another after being formed at the grating, are separated by the cross-dipersing prisms. The resulting spectral format consists of multiple, nearly parallel strips of spectra. (The orders are, in fact, somewhat curved, and are slightly "fanned out" with respect to one another.)

In the illustration below, order numbers are given along the left edge and the corresponding central wavelengths on the right. Longer wavelength orders are at the top and the wavelength in a given order increases to the right as displayed in the Vista image window of the Lick data-taking system.

The length of each order, as drawn, represents its free spectral range (fsr), that is, the wavelength range of a given order not repeated in adjacent orders. The fsr increases towards the red, while the dispersion and order separation increase towards the blue. At the red extreme, order 57 has a fsr of about 176 Angstroms at a dispersion of 5.61 A/mm; at the blue end order 163 covers 21.5 Angstroms at 1.96 A/mm. The fsr's and dipersions of all orders are given in the Table of Orders.

The Hamilton's useful wavelength range is limited to about 1-micron in the red by CCD performance; CCD efficiency, spectrograph optics, and atmospheric blocking constrain the blue end at about 3500 Angstroms. In practice, however, the rapid decrease of throughput at the blue end limits observations blueward of about 3800 Angstroms to all but the brightest, bluest sources.