Goodman Goodman High Throughput Spectrograph

1. Information herein adapted from SOAR web pages. For complete information, please see http://www.soartelescope.org/observing/documentation/goodman-high-throughput-spectrograph/goodman-high-throughput-spectrograph Goodman Goodman High Throughput Spectrograph Goodman image of the barred spiral galaxy NGC 1300. This image is a color composite using the LRGB image processing method. In this image, the four images were taken in white light (no filter), and the BVR imaging filters. Image courtesy of B. Barlow. The Goodman Spectrograph is mounted inside the optical Nasmyth cage (cyan) at SOAR. The spectrograph is attached to the telescope at the silver Instrument Support Box (ISB) shown to the left. The black cylinder above the ISB contains the optical Nasmyth guider and the internal calibration lamp system. The NOAO Staff Contact for Goodman is: Dr. Sean Points: spoints@ctio.noao.edu Queries for SOAR specific information should be directed to: Dr. Steve Heathcote: sheathcote@ctio.noao.edu, or Dr. Sean Points: spoints@ctio.noao,edu

2. (Top): Spectrum of the Crab Nebula taken with Goodman using the 600l/mm Mid setup and a 1 arcsec slit. (Bottom): An expanded view of the Crab Nebula spectrum from 6400Å to 6800Å showing the Hα and [SII] λλ6716,6730 lines. Spectrum courtesy of J. Baldwin. The CCD is read by a Spectral Image controller through 1 amplifier. For 1×1 binning in spectroscopic mode, the CCD can be read in as little as ~20sec (400kHz readout) or as long as ~80sec (100kHz readout). For 1×1 binning in imaging mode, the CCD can be read in as little as ~25sec (400kHz readout) or as long as ~100sec (100kHz readout). Imaging Mode: In imaging mode the plate scale is 0.15”/pix and has a 7.2’ diameter field-of-view (FOV). Currently, UBVR 4-inch diameter filters are available in imaging mode. QE curve of the Goodman CCD. The actual measurements are represented as crosses. The solid line is a Legendre polynomial fit to the data. CCDs and Readout: The Goodman focal plane is imaged onto a 4k×4k Fairchild back-illuminated CCD. A plot of the QE of this CCD is presented below. Goodman Overview & Status: Optics: The Goodman Spectrograph is a Nasmyth-mounted optical imaging spectrograph using a Fairchild 4k×4k CCD with a scale of 0.15”/pixel. The Goodman optics are designed to transmit down to the atmospheric cutoff at 320nm, and includes lenses made of CaF2 and NaCl. The latter are the center elements of fluid-coupled triplets. We do not have direct transmission data for the Goodman optics, but we have a relative comparison with SOI in the UBVR broadband filters that we present below. Goodman Overview & Status (Cont): Spectroscopic Mode: In spectroscopic mode, Goodman is currently deployed with seven fixed long-slit masks with widths of 0.46, 0.84, 1.03, 1.35. 1.68, 3.0, and 10.0 arcsec. The slit masks are 3.9 arcmin long. Goodman is used with any of three (300l/mm, 600l/mm, and 1200l/mm) Volume Phase Holographic (VPH) gratings. A set of fixed observing modes for each grating and an example spectrum using the 600l/mm Mid setup are given below.