Astro 920 / Fixing the WIYN Bench Spectrograph



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Spectrograph Geometry
Input Beam Profile
Throughput Budget
WIYN Simulator
Off-axis Collimator

Topics covered in this course


WIYN Simulator

From WIYN Facts page, the following relevant numbers are derived:

The primary has a 17.1% central obstruction from the baffle for the tertiary. This comes from the ratio of diameters (squared) of the primary (DP = 3498.85 mm) and baffle (DB = 1446.2 mm). The baffle diameter is larger than the secondary diameter (DS = 1200 mm), and so the baffle is the effective limit for the central stop for an on-axis source.

For the f/6.3 beam at the WIYN, MOS, and folded-Cass ports, 17.1% of a uniform beam corresponds to f/15.2. Hence a beam which simulates the true beam for these ports should consist of a uniformly filled beam (a cone with uniform cross-sectional surface-brightness) for apex angles between 7.5 deg (f/15.2) and 17.6 deg (f/6.3).

modified: Dec 02, '02