TELESCOPE MIRROR TESTING
xx TELESCOPE MIRROR
xx TELESCOPE TESTING
Test your telescope's optics. How to use a star at night (or an easy-to-build artificial star) to evaluate the performance of your telescope. ASTRONOMY Jul 1994 (v.22#7) pg. 56
How to grind, polish and test an aluminum mirror. SCIENTIFIC AMERICAN Nov 1963 (v.209#5) pg. 159
Mirror making class at Macalester College (St.Paul, Minn.) uses four specific goals to assure that students are successful in grinding a usable telescope mirror. The goals are described and the results of various Foucault tests are illustrated, along with the corrective action necessary. SKY & TELESCOPE Sep 1978 (v.56#3) pg. 249
How to make a pinhole light source for use with the Foucault test. The light source uses a single fiber from a fiber-optic bundle. SKY & TELESCOPE Nov 1978 (v.56#5) pg. 460
Description of an "almost" null test for parabolic and ellipsoidal mirrors. Includes a chart of minimum separation of mirror and knife-edge for various diameter mirrors (7.5 cm to 30 cm). SKY & TELESCOPE Jan 1979 (v.57#1) pg. 92
A simple test to determine if a telescope mirror has been fully polished prior to aluminizing. Also includes a tip on elutriating or washing polishing rouge. SKY & TELESCOPE Aug 1979 (v.58#2) pg. 180
The volume method for determining the radius of curvature of a deep concave lens or mirror, without need for a precision spherometer. SKY & TELESCOPE Jan 1980 (v.59#1) pg. 71
How to make precision pinholes for use in pinhole cameras, testing telescope mirrors, etc. SKY & TELESCOPE May 1981 (v.61#5) pg. 452
An improved method over the Foucault test shows the actual profile of a mirror's surface. Requires only the standard knife-edge tester. SKY & TELESCOPE May 1982 (v.63#5) pg. 519
A null test for Cassegrain secondaries. SKY & TELESCOPE Aug 1982 (v.64#2) pg. 188
Standardizing the Ronchi test pattern. SKY & TELESCOPE Mar 1984 (v.67#3) pg. 272
Point-diffraction interferometry made easy. How to make and use the point-diffraction interferometer (PDI) to test mirrors, lenses and other optical systems. SKY & TELESCOPE Feb 1985 (v.69#2) pg. 167
Foucault tester features a digital readout of the knife-edge's position accurate to 0.001". SKY & TELESCOPE Apr 1987 (v.73#4) pg. 439
Added Info SKY & TELESCOPE Sep 1987 (v.74#3) pg. 317
Analyzing a Foucault test. A computer program, written in BASIC, converts your zonal knife-edge measurements into actual highs and lows on the glass surface and deduces the "wavefront error". SKY & TELESCOPE Feb 1990 (v.79#2) pg. 195
Mirror testing for non-opticians. How to construct and use a Foucault tester based on the pantograph principle. This allows ultrafine motions of the knife-edge to be measured on an ordinary ruler. SKY & TELESCOPE Feb 1990 (v.79#2) pg. 214
Rayleigh water test, a simple way to check diagonal mirrors and optical flats. It utilizes the interference fringes which occur between glass and water. SKY & TELESCOPE Jul 1990 (v.80#1) pg. 89
A new Ronchi null test for mirrors. The Terebizh null test utilizes a circular grating that you make yourself. SKY & TELESCOPE Sep 1990 (v.80#3) pg. 312
Are today's 10" mirrors any good? Interferometer tests of 10" paraboloidal telescope mirrors from six commercial suppliers. SKY & TELESCOPE Nov 1990 (v.80#5) pg. 482
How to inspect the edge of your telescope mirror for chips, pits, scratches, and a "turned-edge" problem. How to mask these defects using black ink. SKY & TELESCOPE Dec 1990 (v.80#6) pg. 676
A Monte Carlo approach to the Ronchi test. BASIC computer program to compute a set of templates for various positions of the grating when performing the Ronchi test on a telescope mirror. SKY & TELESCOPE Apr 1991 (v.81#4) pg. 416
Setup and complete instructions for reflective null testing of a telescope mirror with the help of its own tube and diagonal. SKY & TELESCOPE Jul 1992 (v.84#1) pg. 85
A more accurate knife-edge formula is supplied for the Foucault mirror test. SKY & TELESCOPE Nov 1992 (v.84#5) pg. 574
Build your own laser interferometer to test optical lenses and mirrors. SKY & TELESCOPE Jan 1994 (v.87#1) pg. 94
Knife-edge testing with a video camera. A video camera and paper masks attached to the screen of a TV (instead of the mirror) are the secret to this multiple-zone Foucault test procedure. SKY & TELESCOPE Apr 1994 (v.87#4) pg. 92
Added Info SKY & TELESCOPE Jul 1994 (v.88#1) pg. 103
The double-pass knife-edge test. Build an improved version of the Foucalt tester which bounces the light off the telescope mirror two (or more) times, thus magnifying any surface errors so they can be measured more easily. SKY & TELESCOPE Aug 1995 (v.90#2) pg. 86
Zonal test tolerances. A description of the Lord Rayleigh method of describing mirror resolution and how it may differ from other methods. TELESCOPE MAKING #2 Winter 1978 pg. 8
Stalking the wild paraboloid. Description of graphical method to calculate the way in which a homemade mirror will perform in order to determine if more figuring (parabolizing) is needed. TELESCOPE MAKING #6 Winter 1979-80 pg. 20
How to make focograms. Focograms are photographs of a mirror being subjected to the Foucault test (knife edge test). TELESCOPE MAKING #6 Winter 1979-80 pg. 25
Build your own Foucault tester (knife-edge tester) and adjustable mirror stand to hold the mirror being tested. TELESCOPE MAKING #6 Winter 1979-80 pg. 28
How to perform the wire test method for surface testing and evaluation of large telescope mirrors. It is an alternative to the Foucault test. TELESCOPE MAKING #6 Winter 1979-80 pg. 40
Description of the Macalester College "Four goal system" for making a first telescope mirror. Includes extensive discussion of a Ronchi-type test, including three pages of photos showing test patterns for various mirrors. TELESCOPE MAKING #9 Fall 1980 pg. 18
A reflecting null test for paraboloids. How to use the Waineo Reflecting Null Test, a version of the Hindle test. Includes diagrams and information on building the test jig. TELESCOPE MAKING #11 Spring 1981 pg. 12
Tip: Use an ordinary Ronchi screen instead of a knife edge when making the Dall null test on a mirror. TELESCOPE MAKING #11 Spring 1981 pg. 19
Making and using a slitless (single-knife) Foucault tester with a movable stage sliding on "Teflon". TELESCOPE MAKING #22 Spring 1984 pg. 16
Added Info TELESCOPE MAKING #24 Fall 1984 pg. 43
Foucault knife-edge testing for concave mirrors. Includes a computer program for "reducing" the knife-edge readings to produce an accurate wave rating of the mirror's surface. TELESCOPE MAKING #23 Summer 1984 pg. 8
Tips on using the Texereau zone testing method for checking telescope mirrors. TELESCOPE MAKING #24 Fall 1984 pg. 42
A simple practical light source for the Foucault test. Uses a tiny flashlight bulb powered by two AA batteries. TELESCOPE MAKING #30 Summer 1987 pg. 18
A new test for figuring convex hyperbolic Cassegrain secondaries against their primaries. TELESCOPE MAKING #31 Winter 1987-88 pg. 24
Testing paraboloidal mirrors. What every telescope maker should know about testing telescope optics. Both the "star test" and the Foucault Test are described. TELESCOPE MAKING #32 Spring 1988 pg. 4
Added Info TELESCOPE MAKING #33 Summer 1988 pg. 6
Added Info TELESCOPE MAKING #34 Fall 1988 pg. 3
Added Info TELESCOPE MAKING #35 Winter 1988-89 pg. 3
Added Info TELESCOPE MAKING #36 Spring 1989 pg. 3
Added Info TELESCOPE MAKING #37 Summer 1989 pg. 44
Added Info TELESCOPE MAKING #38 Fall 1989 pg. 3
Added Info TELESCOPE MAKING #39 Winter 1989-90 pg. 3
Efficient mirror testing. Topics include: (1) Coarse testing using the Everest shadow test. (2) Figuring: Shadow location. (3) Modified Millies-Lacroix reduction method. (4) K1*K2 method of analyzing a mirror surface. (5) Final testing. TELESCOPE MAKING #33 Summer 1988 pg. 40
Added Info TELESCOPE MAKING #34 Fall 1988 pg. 38
Making precision paraboloids is easier with the Ross Null Test. Detailed instruction of a method for null-testing large paraboloidal mirrors. TELESCOPE MAKING #39 Winter 1989-90 pg. 28
Correction TELESCOPE MAKING #40 Spring 1990 pg. 3
Added Info TELESCOPE MAKING #40 Spring 1990 pg. 3
Correction TELESCOPE MAKING #41 Summer 1990 pg. 3
Added Info TELESCOPE MAKING #43 Winter 1990-91 pg. 3
Tip on making a focogram (photograph) of an aluminized mirror in order to reveal information on surface smoothness. Includes information on placement of knife-edge (Foucault) tester, mirror reduction process, Millies-Lacrois graphs, etc. TELESCOPE MAKING #40 Spring 1990 pg. 4
The nuances of optical testing. A thorough overview of the various testing methods employed on telescopes and how to understand and compare the results. TELESCOPE MAKING #41 Summer 1990 pg. 12
Correction TELESCOPE MAKING #42 Fall 1990 pg. 3
A secure mirror holder for workshop testing is made from PVC plastic pipe and some perforated hardboard. TELESCOPE MAKING #43 Winter 1990-91 pg. 30
Variation on the knife-edge Foucault test uses a red glass filter or red/blue acetate filters. TELESCOPE MAKING #43 Winter 1990-91 pg. 44
Comments on the accuracy of testing optical systems with a star and Ronchi grating. TELESCOPE MAKING #43 Winter 1990-91 pg. 45
Added Info TELESCOPE MAKING #44 Spring 1991 pg. 5
Computer program written in Turbo Pascal which makes the setup calculations for performing a Ross Null test on a parabolic mirror. TELESCOPE MAKING #45 Summer 1991 pg. 38
Tip on using a glass slide (half covered with candle soot) in place of the knife edge in a Foucault test. TELESCOPE MAKING #46 Winter 1991-92 pg. 4
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