Jan van Gastel's Astronomy links

Go to: main menu

Go to: A 20 inch f/3.6 computerized Dobsonian Go to: Building a trilateral computerized 20 inch f/5 Dobsonian
Go to: Project: five 12 inch lightweight Dobsonians Go to: Motorizing a 12 inch lightweight Dobsonian
Go to: 20 inch telescope Go to: Equatorial platform Go to: Scotch mount Go to: Binocular mount Go to: Dobsonian tips Go to: Bending aluminium Go to: Collimating Go to: Making a Krupa collimator Go to: Dotting the primary
Go to: A ballhead type telrad/finder mount Go to: Mirror making log of 300 mm mirror Go to: Astronomy
Go to: Using digital finder charts at the eyepiece Go to: Astronomy links Go to: Building a spherometer
Go to: Building a Bath interferometer Go to: A Foucault-Ronchi-Lyot tester Go to: Building a mirror making machine
Go: Home

Emailadres: Jan van Gastel

Amateur telescope making

Sterrenwacht Almere (only in Dutch)
Sterrenwacht Almere op facebook(only in Dutch)
Otte Dobsonian Telescopes and Binocopes
Arie Otte's Dobson Optimalisatie Service (only in Dutch)
The 'Celano Telescope Controller' and other motorizing hardware
The ATM mailinglist archives
Don Peckham's Tensegrity String Telescopes
Andre Heijkoop: 24”ť f3.7 Encased GoTo Dobson
Mel Bartels: a 10.5" f/2.7, 2.4 degree field of view Telescope
Mel Bartels: a 6 inch F/2.8 telescope
Mel Bartels' 13 inch 'zip' Dob, a folding telescope
Mel Bartels: Folding (and sliding) Telescopes
Carl's Astronomy page: Amateur Telescope Making
Steve Houlihan's TriBino
Martin Maters Astronomy website
Uwe Glahn's 27" Dobsonian
ScopeX, ATM in South Africa
Berthold Hamburger: Telescope Making, Optics and Astronomy
Eric Royer's 14 Inch binocular telescope
Chris Forder's ultra portable 10" travelscope
German ATM wiki, with software
Jerry Oltion: a simple star-test telescope
Rex Kindell's circle cutter (!!)
The Alt-Az Initiative. Publications, references and links
Gary Seronik's ATM pages
Dan Gray's 28 inch motorized string Dobsonian telescope
Ross Sakett: Amateur telescope making (single pole Dobsonians)
Jim Miller's 18" f/4 lightweight telescope
Bruce Mills-'Scope Stuff
Sterrenwacht Almere
Stathis Kafalis' website
Marty's ATM pages Fork mounted Newtonians (French site)
Oldham Optical: Basic Telescope Design
ATM-site mirror site (by author)
Dale Kellers ATM pages
Mel Bartels: Telescopes and telescope making
Mel Bartels:Trilateral mounted 20 inch f/4.8 newtonian
Mel Bartels: A smaller upper cage
Company Seven: Astronomical formulae/astronomical formulae for telescopes
Lockwood Custom Optics
AstroSystems products
Antares Optics
Very nice telescope designs (Luc Arnolds pages)
Pierre Desvaux's 300 mm travel Dobson
David Vernet's 600 mm f/3.3 Dobsonian
Robert Houdart's 110 cm (43.3") Dobsonian telescope
Arjan te Marvelde's ATM pages
Philippe Mollet: Bouw zelf een telescoop
Huygens Optics
MCM Spécialiste du traitement Optique (France)
Tom Conlin: Plain talk on SudiBalls
Mel Bartels' Oregon starparty 2015 walkabout

Determining Mirror quality

Very interesting dicussion about TDE, zones and other defects (long thread)
L.C. Roberts Jr et al.: Is that really your Strehlratio?
Mel Bartels: rating mirrors
Mel Bartels: The Contrast Controversy
Sebastien Debruyne, David Vernet: Optical Quality and Large Diameters: Check before to buy!
Vladimir Sacek: Effect on Strehlratio of secondary mirror defects
S. Koehler: Five mirrors having all a 0.08 lambda RMS error but different P-V
S. Koehler: five mirrors having all a 1.0 lambda P-V error but different RMS
R.F. Royce: Move over P-V and make way for Strehl
John Nichol: Optical Standards
Peter Karboulonis (Opticstar): Measuring Optical Quality
Obsession Telescopes: Optics (scroll down to 'Definitions')
Wolfgang Rohr: Mirrors with different amounts of roughness

Mirror making

General information, techniques, grinding, polishing
and figuring tools etc.

Video course: Making a mirror on the Mirror-o-Matic Mirror Making Machine
Gordon Wait's mirror making video's
How to use a polishing machine: basic principles (Zambuto method from halfway the page)
Martin Cibulski: Mirror Polishing Simulation
Mel Bartels: CMP (Chemical Mechanical Polishing) or 'polishing is a chemical mechanical process'
The Mirror-o-Matic: Machines, Documentation, Information for ATM's
Berthold Hamburger's Mirror-o-Matic machine, with video's
Polishing machines
Waite Research. Links to mirror making video's
Stellafane: Amateur Telescope making; detailed Mirror Making information !!!
Making a 71 cm f/3 mirror (in German)
John D. Upton: Making a (sub-diameter) Tile-on-Plaster Tool
Mel Bartels: the joy of making mirrors
Mel Bartels: large, thin mirror grinding
Bob May: So you really want to build a Telescope Mirror
Bob May: 'Making a Dental Stone Tool' method of grinding of a mirror
Mike Lockwood: articles about mirror making and mirror making equipment
Stathis Kafalis: Spiegelschleifen-ein Volkssport (in German)
Stathis Kafalis: Spiegelschleif workshop-Materialbestellung (in German)
Newport Glass: table of grit sizes
Newport Glass: Optical surfaces (about scratch and dig specifications)
Scratch and dig numbers
Max Stone World: Reciprolap machines
His Glassworks: grinding and polishing with a reciprolap (video)
Peter de Baan: Mirror making with circular strokes

Foucault test and testers
Jerry Oltion: Pitch hardness tester
Hans-Heinrich Wenk: VCS, Virtual Couder Screen
Michael Peck: A semi-automated Foucault test
Urania (Belgium): De Foucaulttest (very good site in Dutch!)
Stathis Kafalis' Foucault Tester
Martin Brückner's Foucault Tester
Gunnar Overbeck's Foucault tester
Nils Olof Carlin's Mirror Zone Calculator
Andreas Reifke: Foucault Test Analysis (download page for program)
James Lerch's FigureXP download (Another Foucault analysis program)
Bob May: Foucault Testing and testers
Stellafane: Data reduction software
Mauritz Andersson: Holographic Foucault Null Test
CloudyNights: Holographic Foucault Null Test
building a Foucault tester and XY-table

The Bath interferometer (and how to build one)
Michael Koch: Optical Formulas, Interferometry
Dale Eason: how to set up the Bath interferometer (YouTube video)
Vladimir Galagoza's Bath interferometer page
Airylab interferometric test reports (in French)
Wolfgang Rohr: Bath interferometer
Wolfgang Rohr: Strehl versus Micro-Rauhheit
Wolfgang Rohr: Coma abziehen (in interferometric testing)
Michael Peck: Interferometry, mathematics, algorithms, and data
Michael Peck: Optimal separation of mirror and instrumental aberrations
Stephen C. Koehler: Milligan 12.3" (Part I), Interferometry Comparison
Startests - compared to Interferometric Results
Steven Koehler: Graphics showing which f/value-aperture combination is testable with bath interferometer
Interferometrie und optische Tests (comparisons)
William Beaty: WTF is coherent light (about laser light)
Vladimir Sacek: Zernike aberrations
SPC900 webcam uncovered (how to disassemble it)
'Easy' RAW mod for Philips and Logitech Webcams
Lots of info about the Bath interferometer on CloudyNights
Ceravolo: Interferometry and Telescopes
James C. Wyant, articles about optical testing

Lyot test (phase contrast test)
Astrosurf: Le test de Lyot par contraste de phase
Testez vos optiques : Le contraste de phase

Other tests
Mel Bartels: Star testing a telescope
A Digital Readout Caustic Tester
Bill Thomas: The Slit Image Test (SIT)
Peter Koek: Waineo Null Test
The ATM's workshop: Testing the Quality of Polish
The ATM's workshop: The matching Ronchi Test
Surface roughness. Measurement, analyses, specification
The Roddier test (in French)
Le test de Roddier (another Roddier test article)
Airylab test reports
John Sherman: The spot test
Mel Bartels: Artificial star distance calculator
Nils Olof Carlin: The spherical aberration of a paraboloid mirror for objects of finite distance


The 'Celano Telescope Controller' and other motorizing hardware
Mel Bartels: Computer operated telescopes
Eric Green: Computerizing a 16" Starmaster
Dale Eason: Mounting stepper motors
Rex Kindell: Nylon wormgears
Ben Davies' scope-drive manual

Telescope optics

Vladimir Sacek: Amateur Telescope Optics
James C. Wyant's optics page
Bentec Hyperaspherical Optical Surfaces - free software and polymer optics manufacturing
Phase Contrast
Paul Laughton: Telescope Performance Factors Central Obstruction and Wave Error
David Whysong: A calculation of Airy disks for various telescopes
Rene Pascal: Diffraction Patterns of Obstructed Optical Systems
Astrooptik und Messtechnik (German)
R.F. Royce: Precision optical components
Figuring a Paraboïdal mirror by thermal predistortion
Ivan Krastev: MODAS; Modern Optical Design and Analysis Software
Massimo Riccardi: ATMOS, Amateur Telescope Maker Optical Design and Analysis Software
Mauro Da Lio: How different apertures behave under the same seeing
Mauro Da Lio: Aperture masks and seeing
Thierry Legault: what are the effects of obstruction
Robert Ariail: Cleaning mirrors with collodion

Mirror cooling

Brian Greer: Understanding thermal behaviour in newtonian reflectors
Antoon Maeseele: Cooling a telescope mirror
Brian Greer: Using fans with Newtonian telescopes
Robert Houdart's mirror cooling calculation program
Anthony Wesley: Cooling a 10" Newtonian
Arjen te Marvelde: Modelling thermal mirror deformation
Mauro Da Lio: Boundary layer seeing
Mauro Da Lio: Yet another method for cooling mirrors
Mauro Da Lio: mirror deformation as cuased by cooling the mirror
Cloudy Nights discussion about mirror cooling

Mirror supports

David Lewis: PLOP; mirror cell calculator
Robert Houdart: Mirror edge support calculator
Frédéric Géa: Astatic primary mirror supports
Frédéric Géa: Piano wire lateral primary mirror supports
Arjan te Marvelde: Mirror cell induced astigmatism
Nils Olof Carlin's "Update pages" with the double sling lateral support
Nils Olof Carlin: Mirror edge supports. A case study of the sensitivity to forces out of the mirror plane
Robert Houdart's 54 points mirror cell for a 43.3" Dobsonian


Mel Bartels: Telescope Newtonian Diagonal Offset Study
Astrowiki artikel over het collimeren van een Newtontelescoop (in Dutch)
Jason D.: The collimation curse of the ROC
Steve Smallcombe: Rear View Barlowed Laser Collimation
Brian Greer: Adventures in collimation
David C. Nicholls: The 'Krupa' collimator revised
Nils Olof Carlin: Collimating a newtonian telescope
Nils Olof Carlin: Collimation with a barlowed laser (S&T artikel)
Nils Olof Carlin: Collimate your Newtonian Reflector
Nils Olof Carlin: Colimating with a holographic laser
Nils Olof Carlin: The YACHT, a new collimating tool.
Nils Olof Carlin: Some collimation myths (strongly recommended)
Nils Olof Carlin: The autocollimator
Nils Olof Carlin: The autocollimator and its reflexions
Cloudy Nights discussion about improved (2-hole) autocollimator
Collimating procedure with 2-hole autocollimator
Mel Bartels: Optically Aligning Newtonian Optics
Thierry Legault: The collimation
Adam Perkins: Making a sight tube for collimation
Vic Menard's addendum to his 5th ed. of 'New Perspectives on Newtonian collimation'
Scott McCluney: a Treatise in Newtonian collimation
Collimating a laser collimator
A Procedure for Collimating Ritchey-Chrétien and Other Cassegrain Telescopes
Collimation of a Schmidt Newtonian
Collimating a Schmidt-Cassegrain telescope
Don Pensack: Passive Tool Collimation and the Newtonian
Collimating a refractor
Article (in German) in which the collimation of a Kutter telescope is described
Article about a Kutter, with information about collimating it with a laser

Newtonian telescope design pages and programs

Download of H. Otterstedt's Newton design program My Newton
Online diagonal sizing program, by Mel Bartels
Gary Seronik: Sizing Up the Newtonian Secondary
Arjen te Marvelde: Vignetting in a Newton telescope
Newtonian design planner, by Jim Fly
Dale Keller: ATM newtonian design software
My spreadsheet for calculating secondary size and illumination of FOV (English)
My spreadsheet for calculating secondary size and illumination of FOV (Dutch)

Selfmade focusers

Marco Miglionico: 1.25in Aluminium Crayford Focuser
My first selfmade Crayford focuser
My second selfmade Crayford focuser
Jim Sapp: An Easy to Make, Single-piece Crayford-type Focuser
Crayford focuser
Arjan te Marvelde: Crayford focuser (scroll halfway down the page)
Steve Bedair: Homemade Crayford Style Focuser
Nils Olof Carlin: Updating a telescope; the focuser
Focuser construction
Keith Lohmeyer: Red 10" Dob
Dave Smith's Crayford focusers (click 'Crayfords')
Pieree Desvaux's focuser (scroll down to almost end of page)

(Making) spiders/secondary supports

Jack Brosens: Spikes en Spiders (in Dutch)
Steve Houlihan's wire spider
Vladimir Sacec: Spider diffraction and apodization
Richard Dunna: ALT-AZ secondary support for newtonians
Steve Swayze: How to build a spider for your telescope
Dick Suiter: Spider van thickness and diffraction
J.E.Harvey and C. Ftaclas: Diffraction effects of telescope secondary mirror spiders on various image-quality criteria
Arjen te Marvelde's minimalist spider design
Arjen te Marvelde's wire spider calculation spreedsheet
Mark Cowan's 3-vane wire spider
Mark Cowan's wire spider, for his 14 inch trilateral telescope
Mel Bartel's wire spider
The silent observer's wire spider tensioners
Harro Treur's wire spider (with banjo string tensioners)
David Steinhauer: a wire spider for a small telescope
Jens' wire spider and magnetic secondary attachment (scroll down a little)

Equatorial platforms

Clearsky Observer: siderial tracking platform
Yahoogroup Equatorial Platforms (very much, very good information)
Kurt Maurer's VNS platforms
David Shouldice: A Low Profile Equatorial table (VNS platform)
Reiner Vogel's equatorial platform pages (VNS platform)
Ulli Vedder's VNS platform
Hans Aspenberg's equatorial platform (VNS platform)
David Gilbank's VNS equatorial platform
Dob-Tracker III platform (VNS platform)
Howard Banich's equatorial platforms
Fred van Gestel's equatorial platform's
Web of Dave: Equatorial platform
Birchardville Observatory: What is an Equatorial Platform?
André Heijkoop’s equatorial platform
Nils Olof Carlin: An equatorial platform for a 6" f/5 travelscope
Robert Duvall: An evolved poncet platform
Aluminium platforms
Nils Olof Carlin: Stepper motor driver circuit (mainly) for driving equatorial platforms
Don Peckham's platform
Equatorial cradle
The Hiss Drive
The McCreary Mount
Building the McCreary Mount
Tom Fangrow: A 'hiss drive' platform
Plat-forme equatoriale (a very low and lightweight platform)
Daniel Restemeier's platform (German)

Scotch mount (Barndoor tracker)

Robert Duvall: Barndoor tracker
Brian Rachford: A low tech barndoor drive
Jeff deTray: Barndoor camera mount
Stephen Tonkin: a hand-driven Scotch mount
Stephen Tonkin: a better barndoor (a double-arm Scotch mount)
Evan Williams: a precision double arm drive
Gary Seronik: a tracking platform for astrophotography
Steve Irvine's barndoor mount
Ulhas Deshpande: Selfbuilt Astrotracker Mk2

Stepper motors and circuits

LiniStepper v1; Microstepping Stepper Motor Driver Kit
D.W. Jones: Control of stepper motors
Robert Duvall's Stepper motor drive circuit
Stepper motor controller: another drive circuit with parts list
Astro-electronics about stepper motors (commercial)
Nils Olof Carlin: Stepper motor driver circuit (mainly) for driving equatorial platforms

Binocular mounts

Rex Kindell's paralellogram bino mount
Dennis Simmons' paralellogram bino moiunt
Florian's Binocular Viewing Accessories: Bino-Mirror
Gary Seronik: Gary’s Easy-Go-Round Binocular Mount


Mel Bartels: Observing dark nebulae
Martin Maters: The deepsky visibility indicator
The Sky Quality meter
Alvin Huey's Observing guides (Arp galaxies, Abell planetaries and Hickson groups)
Damian Peach: An examination of the effects of optical aberrations, obstruction and seeing on real Planetary images
Uwe Glahn: Deepsky-visuell.de
Rony de Laet: My pencil sketches
Website Wolfgang Steinicke
Website Uwe Glahn (in German)
Sterrenkunde; website van Bob Hogeveen
Jeffrey Bout: Nederlandse Deepsky dag
Digitized Sky Survey
The Coldfield Observatory: Top 200 most beautiful Double Stars
Albert Highe's observing projects: galaxy clusters
Damian Peach: the Pickering Seeing Scale Nice star animations!
Don McCready: The moon illusion explained
Robert Houdart's telecopic limiting magnitude calculator
Ben Sugerman's (naked eye) limiting magnitude calculator
Estimating Limiting Magnitude
Brian Skiff: How dark can the nightsky get?
Brian Skiff: Photometry of M57 field stars
Bradley E. Schaefer: Telescopic limiting magnitudes
Nils Olof Carlin: About Bradley E. Schaefer: Telescopic limiting Magnitudes (1990) Nils Olof Carlin: Another interpretation of the data from Blackwell, H R (1946): Contrast Thresholds of the Human Eye.
Nils Olof Carlin: Estimating the limiting magnitude of binoculars
Roger N. Clark: Visual astronomy of the nightsky
Dave Gill: Through an Eyepiece Darkly
Mel Bartels: Visual astronomy, an investigation into the visual Optimum Detection Magnification
José R. Torres: Prediction of visisbility software
The night sky in the world: maps of artificial night sky brightness
'Blue Marble' Navigator: light polution in Europe
Light polution (part of) Western Europe 2012
Brian Rachford: A different way of looking at globular cluster magnitudes
Brian Rachford: A different way of looking at galaxy magnitudes
Tony Flanders: Surface brightness
Tony Flanders: Aperture versus Light Pollution.
The Bortle Dark-Sky Scale
Downloadable light pollution maps for European countries
Chris Rock: Starparty - A Documentary (movie)
Love The Night Sky
A Guide On Looking Through Binoculars For Stargazing

Interesting homepages

Astro hollyday at Stellarzac, France: 800 mm and 1000 mm telescope!
Matthijs' astronomy site
Astroforum (Dutch)
Astronomy Picture of the Day (APOD)
Norbert Schmidt's Astropages
Website Niels Grobben
Visual Deep Sky Sterrenkunde, in Nederland en Belgie
Sterrenwacht Ecliptica
Kiminori Ikebe: Visual Observation of Deep-Sky Objects
Homepage werkgroep Maan en Planeten (Dutch)
Astrolab IRIS (Belgium)
Starnights homepage (Dutch)
Steve Swayze's homepage
Stichting De Koepel (Dutch)
Ole's astronomy site
Paul's Astropage
Luc Arnolds homepage


Orbit diagrams
Orbital elements


Dutch Meteor Society Website
International Meteor Organization


Marco Langbroek: Sattraccam, leiden (blog)

The moon

Patrick Chevalley and Christian Legrand: Virtual atlas of the moon: free software.
Digital lunar orbiter photographic atlas of the moon
Astronomical picture of the day index: earth's moon
The moon, by Bill Arnett

Astronomy software and catalogs

Martin Maters: The deepsky visibility indicator
The NGC/IC project
Skyview: the internet's virtual telescope
USNO Flagstaff Station Integrated Image and Catalogue Archive Service
Dan Bruton: astronomy software
Astronomy catalogs
Vizier service
The STScI Digitized Sky Survey
The Interactive NGC Catalog Online
The NGC/IC project
NASA-IPAC: Extragalactic database (NED)
Level 5: A Knowledgebase for Extragalactic Astronomy and Cosmology
Deepsky collections and catalogs
Atlas of the Andromeda galaxy
Jet Propulsion Laboratory
Skytools observing software(strongly recommended)
Megastar; skycharting program
Abbarator homepage: excellent freeware startest simulation program!

Go to: main menu

Go to: A 20 inch f/3.6 computerized Dobsonian Go to: Building a trilateral computerized 20 inch f/5 Dobsonian
Go to: Project: five 12 inch lightweight Dobsonians Go to: Motorizing a 12 inch lightweight Dobsonian
Go to: 20 inch telescope Go to: Equatorial platform Go to: Scotch mount Go to: Binocular mount Go to: Dobsonian tips Go to: Bending aluminium Go to: Collimating Go to: Making a Krupa collimator Go to: Dotting the primary
Go to: A ballhead type telrad/finder mount Go to: Mirror making log of 300 mm mirror Go to: Astronomy
Go to: Using digital finder charts at the eyepiece Go to: Astronomy links Go to: Building a spherometer
Go to: Building a Bath interferometer Go to: A Foucault-Ronchi-Lyot tester Go to: Building a mirror making machine
Go: Home

Emailadres: Jan van Gastel

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