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Amateur Telescope
Making & Open
Astronomy
Gord Tulloch,
RASC, Winnipeg Centre
AAVSO:TGR
ATM
Long history since the late 1800s of
people building their own telescopes
Peaked before WWII when little in the
way of affordable commercial
scopes were available
With the advent of innumerable
commercial options now, it doesn’t
make sense to build EXCEPT:
You want big aperture
You want something unique
You want to convert a commercial
scope to something else
Mirror Making
You can make your own mirror!
Only worth it if it’s > 16”
You will have to make smaller
mirrors to skill up (people usually
start with an 8”)
Very simple tools and supplies
Simple process til figuring
Great exercise!
Mirror Machines
Mirror making machines take
the exercise component out
of mirror making
Mirror-o-matic plans available
on the Internet
Traditional spin and sweep
motions
Motor speed controlled by
belts and pulleys
https://www.youtube.com/watch?v=-UrJnHLqhuo
Fixed Post Machines
Very simple to build and
operate
Motion of mirror spins tool
Differential spins generates
grinding / polishing
Motor speed governed by
belts or variable frequency
drives
https://www.youtube.com/watch?v=4Nw9LsBjJWU
Massive Optics
Not unusual to see amateurs
making up to metre class
mirrors
Latest trend: very fast (f/2.x)
mirrors on mounts that allow
viewing without ladders
Super thin slumped meniscus
mirrors
Mel Bartels 25” F/2.6 ½” thick mirror
https://www.bbastrodesigns.com/JoyOfMirrorMaking/25%20inch%20f2.6%20mirror.html
Slumping Thin Mirrors
Traditional mirrors 1:6 ratio
thickness means 30” mirror
would be 5” thick and
weigh 167kg or 368 lbs!
½ “ Meniscus mirror would
be 13kg or 28lbs
Dave Davis 72” kiln Bartels 30” refractory mold
Bartels 40” and
30” slumped mirrors
Meniscus mirrors do not need more than
A 9 point support mirror cell!
https://www.bbastrodesigns.com/30/30%20inch%20binoscope.html
Really Massive Optics Clemens 70” F/6.1
YouTube https://www.youtube.com/watch?v=KoE9K1QKZ_c
Really Massive Optics 70” F/3
https://www.cloudynights.com/topic/654837-group-70/
Make Your Own Blanks! Glass is widely available but
mirror blanks are rarer and expensive, even float glass
Kilns used for ceramics can also be used to fuse glass for mirrors or slump thin mirrors to approximate focal rations
Kilns that will do 1700deg will fuse glass, 2300 will melt it
Need computer controlled annealing or stresses in the glass renders it useless
https://www.mdpub.com/scopeworks/blanks/index.html
Where do I get glass?
How Can You Aluminize Such Huge Optics??
https://guysmathastro.com/2019/08/05/silvering-mirrors-and-more-at-stellafane/
https://angelgilding.com/kits-chemicals/mirror-kits.html
Mount Innovation
Short focal length massive scopes that
fold up into the back of your car
Alt-Az-Alt designs – rock back and forth
at zenith to eliminate Dobson’s Hole
Drive Systems – OnStep/AstroEQ/
EQMOD
Astrometry closed loop (no encoders)
Hexapod collimation
Bartels 25” F/2.6 telescope
Hexapod Construction
3 Trusses – 3 points define a plane
If you put M and female bolts of
opposite ends of a truss tube you
can lengthen and shorten the tube
Rotating truss tubes allows you to
adjust collimation, including from the
eyepiece
Fixed primary mirror (no collimation
bolts)
Enablers for ATM
Innovation
Internet / Cloud – unprecedented information flows
Operating Systems – LINUX and derivatives
Computers/Microcontrollers – Raspberry Pi, Arduino
Digital fabrication / 3D printing
Software rivalling commercial – Kstars/EKOS, Stellarium
Citizen Science / STEM
Standards – ASCOM / INDI for hardware / software
Internet of Things (IOT)
Community supported hardware / software
Standards for
interoperability: ASCOM
/ INDI
ASCOM – Windows only
INDI - Operates on OSX, Linux, and (with a wrapper) Windows
Communications protocol for clients to talk to drivers for equipment
Local or remote control
Includes drivers for telescopes, focusers, weather stations, joysticks, CCDs, filter wheels, domes, adaptive optics, PiFaceaddon boards (relay, focuser)
ASCOM Alpaca an alternative to INDI for Linux, Mac but not as mature
INDIGO available for Macs / IOS with richer feature set for that platform
Open Source Software
www.gordtulloch.com
Raspberry Pi
The Raspberry Pi Foundation -UK-based charity that works to put the power of computing and digital making into the hands of people all over the world.
Single board computer with MicroSD, gigabit ethernet, Wifi, Bluetooth, USB, HDMI, sound, and GPIO pins
Runs LINUX or Windows (useless)
Stellarmate prepackaged Pi with a custom Raspian LINUX, can be bought separately
Not generally usable as a telescope stepper controller –not real-time
Latest is RPi 4B which is very usable as a stand alone imaging/control platform
Demo – RPi4/Kstars/EKOS
Arduino
USB connection
Wide variety of accessory "Shields" available
It is intended for roboticists, artists, designers and hobbyists
Variety of I/O pins including analog, digital, PWM and more
Based on the ATmega328 (removable DIP IC)
Costs $13
MKS GEN L V1.0 3D Printer Controller Board
running ATMEGA2560
Arduino compatible
Supports up to 3 A4988, DRV8825, TMC2100/30 and LV8729 motor drivers
RA/DEC (Alt/Az) Focuser1 Focuser2 Rotator
12-24v (excellent for telescope steppers)
Fan controller
USB connection to computer
With OnStep looks like an LX200
Completely solderless solution for $25, drivers are $3-$15 ea
Application: OnStep
Telescope Controller
Example telescope controller with Teensy3.2 Arduino board $30 but many hardware combinations supported
ARM 32 bit microcontroller
TMC2100 stepper drivers ($15)
Nema17 Bipolar 0.9deg steppers ($10)
Bluetooth module ($40) optional
OnStep Software – all the hard stuff is done for you! Incl PEC TPOINT etc.
Control from your phone via Bluetooth with OnStep client (Android)
https://onstep.groups.io/g/main/wiki/home
Application: Meteostation
Weather Station
High precision barometer.
Relative Humidity (HR) reading.
Dewpoint calculation.
Far sky temperature using Infrared Thermometer for determining cloud cover.
Photocell to read sun radiance levels.
One internal thermometer.
Two external thermometer.
Clouldy, dewing, freezing and daylight digital flag.
Sensor malfunction flags.
Web Interface with historical data.
INDI Driver
Application: CG5
Revamp
Celestron CG5 with bad electronics
Replaced electronics with MKS Gen-L 1.0 /
DRV8825 drivers running OnStep
Replaced motors with 400 steps per rev
steppers
3D Printed Motor Brackets
GT2 gears and belt drive
Pi 3B+/Stellarmate software with remote
access using TeamViewer
MKS GEN-L
Raspberry Pi
3D Printed
Brackets
GT2 Gears/
Belts
Application: NTT8
Science Imaging Celestron 8” XLT
Sirius EQ-G Mount
EQMOD cable replaces handpad
Canon EOS1100 with DSUSB shutter ctr.
Orion Off-axis Guider and Starshoot
Orion Accufocus with FCUSB ctr.
Raspberry Pi 3B+ running Stellarmate
Kstars/EKOS imaging on Astronomy Linux
Python scripts for data reduction
Wireless joypad or Remote Access
Application: Embedded
Telescope Computer
Raspberry Pi 3B+ with 480x320 touch display
running Raspian LINUX – wifi hotspot
Python program running in kiosk mode with
status display and menu for sky tour
Connects with INDI to get info and issue
commands
Runs INDI server so remote devices
(phone/tablet/laptop) control
iINDO ($) for IOS, PARCOS for Android, or
SkySafari ($)
Application -
PSWAI• “Plate Solved Where Am I”
• Takes sky images with an inexpensive camera
• Run a plate solve on Raspberry Pi with astrometry.net local install
• Update SkySafari or Kstars with telescope position
• Closes the loop on mounts without needing encoders
• Open Source python script
Cloudy Nights User hcfhttps://github.com/arhcf/pswai
Application: NTT16 16”
Dobsonian
New Technology Telescope
16” F4.5 Meade Starfinder Optics
Hexapod collimation
MKS Gen-L 1.0 / TMC2130 drivers running OnStep
Stepper motors in base
Raspberry Pi brain with status/menu display
Remote control via INDI server
GPS dongle for position/time
ETX70 OTA running PSWAI
https://gordtullochcom.wordpress.com/telescopes/16-f-4-5-new-technology-telescope/
Questions?http://www.gordtulloch.com
