Texas Astronomical Society of Dallas (TAS)
High-Tech Alt-Az Telescope Workshop

Back to Past Conferences 26-27 October, 2007

Sponsored by the Texas Astronomical Society of Dallas

Program Organizer: Russ Genet/russmgenet@aol.com, (805) 438-3305

Local Host: Max Corneau, MaxIPTer@aol.com, (469) 338-9310


Evening Kickoff  at the Texas Astronomical Society of Dallas’s General Meeting at the University of Texas, Dallas, Friday evening, October 26, 7:00-8:30 PM.  A 40-minute presentation, High-Tech Alt-Az Telescopes for Research, Astrophotography, and Education, by Russ Genet (California Polytechnic State University) will be followed by a question-answering panel chaired by Max Corneau with panel members Russ Genet, Richard Kay, Tom Krajci, Tom Smith, and Dave Rowe.  See http://texasastro.org/ Highlights and Events for directions and additional information on location and parking.


All-Day Workshop  Saturday, October 27, 2008, 9:00 AM – 5:00 PM.  Please see workshop agenda below.  The workshop will be held in the Mockingbird Room at the Richardson Hotel, just off of the University of Texas, Dallas (UTD), campus.  See www.RichardsonHotel.com, or call 866 593-6300.  The hotel is located at 701 E. Campbell Road in Richardson, Texas.  There is a special room rate for workshop attendees of only $85/night.  Please mention “Dallas Astronomy Workshop.”  The hotel provides free shuttle service to UTD, and is centrally located to many restaurants and shops.


Post-Workshop Texas Bar-B-Que, Saturday, October 27, 6:00 PM – 10:00


Introduction to Alt-Az Telescopes for Research, Astrophotography, and Education


The combination of low-cost alt-az telescope control systems and affordable aerospace materials has reached the point where a revolutionary new class of lightweight, highly capable alt-az telescopes is emerging.  Similar to SCTs, this new class of alt-az telescopes will not only be used visually, but also for CCD-based scientific research and astrophotography.  Similar to Dobs, they will have larger apertures than SCTs, yet will be lightweight.  Unlike the visual Dobs but similar to giant mountaintop alt-az telescopes, this emerging class of precisely controlled telescopes will handle a variety of instruments mounted on field de-rotators with generous back focus.  The primary reason for developing lightweight alt-az telescopes with apertures larger than SCTs is to conduct research on and image (as well as view) fainter objects with affordable telescopes. 


The cost of alt-az telescope control systems has plummeted over the years.  Initially, control computers and telescope control electronics cost tens of thousands of dollars and filled entire equipment racks.  Today, Sidereal Technology makes a microcomputer-based alt-az telescope control system for about $1,000 that you can place in your briefcase with room to spare.  Meanwhile, the cost of aerospace materials has plummeted as their use has moved beyond aircraft and spacecraft to outdoor signs and building exteriors.  Given these two dramatic drops in cost, research-grade alt-az telescopes fabricated from lightweight aerospace materials are now economically viable.


The objective of the Dallas Alt-Az Workshop is to explore, in workshop talks and panel discussions, eight areas:


(1)     lightweight affordable optics

(2)     autoguiding

(3)     precision control systems and drives

(4)     field de-rotation

(5)     high natural frequency mechanical structures

(6)     bearings for alt-az telescopes

(7)     structural alternatives

(8)     observatories (automation, scheduling, and remote sites)



Workshop Agenda


800-830  Coffee and informal discussions


830-840   Welcome/Introduction to the Texas Astronomical Society of Dallas

Max Corneau, Texas Astronomical Society, Dallas (Vice President)


840-850  Workshop Overview   Russ Genet, Cal Poly Univ.


­850-900  Morning Session Introduction   Tom Krajci, Astrokolkhoz Observatory


900-945  Lightweight Affordable Optics   Dave Rowe, Sierra Monolithics

A wide-field photo-visual alt-az telescope supports two basic optical configurations: the corrected Newtonian for smaller systems, and the tertiary-focus Cassegrain for larger systems.  The first part of this talk will address the requirements and trade-offs for telescopes of this class, and will discuss various high-performance optical designs in detail.  Emphasis will be placed on corrected parabolic Newtonian, corrected hyperbolic Newtonian, and corrected Dall Kirkham optical systems.  The second part of this talk will cover the current status and future of large, lightweight mirror blanks and corrective optics.  Lightweight and inexpensive primary mirrors and matched correctors are needed to fulfill the promise of the high-tech telescope.


945-1015  Corrected Dall Kirkham Alt-Az Telescopes   Rick Hedrick, Plane Wave Instruments

The corrected Dall Kirkham design employed in the 20-inch Plane Wave Instruments OTA is being extended to alt-az telescopes of 40-inch (1-meter) telescopes.  Why is this optical design particularly well suited to economical 1-meter telescopes for research, astrophotography, and education?


1015-1030 Autoguiding   Tom Krajci, Astrokolokhoz Observatory

Autoguiding has been the mainstay of long-exposure astronomical imaging.  This talk will cover the current status and future of telescope positioning and position correction.  Topics will include traditional autoguiding using cameras and mount corrections, faster correction methods using movable mirrors and deviator plates, and long-exposure unguided imaging using precision encoders and mount modeling.  The impact on the optical and mechanical design will be discussed.


Midmorning break


1100-1200  Precision control systems and drives   Dan Gray, Sidereal Technology

Sidereal Technology manufactures and supports a control system that can be used for either equatorial or alt-az telescopes.  Over 100 systems have been incorporated into telescopes, including several ATM alt-az systems.  An active Yahoo user’s group helps newcomers and provides ideas for and evaluations of advances.  Besides reviewing the current control system, this talk will describe new developments which include “tick management,” closed-loop operation with high-resolution telescope encoders, and experiments with the control of high-torque brushless DC motors.  This latter development could produce active control systems that directly counter wind gusts one millisecond at a time.


1200-1230  Field de-rotation  Dan Gray, Sidereal Technology

Although new high-speed CCD cameras, such as MalinCan and StellaCam, can overcome field rotation by stacking short exposures, accumulated camera read noise can be a problem for faint-object photometry or narrow-band astrophotography.  Thus instrument rotators are still useful for research alt-az telescopes.  Several off-the-shelf instrument rotators (Meade, Optec, RC Optical Systems) are available.  A proposed development by Sidereal Technology will also be discussed.




200-210 Afternoon session introduction   Tom Smith, Dark Ridge Observatory


200-230   High natural frequency mechanical structures   Russ Genet, Cal Poly Univ.

Control systems that actively counter wind gusts with high-torque motors and high-resolution encoders require, to be effective, very stiff telescope structures with resonant frequencies above 10 Hertz (most of the wind gust energy is from 1 to 10 Hertz).  Sheet steel is very stiff for its weight (and very economical), but aerospace materials, such as carbon fiber and other composites, and aluminum honeycomb and foam core panels are, pound-for-pound, even stiffer and lighter than sheet steel.  Ordinary woodworking tools and structural adhesives can be used to build lightweight alt-az telescopes in a manner very similar to building balsa wood model airplanes.


230-300  Bearings for alt-az telescopes  Richard Kay, Impact Bearings, Inc.

While there are many ways to accommodate rotation in altitude and azimuth, precision bearings is an approach that has been used with success by the smaller mountaintop alt-az telescopes, such as the new 2.4-meter telescope at Magdalena Ridge Observatory built by EOS Technologies.  Although large-diameter slim-line bearings are somewhat expensive, they are a viable option for lightweight alt-az telescopes.  Recent advances in bearing technology will be discussed.


300-330  Structural alternatives panel discussion  Panel Moderator: Max Corneau

Panel Members: Richard Kay, Dave Rowe, Russ Genet, Tom Smith, and Tom Krajci

There are many structural possibilities for lightweight alt-az telescopes.  The panel will address a number of questions.  Newtonian top ends: can they achieve low wind resistance?  Should truss or closed OTAs (shroud or otherwise) be used?  What is the best approach to fork designs?  Is foam filled monocoque or stacked aluminum skinned panels a viable approach?  How can altitude and azimuth drives be integrated into the structure?  Should they be non structural?  How should telescopes be coupled to piers or ground pads?  Is the ground too springy for active control telescopes?


Mid-afternoon break


400-430     Observatories: automation, scheduling, and remote sites

Tom Smith, Dark Ridge Observatory, and Tom Krajci, Astrokolokhoz Observatory

Now that you've decided to build a high-tech alt-az Telescope, how do you automate the observatory so you can sleep through the night?  How do you schedule observations to make the most of dark time?  If you want to operate at a remote site, how do you choose it?


430-500  Final panel discussion and summary statements  Panel Moderator: Max Corneau

Panel Members: Richard Kay, Dave Rowe, Russ Genet, Tom Smith, and Tom Krajci


500 Adjourn


600-1000 Texas-style barbeque (weather permitting).  Poor-weather restaurant alternative.


Biographical Sketches of the Organizers and Presenters


Max Corneau is Vice President and a Life Member of the Texas Astronomical Society of Dallas, a NASA/JPL Solar System Ambassador, and Senior Army Space Operations Officer.  Max possesses a Master of Science Degree in Engineering from Boise State University, and has served as a tour guide and visiting astronomer at the U.S. Naval Observatory in Washington, DC. He served as a guest lecturer in the Explore the Universe Exhibit at the National Air and Space Museum in Washington and at the Udvar-Hazy Annex. In 2006 Max was elected to the Philosophical Society of Washington.   www.geocities.com/astrodad32


Russ Genet is Research Scholar in Residence, California Polytechnic State University, and Adjunct Professor of Astronomy, Cuesta College.  The founder and former Director of the Fairborn Observatory, Russ and Louis Boyd pioneered the development of robotic telescopes.  Author of several books on astronomy and telescope control, Russ was the 51st President of the Astronomical Society of the Pacific.  www.OrionObservatory.org.


Dan Gray is President and Director of Engineering of both Technical Marine
Service (TMS), and Sidereal Technology.  Dan founded TMS, a marine controls company, in
1987, and Sidereal Technology in 2003.  He has innovatively developed many types of control systems for ocean-going vessels as well as telescopes.  An active telescope maker for 30 years, Dan created and popularized the "string" telescope. www.SiderealTechnology.com, www.tms-usa.com.


Rick Hedrick  PlaneWave Instruments was founded in 2006 by Richard Hedrick and Joseph Haberman.  Rick has over 21 years of experience in telescope design.  He worked for 11 years as former Chief Technology Officer and previous owner of Celestron where he was responsible for developing Celestron’s award winning Schmidt-Cassegrain computerized telescopes.  Getting a product like the CDK into the hands of serious imagers and amateur astronomers has been a shared vision of Hedrick and Haberman for many years.  www.planewaveinstruments.com.


Richard Kay is President of Impact Bearings.  His company, with six plants in the Los Angeles area, makes the bearings that many other bearing companies sell.  His experience with bearings includes bearings for large telescopes and, closely related, satellite tracking systems.  Richard is an astronomy enthusiast.  www.impactbearings.com.


Tom Krajci (Major, USAF retired) is an amateur scientist specializing in photometry.  He operates the Astrokolkhoz Observatory at an elevation of 9,440 feet near Cloudcroft, New Mexico.  Tom is translating several books on telescope making and optics design from Russian into English, including the works of Dmitry Maksutov.  http://overton2.tamu.edu/aset/krajci/


David Rowe is Chief Technology Officer and Co-founder of Sierra Monolithics.  An avid amateur astronomer, optical designer and ATM, Dave has designed and fabricated many telescopes, including a corrected Dall-Kirkham, a flat-field concentric Schmidt Cassegrain, and several Schmidt cameras and corrected Newtonians.


Tom Smith is the Director of the Dark Ridge Observatory in New Mexico.  Tom is a retired software and nuclear engineer and an advanced amateur astronomer.  Tom established the Dark Ridge Observatory as a non-profit organization in Weed, New Mexico, and has been working with students and faculty from several colleges and universities as a mentor for CCD photometry and image data reduction.  Tom also conducts research on eclipsing binaries.  www.DarkRidgeObservatory.org.