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Introduction
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.
An informal team has been
established to facilitate the development, production, and use of
lightweight, low-cost, research quality telescopes in the aperture
range, primarily, of 0.5 to 1.0 meters (although both larger and smaller
apertures are also of interest). This team has no commercial aims per
se, although one of its goals is to encourage the manufacture of this
"new" class of alt-az telescopes and the various components that will go
into them. Thus we consider members from commercial firms to be central
to our team, and hope that what we come up with will be useful to them.
Specialty Areas
As our informal team
has expanded there has been, as might be expected, some specialization
(although we all share an irrational love of telescopes and astronomy).
We have a strong optics section with Dave Rowe, Tom Krajci, Tong Liu
(Hubble Optics), Rick Hedrick and Joe Haberman (PlaneWave Instruments),
Gerard Pardeilhan (optician at Strasbaugh in San Luis Obispo) and John
Hall (Pegasus Optics). Steve Kennedy has an interest in the project.
We also have a strong
control section with Dan Gray (Sidereal Technology), Dave Rowe (on large
diameter brushless DC direct drive motors), Art MacCarley (EE chair at
Cal Poly and control systems instructor), Helen Yu (EE professor at Cal
Poly who also teaches control systems), Ty Safreno (President of Trust
Automation in San Luis Obispo), and Russ Genet. Mel Bartels has
provided helpful inputs.
Although not directly part
of our group, Elwood Downey (NM Tech University’s Magdalena Ridge
Observatory 2.4-m Project Engineer) and Kevin Harris (EOS Technology’s
2.4-m Project Engineer) have made vital contributions to both the
control aspects of this project for which we are most grateful. Our
visit to MRO, suggested by astronomer Chris Corbally at the Vatican
Observatory's pioneering 1.8-meter alt-az telescope, was a major
milestone in shaping of our ideas.
Our mechanical team is still
in the formation stage, but already includes Richard Kay (President of
Impact Bearings with six plants in the LA area), Jim Widmann (ME
Professor at Cal Poly), and our Jack-of-all-trades, Dave Rowe.
Supporting University
Cal Poly (California
Polytechnic State University, San Luis Obispo) is the first university
to join our team. The chairs of the ME and EE Departments at Cal Poly,
Tom Mackin and Art MacCarley, are supportive of the project (as are ME
and EE Professors Jim Widmann and Helen Yu mentioned above). They
are challenging some of their best students with various aspects
of lightweight alt-az telescope design. George Roberts (President of
Inca and a longtime supporter of Cal Poly's ME Department) is providing
helpful overall advice to our team. Rich Saenz the Physics chair and
three of the astronomers at Cal Poly, Dave Mitchell, John Keller, and
Michelle Ouellette, have been helpful in defining astronomical research
applications. Cal Poly would like to develop, site, and use a 1-meter
alt-az telescope. We have adopted Dave Rowe's conceptual sketch of the
Cal Poly 1-meter telescope as our project's logo.
Remote Test Site
Tom Smith's Dark Ridge
Observatory (DRO) near Cloudcroft is a willing test site for the team’s
telescopes. Tom, a very active team member, has contributed in many
areas to the team’s deliberations. A nuclear engineer, he worked with
Russ on various astronomical projects in San Luis Obispo for several
years and then took early retirement to set up his observatory in New
Mexico. He is busy pouring concrete and hammering nails for his control
room and the roll-offs for his two 14-inch SCTs and his 20-inch alt-az
telescope. We plan on placing the 25-inch telescope, described below,
at DRO for a couple of years after the telescope’s construction and
testing at Cal Poly.
The 25-inch will eventually
end up at Dave Rowe's Starry Ridge Observatory (SRO), also near
Cloudcroft. After Dave retires in about a year, he will be building his
observatory (complete with a dome). At both the Dark Ridge and Starry
Ridge Observatories, time will be made available on the 25-inch alt-az
telescope for Cal Poly students and others in the San Luis Obispo area
(Cuesta College students, high school students, and advanced amateurs
from the Central Coast Astronomical Society).
Advanced Technologies
Peter Chen (NASA Goddard SFC)
keeps us in touch with developments on ultra-lightweight (carbon fiber)
mirrors. We have to restrain ourselves not to think too much about what
a 2-meter telescope—that weighed under 300 lbs. and could be transported
in a pickup and set up in half an hour—might achieve.
The possibilities for
including some form of adaptive optics are also being considered. The
cost of piezoelectric devices has dropped significantly in recent years
as has the cost of high-speed digital signal processors.
Workshops
We have planned several
workshops. The first one is this coming Saturday (October 20th) in San
Luis Obispo (SLO), the first of a number of SLO Alt-Az Workshops. Dave
Rowe, Rick Hedrick, and Richard Kay are coming up from LA to join the
folks from Cal Poly (professors and students) and several local
industrialists (Ty Safreno, Gerard Pardeilhan, and others) for an
afternoon alt-az workshop in San Luis Obispo (with an optional lunch
before hand and dinner afterwards).
Other workshops in this
series will be scheduled at San Luis Obispo over the school year. The
initial goal of this series of workshops is the design and fabrication
of the 25-inch alt-az telescope mentioned above. The primary mirror
is being supplied by PlaneWave Instruments, and work has already begun
on this mirror. Many of the components and materials are
being funded by Dave Rowe (Starry Ridge Observatory). The control
system is being provided by Dan Gray (Sidereal Technology). Dan is
working on an advanced version of his control system that will handle
direct drive brushless DC motors and very high resolution encoders. Of
critical importance, the telescope's structure will be designed and
fabricated by a graduate Cal Poly ME student team in Jim Widmann's ME
Projects class. A key purpose of this series of workshops is to support
Jim and his students.
This series of San Luis
Obispo workshops is also firmly setting, as its goal, the development
and eventual fabrication and operation of a 1-meter Cal Poly alt-az
telescope. We will carry along the design of this telescope as we work
on the "pave the way" 25-inch system. The optical plan for the
25-inch is a corrected hyperbolic Newtonian, while the plan for the
1-meter is a corrected Dall Kirkham with a tertiary folding flat. The
Cal Poly 1-meter telescope will, on completion, become a major research
tool for Cal Poly. We plan to site it at a dark, relatively fog-free
location just over the coastal ridge—perhaps at Santa Margarita Lake (a
SLO County park) which is just a 20-minute drive from the Cal Poly
campus.
The following Saturday,
October 27th, there will be an alt-az workshop in
Dallas. A number of us will be at this event, and we should
get many helpful inputs from the folks in
Texas (and others flying
in). Max Corneau is not only the local host for this workshop, but an
active member of our alt-az developmental team. There will be invited
summaries of this workshop published in
Astronomy Technology Today
(Gary Parkerson, Editor) and in Amateur Astronomy (Charlie Warren, Editor).
Amateur Astronomy is featuring a special issue next year
devoted to articles on various aspects of our alt-az developmental
project. Russ Genet will be the guest editor for this special issue.
Conferences
Two major conferences are
planned with a number of special focus sessions that will feature the
team's work, including optical, mechanical, control, and other
sessions. The first conference will be in San Luis Obispo this coming
June 20-22 (2008), and the second will be in
Hawaii the following January 1-5 (2009). See
www.STARConference.org for details on both conferences. The
proceedings of these two conferences will be published as hardback
books—part of the prestigious Astronomical Society of the Pacific's
Conference Series managed by J. Moody (Russ Genet will be the editor for
both volumes).
The Small
Telescopes & Astronomical Research (STAR) Conference will,
primarily, be a national conference with about 150 attendees. We had a
precursor to the this conference last year, the
STAR Workshop. A summary of
this workshop was published in
Astronomy Technology Today.
The Hawaii conference,
Galileo's Legacy: Small Telescope Science 1609 and 2009, will
be a major international event with over 250 expected. It will open
with a New Year's Eve inaugural talk by Rick Fienberg (Senior Sky &
Telescope Editor) followed by fireworks to help launch the International
Year of Astronomy. There will be many special focus sessions related to
alt-az telescopes and their use in scientific research. Richard Berry,
the former, long-time Editor of Astronomy, will give the
Luau talk. There will be tours of Mauna Kea before the conference and
Haleakala after the conference.
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