Big Glass Giant Magellan Telescope GMT Las Campanas Chile First Light 2024 Large Binocular Telescope LBTO Mt Graham AZ 2007 Large Synoptic Survey Telescope LSST Cerro Pachon ID: 565386
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Slide1
A Tour of the Largest Ground-Based Telescopes Being Developed
Big
GlassSlide2
Giant Magellan Telescope (GMT)
Las
Campanas, ChileFirst Light 2024Slide3
Large Binocular Telescope (LBTO)
Mt Graham, AZ, 2007Slide4
Large Synoptic Survey Telescope (LSST), Cerro
Pachon
Ridge, Chile
First Light 2022Slide5
What do All These New Observatories have in Common?
They’re built with
BIG GLASS: 8.4 meter primary mirrors Slide6
Caris
Mirror Lab
at U of Arizona Steward ObservatorySlide7
Building the Giant Mirrors
Used in these TelescopesSlide8
The Honeycomb structure controls weight and adaptation to temperatures
One of 1750 alumina-silica cores used in casting an 8.4 meter mirror
Small-scale casting showing honeycomb structure in relation to thickness of mirrored surfaceSlide9
Special borosilicate glass is melted in the spin-casting operationSlide10
Casting the Mirror
Spin-casting the fourth of seven 8.4-meter mirrors destined for the Giant Magellan Telescope (GMT).
The mold cools slowly for three months after casting to prevent introduction of impurities and imperfectionsSlide11
Moving the cast blank in preparation for grinding & polishingSlide12
Grinding and Polishing
Grinding pedestal is visible in the background; back of mirror is ground flat at this station; front is ground to prepare for polishing.
Long bar hanging across the left-center is a laser-measuring device to ensure mirror surface is ground to exacting specificationsSlide13
Polishing the Aspherical (parabolic) surface
The entire mirror surface is polished in stages; here a cleaning assembly is lowered onto the surface
The final
polishing
stage deploys
a “stressed-lap” polishing tool
that consists
of a polishing disk which bends actively to match
the varying
curvature of
the surfaceSlide14
When Complete the Seven Segments will comprise the primary mirror
for
the GMT,
totaling
84.5
ft
acrossSlide15
GMT’s Mission and Stats
Location: Las
Campanas Peak, Chile Elevation 8,500 ft300 nights / year viewing (minimal rainfall)
Purposes: search for exoplanets; study dark matter & dark energy; study formation and fate of galaxies
Scheduled first light: 2024Slide16
LSST Goals
will image the entire visible sky every few nights
(thus capturing changes and opening up the time-domain window to the observable universe)Map the interior of the Milky Way—our galactic home
in 10 years of observing, the goal is to record the greatest movie ever
made
billions of objects will be imaged in six colors in an unprecedentedly large volume of our universeSlide17
LSST Technical Innovations
camera
(3200 megapixels, the world’s largest digital camera) each image the equivalent of 40 full moonstelescope (simultaneous casting of the primary and tertiary mirrors; two aspherical optical surfaces on one
substrate
)
data management
(20-30
terabytes of data nightly, nearly instant alerts issued for objects that change in position or
brightness)
Public facility—access to images and database for amateur astronomersSlide18
What other
ELTs
are in the works(Extremely Large Telescopes)
and how do they differ from these?
Thirty Meter Telescope (TMT)
, Mauna Kea, Hawaii
European Extremely Large Telescope (E-ELT)
, Cerro
Amazones
, Chile
Hint
:
Like the James Webb Space Telescope, these
two telescopes will use large numbers of 1.44 meter hexagonal mirrors in coordinated arraysSlide19
Thirty Meter Telescope (TMT)Mauna Kea, HI 2022 (date delayed)Slide20
TMT Stats
30-meter diameter
492 optical segments (individual mirrors)Mauna Kea Observatory, Hawaii, 13,290 ftScheduled First Light 2022Status: delayed
by court
order driven by Hawaiian protestsSlide21
European Extremely Large Telescope(E-ELT) Cerro
Amazones
, Chile, 2024Slide22
E-ELT Stats
Overall diameter of primary = 39.3 meters
798 individual hexagonal mirror segmentsEach segment 1.45 meters across, 50 mm thickLocated on Cerro Amazones, Chile, at 10,040 ft.
Status: budget approved by European
First light scheduled for 2024Slide23Slide24
Relevant Websites
Large Synoptic Survey Telescope
Giant Magellan Telescope Observatory (this site has many good links, including more detail about
Univ. of
Az’s
manufacture
of 8.4 meter mirrors)
Thirty Meter Telescope
(site may be down)
Large Binocular Telescope Observatory
Caris
Mirror Lab