Jon Holtzman NMSU Astronomy Telescopes are light buckets bigger buckets collect more light and faint far away objects dont produce much light Why build bigger telescopes In principle bigger telescopes make sharper images ID: 400291
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Slide1
Telescopes
Jon Holtzman
NMSU AstronomySlide2
Telescopes are light buckets: bigger buckets collect more light, and faint (far away) objects don’t produce much light!
Why build bigger telescopes?Slide3
In principle, bigger telescopes make sharper images:
Why build bigger telescopes?
But, in practice, this doesn’t usually work, because as light comes in through the Earth’s atmosphere, motions and
inhomgeneties
in our atmosphere blur out images: once you get bigger than several inches in diameter, images don
’
t get sharper!Slide4
So how big do telescopes get? Consider NMSU telescopes:
The telescopes in the domes are 12 inches (0.3m) in diameter
The telescope outside is
16
inches (0.4m
) in diameter: it collects about twice as much lightSlide5
Tortugas Mt. Telescope
Also 24” inches (0.6m) in diameter
Used a lot in 70’s & 80’s to monitor planets, but hasn’t been used much in last 20 years
We’re working to renovate and start getting it used again!Slide6
Apache Point Observatory
Observatory operated by NMSU for the Astrophysical Research Corporation
Four telescopes on site:
0.5m ARCSAT
1.0m NMSU
2.5m SDSS3.5m ARC
Small visitor center at nearby National Solar Observatory
ARC
3.5m collects more than 100x the light of the campus observatory telescopes!Slide7
Other “medium-sized” telescopes
5.0m Hale Palomar Mountain, California
4.2 William Herschel Canary Islands, Spain
SOAR Cerro Pachon, Chile LAMOST
Xinglong Station, China 4.0 Victor Blanco Cerro Tololo, Chile
Vista Cerro Paranal, Chile 3.9 AAT NSW, Australia 3.8
Mayall Kitt Peak, Arizona UKIRT Mauna Kea, Hawaii
3.7 AEOS Maui, Hawaii 3.6 "360" Cerro La Silla, Chile. Canada-France-Hawaii Mauna Kea, Hawaii
Telescopio Nazionale Galileo, Canary Islands 3.5 MPI-CAHA
Calar Alto, Spain New Technology Cerro La Silla, Chile
ARC A pache Point, New Mexico WIYN , Kitt
Peak NMSlide8Slide9Slide10
Bigger telescopes: single BIG mirrors
8.3
Subaru
Mauna Kea, Hawaii 4100 m
NAOJ 8.2 FOUR VLT telescopes Cerro Paranal
, Chile 8.1 Gillett Mauna Kea, Hawaii aka Gemini North8.1 Gemini South
Cerro Pachon, Chile 6.5 MMT Mt. Hopkins, Arizona
6.5 Walter Baade La Serena, Chile aka Magellan I6.5 Landon Clay aka Magellan II
6.0 Bolshoi Teleskop Azimutalnyi Nizhny Arkhyz, RussiaSlide11Slide12
Bigger telescopes: no longer single pieces of glass!
10.4
Gran Telescopio Canarias
La Palma, Canary Islands, 10.0
Keck Mauna Kea, Hawaii
~10 SALT South African Astronomical Observatory
9.2 Hobby-Eberly Mt. Fowlkes, Texas 8.4 -> 12
Large Binocular Telescope Mt. GrahamSlide13Slide14
What about getting sharper images?
Remember, bigger telescope collect more light, but they don’t generally give sharper images because images are blurred as light from objects passes through the Earth’s atmosphere
So what can we do?Slide15
Telescopes in Space!
Hubble Space Telescope: 2.4m diameter (so not so big), but above the atmosphere
sharp images!
-> also can observe in ultraviolet lightSlide16
Another cool idea: “deblur” the atmosphere
New technology uses small “bendable” mirrors to take the atmospheric blur out of the picture.
Blur changes fast, so mirrors need to move fast!
But need to measure what the blur is first – need a nearby bright star
There aren’t enough bright stars in the sky! So what can you do
make your own star!Slide17
Telescopes of the future: bigger and sharper!!