다양한 창문을 통한 우주

내용 왜 다양한 창문 ? 왜 다양한 창문 ? 대기의 영향 대기의 영향 망원경의 성능 망원경의 성능 관측에서 얻는 정보 관측에서 얻는 정보 중요 망원경들 중요 망원경들 차세대 망원경들 차세대 망원경들

왜 다양한 창문 ? 빛 ( 전자기파 ) 의 파장에 따른 분류 빛 ( 전자기파 ) 의 파장에 따른 분류

5 주파수, 파장, 온도

빛 = 전자기파 감마선 : 도 X- 선 : nm : Hz : 10 6~7 도 자외선 : < 350nm : Hz : 10 5 도 광학영역 :<1 micron : Hz : 수 10 3 도 적외선 : > 1 micron : Hz : 수 10 2 도 전파영역 : mm cm : 10 9 Hz : 수 10 – 수 도  각각 다른 망원경 및 검출기 필요

가시 21cm a. 가시,b 전파 c 적외선, d 자외

9 황소자리

M45 광학 IR 전파전파 X선X선

지구 대기의 영향

지구대기 유해한 자외선, X- 선, 감마선 차단 유해한 자외선, X- 선, 감마선 차단 적외선에서는 적절한 온실효과 적외선에서는 적절한 온실효과 그러나 하늘을 보는 데는 장애물 그러나 하늘을 보는 데는 장애물 -> 지구대기 위로 관측기기를 올려야 -> 지구대기 위로 관측기기를 올려야 광학 영역, 전파영역은 투명 광학 영역, 전파영역은 투명

Telescopes focus light into an image in one of two ways. Telescopes focus light into an image in one of two ways. A lens bends (refracts) the light as it passes through the glass and brings it to a focus to form a small, inverted image. A lens bends (refracts) the light as it passes through the glass and brings it to a focus to form a small, inverted image. Two Kinds of Telescopes

If a mirror is given the proper concave shape and a reflective surface, it can form an image by reflecting the light. If a mirror is given the proper concave shape and a reflective surface, it can form an image by reflecting the light. Two Kinds of Telescopes

In either case, the focal length is the distance from the lens or mirror to the image formed of a distant light source, such as a star. In either case, the focal length is the distance from the lens or mirror to the image formed of a distant light source, such as a star. Short-focal-length lenses and mirrors must be strongly curved. Short-focal-length lenses and mirrors must be strongly curved. Long-focal-length lenses and mirrors are less strongly curved. Long-focal-length lenses and mirrors are less strongly curved. Two Kinds of Telescopes

Grinding the proper optical shapes is an expensive process. Grinding the proper optical shapes is an expensive process. The surfaces of lenses and mirrors must be shaped and polished to accuracies less than the wavelength of light. The surfaces of lenses and mirrors must be shaped and polished to accuracies less than the wavelength of light. Creating the optics for a large telescope can take months or years; involve huge, precision machinery; and employ expert optical engineers and scientists. Creating the optics for a large telescope can take months or years; involve huge, precision machinery; and employ expert optical engineers and scientists. Two Kinds of Telescopes

A telescope that focuses light using a lens is called a refracting telescope. A telescope that focuses light using a lens is called a refracting telescope. The main lens is called the primary lens. The main lens is called the primary lens. One that focuses light using a concave mirror is called a reflecting telescope. One that focuses light using a concave mirror is called a reflecting telescope. The main mirror is called the primary mirror. The main mirror is called the primary mirror. In some books, you will find these called the objective lens and objective mirror. In some books, you will find these called the objective lens and objective mirror. Two Kinds of Telescopes

Both kinds of telescopes form a very small, inverted image that is difficult to observe directly. Both kinds of telescopes form a very small, inverted image that is difficult to observe directly. So, astronomers use a small lens called the eyepiece to magnify the image and make it convenient to view. So, astronomers use a small lens called the eyepiece to magnify the image and make it convenient to view. Two Kinds of Telescopes

When light is refracted through glass, shorter wavelengths bend more than longer wavelengths—and blue light comes to a focus slightly closer to the lens than does red light. When light is refracted through glass, shorter wavelengths bend more than longer wavelengths—and blue light comes to a focus slightly closer to the lens than does red light. Two Kinds of Telescopes

If you focus the eyepiece on the blue image, the red light is out of focus—and you see a red blur around the image. If you focus the eyepiece on the blue image, the red light is out of focus—and you see a red blur around the image. If you focus on the red image, the blue light blurs. If you focus on the red image, the blue light blurs. The color separation is called chromatic aberration. The color separation is called chromatic aberration.

Telescope designers can grind a telescope lens of two components made of different kinds of glass—and so bring two different wavelengths to the same focus. Telescope designers can grind a telescope lens of two components made of different kinds of glass—and so bring two different wavelengths to the same focus. Two Kinds of Telescopes

This does improve the image. This does improve the image. However, these achromatic lenses are not totally free of chromatic aberration— because other wavelengths still blur. However, these achromatic lenses are not totally free of chromatic aberration— because other wavelengths still blur. Telescopes made with such lenses were popular until the end of the 19th century. Telescopes made with such lenses were popular until the end of the 19th century. Two Kinds of Telescopes

Another problem for refracting telescopes is that the primary lens is very expensive to make. Another problem for refracting telescopes is that the primary lens is very expensive to make. The glass must be pure and flawless—because the light passes through the lens. The glass must be pure and flawless—because the light passes through the lens. If the lens is to be achromatic, then four lens surfaces must be ground precisely. If the lens is to be achromatic, then four lens surfaces must be ground precisely. Two Kinds of Telescopes

The largest refracting telescope in the world was completed in 1897 at Yerkes Observatory in Wisconsin. The largest refracting telescope in the world was completed in 1897 at Yerkes Observatory in Wisconsin. Its lens, 1 m (40 inches) in diameter, weighs half a ton. Its lens, 1 m (40 inches) in diameter, weighs half a ton. Two Kinds of Telescopes

Although modern glass would make it possible to build slightly larger refracting telescopes, reflecting telescopes have important advantages. Although modern glass would make it possible to build slightly larger refracting telescopes, reflecting telescopes have important advantages. They are much less expensive because the light reflects from the front surface of the mirror. They are much less expensive because the light reflects from the front surface of the mirror. Consequently, only the front surface need be ground to a precise shape. Consequently, only the front surface need be ground to a precise shape. Two Kinds of Telescopes

The front surface is coated with a highly reflective surface of aluminum alloy. The front surface is coated with a highly reflective surface of aluminum alloy. The light reflects off the surface without entering the glass. The light reflects off the surface without entering the glass. Therefore, the glass of the mirror need not be perfectly transparent. Therefore, the glass of the mirror need not be perfectly transparent. The mirror can be supported over its back surface to reduce sagging. The mirror can be supported over its back surface to reduce sagging. Two Kinds of Telescopes

Most important, reflecting telescopes do not suffer from chromatic aberration. Most important, reflecting telescopes do not suffer from chromatic aberration. The light is reflected toward the focus before it can enter the glass. The light is reflected toward the focus before it can enter the glass. For these reasons, every large astronomical telescope built since the beginning of the 20th century has been a reflecting telescope. For these reasons, every large astronomical telescope built since the beginning of the 20th century has been a reflecting telescope. Two Kinds of Telescopes

Astronomers struggle to build large telescopes because a telescope can help your eyes in three important ways—the three powers of a telescope. Astronomers struggle to build large telescopes because a telescope can help your eyes in three important ways—the three powers of a telescope. Most interesting celestial objects are faint sources of light. Most interesting celestial objects are faint sources of light. So, you need a telescope that can gather large amounts of light to produce a bright image. So, you need a telescope that can gather large amounts of light to produce a bright image. The Powers of a Telescope

굴절식 반사식 망원경의 종류

망원경

Astronomers struggle to build large telescopes because a telescope can help your eyes in three important ways—the three powers of a telescope. Astronomers struggle to build large telescopes because a telescope can help your eyes in three important ways—the three powers of a telescope. Most interesting celestial objects are faint sources of light. Most interesting celestial objects are faint sources of light. So, you need a telescope that can gather large amounts of light to produce a bright image. So, you need a telescope that can gather large amounts of light to produce a bright image. The Powers of a Telescope

Light-gathering power refers to the ability of a telescope to collect light. Light-gathering power refers to the ability of a telescope to collect light. Catching light in a telescope is like catching rain in a bucket—the bigger the bucket, the more rain it catches. Catching light in a telescope is like catching rain in a bucket—the bigger the bucket, the more rain it catches. This is why astronomers use large telescopes and why they refer to telescopes by diameter. This is why astronomers use large telescopes and why they refer to telescopes by diameter. They will say, “I’m using a 2-meter telescope,” meaning the primary mirror is two meters in diameter. They will say, “I’m using a 2-meter telescope,” meaning the primary mirror is two meters in diameter. The Powers of a Telescope

The second power, resolving power, refers to the ability of the telescope to reveal fine detail. The second power, resolving power, refers to the ability of the telescope to reveal fine detail. As light acts as a wave, it produces a small pattern called a diffraction fringe around every point of light in the image—and you cannot see any detail smaller than the fringe. As light acts as a wave, it produces a small pattern called a diffraction fringe around every point of light in the image—and you cannot see any detail smaller than the fringe. The Powers of a Telescope

Astronomers can’t eliminate diffraction fringes. Astronomers can’t eliminate diffraction fringes. However, the larger a telescope is in diameter, the smaller the diffraction fringes are. However, the larger a telescope is in diameter, the smaller the diffraction fringes are. Thus, the larger the telescope, the better its resolving power. Thus, the larger the telescope, the better its resolving power. The Powers of a Telescope

Young 의 실험

회절 무니

회절 무늬와 상 분해

망원경의 성능 집광력 : 구경 제곱에 비례 분해능 : 구경에 비례 파장에 반비례 파장에 반비례  지구 대기에 의한 분해능의 저하 : 시상효과  광학 우주 망원경이 필요한 이유 배율 : 대물렌즈 부착 ( 확대 )  검출기 ( 눈, 사진, CCD) : 상 (image)  ; 밝기, 위치,  분광기 + 검출기 : 스펙트럼 :  별의 구성물질에 대한 정보,  운동, 물리적 특성

Nearly all major observatories are located far from big cities and usually on high mountains. Nearly all major observatories are located far from big cities and usually on high mountains. The Powers of a Telescope

Computer control of the shape of telescope mirrors allows the use of thin, lightweight mirrors—either ‘floppy’ mirrors or segmented mirrors. Computer control of the shape of telescope mirrors allows the use of thin, lightweight mirrors—either ‘floppy’ mirrors or segmented mirrors. New-Generation Telescopes

Lowering the weight of the mirror lowers the weight of the rest of the telescope and makes it stronger and less expensive. Lowering the weight of the mirror lowers the weight of the rest of the telescope and makes it stronger and less expensive. Also, thin mirrors cool faster at nightfall and produce better images. Also, thin mirrors cool faster at nightfall and produce better images.

Astronomical telescopes must be aligned with the north celestial pole. Astronomical telescopes must be aligned with the north celestial pole. Polaris, the North Star, marks the location of the north celestial pole. Polaris, the North Star, marks the location of the north celestial pole. Equatorial mountings have an axis that points toward Polaris. Equatorial mountings have an axis that points toward Polaris. New-Generation Telescopes

Alt-azimuth telescopes are run by computers, which align their motion with Polaris. Alt-azimuth telescopes are run by computers, which align their motion with Polaris. Even telescopes in the Southern Hemisphere— where the north celestial pole lies below the horizon—must tip their hats toward Polaris. Even telescopes in the Southern Hemisphere— where the north celestial pole lies below the horizon—must tip their hats toward Polaris. New-Generation Telescopes

New giant telescopes are being built all over the world. New giant telescopes are being built all over the world. An international collaboration of astronomers built the Gemini telescopes with 8.1-m thin mirrors. An international collaboration of astronomers built the Gemini telescopes with 8.1-m thin mirrors. One is located in the Northern Hemisphere and one in the Southern Hemisphere to cover the entire sky. One is located in the Northern Hemisphere and one in the Southern Hemisphere to cover the entire sky. New-Generation Telescopes

세계의 광학 천문대와 망원경들 - 구름이 적게 끼는 곳, 비가 적은 곳 -> 건조 지역 - 공기에 의한 차광 효과 최소화 -> 높은 곳 - 지구대기의 요동을 피해야 -> 높은 곳, 건조한 곳 - 기반시설이 있어야

Keck 망원경 하와이 마우아 케아 10 m : 1.8m * 36

Very Large Telescope (VLT) ESO ; 칠리 안데스 8.2m ; 4 대 광학 간섭계

세계의 전파망원경들 - 최초의 우주전파 검출 : 잰스키 1931 년 -2 차대전 이후 급격한 발달 - 분해능을 높이기 위해 간섭계 기술을 사용

아레시보, 푸에토리코 305m

막스 프랑크 전파연구소 ; 100m 본, 독일

전파간섭계 ; Very Large Array (VLA) ; 25m

한국 천문우주 연구원 대덕, 14m

KVN Korean VLBL Network KVN : 서울, 포항, 제주

서울대학교 전파천문대 6m

세계의 우주망원경들 주로 지상에서 관측이 불가능한 파장대역 주로 지상에서 관측이 불가능한 파장대역 근래에는 광학 ( 시상에 의한 분해능 저하 제 거 ), 전파 ( 기선 확장으로 분해능 높임 ) 도 포 함 근래에는 광학 ( 시상에 의한 분해능 저하 제 거 ), 전파 ( 기선 확장으로 분해능 높임 ) 도 포 함

Chandra X- 선 망원경

허블 우주 망원경 : 2.4 m, 1990

차세대 망원경들 지상 광학 망원경  수 십 m 급 (GMT, TMT)  대기 시상 보정 망원경  대기 시상 보정 망원경 (Adaptive Optics) (Adaptive Optics) 지상 전파 망원경  장기선 network  KVN ( 천문연구원 )  KVN ( 천문연구원 ) 우주 궤도 망원경들 달, 화성에 망원경 설치

공기의 요동을 측정하기 위하여 레이저 이용

차세대 지상 광학 망원경 GMT : 7 * 8 m GMT : 7 * 8 m (24.8 m ;2018) (24.8 m ;2018) TMT : 492 segments TMT : 492 segments (30m : 2018) (30m : 2018) E-ELT : 5 mirrors E-ELT : 5 mirrors (42 m : 2020) (42 m : 2020)

결론 파장에 따라 다른 망원경이 필요 파장에 따라 다른 망원경이 필요 지구 대기의 영향 ( 시상 )  우주광학 망원경 지구 대기의 영향 ( 시상 )  우주광학 망원경 지상 망원경의 크기 증가  새로운 기술 지상 망원경의 크기 증가  새로운 기술  더 먼 천체  더 먼 천체  더 옛날의 우주  더 옛날의 우주  더 자세한 구조  더 자세한 구조