Lehdistötiedote

ELT-teleskoopin sekundääripeili on valettu onnistuneesti

Suurin milloinkaan tehty kupera peiliaihio

22. toukokuuta 2017

SCHOTT on saanut ESO:n ELT-teleskoopin (Extremely Large Telescope) sekundääripeilin aihion valamisen valmiiksi Mainzissa, Saksassa. Valmiina peili on halkaisijaltaan 4.2 metriä ja painaa 3.5 tonnia. Siitä tulee suurin milloinkaan teleskooppiin asennettu sekundääripeili ja myös suurin milloinkaan valmistettu kupera peili.

ESO:n 39-metrin ELT-teleskoopista tulee lajissaan suurin milloinkaan rakennettu teleskooppi, kun se taltioi ensivalonsa vuonna 2024. Uusi virstanpylväs on nyt saavutettu teleskoopin sekundääripeili (M2) valamisen myötä. Se on suurempi kuin useimpien nykyään käytössä olevien tutkimusteleskooppien pääpeili.

Peilin aihio on valettu materiaalimöhkäle — tässä tapauksessa keraamista Zerodur® -lasia — joka sitten hiotaan ja kiillotetaan valmiin peilin aikaansaamiseksi. Tammikuussa 2017 ESO myönsi SCHOTT:ille urakkasopimuksen M2-peiliaihion valmistamisesta (eso1704). ESO on tehnyt tuottoisaa yhteistyötä myös ESO:n Paranalin observatoriolla sijaitsevan VLT-teleskoopin (Very Large Telescope) 8.2-metriset pääpeilit valmistaneen SCHOTT:in kanssa (ann12015). Erittäin korkeat vaatimukset täyttävien, poikkeuksellisten tähtitieteellisten tuotteiden valmistaja SCHOTT on jo toimittanut aihiot muovattaviin, ohuisiin kehikkopeileihin, joista tulevat ELT:n kvaternääripeilit, M4 (ann15055), ja tulee myös valmistamaan tertiääripeilin, M3, aihion.

Sekundääripeilin aihion tulee nyt käydä läpi hidas jäähdytysprosessi, työstöprosessi ja kuumakäsittelysarja, jotka suoritetaan tulevan vuoden aikana. Sitten se on valmis hiottavaksi täsmällisesti oikeaan muotoonsa ja kiillotettavaksi. Tämän suorittaa ranskalainen yhtiö Safran Reosc yhdessä lisätestien kanssa (ann16045). Aihio hiotaan ja kiillotetaan 15 nanometrin tarkkuuteen (15 miljoonasosaa millimetristä) kautta koko optisen pinnan.

Kun M2-peili on valmis ja asennettu, se roikkuu ylösalaisin teleskoopin suunnattoman pääpeilin yllä ja muodostaa ELT:n uudenlaisen optisen viisipeilijärjestelmän sekondäärielementin. Peili on hyvin kaareva ja asfäärinen, mikä tekee sen valmistamisesta ja testaamisesta erittäin haastavaa.

Lisähuomiot

[1] Alunperin 1960-luvun lopulla tähtitieteellisiin teleskooppeihin kehitetty Zerodur® on lähes täysin vapaa lämpölaajenemisesta jopa suurien lämpötilanvaihteluiden vallitessa. Se on kemiallisesti hyvin vastustuskykyinen ja se voidaan hioa erittäin tarkasti. Monissa teleskoopeissa Zerodur® -peilit ovat toimineet luotettavasti vuosikymmeniä, mukaanlukien ESO:n VLT-teleskooppi Chilessä.

Linkit

Yhteystiedot

Marc Cayrel
ESO
Garching bei München, Germany
Puh.: +49 89 3200 6685
Sähköposti: mcayrel@eso.org

Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Puh.: +49 89 3200 6655
Matkapuhelin: +49 151 1537 3591
Sähköposti: rhook@eso.org

Pasi Nurmi (Lehdistön yhteyshenkilö Suomi)
ESO Science Outreach Network ja University of Turku
Turku, Finland
Puh.: +358 29 4504 358
Sähköposti: eson-finland@eso.org

Connect with ESO on social media

Tämä on ESO:n lehdistötiedotteen käännös eso1715.

Tiedotteesta

Tiedote nr.:eso1715fi
Nimi:Extremely Large Telescope
Tyyppi:Unspecified : Technology
Facility:Extremely Large Telescope

Kuvat

ELT secondary mirror blank successfully cast
ELT secondary mirror blank successfully cast
Englanniksi
ELT secondary mirror blank during transport
ELT secondary mirror blank during transport
Englanniksi
Transfer of ELT secondary mirror blank
Transfer of ELT secondary mirror blank
Englanniksi
ELT secondary mirror during transport to annealing facility
ELT secondary mirror during transport to annealing facility
Englanniksi
ELT secondary mirror blank in the streets of Mainz
ELT secondary mirror blank in the streets of Mainz
Englanniksi
ELT secondary mirror during transport to annealing facility
ELT secondary mirror during transport to annealing facility
Englanniksi
Arrival of ELT secondary at SCHOTT annealing facility
Arrival of ELT secondary at SCHOTT annealing facility
Englanniksi
Watching the opening of the ELT M2 mould
Watching the opening of the ELT M2 mould
Englanniksi
The secondary mirror of the ELT is successfully cast
The secondary mirror of the ELT is successfully cast
Englanniksi
Temperature determination of ELT secondary mirror during annealing
Temperature determination of ELT secondary mirror during annealing
Englanniksi
Opening of the ELT secondary blank mould
Opening of the ELT secondary blank mould
Englanniksi

Videot

ESOcast 107 Light: Secondary Mirror of ELT Successfully Cast
ESOcast 107 Light: Secondary Mirror of ELT Successfully Cast
Englanniksi
Transporting and opening the mould containing the ELT secondary mirror blank
Transporting and opening the mould containing the ELT secondary mirror blank
Englanniksi

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