mfb- t1_iu3eer0 wrote on October 28, 2022 at 7:10 AM

> silicon carbide

That's SiC.

Did they just made this as demonstration object? I don't see a specific telescope being mentioned.

tommos OP t1_iu3emtf wrote on October 28, 2022 at 7:13 AM

I think it's for the Xuntian space telescope they're launching at the end of 2023.

https://en.wikipedia.org/wiki/Xuntian

the_fungible_man t1_iu3f484 wrote on October 28, 2022 at 7:19 AM

It's not. The Xuntian telescope has a 2 m primary mirror.

mfb- t1_iu3ezc6 wrote on October 28, 2022 at 7:18 AM

They made a 4 meter mirror with a hole in the center while the telescope will have a 2 meter mirror with an off-axis design (no hole in the center). But the material is the same in both cases.

Arcosim t1_iuaey39 wrote on October 29, 2022 at 8:28 PM

Xuntian has a 2m mirror, and Earth 2.0 (the space telescope China is launching in 2026 into L2) is an array of six smaller telescopes sharing the same superstructure. So if this mirror is used it'll be used in another not currently announced space telescope.

Which makes sense, because Xuntian is a survey telescope (with a modest mirror but huge 2.4 gigapixel sensor) and Earth 2.0 is an exoplanet finder (5 IR telescopes plus a microlensing telescope). Which means there's a gap right in the middle for a depth of field telescope (think Hubble). This mirror would be perfect for it.

ThickTarget t1_iu3y0k7 wrote on October 28, 2022 at 11:32 AM

The article states that it was delivered to a customer in 2019, but nothing further. Not heard anything about a 4 meter before. I looked around and all I can find is one SPIE paper presenting an instrument for an upcoming Chinese 4 meter, but it doesn't actually name the telescope.