<p>Of the three giant (or 'Extremely Large') new telescopes being built, the Thirty-Meter (TMT), the the Giant Magellan (GMT) and the Extremely Large Telescope (ELT), only the Magellan, from what I understand, will not feature a Cassegrain-type telescope, or some variant thereof.</p>
<p>Instead, the GMT will have a 'Gregorian'-style telescope, which is supposedly a predecessor of the Cassegrain....</p>
<p>But... What, exactly, is the difference?</p>

CC BY-SA 4.0
2021-08-02T08:05:11.847Z
Is this it? https://astronomy.stackexchange.com/questions/21478/in-a-reflecting-telescope-cassegrain-is-there-a-difference-between-using-a-co/21479#21479
James K
CC BY-SA 4.0
2021-08-02T09:30:44.190Z
@JamesK bingo! Thanks.
uhoh
<observational-astronomy><telescope><observatory><newtonian-telescope><cassegrain-telescope>
What is the difference between a Cassegrain telescope and a Gregorian one? Which one is better?
Kurt Hikes
# What is the difference between a Cassegrain telescope and a Gregorian one? Which one is better?

(Asked by: username_0 on 2021-08-02)

Of the three giant (or 'Extremely Large') new telescopes being built, the Thirty-Meter (TMT), the the Giant Magellan (GMT) and the Extremely Large Telescope (ELT), only the Magellan, from what I understand, will not feature a Cassegrain-type telescope, or some variant thereof.

Instead, the GMT will have a 'Gregorian'-style telescope, which is supposedly a predecessor of the Cassegrain....

But... What, exactly, is the difference?

**Tags:** observational-astronomy, telescope, observatory, newtonian-telescope, cassegrain-telescope

> **Comments:**
> **username_1**: Is this it? https://astronomy.stackexchange.com/questions/21478/in-a-reflecting-telescope-cassegrain-is-there-a-difference-between-using-a-co/21479#21479  
> **username_2**: @username_1 bingo! Thanks.  

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## 0 answers

