I found a table of historically largest telescopes here, so I'm guessing it's the Hale Telescope of the Palomar Observatory on Mount Wilson. However, that Wikipedia article warns that size is not everything when it comes to light-gathering-power.

So I want to know: In the 1960's, what was the best optical telescope on Earth, in terms of apparent magnitude or light-gathering-power? And what is the faintest apparent magnitude it could see? I'm hoping it will be able to observe things down to an apparent magnitude of at least 15.


closed as off-topic by kim holder, mins, ReactingToAngularVues, Russell Borogove, andy256 Jun 11 '15 at 4:45

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This related list shows nothing even close to the size of Hale through the 1960s. Size is not everything but it is certainly the dominant factor in limiting magnitude; I'd be extremely surprised if improvements in optical quality between 1948 and 1969 could compensate for the sheer size of that scope.

Magnitude 15 would be no problem, achievable even in modestly sized telescopes; this table suggests the limit would be beyond magnitude 20. Long photographic exposures extend the limit; Palomar's 1948-1958 survey on the much smaller 48" Samuel Oschin telescope was sensitive to magnitude 22.

  • 1
    $\begingroup$ Thanks this is what i needed. I may post related questions on astronomy because im still not 100% sure on how to calculate exactly what is the limit of magnitude that can be imaged, given mirror sizes and all that. $\endgroup$ – DrZ214 Jun 10 '15 at 23:50

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