I just got a 20 inch telescope. I’m trying to figure out what it can achieve vs my 12 inch telescope. Is it possible to actually see the disc of Saturn’s moon Titan? Or is that going to depend on the seeing conditions more than anything?
I just got a 20 inch telescope. I’m trying to figure out what it can achieve vs my 12 inch telescope. Is it possible to actually see the disc of Saturn’s moon Titan? Or is that going to depend on the seeing conditions more than anything?
According to its wikipedia page, Titan’s disc is 0.8 arcseconds in diameter.
Dawes’ Limit stipulates that a 20 inch scope can resolve objects no smaller than 0.22 arcseconds.
So under exceptionally stable atmosphere, there’s a chance you could see Titan as more than a point of light.
Ganymede (Jupiter’s largest moon) subtends 1.2-1.8 arcsec and I’m able to resolve it as non-stellar (and occasionally see some surface coloration) using my 14" scope. But it takes exceptionally stable air, a well collimated and thermally equalized scope, and some luck. Seeing Titan as non-stellar would be at least twice as difficult, bordering on impossible. And it doesn’t help that Titan has a thick cloud deck, meaning you don’t have the benefit of surface coloration to make it obvious that you’re not just seeing a single unresolved point of light. You would need a star nearby Titan so you could compare the size of the Airy disc to confirm whether you’re actually seeing more than a point of light.