Quote:
Originally Posted by Rob_K
Hi Glen, this is excellent stuff, congratulations! 
However, your formula should be expessed as [9.1 + 5logD] x 85%. Took me a while to work this out, as I punched in my aperture and got a WML of mag 11.8, which was obviously too high (more like my threshhold, although I have seen some mag 12 objects). 10.5 is a better figure, but still maybe a touch high. Perhaps the formula might fall down a little with small apertures - would like to know your opinion on this. Certainly, no 2" telescope would have a WML in excess of mag 9.1, you'd think.
Cheers -
Rob |
I regularly observed variable stars as faint as 11.5 mag with my 20x65 binoculars and my 60mm refractor (in the 1970s). Averted vision again.
And Herchell's telescope optics weren't too flash either by modern standards. Specula mirrors - reflectivity only about 0.72 (varies from 63% at 4500 A. to 75% at 6500 A , and less if tarnished).