理论计算
If we assume a 6.5mag visual sky (common used for calculation of limiting visual telescope magnitude)
we can reach 12.5mag within 1 sec exposure time and a simple 56mm lens.
30 stacked frames of 1 sec can reach 14.5mag even with fixed mount. So you are able to see PLUTO with this simple telescope !
在目视星等6。5等的天气下,采用焦距56mmF2。2的照相镜头,1秒曝光能达到
12。5等,30张叠加能到14。5等,可以用这个镜头看到冥王星
If we assume a 14" SC with a 30 times more light collecting area than a 56mm lens, you can reach 16 mag within one second!
With a single 30 second exposure and 14" SC you are able to reach 19 mag.
如果用比56mmF2。2焦距照相镜头集光能力强30倍的14寸SC望远镜,1秒曝光能达到16等。30秒曝光能达到19等!
实际测量
With 56mm lens and 1 sec exposure of "first light" i have reached 10.5mag. If we extrapolate
exposure time and light collecting area i can calcalate:
100*100/56*56 * 30/1 = 95 times more light -> approx. 5mag
10.5mag + 5mag -> 15.5 mag
If we compare this extrapolation with measured photometric datas of "second light"
and a limiting magnitude of 16 mag, it fits well.