Size matters

Some calculations will seem very intimidating at first. They won't bite.

Telescope

\[\text{Diameter of mirror, }D_1 = 150 mm\] \[\text{Focal length of mirror, }f_1 = 750 mm\] \[\text{Focal length of eyepiece, }f_2 = 28 mm\] \[\text{Resulting magnification}\frac{f_1}{f_2}=\frac{750}{28}\approx{27}\] \[\text{f-number, }N = \frac{f_1}{D_1}=\frac{150}{750}=5\]

Next up is a concept I don't fully understand. Macimum theoretical resolution of a telescope. Capability to see small details. This is apparently a function of telescope diameter and light wavelength. At least in theory. Stuff like aberrations and seeing come in the way, but there is a maximum theoretical resolution. For visual light we get

\[\alpha = \frac{140}{D_1} = \frac{140}{150} \approx 0.93 \text{ arcseconds}\]

So, I won't be able to distinguish details smaller than about 1 arcsecond. For reference, the moon is about 30 arcminutes.

Camera

The telescope is interesting in itself. Let's see what happens if we attach a camera to the telescope. First we figure out the plate scale measured in arc seconds per mm.

\[\text{Width } 3888 \text{ px}; 22,2 \text{mm}\] \[\text{Heigth } 2592 \text{ px}; 14,8 \text{mm}\]

\[\text{Plate scale } = \frac{206 265}{f_1} = \frac{206 265}{750} \approx 275 \text{ arc seconds per mm}\]

Sooo... images I take with my camera will be roughly 1,7 by 1,1 arch degrees.  The moons diameter is roughly half an arch degree. This seems to be in line with my first experimental photos. Waiting for the moon to come up so veryify this. Moon, where are you?

What about resolution?

\[ 1,7 \text{ arc degree divided by } 3888 \text{ pixels gives roughly 2292 pixels per arch degree}\] \[\text{or } 0,63 \text{ pixels per arch second}\]
Seems the camera resolution is comparable to the telescopes theoretical maximum resolution. Cool.