Close-up of the Moon

© Rik ter Horst

On the cold and windy evening of the 24th of February I had the chance to make some test-images with the 40 cm F/13 I recently finished (well, almost). Luckily, the seeing was quite reasonable so I took advantage to make some high-resolution images of the Moon.

This image shows the area of the craters Clavius (below) and Tycho (on top). Using 'Lucky Imaging' techniques, the resolution of this image comes very close to the theoretical limits for a 40 cm telescope. The smallest details visible are well under one kilometer (around 600 meters).

The telescope's primary mirror is a 18 mm thin-meniscus mirror, and because it's so thin it cools down very fast, reducing the internal air currents WITHIN the telescope considerably. This was the main reason to start making a thin-meniscus mirror, despite all the challenge involved in grinding and polishing such a thin mirror.

For full resolution, please click on the image.