Plato [516 N 93 W

We have already looked at Plato's smooth, dark floor with regard to resolving the tiniest craterlets, but Plato (Figure 10.21) is a fascinating crater in its own right. With such a smooth floor and such high mountain peaks on the eastern

Figure 10.20. Brilliant Aristarchus, plus Herodotus and Schroter's valley, imaged with a 37-cm Newtonian working at f/14. Starlight Xpress HX516 CCD camera. A single 0.01-second exposure taken on March 29, 1999. The inset shows how the subtle banding on the western wall can be revealed with a short exposure. Image: Mike Brown.

Figure 10.20. Brilliant Aristarchus, plus Herodotus and Schroter's valley, imaged with a 37-cm Newtonian working at f/14. Starlight Xpress HX516 CCD camera. A single 0.01-second exposure taken on March 29, 1999. The inset shows how the subtle banding on the western wall can be revealed with a short exposure. Image: Mike Brown.

crater rim, sunrise over Plato, at selenographic colongitudes of 10° to 13° can be a fascinating time. The highest peak on the eastern wall (just south of east) casts an incredibly straight pencil-like shadow onto the crater floor. If you catch the crater one-quarter filled with shadow, as sunrise is well underway, you will forever wonder if this needle-like shadow is capable of reaching the western wall

Figure 10.21. Plato and its tiny floor craterlets, imaged with an Orion Optics 250-mm f/6.3 Newtonian and an ATiK 1HS webcam on March 19, 2005. Image: Jamie Cooper.

and you will just have to resolve to catch it earlier the next month. In fact, the shadow really does reach the base of the western wall, although at the point where it just becomes visible the lighting on the crater floor is so dark anyway, compared to the dazzle from the illuminated lunar surface, that enhanced photographs or images are needed to be really sure. (Unless, that is, you are a really experienced visual observer.) In fact, the two-kilometer-high mountain peak shadow stretches an incredible 80 kilometers across Plato's floor, despite the Moon's curvature.

With webcam images and a GIF animation facility (available with most image processing packages) a dozen frames of a crater at sunrise and sunset, taken over a period of several hours, can be most instructive. An animated GIF can produce a fascinating jerky movie of shadows growing or receding. The Plato sunrise shadows are especially attractive to image, as they occur at first quarter when the Moon transits in the early evening. In spring, this is when the Moon is high in the sky.

Not far from Plato one can find the Alpine Valley and its rille, referred to earlier in the text.

Telescopes Mastery

Telescopes Mastery

Through this ebook, you are going to learn what you will need to know all about the telescopes that can provide a fun and rewarding hobby for you and your family!

Get My Free Ebook


Post a comment