Craters on the Moon

 
 

Some prominent craters are Theophilus (98.6 km), Cyrillus (98.1 km) and Catharina (98.8 km) in the center. Western side of Mare Nectaris (333 km) is visible. On top of this Mare, Vallis Capella (49 km) is seen in the top right corner of the image with the Capella crater (48.1 km) and Isidorus Crater (41.4 km). To the lower right, this half filled crater Fracastorius (124 km) was invaded by the lava from Mare Nectaris, hence the North Wall is missing.

On the bottom left, Sacrobosco Crater (97.7 km) is half lit. The big Rupes Altai (427 km) is near. To the middle left, some part of Catena Abulfeda (438 km) is also visible.

Many more craters are here.. Ibn Rushd (31.1 km), Kant (30.9 km), Zollner (47 km), Taylor (41 km), Alfraganus (20 km) and many more.

PS: On April 16, 1972, We landed the crewed three days mission Apollo 16 on the moon. The image above has the location where it landed. Can you find the location?

Sky Brightness Continuous Measurement

 
 

Sky brightness, or darkness as we here prefer, is probably one of the most important factor in visual or instrumental observation of celestial objects. The lower the sky brightness number, the better the contrast we can have for the target object.

Here is a simple chart that shows two weeks of continuous monitoring of the sky. The top numbers are when it was night time. These numbers are in calibrated magnitude scale.

The dips there are the presence of clouds which made the number go a bit higher momentarily during the nightime. Remember, magnistude scale is reversed.