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.

My 300th observation of Near Earth Asteroids

Near Earth Asteroids are the ones whose orbits come very close to the orbit of planet Earth. Astronomers want to keep an eye on these objects all the time and since they cannot do it, amateur astronomers happily do that for them. As of today, there are 24,158 Near Earth Asteroids known to us.

For the last few months, I have been actively involved in the follow-up observations of Near Earth Asteroids from my observatory (N31) and as far as I know, this is the only observatory which is observing NEA from Pakistan.

The following picture is the stacked image of 100 NEA 2013 PY6 images, which I observed at around 17 magnitude. The three straight lines are the lights of an airplane, which crossed the field of view of the telescope.

You can see how many asteroids are in fact in the field of view

And this is the orbit (in Grey) of this Near Earth Asteroid.

orbit-viewer-snapshot (2).jpg


Periodic Error Correction

Worm gears in the mounts has an inherent error where they introduce a star going back and forth in the image, resulting in a not a perfect round star. Worm gear cannot be made perfect.

Since this is a periodic error, this problem can be reduced by using software to figure out the error and then tell the mount how to move in order to solve the issue. This is called Periodic Error Correction.

Pempro is an amazing software which i have used to ‘perfectly’ polar align my mount and the minimize PE. Recently i had opened the whole mount and cleaned and re-greased everything. Later i put a lot of effort to properly, as far as i can, adjust all the gears back. and today i ran Pempro and here are the results:

 
 

On the top right is the PE which is stunningly good for my mount.. i would want to believe that something is not right.. an error of just and arcsond.. really? is Losmandy Titan such an amazing mount? I am very very happy with these numbers.. but seriously.. 1 arcsecond?

ZWO 183 CMOS Linearity Test

A quick linearity test of ZWO 183 CMOS chip.. this is so surprising.. the linearity goes above 60k ADU. Is the CMOS chip that good or am i doing something wrong here?