Today, I made some observations that could be so simple and trivial that most people wouldn't give a damn on my discoveries. Today, I found evidence of rotation motion between the physical ground and the observable sky. More on that later, for now just enjoy these photos. I just love the clear sky after rain.


Sunset view outside kitchen. All photos taken with H1.


Starry starry night.


Another H1 Moon, this one is almost full, it's the 13th of the month.


Stars at full telephoto, 15 sec exposure. It looks like short lines


100% Crop of the stars at full telephoto, and the evidence for rotation mentioned above.

Okay, here's the discovery. Look at it. It's raining stars. At first I was puzzled, why are my stars not sharp, could it be vibration? It couldn't be because I'm using a tripod and I did not even extend the legs at all! The effects look like motion blur and indeed it is. 15 secs is more than sufficient to make that observation. In fact, I tried to estimate the angular displacement of the stars in 15 sec, it got to be somewhere around 0 degrees 3 minutes and 45 seconds.

Making use of the angle of view formula found in wikipedia and the specifications of the H1. I estimate that the angle of view of H1 at full telephoto is about 8 degrees. So the stars would have travelled about 16 pixels over the course of 15 seconds exposure. Which is reasonably good estimation given that the stars moved about 30 pixels in reality. Cool! Maybe I could use this as a teaching material in the future, who knows.

Tagged: singapore stars dsc h1 moon sunsets photos