Thursday, 16 July 2009

Polar Mesospheric Clouds a long way South

On our observatory meeting night, we were treated to the usual clouding over and sprinkling of rain, while we were inside chatting. I was upstars in the dome, hoping we would be able to see a star or have something to point the scope at. We were watching a clear patch start to roll over revealing the twlinkly red star Antares and there were some cirrus-like clouds appearing right across the sky as the twlilight was fading at about 22:00 BST. I presumed they were cirrus but as the sky grew darker I realised they had some wonderful wave like patterns in them, and they continued to stand out from the darkening sky. They were Noctilucent clouds, covering the whole sky at 52 degrees North! I ran to the car while they faded to fetch my Canon 350D and took a few shots with it resting on a chair seat on the observatory roof, pointing NW. This particular shot taken at 22:36 on 15/07/09 is 1/5 second at ISO 1600, f/5.6 and about 35mm focal length (48mm @ 35mm-equivalent) with auto dark subtraction on. I continued at 4 seconds and ISO 100 thereafter for better noise, but the composition and scale of this earlier display looked the most impressive.

Wednesday, 15 July 2009

What was in front of the Space Station?

The Shuttle mission STS-127 has been delayed several days by bad weather, so what was the mystery object 30 seconds ahead of the International Space Station when it flew over Southern Britain at 23:07 UT(GMT) on 12/07/2009? Quite bright, it is clearly in the same orbit because the trails just appear to touch on this 30 second picture, as they did in the consecutive pictures. Take a look as it passed below Arcturus, viewed from just North of Norwich. Remember the light from the satellite has been spread out across its path and the ISS appeared much brighter than Arcturus.

Friday, 10 July 2009

Messier mosaic

Here is a 4x3 snippet of my new Messier object mosaic. Each picture is a 300x300 pixel image I have taken of the object. Some are awfully low in altitude from 52ºN. It's surprising how different each image is. Each have their own image processing challenges, whether it is light pollution subtraction, bringing out faint spiral arms, or eliminating the blurry disc effect on the small globular clusters. I learned that not all globulars look alike, and they all look impressive with a 20" scope. I used different magnifications for different objects, e.g. M24 in Sagittarius is huge! I have arranged my mosaic as 11 rows of 10, so each column ends in the same digit - but it's not complete. Here is a complete section so you can guess what columns and rows I have shown - if your astronomy knowledge is up to it, that is!

My best shot of Pluto yet

Pluto still has a place in our mind as a planet, but it's just too small. Smaller than the moon, a little bit brighter, but about 12,000 times further away. It is about 3,000,000,000 miles away in this photo and the light from the sun that's reached it is having to come all that way back in to us. It's amazing we can see it at all, because that light is the 'lucky' portion that has reflected almost straight off the rocks or ice on its surface. But nevertheless, it is clearly visible when you capture 30 seconds worth of those photons by bouncing them yet again off a 20 inch highly silvered mirror in a hole in a dome in a field in Norfolk. Pluto's moon, Charon, would also be visible if it didn't lie within the small circle of fuzz around the image of Pluto.