Wednesday, 26 October 2011

Our society's new "star camp" venture

Here's Cygnus the Swan and Delphinus the Dolphin setting over trees at my society's new star camp site. Unfortunately, the night I choose to camp out with my telescope was the mistiest night of the year. Still, this scene looked rather lovely. This is a composite of 13 images of the constellations setting in the west, in the wee hours.

Tuesday, 25 October 2011

ζ Scorpii

Embedded deep in the centre of the milky way is a stunning stellar asterism around the star ζ (zeta) Scorpii. Here I show the area in four levels of magnification taken with various optical pieces of equiment, while in La Palma. The wide view was produced by continuously taking 15 second pics on a little tripod, through a 50mm f/1.4 lens. The next level was 2 minute exposures through a telephoto lens on a low zoom atop an Astrotrak platform that wasn't quite aligned, at f/3. The following image was produced from 4 x 5-minute exposures at nearly full zoom that were possible once the Astrotrak had been aligned. The last picture is a mosaic of two 5 minute pictures taken through a guided 4-inch vixen refractor, using an astronomy-modified Canon 350D.

Monday, 17 October 2011

Space ripples.

Here's take 2 on an object I virtually started my blog with. That's 200 posts ago. Yes, it's yet another big swirly nebulous thing! 6 x 2 minute exposures on the 20" newtonian at f/3 (focal reduced) with my astro modified Canon 1000D. Then I went back on a moonlit night, reassembled my focal reducer and got some flat fields. They made all the difference, even just as jpegs, which are pre-processed. Andy, you seriously have to try that man, it's a gas. You can see where I had to do my detrailing trick on the stars at the right hand side. This picture demonstrates the reason why you shouldn't expose for over a minute on a flipping "alt-az" when it's pointing high. Field rotation is the reason I focal reduce an already f/5 scope. I have over blurred the fainter regions in processing so I can enhance the contrast just a little bit more. The pretty object is a supernova remnant and what you are seeing is shock fronts as ripples expanding from what I guess is now a black hole or an inactive neutron star, but no one has been able to see much, just a little bit of hot metallic plasma. It all happened just a few thousand years ago, plus the 1500 years or so that it took the light to reach us.

Wednesday, 5 October 2011

By Jove!

We stayed up on a crisp, clear night until the dazzling Jupiter rose high in the South at our observatory. We put our cameras on the 20" scope and spent ages tweaking focus and getting sequences of shots. I settled on covering the scope with an 8" mask, positioned at the lower end of the aperture to minimse the seeing distortions. This helps by matching the aperture scale with that of the atmospheric turbulent cells. We got a dimmer, but much sharper picture. I grabbed forty 1/50" exposures using a 2x barlow on this set up, to give an overall focal length of 4.8m at 0.2m aperture = f/24. I used large jpeg format on the Canon EOS 1000D(mod). I stacked 39 in Registax and upon wavelet sharpening, it revealed this wonderful detail. I had some trouble using Registax that wasted many hours, but I got there. Still, I didn't manage to select only the best quality pictures, so all got stacked. The highlight of this night was peering into the eyepiece and seeing the sharpness of the storms, belts, the light pink GRS, and best of all... the moons appeared as sharp disks! I was blown away!