Tuesday, September 23, 2014

webspotting 36 - the panoramic Milky Way

As published in the October/November 2014 issue of SCOPE, the newsletter of the RASC Toronto Centre. Republished here with permission.


I've noticed the Milky Way galaxy arcing overhead at some point in the evening during my last few observing sessions. This time of year it is usually high in the sky around midnight. If you're fortunate to escape city limits, it is a wondrous site. Our home. Our galaxy.

In the late spring and early summer, I enjoy looking toward the centre of the Milky Way, in Sagittarius and Scorpius, taking in the myriad of objects huddled around the bright galactic hub. During the long, dark nights in winter, we are turned the other way. As we take in Orion and Gemini, Taurus and Auriga, we are looking into the outer spiral arms of our island universe.

You have perhaps photographed the Milky Way. Or caught the light star-filled regions or dark dusty spots in images. It is a popular target for amateur astronomers in time-lapse photography.

Axel Mellinger has been photographing the skies for many years. He started imaging when he was 14 years old.

In 1996, Axel undertook a project that required three years of imaging at different sites. He ended up with 51 wide-angle all-sky images captured with a film SLR camera using a 28mm f/4 lens which rode on a Super Polaris equatorial mount. He then began digital image processing, correcting for lens effects, and ultimately stitching together 16 of the separate photos for a single high resolution mosaic. That took another 3 years.

This impressive image file can be viewed in different ways including the Aitoff projection or equidistant azimuthal or polar projection. But it's 300 megabytes. Axel's composite is the only amateur contribution to the NASA Multiwavelength poster.

With the advent of quality digital cameras, Mr Mellinger decided to redo the panorama. For 2 years he gathered images from 3000 CCD frames using an SBIG camera. He used complex techniques for gathering the data and developed a specific processing pipeline for processing. The end result, completed in late 2009, was a panorama with 3 times the resolution of his first effort. At full resolution, it is a 7.7 gigabyte FITS cube.

You can view his result at his web site, Milky Way Panorama 2.0. It is best viewed with a "full" computer as he uses the Flash plug-in. This supports smooth zooming and panning. Messier and NGC objects are identified. Large-scale star and dust clouds are well defined. When you start panning about, looking around, there is a strong feeling of floating in space, in your little spaceship, touring the massive spiral structure.

Turn the lights off. View on a large monitor at high resolution. Dive into the Milky Way!


He also offers a JavaScript version.

If you can't get to a dark sky site, if clouds thwart your attempts, enjoy Axel's faithful depiction of galactic dust and glow of millions of distant stars in our home galaxy the Milky Way.

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