Milky Way in hydrogen glory

One of the losers in STFC's cuts is the Issac Newton Group of Telescopes on La Palma which, I think, are now having their planned closure accelerated (perhaps someone who knows better can confirm that). Given these events, yesterday saw the release of the first part of a huge survey of the Milky Way by the Wide-Field Camera on the 2.5 m Issac Newton Telescope (INT). The section of the survey chosen for the press release shows a central part of the Rosette Nebula (NGC 2244) and is pretty stunning.

Rosette Nebula
Centre of the Rosette Nebula, as imaged in Hydrogen alpha emission in the IPHAS survey. CREDIT: Nick Wright, University College London/IPHAS
The image above (click on it for the full 5388x3777 pixel glory!) was created using two broad-band filters and a special filter that selects the particular red colour of light emitted by hydrogen atoms - H-alpha (656.3 nm). The image covers an area a little smaller than that covered by the Moon in the sky although given its distance that probably makes this image about 20-40 light years or so across (various sizes for the nebula are given so this is a rough estimate by me).

The data release yesterday is of the northern plane of the Milky Way galaxy and covers around 1600 square degrees. Once the rest of the survey is released that should go up to about 4000 square degrees! Another exciting thing about this data is that it has been integrated into the Virtual Observatory - an international effort by astronomers to provide easy access to many huge astronomical surveys and databases.

You can use the IPHAS survey's swishy flash-based interface to search by object name (e.g enter something like "Eagle Nebula") or by position on the sky. The 'Postage Stamp' option gives a nice interface to the images and is clearly inspired by the album art display in iTunes! The only problem I had was after having tried searching for NGC 7027, then searching for the Eagle Nebula only to find NGC 7027 popping up; it may be geeky of me to say but I recognised it from the r filter image so knew it wasn't the Eagle Nebula. Despite these minor quirks, it looks like a pretty nice front-end to a vast optical survey of our galaxy.

Posted in astro blog by Stuart on Thursday 13th Dec 2007 (23:38 GMT) | Permalink
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