It was a little easier than this

As I announced in my previous post, my blog has now moved to its own domain. The content here will stay up as it is now on the usual pages, but this is all replicated over on the new page. All new stuff will be posted there from now on too (July 2009).

Please update your feed readers and bookmarks.

Thanks!

Image: Tom Turnbull

When I started writing this blog about a year ago I had no idea whether I, let alone anyone else, would enjoy it. But it’s been fabulous.

So I decided to quit my little two-by-two WordPress rental and move to somewhere more upmarket. I put down some cash, signed the papers and picked up the keys to my own domain. In the last few weeks I’ve been pimping the new pad and gradually moving in my stuff. A couple more vanloads and the move will be complete. Consider this, dear visitors, my two weeks’ notice.

Go take a look and please move across your bookmarks and feed reader thingies. Can you tell the difference?! This blog page will continue to exist in its current form, so you can still see old posts, but I’ll replace the front page with one linking to the new address. My twitter feed and tumblelog are still in the usual places.

After the early sneak preview from the PACS instrument on board the recently launched Herschel infrared space telescope, more images have now been released from its other instruments, SPIRE and HIFI. The above image shows images taken with the IR imager and spectrometer SPIRE of nearby galaxy M74 at 250 micron. The amount of detail visible in the images is really great, particularly as all the image reconstruction software hasn’t even been optimised yet. We may be very used to seeing spectacularly detailed images from Hubble, but achieving these resolutions at Herschel’s far-infrared wavelengths is very new.

Because of diffraction, the resolution of an image scales linearly with the wavelength of the light for a given telescope size (in the absence of the Earth’s atmosphere, which tends to interfere!) – so as the wavelengths get longer, the image gets fuzzier. Hubble observes the Universe at wavelengths around 1000 times shorter than Herschel and is therefore capable of imaging at much higher resolution (i.e. more detail is visible) from the outset. At the same time, the comparison in the image above with the Spitzer space telescope, whose mirror is only a fifth of the the size of Herschel’s, shows the gains to be made with a larger telescope size at a given wavelength.  Even though optical and infrared astronomy are often placed under the same header, the technology required to produce images in the infrared is a little different, more challenging to produce and therefore pricier – particularly at the far-infrared wavelengths where Herschel operates.

The Herschel science team also published some images from the telescope’s third instrument, the high-resolution spectrometer HIFI. The picture on the left shows an overlay of HIFI high-resolution spectra of newly forming stars in giant molecular cloud DR21 on mid-infrared Spitzer images of the region.

In summary, all the news from Herschel is good! I look forward to much more new science from it, and congratulations to all the teams who’ve been working hard to make this happen.

The ESA webpage with more details of these images is here. The CoolCosmos site at Caltech gives an excellent and accessible overview of infrared astronomy.

Update 11/07/09: Watch a video of the Herschel/PACS team as they receive the beautiful picture of M51 from the telescope, here. Great stuff!

This beautiful picture of the Omega Nebula (M17) was release today by ESO. It’s a three-colour composite image taken with the 3.6-m New Technology Telescope at ESO’s La Silla site in Chile. The nebula is a region of active star formation, one of the youngest and nearest to our solar system. A recent paper by Matthew Povich and collaborators reported over 90 candidate newborn stars in the region at varying stages of starbirth. Energetic radiation from hot young stars is exciting and lighting up the gas in the nebula.

The Povich paper contains a complete description of this hotbed of star formation at wavelengths from the radio to X-ray and is an excellent reference if you wold like to learn more.

Image credit: ESO

Today, the 4th of July, the Earth’s elliptical orbit takes our planet to its farthest point from the Sun (‘aphelion‘). This composite image demonstrates nicely how this causes the Sun to appear just a tad smaller in the sky compared with the perihelion size, at the closest approach.

Image credit: E.L. Cervigon