Astroblog: It's just like having your own cloud-free telescope

Thursday, March 13, 2008

It's just like having your own cloud-free telescope

As you know, I regularly download images from the STEREO SECCHI imagers to search for comets. I haven't found any yet, but Comet Al has found one or two (or three). But you can see lots more than comets (and coronal mass ejections) in the STEREO images. Like lots of asteroids. As the H1 and H2 instruments only go down to about magnitude 14 at best, you are unlikely to discover any new asteroids though. Nova too, Comet Al caught this image of Nova Scorpii 2007 near comet McNaught in the H2 imager. And variable stars.

The animation above is of the minima of Algol that took place on the 7th of February. Now, this is no big deal for many people, but I have never seen a minima of Algol before (Algol is always too close to my horizon to reliably check it out), so catching it in the STEREO images was something special. Of course, Algol is old hat and well known, but the STEREO images could be used to monitor other less well characterised variables (or at least harder to follow in my scopes). Also, as these at FITS images, you can quantitate the intensity of the star and its drop in magnitude.

Could you use the SECCHI imagers to detect exoplanets? It's a possibility, the exoplanet bearing star has to be relatively bright, lie within the H1 or H2 field of view and have a fairly deep eclipse. WASP-2 and HD 209458 might scrape in under these conditions. HD46375 and HD46375 are within the field of view, fairly bright but have only shallow eclipses. HD2638 is relatively bright (magnitude 9.3), in the field of view of the H1 imager and has a fairly deep eclipse (about 1.2% of total brightness, not to dissimilar to TRES-1's 1.7% fall). Sadly, TRES-1, which has been observed by amateurs, is too far away from the H1 instruments to be imaged.

Still, there is so much out there that is caught in the STEREO imaging cameras, on rainy or cloudy nights it's like having your own personal telescope. Of course, STEREO is a research instrument, actually intended for studying the solar atmosphere, so for us astronomers everything else is gravy. So don't go crazy and download huge chunks of data, think about the researchers who don't need their bandwidth hogged by frenzied amateurs sucking down every last image. Remember, play nice, it's due to them that we get to play with such and awesome instrument for free.

Labels: asteroids, Stereo comet astronomy, variable star