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Sky Surveys (Hubble Isn't the Only Show in Town)

© Sonya Thomas-Haley

The Hubble gets all the glory, but there are many other nice catalogues of images out there. All kinds of sky surveys have been going on and continue to go on and the database of astronomical images and info continues to mushroom. The Internet allows everyone access to this material -- well, most of it, anyway. Those databases you can't get into are undoubtedly too technical anyway. Here I highlight two very impressive sky surveys.

2MASS is the Two Micron All-Sky Survey. It is scanning the entire sky in the near-infrared. The primary advantage of infrared wavelengths is that they enable us to peer through dust that obscures the shorter optical wavelengths. It makes use of two 1.3-meter scopes,one at Mt. Hopkins in Arizona and another at Cerro Tololo in Chile. The Cerro Tololo site is fascinating in its own right. It is a high, dry and desolate place. I came across this web site put together by Charles Danforth and I highly recommend checking out his account and pictures of his visit to Cerro Tololo.

An absolutely amazing example of some of the images this survey has produced is this one of M17, the Omega nebula. This will take a while to download because it is 1.4 Mb, but it is well worth the wait. You might ask why the image isn't "red" since it was acquired using infrared. The reason is that the images were processed assigning red, blue and yellow to three slightly different infrared wavelengths.

And here is one more image that will blow your mind. This is a shot looking towards the galactic center in the constellation Sagittarius. If you wear glasses like I do, this image will make you jiggle them to straighten them and make sure you are seeing right and focusing properly. All I can say is WOW!

SDSS is the Sloan Digital Sky Survey. It has a more narrow focus covering one quarter of the sky, but it is doing so in extremely great detail, making it a very ambitious undertaking. It will measure distances to millions of galaxies and thereby help cosmologists better understand the structure of the universe.

Galaxies are not dispersed uniformly. They group into clumps, which in turn are part of sheets, like the surfaces of bubbles, and inside the bubbles are great, empty voids. Understanding more details about the distribution of galaxies will help cosmologists understand how the universe has evolved.

The copyright of the article Sky Surveys (Hubble Isn't the Only Show in Town) in Amateur Astronomy is owned by Gregg Pasterick. Permission to republish Sky Surveys (Hubble Isn't the Only Show in Town) in print or online must be granted by the author in writing.