In April 1990, our universe opened up to us in a whole new way.
That’s when the Hubble Space Telescope was launched and deployed, the most powerful space telescope ever created.
Although the instrument got off to a bumpy start, Hubble has been in use for three decades since April this year. And to celebrate this amazing milestone, NASA has just handed over riches: 50 newly edited images of objects from the Caldwell catalog, first released to the public.
Cosmic objects can be categorized in many different ways. What makes the Caldwell catalog special is that it only contains objects that can be observed by backyard astronomers. Grab a telescope (or, in some cases, your own two eyes) and you can find these objects in the night sky for yourself.
The Caldwell Catalog, compiled by amateur astronomer and writer Sir Patrick Alfred Caldwell-Moore, was first published in 1995 in Sky & Telescope, intended to complement the Messier catalog of 110 objects compiled by French astronomer Charles Messier in the 18th century.
Galaxy NGC 55, also known as Caldwell 72. (NASA, ESA, R. de Jong, G. Illingworth; edited by Gladys Kober)
Messier compiled his catalog out of frustration. He was interested in finding comets; the catalog was a list of nasty things that weren’t comets, and that could therefore be safely ignored by comet hunters.
Ironically, it turned out to be a very useful list of bright targets for amateur astronomers to look at, including nebulae, star clusters, and nearby galaxies.
Star cluster NGC 6193 or Caldwell 82. (NASA, ESA and J. Maiz Apellaniz; edited by Gladys Kober)
The Caldwell Catalog, which contains 109 objects, consists of 28 nebulae, 46 clusters and 35 galaxies that were not included in the Messier catalog, but are still of great interest to anyone who likes to look at the sky at night.
It is wonderful to find these objects for yourself and see them with your own eyes, light years away. It’s also nice to compare your own observations with what Hubble has seen with its much more powerful “eye”. And, well, they are simply delicious.
Thirty Caldwell objects appear in the 50 new NASA images, and some objects appear in more than one image.
Spiral Galaxy Caldwell 45, or NGC 5248. (NASA, ESA, J. Lee and A. Filippenko; edited by Gladys Kober)
“ Because of Hubble’s detailed field of view, some of the photos do not capture the entire Caldwell object, but sometimes zoom in on clusters of young stars in the arms of a spiral galaxy, stars at the edge of a cluster, or the zombie star in the heart of a nebula, ” Vanessa Thomas of NASA’s Goddard Space Flight Center wrote on the NASA website.
“But in other cases, a mosaic of Hubble observations comes together to create a complete or nearly complete portrait of the celestial wonder.”
In total, Hubble’s Caldwell catalog – first published in December 2019 – now includes 87 of 109 Caldwell objects. The space telescope has not ignored the Messier catalog either; Hubble has imaged 96 of the 110 Messier objects. Each object in both catalogs includes a viewing guide on how to see it in the sky.
Coalsack Nebula or Caldwell 99. (NASA, ESA, and R. Sahai; processed by Gladys Kober)
Together, the two collections contain some of the most breathtakingly beautiful images of the space around us – an awe-inspiring tour of the wonders of the cosmos.
And an absolute testament to the priceless treasure that Hubble has turned out to be.
You can view more stunning photos in the full Caldwell collection and Messier collection on the NASA website.