In April 1990, our Universe opened up to us in a whole new way.
That’s when the Hubble Space Telescope, the most powerful space telescope ever, was launched and deployed.
Although the instrument started off accidentally, as of April of this year, Hubble has been in operation for three decades. And, to celebrate this wonderful milestone, NASA has just handed us space wealth: 50 images of recently processed Caldwell catalog objects, first published to the public.
Cosmic objects can be classified in many different ways. What makes Caldwell’s catalog special is that it only contains objects that can be observed by garden astronomers. Grab a telescope (or, in some cases, both your eyes) and you will be able to find these objects in the night sky.
Caldwell’s catalog, compiled by astronomer and amateur writer Sir Patrick Alfred Caldwell-Moore, was first published in 1995 in Sky & Telescope, designed as a complement to the Messier catalog of 110 objects compiled by the French astronomer Charles Messier in the 18th century.
Galaxy NGC 55, also known as Caldwell 72. (NASA, ESA, R. de Jong, G. Illingworth; prosecuted by Gladys Kober)
Messier, famously, compiled his catalog out of frustration. He was interested in finding quotes; the catalog was a list of annoying things that they were not comets, and this, therefore, could be ignored by comet hunters.
Ironically, it turned out to be a very useful list of bright targets for amateur astronomers, including nebulae, star clusters, and nearby galaxies.
Star cluster NGC 6193 or Caldwell 82. (NASA, ESA and J. Maiz Apellaniz; processed by Gladys Kober)
Caldwell’s catalog, which contains 109 objects, consists of 28 nebulae, 46 clusters, and 35 galaxies that are not included in the Messier catalog, but are still of intense interest to anyone who enjoys looking into the night sky.
There is a joy in finding these objects yourself and seeing them, light years away, with your own eyes. There’s also joy in comparing your own observations to what Hubble has seen with its much more powerful “eye”. And, well, they’re just glorious.
Thirty Caldwell objects appear in NASA’s 50 new images, with some objects appearing in more than one image.
Caldwell Spiral Galaxy 45 or NGC 5248. (NASA, ESA, J. Lee, and A. Filippenko; processed by Gladys Kober)
“Due to Hubble’s detailed field of view, some of his images do not capture the entirety of a Caldwell object, sometimes zooming in groups of young stars in the arms of a spiral galaxy, stars on the outskirts of a cluster or 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 full or near-complete portrait of the celestial wonder.”
In all, Hubble’s Caldwell catalog, first published in December 2019, now includes 87 of Caldwell’s 109 objects. The space telescope has also ignored the Messier catalog; Hubble has represented 96 of the 110 Messier objects. Each object in the two catalogs includes a visual guide to how to see it in the sky.
Coalsack Nebula, or Caldwell 99. (NASA, ESA and R. Sahai; prosecuted by Gladys Kober)
Together, the two collections contain some of the most impressive images of the space around us: an impressive journey through the wonders of the cosmos.
And it has proven to be an absolute testament to Hubble’s prized treasure.
You can see more stunning images in the entire Caldwell collection and the Messier collection on the NASA website.