A famous old telescope has spent nearly half a century in New Zealand while awaiting a new home. There is now a good chance that a new life for the 18-inch (45-cm) Brashear refractor will be found.

The telescope has an illustrious history. It was installed in 1897 at the Flower Observatory in Pennsylvania, which was owned by the University of Pennsylvania. The mechanical construction took place in 1895-96 at the Warner and Swasey Co. in Cleveland Ohio. The optics were figured by John Brashear (1840-1920) in Pittsburgh. He was the famous American optical engineer and the equal of Alvan Clark. Together Clark and Brashear built some of the largest refractors of the late nineteenth and early twentieth centuries.

In an earlier article written for Cosmic Diary I gave my personal list of the top 25 discoveries in astronomy and astrophysics of the twentieth century (see Cosmic Diary for 18 June: http://cosmicdiary.org/blogs/john_hearnshaw/?p=96). The list was originally prepared for a seminar on this topic, but in compiling my list of 25, I actually considered a larger list of at first 50, which grew to 51 after the seminar!

So in this blog I am going to present what are the most important discoveries between numbers 26 and 51. The criteria for selection were only to include astronomy and astrophysics of the Sun, stars and beyond. Cosmology is of course included, but solar system exploration of planetary bodies by spacecraft was not part of my deliberations (important though that may be). By importance I am referring to impact in discovering something completely new, such as a new phenomenon or type of object, and research which went on to spawn a whole new branch of subsequent investigations. For sure, my judgement is very arbitrary, and I have not done a more careful analysis based on citations, though that would have created its own set of biases.

A few years ago (in fact in 2006) I considered the issue of how the support for astronomy in any country depends on its economy. It’s an interesting question, but the problem is how to measure an index of astronomical vitality in a country.

The very simplest and crudest measure is just to count the number of International Astronomical Union (IAU) members present in any country. The IAU is recognized as the main international organization for professional astronomers.

For anyone who analyses some simple truths about astronomical publishing, it should be obvious that there is a crisis in publishing which must soon explode. The crisis is that far more papers are being published than any astronomer could ever possibly read. Even in narrow subdisciplines of astronomy, the rate of publication is relentlessly increasing far beyond our ability to read the published output. As a result, many papers are probably never read by anyone other than the author and perhaps the referee, many only have the abstract skimmed by a few people, and many are never cited in other works. The present practice of many astronomers publishing several refereed papers a year is simply unsustainable. Let’s look at some numbers.