Sky & Telescope October 1955 Cover

Folks,

Just sitting in work reading Sky & Tel and I noticed in the 50 & 25 years ago section that the cover for the October 1955 issue has a picture of Dunsink on the cover.

Does anybody have any idea why this was. Was there an article on Dunsink in the issue?

Cheers,

Spaceboy

Note the S&T archives on skyandtelescope.com are searchable. You'll see the Oct 1955 issue contained an article called:

"Dunsink Observatory -- Then and Now"

I've a subscription that allows downloads from the archive content, but only back as far as the mid-ninties (they probably used some manual typesetting technology before then). So I can't help you on the article content ...

/Eoghan

The Ninth General Assembly of the International Astronomical Union was in Dublin on August 29 to September 5, 1955. Professor Struve gave the Presidential Address with the full text in the 1955 October issue of Sky & Telescope. Dunsink Observatory was the main location for some of the IAU Commission meetings. The main ceremonial opening was at the Ambassador cinema, Dublin.

At the previous Rome Congress in 1952, it was a complete surprise to the Irish astronomers that the IAU would hold its next General Assembly in Ireland. Because the instruments were old at Dunsink, it was decided to commission a modern 28 inch Cass. telescope with photoelectric detector.
This was built within 2 years and demonstrated to the delegates. There were 800 astronomers in attendence.

Eamonn A

eansbro wrote

Because the instruments were old at Dunsink, it was decided to commission a modern 28 inch Cass. telescope with photoelectric detector.
This was built within 2 years and demonstrated to the delegates. There were 800 astronomers in attendence.

A 28 inch Cassegrain :shock:
Any idea what happend to this instrument?

Spaceboy

It was used from 1955 to the early 1970s for scintillation and variable star research.

Because the telescope was made urgently, under a time constraint of two years for the IAU Congress in Dublin, the mounting wasn't perfect. The optics were made by George Hole & Son (high accuracy mirror makers) in the UK- they were excellent.

However, the 28 inch Cass telescope went into disrepair. The primary mirror was disfigurred, this was noticed with the anstigmatism present in star images and when it was time for recoating, it was sent to College of Technology, Kevin Street (as it was known), the Colleges high vacuum tank for thin film coatings had an unknown leak. This resulted with a partial vacuum resulting with a very poor coating of aluminiun. A number of attempts were made to seal the vacuum, with frequent bad results of aluminium coatings. I suspect that the mirror degraded on the surface with the frequency of coatings and cleaning.

It was decided to bring the mirror back, and eventually it was left boxed in the basement of Dunsink Observatory.

Eamonn A

What a terribly sad end for what should have been a great instrument