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My July fund-raising campaign to celebrate the fifteenth anniversary since I began Behind the Black is now over. I want to thank all those who so generously donated or subscribed, especially those who have become regular supporters. I can't do this without your help. I also find it increasingly hard to express how much your support means to me. God bless you all!

 

The donations during this year's campaign were sadly less than previous years, but for this I blame myself. I am tired of begging for money, and so I put up the campaign announcement at the start of the month but had no desire to update it weekly to encourage more donations, as I have done in past years. This lack of begging likely contributed to the drop in donations.

 

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A telescope using a liquid mirror about to become operational

Link here. The telescope, located in the Himalayas, is “an international collaboration between institutions in India, Belgium, Poland, Uzbekistan and Canada.”

The mirror works by rotating it so that its thin layer of liquid mercury forms a parabola.

The tradeoff is that the [telescope]is fixed in a single position, so it only observes one strip of the night sky as the Earth rotates below it. But since the telescope will be hyper-focused on just one area, it’s well-suited for spotting transient objects like supernovas and asteroids.

It appears the scientists will use it to study this same strip of sky over five years, hoping to detect changes in that time period.

This telescope is more a technology test than an actual observatory. Eventually the best place to put such a telescope — and much larger — will be on the Moon, and to do that requires some construction and testing beforehand.

Genesis cover

On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

 

The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.


The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
 

"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News

6 comments

  • Ray Van Dune

    Canada has been a pioneer in rotating mercury mirror technology – I recall reading about an experimental observatory using a rotating mercury mirror in southern British Columbia 20 years ago. They were pretty cagey about where it was located, since it was on park land and they were afraid of vandalism or other kinds of disturbance. IIRC at that observatory they experimented with a flat mirror to allow the scope to scan to a degree. But of course, that was an alt-azimuth scan since the mirror could not be tilted, which would rotate the image. In addition, every reflection reduces the light transmitted by some percent, so there was speculation that future such telescopes would forgo such a scanning mirror.

  • Captain Emeritus

    I made liquid lens for years to pass vision acuity tests for the Feds.
    Just yank a few hairs from a nostril, cause a tear to form, and squint…
    you can read the bottom line without correction.

  • pzatchok

    Some one tried making a mirror out of Mylar.

  • This was first tried in 1908. H. C. King, The History of the Telescope. A very interesting book for all telescope fans.

  • Kelly Ambrose (Sr.)

    Is mercury too heavy for a vacuum or too weird for a magnet to enable tipping?

  • pzatchok

    In a vacuum the mercury would be fine.
    In zero G it would be spun to the edge of its tray or container, It needs the gravity to pull it back down to the center to form a dish shape.

    If it tilted in gravity the gravity would pull it down to the lower edge thus distorting the shape.

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