Stupid astronomy tricks

[Mark Wagner]

Do professionals make mistakes in building telescopes?  Yes, you needn't be an amateur.

Many of us recall HST and it's initial optical deficiency (repaired by a local with indirect ties to this group).  But with  Lick's 36" too!  It did not come to focus on first light.  The Clarks' provided objective focal length was to long, and Warner & Swasey built the pier to tall, and 55' tube to long!  Imagine the consternation.

Quicky repaired, it's initial views were of Saturn (by Keeler) and M42, revealing for the first time a 6th star in the Trapezium.  How cool that we amateurs now pick out that 6th star in much smaller apertures from our backyards on good nights.

Making telescopes in an adventure.  I make plenty of professional quality errors.

Mark

[Steve Gottlieb]

Just to give the 19th century visual observers a little more due credit, the 6th star was discovered much earlier (1830) by John Herschel.  It was the 7th star — the much dimmer “G” star WITHIN the Trapezium — that was seen on first light of the 36” in 1888.  The “G” component is dim and isn't visible in small scopes.

Barnard also discovered the "H" component using the same scope later that year, and resolved it as a very close double!

Steve

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[Mark Wagner]

Thanks Steve.  I just checked the book (I am reading on Lick Observatory) and indeed it says 6th.

Mark

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[Richard Ozer]

Interestingly, the G star was discovered by Alvin Clark himself while testing the 36" in 1888.

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[Mark Wagner]

LOL!  Two errors on one item in a book book by one of the observatory's directors?  Amazing.

The book also refers to Clark (and the director at Oakland's Chabot) as a curmudgeon and perhaps jealous, spreading bad juju toward the 36 (and builders).

Mark

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[Stanley Sokolow]

I think I recall that the HST optical error was due to a computer programmer's error in converting between American and metric units. That was a costly error but fixable. Worse than that was the metric conversion error in under-filling a commercial airplane's fuel tanks, which caused fuel to run out at 41,000 feet elevation.  QUOTE:

On July 23, 1983, Air Canada Flight 143 made aviation history for all the wrong—and right—reasons. The Boeing 767 ran out of fuel mid-flight at 41,000 feet with 69 people onboard, all because of a simple metric conversion error: the crew loaded 22,300 pounds of fuel instead of 22,300 kilograms.

With both engines dead, the plane became a 132-ton glider. Thanks to Captain Robert Pearson’s experience as a glider pilot and First Officer Maurice Quintal’s quick thinking, they managed to glide more than 80 miles and land safely at an old airstrip in Gimli, Manitoba. With skill, the pilot did a side-slip landing to slow the plane using aerodynamic drag.

No one was killed. The landing was so smooth it became legend—the day a commercial jet turned into the Gimli Glider.

Sometimes skill, calm, and a bit of luck make all the difference. ✈️

On Sat, Feb 14, 2026, 5:17 PM Richard Ozer <rich...@gmail.com> wrote:

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[Alan Agrawal]

The HST error was due a penny’s worth of missing antireflective paint from the cap of an invar spacing rod used for null testing. That led to the inappropriate placement of washers into the null testing device, and the rest is history.  Time pressures, cost pressures, repeated poor decision making by technical staff and management, at all levels for both across multiple points of time led to the error not being picked up and corrected.

Alan

On Feb 14, 2026, at 5:41 PM, Stanley Sokolow <stanley...@gmail.com> wrote:



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[Ted Hauter]

Excellent points gentlemen.

Mark is that the Eye on the Sky book on Lick?

Sometimes the statements clear up at the end did you finish the book?

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[Jay Freeman]

See https://en.wikipedia.org/wiki/Hubble_Space_Telescope#Flawed_mirror

-- Jay Reynolds Freeman

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Jay_Reynol...@mac.com
http://JayReynoldsFreeman.com
(personal web site)

On Feb 14, 2026, at 5:41 PM, Stanley Sokolow <stanley...@gmail.com> wrote:



I think I recall that the HST optical error was due to [...]

[Richard Ozer]

There is a long line of Curmudgeons in Chabot's history.

Burkhalter, who was director during the acquisition of Leah, the 8" Clark, always wanted a bigger telescope.  I'm sure the jealousy story has some truth to it.

The story goes (and I paraphrase), that when asked why the 20" Brashear (acquired 30 years later) was named Rachel, he said just like when Jacob was fooled into marrying Leah, it was Rachel he always wanted.

In truth, Rachel is an impressive scope and loads of fun to operate and maintain, but the 8" Alvin Clark is a peach.

Rich

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