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BrianL
member
Reged: 08/07/08
Posts: 11
Loc: California
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Comparison Table of Mirror Diameters and Correspondent Planar Diametric Surface Areas
For your perusal and amusement, to all ATMs and astronomy adepts, everywhere.
‘Lest we also forget, Rudyard’:
Created and contributed by myself for all amateur astronomers everywhere in appreciation of the hobbies of amateur astronomy and amateur telescope making; for use, conversational comparison and reference by astronomers, would-be astronomers and all telescope makers everywhere … in appreciative awe of the magnitude and depth of human technologicical and historical achievement implied by these dimensions which simply ‘are’.
Dedicated to the memories and interests of the following individuals who have so earnestly in their lives either directly or indirectly given their time, efforts and interest to the preoccupations of Mathematics, Science, Astronomy, the hobbies of amateur astronomy and telescope making. With this I also express my appreciation of those individuals that I have had the privilege of meeting and sharing with the experience of amateur astronomy.
Friedrich Wilhelm Herschel (Nov 15, 1738 – Aug 25, 1822) / Caroline Lucretia Herschel (16 Mar 1750 – 9 Jan 1848)
http://en.wikipedia.org/wiki/William_Herschel http://en.wikipedia.org/wiki/Caroline_Herschel
Albert Einstein (14 March 1879 – 18 April 1955) http://en.wikipedia.org/wiki/Albert_Einstein
"The most incomprehensible thing about the universe is that it is comprehensible."
Carl Sagan (November 9, 1934 – December 20, 1996) http://en.wikipedia.org/wiki/Carl_Sagan
“Who are we? We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people.”
John Lowry Dobson http://en.wikipedia.org/wiki/John_Dobson_(astronomer)
“The sky is a ‘zoo’ of innumerable ‘objects’ just waiting to be seen by many who have the least suspicion that
they are even there at all.” … in person, to me in the early 1980s
Honorable Mention:
Rolin J. Gebelein Sky Research Co. of Bonny Doon, CA (circa 1986) 12.5”- f/2.9 Newtonian, amicable provision.
http://www.freepatentsonline.com/4571036.html
Thomas Mathis Thomas Mathis Gear Co. (circa 1986) for instruction and enablement to learn about ATM.
http://www.carinasoft.com
http://www.marstown.org/telescope/
Earl Watts Earl Watts Optics, Telescope World (circa 1986) for kind guidance and comradery in ATM.
http://chabotspace.net/visit/telescopeworkshop.asp
100 inch (2.5 m) Hooker telescope (circa 1906) in appreciation for preceeding all of us today over 100 years ago.
http://en.wikipedia.org/wiki/Mount_Wilson_Observatory
…And all of the many others… thankyou for your inspiration to enjoy astronomy…
Brian L. Holbrook, ATM, San Francisco, CA
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BrianL
member
Reged: 08/07/08
Posts: 11
Loc: California
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Mirror Diameter
(inches) Diametric Surface Area
(inches square) Diametric Area Difference
(inches square)
(25.4mm) 1” .785398
(60mm) 2.36” 4.37435 3.58895
(70mm) 2.7559” 5.96508 2
3 7.06858 1
(80mm) 3.1496” 7.7911 .7
(90mm) 3.5433” 9.8606 1
(100mm) 3.937” 12.1736 2
4 12.5663 .4
4.5 15.904299375 3
5 19.6349375 3.73
6 28.27431 8.6393
7 38.4845 10.21019
8 50.26544 11.78
9 63.617251 13.3518
9.25 67.2 3.5827
10 78.53975 11.33975
11 95.0331 27
12 113.0973 18.064
12.5 122.718 9.621
13.1 134.78206 12
14 143.86841 9
15 176.7144375 33
16 201.06176 25
17 226.9800 26
17.5 240.52818 14
18 254.46879 14
19 283.528497531 29
20 314.14159 30.613
22 380.13239 66
23 415.4752775 35
24 452.38896 47
24.5 471.434849375 19
25 490.8734375 19
25.25 500.73999359375 10
25.5 510.704724375 10
26 530.92915 20
27 572.5552 42
28 615.7521 43
29 660.5198 45
30 706.8583 46
35.68248232 1000 294
36 1017.876019 18
(1 meter) 39.37” 1217.3647 303
40 1256.637 39
50.46265” 2000 744
61.8038” 3000 1000
71.36496” 4000 1000
79.7884” 5000 1000
87.40387” 6000 1000
94.40697” 7000 1000
100.9253” 8000 1000
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Matthew Ota
Pooh-Bah
Reged: 04/30/05
Posts: 1096
Loc: New England
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Here's a photo I took of the Hooker back in 1998. I worked at Mt Wilson from 2002 to 2007.
--------------------
Matthew Ota
Meade LX250GPS 10 inch SCT (Frankenscope)
Orion ED 80
ETX-90 OTA
Coronado Helios 1 H-alpha
TheSky 6 Pro
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BrianL
member
Reged: 08/07/08
Posts: 11
Loc: California
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To Matthew...
I'm sorry to reply so late... as I only check this site every once in a while... maybe once a month. Thankyou for
your response about the Hooker Telescope. It so impresses me
considering the amount of effort that it even takes to make a 16 inch mirror, like the one I made back in the 80s... and to make it come out right... for the staus quo of those times to make a giant mirror of 100 inches in diameter. What an impressive achievement. Now mankind has changed the format of how to even make the large lenses... it makes us wonder what the future formats of signal reception will be in that future.
I would be interested to learn more about your adventures at the Hooker Telescope.
I take this moment to apologize that the table I made for the planar diametric surface areas did not come out like a
table as it should have... however the values are there for
those interested to make their table using the values that
I had put there. I have an updated table that I will send to anyone requesting it. Please send me a message at DKchannel@yahoo.com and I will respond with a useable and interesting table that includes significant information regarding surface areas if anyone would request. Again, please send your request to the above indicated
email address.
Sincerely, BrianL
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Matthew Ota
Pooh-Bah
Reged: 04/30/05
Posts: 1096
Loc: New England
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My "adventures" at the Hooker telescope were limited. A personal friend of mine was one of the operators, and I got an inside tour of it once when I took a woman visitor there.
On another occasion I served as a docent when students visited from Princeton University. The operator did the "trick" of making the telescope appear to rotate as the guests were on the catwalk level. The catwalk level rotates in unison with the dome. The motion is so smooth that you do not feel motion and your eyes give a false impression that the telescope is moving around instead. So I further entertained the guests by pulling on the handrail, which did not rotate with the dome, so it appeared that I was pulling the entire Hooker telescope around with my bare hands!
I hung out more at the 60 inch in my latter years there. But my scopes were the 16 and 24 inchers. They were fun to operate.
--------------------
Matthew Ota
Meade LX250GPS 10 inch SCT (Frankenscope)
Orion ED 80
ETX-90 OTA
Coronado Helios 1 H-alpha
TheSky 6 Pro
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