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Project Moonwatch

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#101 Terra Nova

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Posted 17 January 2016 - 11:49 PM

All's well that ends well Carol. A little bird told me that there will be a happy ending all the way around. :)
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#102 Vesper818

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Posted 17 January 2016 - 11:50 PM

Yeppers!:-):-):-)
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#103 Terra Nova

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Posted 19 January 2016 - 05:54 PM

Check this out:

 

http://www.ebay.com/...-IAAOSwgQ9V4cRX


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#104 TOM KIEHL

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Posted 19 January 2016 - 06:02 PM

 

W T :scratchhead:


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#105 DreamWeaver

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Posted 19 January 2016 - 06:54 PM

Here's a link with plans to "Build a Moon Watch Telescope" from the August 1957 Popular Mechanics magazine.  https://books.google...e rings&f=false


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#106 Chuck Hards

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Posted 19 January 2016 - 07:01 PM

I bought that actual issue on your recommendation Keith, and plan on building one this year.  Thanks!


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#107 catboat

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Posted 19 January 2016 - 07:14 PM

Here's a link with plans to "Build a Moon Watch Telescope" from the August 1957 Popular Mechanics magazine.  https://books.google...e rings&f=false

 

That’s a nice how-to/can-do.  Perfect for the big Edmund finder -- it looks like that’s what they’re using.  (And on the next page you’ll find the predecessor of the Martha Stewart Nail-Tote.)


Edited by catboat, 19 January 2016 - 07:45 PM.

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#108 DreamWeaver

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Posted 19 January 2016 - 07:33 PM

I bought that actual issue on your recommendation Keith, and plan on building one this year.  Thanks!

I hope we get to see one of your detailed posts on the build!



#109 Chuck Hards

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Posted 19 January 2016 - 07:46 PM

 

I bought that actual issue on your recommendation Keith, and plan on building one this year.  Thanks!

I hope we get to see one of your detailed posts on the build!

 

 

Of course!


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#110 Vesper818

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Posted 13 February 2016 - 01:20 PM

If anyone has the Edmund downward facing scope, would you mind measuring dia. and fl of the objective? I believe I might have the same lens in an old ebay ATM terrestrial scope on the back shelf.
Would be fun to find out.

#111 Vesper818

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Posted 13 February 2016 - 01:21 PM

PS, thank you Frank for all the Smithsonian links. What a great source of material, and way fun reading!
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#112 Joe Cepleur

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Posted 15 February 2016 - 11:19 AM

So, ol' Joe Cepleur is suffering "Monkey's Uncle Syndrome?" From what I thought I had read on this forum, Project Moonwatch was intended to track Soviet satellites! Was I delusional (never ye doubt the possibility!), or is such misinformation passed about? Now I read, in a link posted earlier in this thread, that the Smithsonian Institution established Project Moonwatch to track an American geophysical satellite! Must say, that makes more sense to me. An army of amateurs tracking Soviet military satellites would have made a great script for a movie, yet seemed odd. 



#113 Chuck Hards

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Posted 15 February 2016 - 11:54 AM

Moonwatch was part of the International Geophysical Year effort by the United States.  It was intended to track all artificial satellites, but most people assumed that the Americans would be first.  The Soviet Sputnik launch caught everyone by surprise.  And of course, the Moonwatch teams did in fact track everything.  Not just the satellites, but boosters and debris, as well.  From launch to re-entry.

 

So go ahead and write your movie script, because it did happen that way, as it turned out.  



#114 Terra Nova

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Posted 15 February 2016 - 12:51 PM

The reason Moonwatch was part of IGY is that satellite tracking would provide a more accurate determination of the true figure of the Earth (the Geoid), than had heretofore been possible with geoundbased trigonometrical and gravity surveys. Geodesy is an important part of the broader field of Geophysics, from which IGY took its name. As far as timing, IGY actually overlapped 1957 and 1958 and was planned for that time period so that it would coincide with the 11.2 year Solar Maximum which was predicted to be hugh. Solar physics and solar-upper atmospheric teleconnections are also part of Geophysics. There was much work done at that time on upper atmospheric physics and Earth's geomagnetic field. It was a very exciting time!


Edited by terraclarke, 15 February 2016 - 02:11 PM.

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#115 Ken Launie

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Posted 15 February 2016 - 02:04 PM

Moonwatch was part of the International Geophysical Year effort by the United States.  It was intended to track all artificial satellites, but most people assumed that the Americans would be first.  The Soviet Sputnik launch caught everyone by surprise.  And of course, the Moonwatch teams did in fact track everything.  Not just the satellites, but boosters and debris, as well.  From launch to re-entry.

 

So go ahead and write your movie script, because it did happen that way, as it turned out.  

There's an excellent history of the Moonwatch program that's entertaining reading, published by Patrick McCray in 2008:

 

"Keep Watching the Skies!: The Story of Operation Moonwatch and the Dawn of the Space Age", published by Princeton University Press:

press.princeton.edu/titles/8645.html

It's still in print and though expensive from the publisher, it can be found readily on the used market.

 

I'm sure I'm not the only CN member who has a number of friends who were participants (I'm about a dozen years too young).


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#116 Chuck Hards

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Posted 15 February 2016 - 03:02 PM

Thanks Ken, that title has been mentioned in this thread a couple of times.  I read it last year, very informative.  

 

Moonwatch was still active for my first seven or eight years of astronomy, but I wasn't aware of any local teams.  It ended officially when I was in high school.



#117 Joe Cepleur

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Posted 15 February 2016 - 06:18 PM

Thanks, everyone! Terra, always helps to have a real geologist on the forum! I think you are saying that because artificial satellites are held in their orbit by gravity, carefully tracking their motions reveals the shape of the Geoid. If the world were a perfect sphere, the orbits would also be (close to) a perfect sphere; but, if it were heavily or unevenly elliptical, the satellites would follow those shapes instead (?). 

 

I would have loved to have been part of Project Moonwatch. I love the notion that, in that era, so much could be learned by aggregating observations made with simple tools. 


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#118 Terra Nova

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Posted 15 February 2016 - 07:58 PM

That pretty much sums it up Joe. The 'Geoid' is an equipotential gravity surface reduced to sea level. If mass were evenly and concentrically distributed in the Earth from the center outward, it would take the form of an oblate spheroid or ellipsoid of rotation. Since mass is not evenly distributed, the Geoid undulates above and below the surface of the oblate spheroid. These heights or departures are positive and negative and vary with the particular ellipsoid model used as the reference datum. In the USA we currently use the NAD1983 (North American Datum of 1983) which superceeded the NAD1927. NAD1983 is the same as the International GRS1980 and is geocentric. NAD1927 was not geocentric but was a better fit for mapping our continent, but its use resulted in greater departures outside of North America. It's much better if all or most of the world uses the same datum and geocentric models work better for this. They are also better when we are figuring satellite trajectories and calculating positions by GPS.

Anyway, positive geoidal departures generally equate to negative gravity anomalies and vice versa. A gravity anomaly is the difference between the observed gravitational acceleration at a particular place and what would be expected given the homogeneous ellipsoid. A positive gravity anomaly means that gravitational acceleration is greater than what would be expected (~9.81m sec^-2 reduced to sea level) and indicates increased distribution of mass (higher density rocks) in the subsurface. The height of an orbiting satellite above the surface is deflected from a perfectly smooth elliptical orbit by these gravity anomalies. Precise mapping of the tracks of satellites can then give us a better understanding of Earth's gravitational field and the shape of the Geoid. A better defined ellipsoid allows for more precise mapping and geodetic positioning. This is also very useful in determining things like crustal deformation, the location and movement of magma and our overall understanding of global tectonics.

#119 Mr. Bill

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Posted 15 February 2016 - 08:28 PM

And the possible presence of oil and precious minerals....

:question:
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#120 PawPaw

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Posted 15 February 2016 - 08:29 PM

If anyone has the Edmund downward facing scope, would you mind measuring dia. and fl of the objective? I believe I might have the same lens in an old ebay ATM terrestrial scope on the back shelf.
Would be fun to find out.

Edmund used the same scope they sold for the moonwatch program that was used as the finder on the 8" F/8 reflector.  it was a 5.5X 50mm dia. with a 12 degree field.  The eyepiece was a wide angle 68 degree erfle army surplus with a 32mm FL set in a spiral thread focusing mount.  The only difference between the moonwatch and the finder is the finder had a sliding cross-line reticle mounted in the barrel.  Here is a picture of my moonwatch finder minus the mounting.  You can see the pre-drilled holes used for the moonwatch mounting.  I could not find the fl listed in the literature but I come up with FL 4.6  approx.

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Edited by PawPaw, 15 February 2016 - 09:22 PM.

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#121 Terra Nova

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Posted 15 February 2016 - 09:09 PM

And the possible presence of oil and precious minerals....

:question:


Yes, that too! :)

#122 Chuck Hards

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Posted 15 February 2016 - 09:14 PM

Terra, how do you geophysicists account for density differences vs. shape anomalies?



#123 Chuck Hards

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Posted 15 February 2016 - 09:18 PM

 

If anyone has the Edmund downward facing scope, would you mind measuring dia. and fl of the objective? I believe I might have the same lens in an old ebay ATM terrestrial scope on the back shelf.
Would be fun to find out.

Edmund used the same scope they sold for the moonwatch program that was used as the finder on the 8" F/8 reflector.  it was a 5.5X 50mm dia. with a 12 degree field.  The eyepiece was a wide angle 68 degree erfle army surplus with a 32mm FL set in a spiral thread focusing mount.  The only difference between the moonwatch and the finder is the finder had a sliding cross-line reticle mounted in the barrel.  Here is a picture of my moonwatch finder minus the mounting.  You can see the pre-drilled holes used for the moonwatch mounting.  I could not find the fl listed in the literature that I have but measuring with a tape it looks to be approx. 9 inches or 228 mm.

 

 

I'm sure it's much shorter than 9 inches.  I have 3 of those finders, and the reticle is located well up inside the tube.   The reticle is located at the objective's focal plane.  So I'm guessing that the focal length is probably closer to 6 inches.

 

I'll pull one out and get a precise measurement in the next day or two, unless someone beats me to it.



#124 PawPaw

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Posted 15 February 2016 - 09:26 PM

 

 

If anyone has the Edmund downward facing scope, would you mind measuring dia. and fl of the objective? I believe I might have the same lens in an old ebay ATM terrestrial scope on the back shelf.
Would be fun to find out.

Edmund used the same scope they sold for the moonwatch program that was used as the finder on the 8" F/8 reflector.  it was a 5.5X 50mm dia. with a 12 degree field.  The eyepiece was a wide angle 68 degree erfle army surplus with a 32mm FL set in a spiral thread focusing mount.  The only difference between the moonwatch and the finder is the finder had a sliding cross-line reticle mounted in the barrel.  Here is a picture of my moonwatch finder minus the mounting.  You can see the pre-drilled holes used for the moonwatch mounting.  I could not find the fl listed in the literature that I have but measuring with a tape it looks to be approx. 9 inches or 228 mm.

 

 

I'm sure it's much shorter than 9 inches.  I have 3 of those finders, and the reticle is located well up inside the tube.   The reticle is located at the objective's focal plane.  So I'm guessing that the focal length is probably closer to 6 inches.

 

I'll pull one out and get a precise measurement in the next day or two, unless someone beats me to it.

You are correct.  I removed the eyepiece from the barrel and re-measured:  I come up with approx. 7.5 inches which makes the FL approx. F/3.8


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#125 Vesper818

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Posted 15 February 2016 - 11:13 PM

Thank you for the info. I'll take my objective out and check fl tomorrow. I do have an old Edmund 32 mm eyepiece. Would be fun to "reassemble" one of the scopes.🌙🚀

On the other hand, I did take the titanic tiny Tecnar out moon watching tonight. The moon was sharp, but miniscule. Orions sword and nebula were pretty,and Pleiades pleasing. I cannot see how any serious satellite hunting could be done with this sub-dinkerscope. Unless Sputnik was more sparkly than most of the current satellites, 30mm aperture would have promised little chance of catching it. All in all, tho, it is a wonderful "trophy scope" of a wonderful time for space.
Thank you Chuck for being willing to part with the little Swift. It holds a place of honor next to my one-sided Moon globe bank!

Edited by Vesper818, 15 February 2016 - 11:14 PM.

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