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From the book The Astronomical Scrapbook

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#1 Carl Kolchak

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Posted 23 January 2020 - 01:04 PM

The Astronomical Scrapbook by Joseph Ashbrook:

 

In the forum Astro Art, Books, Websites & Other Media, there is a topic about this book. I have an old hardback copy of it and decided to check it out again. I came across this section of the book:

 

Section 46. Lunar studies before the telescope pg. 233

 

William H. Pickering choose 12 features on the Moon that may be seen with the naked eye. They are listed below in increasing difficulty.

 

William Pickering's 12 test features on the face of the Moon.

 

1 Bright surroundings of Copernicus
2 Mare Nectaris
3 Mare Humorum
4 Bright surroundings of Kepler
5 Region of Gassendi
6 Plinius region
7 Mare Vaporum
8 Lubiniezky region
9 Sinus Medii
10 Faint shading near Sacrobosco
11 Dark spot near foot of Montes Apennines
12 Montes Riphaeus

 

Anyone know for sure what area Pickering was talking about for #10, the "faint shading near Sacrobosco" and for #11, "dark spot near foot of Montes Apennines". He says, "...a dark patch at the edge of Mare Imbrium, just across the Apennine Mountains from Mare Vaporum." Is it the area known as Palus Putredinis? What shading appears near Sacrobosco? What are your thoughts? Any images/sketches of these two "features"?

 

Thanks for your help,

 

 

 


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#2 Carl Kolchak

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Posted 24 January 2020 - 12:58 PM

Here is an Excel spreadsheet (Naked Eye Observing on the Moon.xls) with the naked eye objects along with Rukl (Atlas of the Moon) sections and Sky & Telescope's Field Map of the Moon quads and map locations.

 

I have also included a Lunar Terminator Visualization Tool (LTVT) .cvs (Pickering's Lunar Naked Eye Objects.csv) file to use in the application to identify Pickering's naked eye objects. I was not sure of the exact location of feature #11 "dark spot near foot of Montes Apennines". In the image of page 234 from the book, The Astronomical Scrapbook, I believe the dark spot is Palus Putredinis. I compared the LTVT image to the book page image with a magnifier and the dark spot across the Apennine Mountains from Mare Vaporum and is on the border of Mare Imbrium is Palus Putredinis. Plus you can see Archimedes in the book image. Archimedes is included in the cvs file. You can remove * comment and save the file, refresh the "Compute Geometry" button to add Archimedes to the LTVT view.

 

The Astronomical Scrapbook pg 234

 

Map from Astronomical Scrapbook Pg 234

 

LTVT image

 

Map LTVT with Archimedes

 

One last image to share from the June 1962 Sky & Telescope magazine article, "Lunar Studies Before the Telescope". This image is much brighter than the one in the book.

 

Astronomical Scrapbook June 1962

 

 

In the book Joseph Ashbrook suggests the best time to look for these objects is a "waning gibbous Moon during the latter part of morning twilight".

 

 

Good luck, good hunting,

 

Attached Files


Edited by Carl Kolchak, 25 January 2020 - 11:54 AM.


#3 John_Moore

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Posted 26 January 2020 - 05:47 PM

Hi Richard (Carl Kolchak)

 

On the No. 10 'Faint shading near Sacrobosco' observation, I wonder was it the Altai Scarp, which drops by some 2.4 km to the east (arrowed), that was causing the 'shading' effect Pickering mentioned.

 

Below, is a Waning Gibbous view, and while the scarp is some 140 km away from Sacrobosco's centre, I would think that viewing the crater by naked eye during such a phase would have been near impossible to actually see, as it really is still in near full light ('Faint shading near Sacrobosco' might not always mean it was exactly right up to the crater's rim/outer rim sector).

 

I don't know what time he made such an observation, however, that area near the scarp would eventually be getting darker anyway as the terminator progressed westwards, so, you never know. 

 

Just my two cents worth.

 

John Moore

 

ShadingNearSacrobosco

Edited by John_Moore, 26 January 2020 - 05:48 PM.

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#4 Carl Kolchak

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Posted 29 January 2020 - 11:18 AM

Hi John

 

Thanks for your "two cents worth" and pointing this area out. I quoted only a bit about the "best time to view" from Joseph Ashbrook. Here is the full quote, "Careful experiments of this kind reveal a surprising amount of lunar surface features. The best results, I have found are obtained by viewing the waning gibbous Moon during the latter part of morning twilight. Much less is visible by night, when glare hampers, or in full daylight, when contrasts are diluted. Thus seen against the deep blue sky of a cool dawn, the pale lunar disk is richly dappled with recognizable markings..." But no specific mention of a "best time" to view these naked eye objects. frown.gif

 

"Pickering thought that his No. 12, the Riphaeus Mountains, might be beyond even the keenest naked-eye vision."

 

 

 

 



#5 John_Moore

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Posted 30 January 2020 - 07:13 PM

Thanks, Richard (Carl Kolchak)...apologies, if I'm getting your correct avatar/name wrong

 

As I don't know what Ashbrook's research involved, Fred Schaaf referred to he... Pickering's, naked-eye observation, too (page 182, 2002 publication of 'The Starry Room: Naked Eye Astronomy in the Intimate Universe' - Amazon available ).

 

While there seems to be no additional information given in Schaaf's work, to the Sacrobosco shading etc.,, he does go in to some detail of the whole 'naked-eye' phenomenon (Chapter 10 'The Powers of Vision' - pages 167 to 192). Such reference is available free online - thanks to the author.

 

John Moore

 

Pickering Schaaf

Edited by John_Moore, 31 January 2020 - 03:15 AM.


#6 Carl Kolchak

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Posted 30 January 2020 - 10:14 PM

I've answered to a whole lot worse laugh.gif, John.  So Richard or Carl is fine! I have the 1988 paperback (I think 1st edition) on one of my shelves. I'll take a look at it. Thanks again.

 

 




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