whitepeak observatory

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Last Update: 03-27-11

NOTICE: The latest (2011) version of Alan Chu's Moonbook is available on the mirror--see "Links" near bottom of page.

This small amateur observatory was located in the city of Tacoma, WA--thus "cityastronomy.com"-- and was primarily purposed for planetary study with, as the name indicates, the primary target of interest being our Moon. The main instrument, pictured above, was a 152mm f/8 achromatic refractor made by Zhumell Optical on an LXD-75 computerized equatorial mounting. The attached auxiliary/solar scope is a Meade 80mm f/11 achromatic refractor. Changes in my situation resulted in a move and as a result this obervatory no longer exists. I still pursue the hobby from my new home using a rooftop deck as an observation platform. It isn't an observatory, but it is better than the front yard...My current instrument is a Celestar Deluxe 8" cat on an LXD-75 computerized mount.

I am primarily a visual observer with imaging activities purposed towards reference for later study. I have also pursued an interest in relevant optical science to better understand how a telescopic system produces the visual images that it does & thus it's capabilities. The observations/images I make are primarily done to further my ongoing study of lunar geology, lunar morphology, planetary geology.

M. Clark

In the interest of free exchange of ideas and information, unless otherwise noted, nothing produced by Whitepeak Observatory within this website is under copyright. Free use applies. I only ask that you credit "Whitepeak Observatory" if published or used elsewhere.

Last Update: 03-27-11 (Red "New" items apply to additions made in the last 60 days or so.)

Building a 120mm f/5 Widefield Achromatic Refractor (RFT)

Comet Holmes 17/P Pages

An image analysis, including high resolution images of the core area. Click Image below to go to Comet Holmes page.

Monitor Calibration

(If you cannot see evenly spaced equal sized blocks of different grayscale shades from one end of the above bar to the other, with the last block to the right jet black and the last to the right pure white, your monitor needs to be adjusted. I recommend this site if you need any guidance in this.)


"I was very pleased to read your descriptions of lunar features - finally someone
was observing and thinking about geologic processes - and had read the literature!
I also enjoyed your geologic excursions on your website.

Dr. Charles A. Wood"
(with permission)


Splitting Posidonius' lunar peaks and Fabricius' weird floor ranges A graphic examination of two novel features

Litrow Posidonius Lacus Mortis Observer's Guide: Littrow to the Lake of Death

Alphonsus: Nectarian or Pre-Nectarian? An in-depth examination of the age of the crater Alphonsus This article, published in the Lunar Observer in 2006, has served as a listed reference for four abstracts presented at the Lunar & Planetary Science Conference 2008 through 2011, authored by U of Texas, Austin geologist William Ambrose

Observing Rilles in the Gassendi and Arsitarchus Areas An examination of the rille systems in the Gassendi and Aristarchus areas in an example observing report format.

1) Changing Faces: Rupes Recta
2) Image map and comments about the lunar south polar area
3) Image map and comments about the Mare Humboldtianum area
4) 24 Hours on the Terminator--Petavius area
5) Longest Lunar Valleys
6) Saturated color/grayscale comparison; Mare Crisium
7) An Illustrated study of Crater Humboldt and Environs (made during favorable libration)
8) An Investigation of a Possible Ghost Crater on the Floor of Crater Alphonsus
9) Examination of the Southwest Limb Gassendi to Tycho to Schickard
10)Copernicus' Lunar Volcano Field Details of an obscure volcanic area southeast of Copernicus
11)Cassini and the ValleySurvey of the area between crater Plato and Casini
12)Ptolemy's NeighborhoodAn in-depth examination of the area surrounding the crater Ptolemaeus

Sequenced Crater Charts (craterlet sizes charted for selected regions)
New!Photochart of the Apollo 11 craters, Armstrong, Aldrin, Collins, and the "Cat's Paw"; (locations and high reoslution measures)
Geologic time scale: Earth and Moon (1mb)(Relative comparison between the geologic timescales for the Earth and the Moon)
Example Observing Session Log/reportSome tips on conducting an opbserving seeion with ideas on recording observations with example provided.
A Tale of Two Brothers and their CratersThe story behind the renaming of Crater Pickering, Messier A, plus "Pickering's Harem" and a re-examination of W.H. Pickering's legacy

"Walking the Moon on the Earth" Geologic Fieldtrip to Ape Cave Lava Tube
"Walking the Moon on the Earth Part II" Central Oregon Lava Fields Expedition


Mercury Transit 2006 Images and Observations

Large Mars albedo image; Longitude ~290-180 Complete with labelled features

Large Mars albedo image; Longitude ~160-30 Complete with labelled features

Large Mars albedo image; Longitude 0~220 Complete with labelled features


Trapezium; component magnitudes, separation, etc

Test your scope on 52 Orionis

Optimize your Achromat for Double Stars

Degrees of separation in close double star observation (chart)


Resolution, Magnification and Contrast: Their Interrelationships Explained Rayleigh, Dawes, Abbe and Sparrow defined, plus the 50X magnification limit explained and a discussion of the eye's relationship with the telescope's contrast transfer function

Contrast Transfer Comparison Between Perfect and Rayleigh Criterion Unobstructed Systems What 20 points of strehl does for contrast.

Roddier Optical Testing 152/1200 and 127/1180 and 80/880 achromats are evaluated

Lunar Resolution Table

Lunar Observing: Magnification, Seeing, Resolution and Aperture

Resolution Limits in Lunar Imaging Examining the state-of-the-art in Lunar Imaging

Magnitude Gain per Increase in Aperture Charted from 50mm to 20 inches of aperture

Maximum Field of View per Telescope focal length; chart

Chromatic Aberration in Achromatic Refractors

Color correction, APO vs. high and low CA Ratio achromatics


Refractor cooldown time measurements

Whitepeak Observatory design & construction

The 'Tacoma Chair" An easy to make inexpensive observing chair

Storing eyepieces & accessories

Deepsky imaging under bright citylights (limiting magnitude=4)

1) M57 area with selected magnitudes to 15
2)M2 152-f/8 achromat DSI Pro NELM 4M
3)M57 152-f/8 achromat DSI Pro NELM 4M


Barska X-Trail 20x80 Binoculars Review

Meade DS-80 review

Orion Accufocus review


Basic Lunar Imaging (under revision)

Inexpensive Flip Mirror for Imaging Make a nice flip mirror out of an old cheapie diagonal


UPDATED for 2011!North American Mirror for Alan Chu's Photographic Moon Book Download the latest version (Mar. 2011 V. 3.5) of this excellent photographic lunar guidebook here!

email: mclark (at) cityastronomy (dot) com

whitepeak observatory
Prior scope: 127mm-f/9.3 Meade AR-5.

whitepeak observatory
Currently in use: Zhumell 152mm-f/8 refractor with 80mm f/11 Meade guidescope and counterbalance bar.