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each of the superior images selected from

each photographic plate.

I spent close to one thousand hours

from 1963–69 performing this interesting

task, up to the fi nal prints (which were

third-generation) for the Mars report and

for numerous other studies, documents,

and PR for NASA JPL.

James W. Young

Retired JPL astronomer (1962–2009)

Via e-mail

Surprise Discovery

Alan MacRobert’s short note in Celestial

Calendar about the Moon’s occultation of

bright Lambda Geminorum (S&T: Mar.

2014, p. 52) brought to pass a special event

for me.

I was watching the lunar occulta-

tion the evening of March 10th, near

the Moon’s culmination. I have watched

hundreds of occultations over the past 53

years, but this one was diff erent. In my

8-inch at 102×, the star went blink, blink.

That is, it was a step disappearance, not an

instantaneous one.

Intrigued, I looked up the event in the

Royal Astronomical Society of Canada’s

Observer’s Handbook 2014. It lists Lambda

Gem as a very tight double, with compo-

nent stars of magnitudes 4.0 and 5.0 and a

separation 0.04 arcsecond, position angle

300 °°. I did not know Lambda Gem was a

double before the occultation.

Fortunately for me, the star was well

Photographic Memories

Klaus Brasch’s article “The Origin of

Stacking” (S&T: Mar. 2014, p. 68) brought

back long-ago memories. I had the distinct

pleasure of being Chick Capen’s under-

study at JPL’s Table Mountain Observa-

tory (now Table Mountain Facility) from

1962–70. At his prompting, I developed a

technique that we called composite imag-

ing. From 1964 –69, I made more than

450 such images of Venus, Mars, Jupiter,

and Saturn, with the majority of the Mars

images being for JPL Technical Report No.

32-990, “The Mars 1964 –1965 Apparition,”

published in 1966. We took 3¼ -inch × 

4¼ -inch Kodak spectroscopic plates with

a special planetary camera on the observa-

tory’s 16-inch f/50 refl ecting telescope. We

acquired as many as 36 images on individ-

ual plates, using fi ve diff erent wavelengths

from ultraviolet to infrared.

We thus composited up to 15 superior

images per plate, making a positive image

on Dupont cronopaque fi lm paper. We

then made a negative for producing the

fi nal “prints” in the technical report.

A unique plate holder with micro-fi ne

adjustable x-y axes was designed for our

Beseler enlarger. We centered image

projection on a fi xed, circular graph paper

target, directly on top of a 3¼ -inch × 4¼ -

inch plate holder. We manually adjusted

each projected image to an exact position

centered on the circular graph target.

With the fi xed graph target removed and

the plate-holder slide pulled out, the fi lm

received the proper exposure. Then we

returned the slide, repositioned the graph

target, and selected and positioned the

next image. We repeated this process for

south of the lunar disk’s center — the

event was far from a graze, but the

binary took longer to be occulted on this

chord (from longitude 119.6°W, l at it u d e

49.4°N) than if the Moon had moved more

centrally across the star. Now my list of

resolved double stars includes a 0.04 arc-

second double. Thanks Luna!

Alan Whitman

Via e-mail

Going Super-Deep from

Your Back yard

I enjoyed Bob Cava’s “New Jersey Quasar

Quest” (S&T: Mar. 2014, p. 34). I myself

started a small quasar quest with my

10-inch Dobsonian a few years ago, in

the deserts of southern California and

Nevada. Cava’s article does a great job

introducing readers to observing some of

the most distant objects that we can visu-

ally observe with amateur equipment.

I was surprised, however, by the list of

bright quasars available in the northern

sky. Although it’s a nice list, it is missing

several much easier “beginner quasars.”

When I fi rst stepped out on my quasar

quest I was guided to http://washedoutas-

tronomy.com/content/fi st-full-quasars as a

good source of information. Contained are

quasars ranging from magnitude 12.8 to

14.2, which provide a nice progression in

hunting these super-deep objects.

Although my quasar hunt has been put

on pause with a recent move to suburban

Virginia, Cava’s article has rekindled my

desire to peer ever deeper. Best wishes and

happy hunting.

Mike Lyons

Staff ord, Virginia

Editor’s Note: We excluded three of the four

objects in the beginner’s list mentioned (Mrk

421, Mrk 501, and OJ 287) because they

are classifi ed as BL Lacertae objects rather

than quasars. (Two of them appear in Steve

Gottlieb’s 2010 article on blazars; S&T:

April 2010, p. 70.) The distinction between

diff erent types of active galactic nuclei is

somewhat arbitrary, but BL Lac objects and

quasars aren’t usually lumped together, so we

excluded them.

Reader James Young built this x-y axis plate

holder (largest rectangle) in the 1960s. The

smaller 3¼ -inch × 4¼ -inch plate holder appears

above the adjustable holder (with the graph

target in position).

This nine-image composite of Saturn was taken

in September 1968 with the 16-inch telescope at

JPL’s Table Mountain Facility.

JAMES YOUNG

JAMES YOUNG

SkyandTelescope.com August 2014 11