Australian Sky & Telescope — July 2017

82 AUSTRALIAN SKY & TELESCOPE July 2017

COURTESY OF STEPHEN COOK

The bright one that got away

Fifty years ago this month, the author, then 16, came a hair’s breadth from making a huge discovery.

IN THE CONSTELLATION Delphinus

the Dolphin, on the evening of July 8,

1967, British observer George Alcock

discovered what became the brightest

nova in 25 years, peaking at magnitude

3.5. He spotted Nova Delphini 1967

(later designated HR Del) with

binoculars after 800 hours of nova-

searching during the previous six and

a half years. While Alcock is rightly

credited with discovering this star, I

saw it as a 6th-magnitude interloper

two nights earlier from my backyard

observatory in Burbank, California —

and I wasn’t even looking for novae!

I was 16 that summer and had

become a prolific variable star observer.

During the 1966–67 American

AssociationofVariableStarObservers

observingyear,Isubmittedover5,200

magnitudeestimates,fourthinthe

worldintheAAVSO’stallythatyear.

Asthesummerof1967beganIadded

twobrightsemi-regularvariablesto

myobservinglist,UandEUDelphini,

whichwerenotpartoftheregular

AAVSOprogram.Thisseemedalogical

thingtodosincetheywerenear

SDelphini,along-periodvariableI’d

made 17 observations of in the previous

year.Isecuredmyfirstestimatesof

thesevariables,atmagnitudes6.5and

6.0, respectively, on June 26th.

Around 12:20am on the night of

July6–7,Iagainpointedthe6× 30

finderofmy15-cmOpticalCraftsmen

reflector to the diamond of Delphinus,

above the avocado tree in my parents’

backyard. After checking mySkalnate

Plesostaratlas,Iquicklyfoundthepair

I saw it as a 6th-magnitude interloper two nights earlier

— and I wasn't even looking for novae!

S The author in his backyard observatory the year he just missed eternal fame.

of 6th-magnitude stars I’d long used in

locating S Del. As I identified U and EU

Del, I noticed something near the top

of the 5° field of the finder. It surprised

me to see a roughly 6th-magnitude

star there; I didn’t recall anything that

bright forming such a nice equilateral

triangle (roughly 2° on a side) with U

and EU Del.

Unfortunately, I remembered just

enough of my charts to judge my

magnitude estimates without referring

back to them, and I just assumed that

the questionable object belonged there.

So I moved on to the next variable on

my list. In those days I often made

more than 30 variable-star magnitude

estimates per hour, a pace that was

perhaps a little too fast for me to

appreciate anything unusual.

Pre-discovery photographs put Nova

Del at magnitude 5.8 that night, and at

6.7 when I'd conceivably had an earlier

chance on June 26th.

I told this story the next summer

to my friend Douglas Duncan. Forty-

two years later — he was by then a

university astronomer and director of a

planetarium, and still is — he told me

he often shared the story as a lesson to

his students. So after all those years I

had some consolation: My failure was

being used as an example of the need

to be careful and meticulous in making

observations!

■ STEPHEN COOK, a former university

professor and high school physics

teacher, runs Project Worldview

(projectworldview.org) and does CCD

variable star photometry from his home.

In 2008, his old Optical Craftsmen

telescope helped in the discovery of a

new eclipsing binary star (V1047 Persei).

FOCAL POINT by Stephen P. Cook