PMAA Newsletter Summer 2020-21 Edition—Editor Françoise Coffre 1

Hopefully, in 2021 things will get better and perhaps one day soon, all will return to nor-

mality.

We have resumed our monthly activities with Café Astronomy and Side Walk Astronomy

held on a Saturday afternoon at the Observatory.

In this edition, we will have a look at:

Some of our activities since December

What’s new with our new building?

Open up Open Nights

The Babylonian legacy to Astronomy

Interesting links shared by some of our members

PMAA NEWSLETTER

SUMMER 2020-2021

PORT MACQUARIE ASTRONOMICAL ASSOCIATION INC. PO Box 1453. PORT MACQUARIE. NSW. 2444

Email: pmobs.info@gmail.com ABN 45 697 909 376

www.portastronomy.com.au www.facebook.com/portobservatory

Patron Prof. Fred Watson – AM

PMAA Newsletter Summer 2020-21 Edition—Editor Françoise Coffre 2

A SURPRISE VISIT FROM ALBERT YORK’S GREAT GRAND-

DAUGHTER

Katherine, the great-grand daughter of Albert York paid us a visit.

Some history: It was through the efforts of Albert York that the current Observatory

was built in 1961/62 (check our Website for the whole story )

Katherine is holding Albert York’s photo next to Jim Daniel’s Celestial Clock

CHRISTMAS PARTY

Many of the PMAA members got togeth-

er at Rivermark Café to celebrate the end

of a tough year.

FLY ME TO THE MOON

Graeme entertained visitors on Thursday 14 January during an

afternoon session during which we looked back at the missions

to the Moon.

A very informative, entertaining afternoon.

SOME OF OUR ACTIVITIES SINCE DECEMBER

CAFÉ ASTRONOMY

“WHAT ABOUT DNA” Presented by

Bruce Dawson on 20 February

Café Astronomy is a fun, educational,

entertaining monthly session held on a

Saturday afternoon at the Observatory.

GENERAL MEETING 6 MARCH 2021

New initiatives are being tried

• Cube Satellite proposal by Chris Francis

• Cassini Project by Karl Georg Scheuter

In the pipeline:

• Winter Solstice Celebrations – contact Sophie or pmobs.info@gmail.com

• Bunnings BBQ – contact Emilie or pmobs.info@gmail.com

PMAA Newsletter Summer 2020-21 Edition—Editor Françoise Coffre 3

WHAT’S NEW WITH OUR NEW BUILDING BY CHRIS IRELAND

An Update from Chris Ireland—Vice President PMAA

FROM THIS

TO THIS

See link for more details: https://spaces.hightail.com/receive/JGHr6bqkpg

The PMAA has come a long way since 2015.

After numerous meetings with interested members of the PMAA we have now developed a Building concept, a Strategy

plan, A Business Plan and a Financial Plan.

We now have a building design which is amenable to the Rotary Park and able to accommodate our anticipated needs into

the future.

Following an approach to our DA consultants, King and Campbell, we have developed a relationship with the construction

company, A.W. Edwards Pty Ltd. They have been most helpful in pointing us in the right direction with advice and pro bono

work. So far they have given us a “Fixed Price” quotation and assisted us with our grant applications for funding.

The anticipated price for the build and partial fit out is $4.27 million ex GST. For the style of building we envisage, this ap-

pears to be a reasonable amount. So we have recently applied for a $5 million grant from the State Government of NSW.

We are awaiting a result of this in June.

We will also need to seek funding for a full fit out. Currently this will be in the order of $1.2 – 1.5 million dollars. The high

price here will produce a state of the art interior to suit the desired space education aspirations of PMAA. It will also provide

(hopefully) a robotic dark sky telescope for superior viewing.

We have been invited to attend a meeting with Federal, State and Local government representatives to discuss our funding

requirements. This will be in mid-April. All parties are aware and supportive of our requirement for a new and improved

building so we hope that we can gain some leverage through this meeting.

The PMAA committee believes that the new building will be an important asset for the town and become a much bigger

tourist draw than at present.

If you have any supportive ideas, then the Committee looks forward to hearing from you.

Keep looking skyward.

PMAA Newsletter Summer 2020-21 Edition—Editor Françoise Coffre 4

OPENING UP OPEN NIGHTS by Graeme Marks

Don’t you just love COVID?

Sometimes a negative situation is forced upon you but something positive can emerge. Thank you COVID. Because of you we launched our Open Nights in a different way. Because we need to collect contact details and limit the numbers of people at each of our Open Nights, everyone, (members and Guests), has to prebook rather than just rock up on the night. This means all our Open Nights pro-ceeded irrespective of the weather.

Our Open Nights consist of an hour’s presentation on various astronomical topics as well as, weather permitting – telescope viewing, examining one of our prides and joy – our meteorite, our gift shop and a tour of our museum! Did you know we had one?

This year we’ve seen Open Nights on Fridays, Sundays and Wednesdays during the Christmas school holidays. All in all, so far this year over 300 people came though the Observatory generating over $3,500 of revenue.

Our Open Nights are completely dependent on our volunteers so thank you to those who have stepped up. We’re always looking for more volunteers. Full training is provided so here’s your chance to learn how to operate our 14” Schmidt-Cassegrain reflecting telescope or help out on the Front Desk.

PMAA Newsletter Summer 2020-21 Edition—Editor Françoise Coffre 5

The Sumerians who lived in Mesopotamia (nowadays Iraq) 5000 years ago, developped a sexagesimal computation sys-

tem.

The sexagesimal system is a base 60 computation system. Why? Why not base 10 (decimal), base 2 (computers), base 12

(Egyptians), base 20 (Mayans)?

The sexagesimal system is still in use today after 5000 years: Clocks, Coordinates of maps, Trigonometry

Why was the number 60 so valued in Mesopotamia? 60 is countable on the fingers of both hands, 60 is a highly composite

number, 60 has an astronomical significance.

Strange enough that 60 is the first number between two prime numbers (59 and 61)

For more details go to: https://en.wikipedia.org/wiki/Sexagesimal

If this finger-counting method was the reason for the Mesopotamian sexagesimal system, why was its sub-base 10 instead

of 12?

It is inconsistent that the counting system is 12×5=60, while the decimal notation system is 10×6=60.

Note that Egypt uses this duodecimal finger-counting method (base 12).

The Ancient Egyptians had a decimal system and did not accept a sexagesimal system. They did not need to count to 60,

but they divided day and night into 12 hours each and they needed only to count 12.

Therefore we can safely assume that this finger-counting method was originally developed to count 12 and later convert-

ed to count 60 and that Sumerians developed the sexagesimal notation independent of this counting method and then

was passed on the Babylonians.

Remember that Mesopotamia was the cradle of an agriculture area back in 3000BCE and the Sumerians were also traders

with the rest of the region – Egypt, Persia (Iran), Asia Minor (Turkey), Phoenicians, etc...

They had to find a quick way to count the number of sacs or amphorae ready to be shipped, hauled.

60 is a number that can be done using two hands only!

How?

The thumb of one hand is used as a pointer to each of the phalanges (3 per finger) so 4 fingers x 3 phalanges = 12. The

fingers of the other hand will count the number of 12 increments therefore: 5X12 = 60.

This was much easier and faster than the ten fingers of both hands!

The sexagesimals system is still in use today: Hours, minutes, seconds or Degree, minutes, seconds

The Sumerian divided the hour in 60 minute (minor) parts that became the minute. The minute was also divided in 60 sec-

ondary parts that became the second.

THE SUMERIANS , THE SEXAGESIMAL SYSTEM

AND THE BABYLONIAN LEGACY TO ASTRONOMY

by Paul Coffre

PMAA Newsletter Summer 2020-21 Edition—Editor Françoise Coffre 6

The Babylonian Legacy to Astronomy It takes somewhat more than twelve lunar months for the Sun to make its yearly trek around the heavens along the ecliptic

circle and return to the same place relative to the background stars. One-twelfth of the way around this 360-degree circle

should be roughly equal to a month, the time it takes for the Moon to go through a full cycle of its phases. This amounts to

360◦÷ 12 = 30◦, a nice round number in the sexagesimal sys-

tem (consisting of exactly one half of a unit of sixty parts).

Thus the Sun travels along a 30◦ arc of the ecliptic circle

about once a month, and so, each of these 30◦ arcs was

matched to a corresponding constellation along the zodiacal

band.9 This was the mechanism whereby the Babylonians

used the sky as a calendar. Since their year began at the

spring equinox, the Sun would pass through the first of these

constellations, Aries the Ram, during the first month of the

year, corresponding to the 0◦ to 30◦ band along the eclip-

tic.10 During the second month, the Sun would be in Taurus

the Bull (30◦ to 60◦ along the ecliptic), then Gemini the Twins

(60◦ to 90◦ along the ecliptic), etc. By the end of the following winter, the Sun would complete its journey through the

twelfth zodiacal band, for Pisces the Fish (330◦ to 360◦ = 0◦ along the ecliptic), returning to its starting point for the next

year’s course. (The diagram below sketches how this works, but it is drawn from the modern perspective, showing the Earth

orbiting the Sun.)

Reference: Daniel E. Otero, ‘Teaching and Learning the Trigonometric Functions through Their Origins’ MAA Convergence (March 2020)

Counting to 12 with one hand

The face of an ancient Sumerian

6 7

3

1

5 4

2

8

12

pointer

10

11

9

6

PMAA Newsletter Summer 2020-21 Edition—Editor Françoise Coffre 7

INTERESTING LINKS SHARED BY SOME OF OUR MEMBERS

SEXAGESIMAL IS A NUMERAL SYSTEM WITH SIXTY AS ITS BASE…

https://en.wikipedia.org/wiki/Sexagesimal

ABC SCIENCE…

https://view.mail-list.abc.net.au/?

qs=b9af1efc539bc92076277a37233844c373793260626690786d103818d04f4d9c10b229ff8ce245bc2f237dc111bd

5 3b5f93d985af0a05d692ad4c1247ee191189112a9b1fdc727f5133019c76a949490d58ec957fba0ea01

NEWFOUND SUPER-EARTH ALIEN PLANET WHIPS AROUND ITS STAR EVERY 0.67 DAYS

https://www.space.com/super-earth-alien-planet-toi-1685b

A BIG THANK YOU to my fellow members who contributed to the newsletter