Message from our new President

10 11 2012

Hello all NSAS members

As newly elected President of NSAS I would like to bring you up to date following the recent monthly meeting and AGM. Bob Fuller was away in the US and so as Vice President I took the chair for the monthly meeting. I noticed the attendance at the Monthly / AGM was fairly low, which was hard to understand. Perhaps we should put on a full buffet next year, but otherwise I can’t understand why attendance at an AGM would not be stronger!

At the Monthly meeting, quite a few points came up, many of which had been raised at the Committee Meeting. In point form:
- Astronomy 2013 is now available (being ordered)
- expenses for the year exceeded income, and which point led to later discussion on whether the annual fee should be considered (it has been unchanged for decades)
- Macquarie Open Night was discussed (the event was held the next weekend and was very successful, though observing was restricted)
- the meeting discussed the prospect of sending out Reflections by email only, and whether that would affect many of our members – the Committee will consider further, but any member having a view on this should let the Committee know by email
- the Christmas Party is coming up – 18 Dec – a big attendance is hoped for, and members are asked to please bring a plate of their favourite goodies. Drinks are supplied.
- the Committee will work through a more formal procedure for assisting our visitors and new members
- Lawrie Webb will be setting up at Tantallon Oval to observe the partial eclipse of the sun, and he would be delighted to have as many join him as possible approx 7am Wed 14 November ie next week
- Bob Roeth was to hold (and did hold) the 5th Tuesday Mathematics in Astronomy later in October
- Publications available: Astrovisuals Calendar $9 (contact Bob Roeth); Paul Shallow has the 2 CD Ceduna Eclipse for sale at $5
- Geoff Welch Prize: the three winners of the $50 (each) and a copy of Geoff’s book and a Presentation Certificate were Arthur Boyd for “La Perouse’s Incomplete Voyage”, Irene Justiniano for “Clear with a Chance of Meteor Shower”, and Bob Roeth for “Magnitudes, Wikipedia and Errors”

After the Monthly Meeting the AGM was held and again I acted as Chairman in Bob’s absence (Bob was acting as NSAS operative covering the US election and its impact on NSAS, and world, amateur astronomy) . In summary:
- all went well
- a discussion on annual fees occurred, and the Committee will consider further and come back to the members
- the Committee will discuss reinstating the Gordon Stott Imaging Prize
- I provided some comment on the last 12 month’s activities for the club, including observations, the sub groups and field trips (to Canberra / Tidbinbilla and Coonabarrabran)

Prior to the elections for the next twelve months, appreciation was expressed to the outgoing Committee, in particular to Bob Fuller who as President and Vice President before that, has carried far too heavy a burden for NSAS for several years – it was agreed a small gift of appreciation should be purchased for Bob.
The Committee then stood down and elections for the next twelve months were held, with the following results:
President – Bruce Retallick
Vice President – Gordon Ogborne
Treasurer – Ken Schofield
Secretary – Irene Justiniano
Committee Without Portfolio – Peter Korda, Anna Koeneman and Chris Anderson
As President I thank those who have volunteered their services. There has been quite a turnover in Committee membership and over the next few months we will work on getting a handle across all those tasks that need to be undertaken. We have the benefit of the previous members having all offered their assistance – and this will undoubtedly be called upon!
I offered a few comments as President:
- my interests are fairly broad but unlike previous Presidents, I am not a technically oriented person, and will need support in those areas – I will not be able to take on any technical roles or lead in discussions
- I will be working on assessing our collective knowledge and expertise to ensure that we fully understand our capacities and commitments – and including that of our new members
- we must look after our visitors and new members better – we all have a responsibility to make them feel welcome
- we must all wear our name tags at meetings – such a small point, but so important
- we should pay some attention to formalising our aims and objectives, including the Outreach program, and in accordance with our capacity and our desires
Since becoming President I have noted many possible actions and points of interest. I look forward to bringing at least some of them forward for consideration, and to a successful twelve months.
Regards to all
Bruce Retallick





5th Tuesday Mathematics – October 2012

23 10 2012

This month has 5 Tuesdays, which means Bob Roeth will be giving his mathematics class on Tuesday October 30, at 7:30pm.

Bob will be showing:
  • that eclipses and transits obey the same kinds of conditions
  • that the strange timing for Venus transits has a simple explanation that it is quite surprising
  • that Kepler’s understanding of three-dimensional geometry did not lead him to recognise the likelihood of pairs of transits
  • introduce the term  ‘eclipse season’ and its dependence on inclination of relevant orbital planes as well as diameters of the bodies involved
  • talk about some statistics of solar and lunar eclipses, and
  • perhaps to spend some time on the saros and repetitions of similar eclipses.
As usual, remember to bring a scientific calculator, pen and paper, and a protractor and compass.




Tuesday Astronomy and Mathematics Lecture

25 11 2011

Bob Roeth will continue his series of lectures on astronomy and mathematics next Tuesday the 29th at Regis Hall, 7:30 PM. Subjects include:

Co-orbital moons of Saturn and their swapping inside running to outside running – a case of the process predicted by Charles Darwin’s son , George
Apparent horse-shoe orbits
The inter-planetary highway involving Lagrangian points L1 and L2
A simplified look at the Roche Limit – a limit to close approach without fracture – a tidal effect.
Isaac Newton’s simple geometric derivation of a somewhat generalised form of Kepler’s Area Law – generalised to shapes other than ellipses – all being examples of ‘central force’.





Astronomy Related Mathematics – May 31st

31 05 2011

Tuesday May 31st 2011 is our periodic 5th Tuesday Math and Astronomy program by Bob Roeth.  This will be our last meeting at the Sports Pavilion, as we will move to Regis Hall at St. Ignatius in early June (we’ll provide details later for the new venue).  The Math program will start at 7:30, as usual.

Bob Roeth’s comments follow:

Having a scientific calculator will be helpful in the first part of the evening.  Included will be some calculations based on an [approx] ellipse made by the string and pins method and then on the Earth orbit.
After that, I will try to show how Ptolemy’s epicycles and equants combined could produce a very close approximation to the picture according to Kepler.  This involves:
Showing how an epicycle can be made to produce a shape that satisfies the mathematicians’ standard formula for an ellipse, and
 showing that the planets in our solar system have small enough eccentricities that the unoccupied focus has properties very close to what Ptolemy wanted for his equant.  His positioning of his equants was by mere trial and error and he was so good at it that his results  added greatly to the difficulties the Copernicans already had in trying to establish the Sun as central in what we call the Solar System.




NSAS Events for May

2 05 2011

We have the usual busy month ahead in May for NSAS, with the Theory Group meeting Tuesday the 10th, the New Astronomers Group restarting after a break at Easter on Tuesday the 24th, and Bob Roeth entertaining us again with one of his “fifth Tuesday” math-rated astronomy exercises on the 31st.  The General Meeting his month is Tuesday the 17th, and we’re lucky to have been able to get Jason Spyromilio, from the European Space Organisation, who is visiting, to talk to us about the ESO’s new ELT (Extremely Large Telescope) project.  As usual, all meetings are at St. Ignatius, starting at 7:30 PM.  Also as usual, visitors are welcome to the General Meeting and NAG.





Astronomy Related Mathematics (5th Tuesdays)

10 03 2011

Beginning in March 2011 Bob Roeth will be starting a series of presentations on Astronomy related mathematics. These talks will be held periodically on the fifth Tuesday of the month (when there is one).

The first session on March 29th will cover the following (time permitting):

  1. Spherical Aberration with concave spherical mirrors. This uses the geometry of triangles, parallels and parallelograms along with the laws of reflection.
  2. Use of Conjunctions to determine planetary periods, advance through the civil calendar of the onset of retrograde motion. This is just arithmetical and treats the orbits as circles – they are very close to circular except for Mercury (and demoted Pluto).
  3. Constructing ellipses – another meaning for ‘envelope’. This is practical and will require using a table with compasses, rule, pencil, eraser if you think you might need one and scissors.  Cutting out a couple of paper circles with diameters about 200 mm beforehand could save time.  The least well known method to be tested is surprising and simple but the maths needed to show that it should produce an ellipse is quite daunting.  We will only look at the practical side.

Below is a list of the topics which may be covered as the series progresses. This list may be revised throughout the year, so please have a look and let us know of any topics which you may have a particular interest in. This feedback will help in deciding which topics will be covered in future sessions.

Note: These topics are not in any particular order

1. Eccentricity calculations with a simple calculator with square roots and with a scientific calculator having Sines and Cosines from trigonometry,
2. Newton’s invention of Gravity,
3. Easy ellipse mathematics,
4. How close was Ptolemy’s orbit to the ellipse when he used the equant?
5. Constructing ellipses – another meaning for ‘envelope’,
6. Sundial maths, shadow paths and the Equation of Time,
7. L1,L2 and L3 e.g., SOHO ‘at’ L1,
8. Combining magnitudes e.g., Venus and Jupiter in very close conjunction in 2BC and 6BC,
9. Co-orbital Janus and Prometheus in Saturn’s family of satellites,
10. Horseshoe orbits, The Interplanetary Highway of cheap Solar System Tours (cheap on fuel – EXPENSIVE IN TIME).
11. Gravity Assist e.g., the Pioneers and/or VEEGA, Jupiter’s effect on orbiting junk,
12. Spherical Aberration with concave spherical mirrors,
13. Sagittal calculations for spherical mirrors in the stage before parabolising,
14. Calculations relating to the Calendars,
15. Kepler’s mathematics,
16. Use of Conjunctions to determine planetary periods, advance through the civil calendar of the onset of retrograde motion,
17. Estimating the declination of the Sun from the day-number in the year.

 

We hope to see you there.

Peter Nosworthy

 








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