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Using Redshift 4, and a few other similar programs, I investigated future close approaches of Venus and Jupiter, more properly called an appluse. The definition of an appluse is usually implying that both object to the naked seem to merge, but do not occultate (or transit) each other. For this to happen, the separations must fall below 300 second of arc (5' or 0.08o), which is based on the resolution of the “human telescope”s aperture - the eye. If they do occultate each other, this is called a planetary occultation.
(A term for a planet occultated by the Moon a planetary lunar occultation.)

For these two planets predicted events between 2000 and 2100 includes ;



17 May 2000 08:29 pm 0.012o
28 Aug 2016 08:28 pm 0.068o
29 Aug 2097 12:54 pm 0.071o

Planetary Occultation

21 Nov 2065 10.44 pm 0.003o

Next Twilight/ Night Planetary Conjunction

15 Nov 2006 05:40 am 0.5o

A Triple Planetary Conjunction of Venus, Jupiter and Saturn last occurred at 7:14 pm UT on 26th July 1802AD when all three passed within 0.49o of each other. This is the only triple conjunction within 0.5o for these planets between 1500AD and 2500AD. Those who have astronomical software that allows mutual events to be observed into the future might like to check the examples above, especially the planetary occultation of Jupiter and Venus in 2065. This will be one of the most interesting event of its type for many hundreds of years. Unfortunately, this is not visible in Australia.

Planetary Occultation

21 Nov 2065 10.44 pm 0.003o

Next Twilight/ Night Planetary Conjunction

15 Nov 2006 05:40 am 0.5o


On Saturday 20th February 1999, the close approach of these Venus and Jupiter was to be a spectacular event. I had travelled up to Bowen Mountain. Arriving around 4.30pm, the area around the observatory was the best I’ve seen, as the entire vegetation was a lush green and even the gum trees weren’t looking too sad under the summer heat that often lilts the branches and leaves. The grassed area surrounding the observatory has certainly come to life, and through the regular rains, even some of the grasses are heavy with seed.

A comment or two for those members using Bowen is desirable. One of the major problems with the site was all the mosquitoes were far more prolific than I had noticed before - so insect repellant is still required, maybe as late as mid-May. This might be due to the grass. Soon this area might have to be mown more often to keep the grasses at bay. Regular observers should bear in mind, that the grassed areas can become laden with dew, and this can be a problem with getting damp feet and trousers. Secondly, it is advisable where you observe east of the observatory to check for “Joe Blakes” (snakes) before dark or before setting-up. Overall the grassed region is certainly so much more pleasant than the sand and dirt. Although it has been placed there to retain the topsoil, it makes a great place for a picnic!

Overall, it was a disappointing night, mainly because of the high and low cloud cover, and the local bush fires to the west of the mountains. The entire evening went from bad to worst, though it was almost thrilling to see a bright purple valley and a vermillion sunset. When the Sun reached the horizon to set, a small slit of clear sky let the rays of the Sun shine through. Most spectacular was an intense orange-deep fluorescent red and an intense yellow of the Sun. The 3-day-old Moon was prominent in the north-west, with Saturn appearing some 3o eastward. Soon, the eastern and southern sky became dark and heavy with clouds, and yet another evening of observing was dashed. Packing the telescope was quick and at 8pm and I headed home. After closing and re-locking the gate, Venus and Jupiter appeared just above the clouds, tainted reddish-orange and “Mars-like”. I wish I had my camera at the time, as the image of the two planets peering through the smoke and trees was almost magical. Again on the 21st, a similar picture was seen from the night before, except the separation was notably smaller, thus showing their relative motions. Both the 22nd and 26th were predictably numilus interruptus - clouded out.


I received an e-mail asking for times of the next few conjunction events on the May 2000 Jupiter and Saturn close approach, that I thought my readers might be interested in. My investigations on this problem show the times between close approaches of Jupiter and Saturn happen once every 19.664±0.005yr. (1.9days) According to Jean Meeus the real possibility of finding these two planets in the same region of the sky is three times longer. Ie. 58.99 years.

For example, Spica (Alpha Virginus) is near these conjunctions in 1980-1981, 2040, 2100, 2159 etc.

Looking at the table below this twenty-odd year interval is obvious. The triple conjunction events are the rarest, averaging once every 257.75 years, that last occurred in 1981. One particular event that I am looking forward to the 21st December 2020 event, as both planets will be able to be seen in the same telescope field. The best place in the world to see this close approach is New Zealand and some of the Polynesian islands of the Pacific.

              TIME    Min. 
  DATE       (AEST)   Sep. 
 19 Feb 1961  00:22am  0.229   
 05 Dec 1980  09:15pm  1.733   
 11 Jan 1981  09:54am  1.114   
 25 Mar 1981  11:07am  1.445   
 13 Aug 1981  00:57am  1.323   
 17 May 2000  09:14pm  1.629   
 21 Dec 2020  01:43am  0.102 * 
 29 Oct 2040  05:35am  1.149   
 09 Apr 2060  10:01am  1.132   
 15 Mar 2080  00:26am  0.100 **
 16 Sep 2100  07:58pm  1.229   

* Appluse? Visible in Sydney 0.12o apart during twilight.

** Appluse?

Note: Those who have similar computer software may like to “observe” these results, as most happen long after we are dead and buried.

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