# I've just been at the Observatory, viewing the planetary alignment (Mercury, Venus, Mars & Jupiter) **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [May 12, 2011, 9:04pm UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705 "2011-05-12T21:04:15Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Cunctator](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Cunctator](https://boards.straightdope.com/u/Cunctator)\ **Post date:** [May 12, 2011, 9:04pm UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705/1 "2011-05-12T21:04:15Z")
On a chilly May morning (9C) there was quite a large crowd (100+) as the Observatory opened at 5.00am. Fuelled by the free coffee and croissants, we got lovely views of the four planets, as well as three of the Jovian moons, in the north-eastern sky. The observatory staff had also set up a number of other telescopes, and had lots of pairs of binoculars on hand as well, so everyone was able to have a good look. And, rather fortuitously, the police closed the Harbour Bridge to traffic at about 5.15am (a would-be suicide, I gather), so the Observatory was unusually quiet with the lack of any noise from vehicles. According to the Observatory: > [@](#): > > Close alignments of these four planets occur every 50 to 100 years. The last time was in 1910 and it will next occur on 13 February 2056. A very enjoyable way to start the day! ---
**Author:** ![FloatyGimpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/floatygimpy/32/7750_2.png) [@FloatyGimpy](https://boards.straightdope.com/u/FloatyGimpy)\ **Post date:** [May 13, 2011, 12:20am UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705/2 "2011-05-13T00:20:42Z")
I’m jealous! ---
**Author:** ![Gleena](https://avatars.discourse-cdn.com/v4/letter/g/b3f665/32.png) [@Gleena](https://boards.straightdope.com/u/Gleena)\ **Post date:** [May 13, 2011, 12:25am UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705/3 "2011-05-13T00:25:10Z")
Naw, he didn’t want to kill himself, he just wanted to hang banners and be crazy. Allan Jones talked him down. :rolleyes: I wish I would have known the Observatory was open though, it would have been awesome to go. ---
**Author:** ![Girl\_From\_Mars](https://avatars.discourse-cdn.com/v4/letter/g/3da27b/32.png) [@Girl\_From\_Mars](https://boards.straightdope.com/u/Girl_From_Mars)\ **Post date:** [May 13, 2011, 9:12am UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705/4 "2011-05-13T09:12:14Z")
I only found out about this after you posted, but it would have been cool to see; I went to the Wellington observatory in 1994 to see the Shoemaker impact. Just saw last night’s coverage on TV - perhaps you were there! ---
**Author:** ![DHMO](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@DHMO](https://boards.straightdope.com/u/DHMO)\ **Post date:** [May 13, 2011, 12:43pm UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705/5 "2011-05-13T12:43:21Z")
> [@Girl\_From\_Mars](#): > > I only found out about this after you posted, but it would have been cool to see… > [@FloatyGimpy](#): > > I’m jealous! The grouping of the planets is still there. Just look low in the eastern sky about 30 minutes before local sunrise. It’s actually kind of neat to watch as the planets shift position over the next few days, too. They are relatively easy to pick out with the unaided eye, but even moderate binoculars will improve the view. They would not be set up pre-dawn, usually, but many local observatories have open-house type events on at least a monthly basis, so you should check it out. At many of these events where I have attended, there are dozens of amateur astronomers with their home-built and commercial telescopes set up to look at whatever interesting objects are in view at the time. The shifting positions of the four Galilean moons of Jupiter is fascinating to watch night-to-night, or even hour-to-hour. Even binoculars or a low-powered telescope will make the Jovian satellites visible. Here’s a [link](http://www.astroengine.com/2009/08/amateur-captures-io-eclipse-on-ganymede/) to a site showing a view when, on August 16, 2009, the shadow of Jupiter’s moon Io fell on another moon, Ganymede, with an animated .GIF made from photos the observer (Christopher Go from Cebu, Philippines) took with an 11-inch Celestron telescope (which is not very big, as telescopes go.) It’s amazing how much surface detail on the moons he was able to record. ---
**Author:** ![medstar](https://avatars.discourse-cdn.com/v4/letter/m/f07891/32.png) [@medstar](https://boards.straightdope.com/u/medstar)\ **Post date:** [May 14, 2011, 2:40am UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705/6 "2011-05-14T02:40:38Z")
Are there any 2012 doomsday cults who have decreed the end of the world based on this phenomenon? ---
**Author:** ![Cunctator](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Cunctator](https://boards.straightdope.com/u/Cunctator)\ **Post date:** [May 14, 2011, 4:28am UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705/7 "2011-05-14T04:28:14Z")
> [@Girl\_From\_Mars](#): > > I only found out about this after you posted, but it would have been cool to see As \*\*DHMO \*\*notes, the planetary alignment is visible in various permutations in the north-eastern sky in the early morning for most of the rest of May. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [May 14, 2011, 9:24am UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705/8 "2011-05-14T09:24:11Z")
> [@DHMO](#): > > Here’s a [link](http://www.astroengine.com/2009/08/amateur-captures-io-eclipse-on-ganymede/) to a site showing a view when, on August 16, 2009, the shadow of Jupiter’s moon Io fell on another moon, Ganymede, with an animated .GIF made from photos the observer (Christopher Go from Cebu, Philippines) took with an 11-inch Celestron telescope (which is not very big, as telescopes go.) It’s amazing how much surface detail on the moons he was able to record. Here’s a challenge: What would have been the apparent size of Io, from an observer on Ganymede, relative to the apparent size of the sun? ---
**Author:** ![blue\_infinity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/blue_infinity/32/2817_2.png) [@blue\_infinity](https://boards.straightdope.com/u/blue_infinity)\ **Post date:** [May 14, 2011, 9:37am UTC](https://boards.straightdope.com/t/ive-just-been-at-the-observatory-viewing-the-planetary-alignment-mercury-venus-mars-jupiter/581705/9 "2011-05-14T09:37:21Z")
> [@panache45](#): > > Here’s a challenge: What would have been the apparent size of Io, from an observer on Ganymede, relative to the apparent size of the sun? Very rough estimate: Io would have around two-thirds the apparent diameter at closest approach.