Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Night video from Down Under
    From: Frank Reed
    Date: 2013 Feb 26, 13:28 -0800

    Noell Wilson, you wrote:
    "Look at http://vimeo.com/59571509"

    Thanks. Beautiful! I like the insets where we can see the actual motion of the comets among the background stars.

    So let's get down to the navigation. First, we visit his web site and guess that he is observing from somewhere near Flinders in Australia. There's a Flinders on the coast south of Melbourne, and the altitude of Achernar (lower right towards the end of the video) at lower meridian passage confirms this latitude to within about a tenth of a degree by my estimate, so we're on the right track. For Greenwich date, we could look at the positions of the comets. Then for an exact position fix, to within a few hundred feet, we could look at the positions of several artificial satellites that fly by. Putting it all together (and leaving the details to the reader), I find that the video was taken from 38°29'02"S, 144°59'24"E, give or take 50 feet. There's a little parking lot there at the end of a small road called "Blowhole Track". The rocks in the foreground to the left are known as "Elephant Rock".

    Pretty amazing, right? Imagine trying to work this out just twenty years ago...

    But there's more of navigational interest. Flinders?? This town is, of course, named after Matthew Flinders, a famous navigator who was an expert in lunars. He was the first person to circumnavigate Australia, as far as we know, and he was personally responsible for the name of the new continent. From 1803 to 1809, Flinders was held under arrest at Mauritius (where Antoine is often found) and spent his days observing and working lunars to maintain his sanity. See the lesson here? Lunars keep you sane.

    You also wrote:
    "It's a wonderful video of two comets and the Magellanic clouds which are only visible when it is DARK. I saw the Magellanic clouds beside the Milky Way one time in the Kruger Park in South Africa and didn't know what they were at the time."

    Well, not THAT dark. This observing site is only about ten miles south of brightly lit suburbs south of Melbourne, Australia (the center of the city is only 50 miles from this site). You can see the Milky Way and the Magellanic Clouds much closer to major cities than most people think. You only need to get away from local lighting. Here on Conanicut Island, we are just across the bay from light-polluted Newport where the Milky Way is most certainly not visible. But here, in summer, the Milky Way is quite spectacular away from the village area, and the limiting visual magnitude for stars is around 5.5-6.0 (not perfectly dark, but it certainly qualifies as a "rural" sky). In winter, it's worse since the leaves are down and also because snow reflects a lot of light. Within an hour of most major cities, there are still locations that are very dark at night. We only have to seek them out...

    -FER

    ----------------------------------------------------------------
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com
    ----------------------------------------------------------------

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
    Email:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site