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: Space sextants
    From: Frank Reed
    Date: 2010 Oct 24, 19:50 -0700

    I wrote yesterday:
    "The Apollo spacecraft also had an instrument called a "telescope" mounted right next to the sextant. This was actually just a unit power viewer with a computer-readable orientation, useful for gross alignment of the sextant. The astronauts enjoyed joking about the fact that only a government project could pay good money for a telescope with no magnification. This telescope was used occasionally in experiments and at least once in actual practice. In 1968 on Apollo 8, returning from their historic lunar orbit mission, Jim Lovell accidentally entered a key sequence that told the computer it was back on the ground in pre-launch mode potentially wiping out the inertial platform's alignment. Just to be safe they ran "P51" which re-aligned the platform starting from scratch with gross alignment provided by the so-called telescope. This was a case where the astronaut had to identify the bright stars visually based on his knowledge of the constellations. It was a rare moment in manned space flight."

    I found the quotation on the unit power telescope. It's from Neil Armstrong who said, "NASA is probably the only organization in history that's been sold a one-power telescope." Of course, it was the computer-driven telescope mount that made it so useful. You could tell the computer "Point at Betelgeuse" and it would do just that. The view through the eyepiece would be centered on Betelgeuse with the stars of Orion around it at exactly the scale seen with the unaided eye. The computer-driven sextant could then slew to the same spot.

    It's funny. It's taken almost fifty years, but we can now do that (the computer-driven, unit-power telescope part) with pocket devices. The other day I was outside in front of a restaurant with some friends along with some other people who had popped out for a smoke. I said, "There's Jupiter" and pointed at it in the sky. Then I took out my phone/computer, started up "Google SkyMap" and showed them that it pointed right at it. Over my shoulder I heard, "oh yeah, it is Jupiter" and when I turned around I was amazed to see three other people holding their phones up. They ALL were running Google SkyMap. We had a couple of minutes of fun identifying a few more of the two or three dozen stars visible from downtown Chicago.

    -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