Welcome to the NavList Message Boards.


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

Compose Your Message

Add Images & Files
    Re: Software for Star Recognition
    From: Marcel Tschudin
    Date: 2014 Jan 26, 18:00 +0200
    Paul, you wrote:

    Doesn't the astrometry.net plate solver output the classic "plate
    constants"? With them you can transform the image's xy pixel coordinates
    (measured with the Windows Paint utility or similar program) to the
    corresponding right ascension and declination.
    From the downloadable FITS-files provided with the analyzed photo I was only able to look at the one called "new-image.fits" using the program DS9. This program shows then the analyzed photo and for the cursor location both, the x/y-pixel location and also the corresponding RA/Dec from the fitted function.

    As part of his off-line help to solve my "problem", David Walden provided me also with the following publication

    "The SIP Convention for Representing Distortion in FITS Image Headers" Shupe and Hook, Astronomical Data Analysis and Systems XIV, ASP Conf series, vol XXX 2005 ( http://irsa.ipac.caltech.edu/data/SPITZER/docs/files/spitzer/shupeADASS.pdf )
    which explains the type of function used by astrometry.net for their fits. If I remember right the classic 6 "plate-constants" which you mention do only depend linearly from x and y whereas their 6 parameters seem also to contain quadratic terms.

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    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 Settings

    Posting Code:

    Custom Index

    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