Recent Blogs Posts

  1. Back to basics - been away from the blog for a while

    by , 06-20-2017 at 12:50 AM
    Some of you may know that I have been having issues getting the GSO coma corrector to play nicely with my setup. As a refresher, in January I installed a linear bearing two inch dual-speed focuser and picked up a spacer to get the documented 70mm of spacing between the back of the CC and the DSLR sensor. With the glut of sucky weather that has been going on around here, the first chance I had to try it out was an abbreviated session in May (abbreviated because the clouds rolled in 20 minutes after ...
  2. Deep Sky This Month - June 2017 (Northern)

    by , 06-01-2017 at 12:54 PM
    Welcome to a new month and a new edition of the DSTM. As I normally do, I have included some finder charts to aid your search, which are made with Sky Tools 3 with the kind permission of Greg at Skyhound.

    From the northern hemisphere we will take a look at an object that is often seen but seemingly given only a cursory glance at best a great deal of the time. Then we will visit a curious pair of galaxies that can inspire the imagination. Looking below the celestial equator we will pick ...
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  3. Deep Sky This Month - June 2017 (Southern)

    by , 06-01-2017 at 12:53 PM
    We now move southward to take a look at the offerings for those living closer to or below the terrestrial equator. I hope you find these are fun to pursue, and they offer you something new to add to your normal sessions this month.


    Southern Celestial Hemisphere:


    NGC 5460 (Centaurus)


    Open Cluster, mag=5.6, size=30.0’


    The constellation representing the fabled centaur is the ninth largest by area and contains nearly ...
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  4. a different kind of "fifth force"

    by , 05-28-2017 at 06:30 PM
    Quote Originally Posted by not_Fritz_Argelander View Post
    Let me give a hint of my thinking about why fifth, sixth, ... nth forces might be reasonable. It has to do with gauge fields and their internal dimensions.

    Electrodynamics is a gauge field described by a 1 dimensional gauge group, U(1). That U(1) just means that the internal symmetry multiplies the wave function by a phase factor. The U means it preserves the wave functions probability. It's a fancy way of saying that adding a constant to the electric potential makes no difference.
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  5. a different kind of "fifth force"

    by , 05-28-2017 at 06:28 PM
    Quote Originally Posted by not_Fritz_Argelander View Post
    A general survey of the goodies that can come from testing GR at Sgr A* is found at

    https://arxiv.org/pdf/1512.03818.pdf

    Figure 1 is especially instructive as it parameterizes (by potential and curvature) all relevant gravitational astrophysical regimes and all available experimental and observational methods in separate graphs that can be compared.

    I beg forgiveness for headaches caused. I think that a search for additional forces (fifth, sixth, ...)
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