Discussion in 'My Astrophotos' started by ROBERT T SCHAEFER JR, Sep 15, 2019.


    ROBERT T SCHAEFER JR Cyanogen Customer

    May 13, 2018
    This is Jupiter with the New … ZWOASI120MC-S webcam thru a 152mm A+M Refractor(OfficinaStellare) that is 1200mmF/L ,
    using a TeleVue 2.5XPowerMate into a TeleVue 2XPowerMate which is 5900mmF/L according to a "PinPoint Astrometry" 'solved'
    DSLR image .
    ZWO thru a TeleVue 2.5XPowerMate into a TeleVue 2XPowerMate using a 152mm A+M Refractor(OfficinaStellare) for 5900mmFL as .ser RAW16 file thru "SharpCap" camera control and put into "RegiStax 6" and set 'Alignpoints' and 'De-rotate' and 'Scamframes' and then 'Align' and 'Limit-40' and 'Stackgraph-checking frames for high spike frames making stack 13 frames by using the upper graph area toggle control to decrease the amount of frames to 13' ... and then 'Stack' and then 'Wavelets' .x
    read this ??! = ' www.cloudynights.com/topic/562139-how-to-measure-the-focal-lenght-of-barlow-teleconverter-telecentric-PowerMate-concave-lens ' ,
    on the cloudynights site . Someone there has a TeleVue 2XPowerMate and he put it in a vice and put a piece of paper in front of it which would be
    the back-end of the PowerMate and with another vice he put into it a Collimator that's a laser light and marked on the paper that's about 135mm distance
    … where the light from the laser lands on the paper … like straight down the middle and on each side , and at the sides the light is at a position different than the straight down the middle light position and looks like it's positioned out of a straight line to a more outer position . This shows an expansion to show
    that an image would be enlarged when it exits the PowerMate and lands on the camera 'sensor' .
    Another person there is talking about the theories of PowerMates and Barlows and says that a Telescope is always at the same Focal-Length that it
    is originally made for at Prime-Focus ….. but what a PowerMate or Barlow is doing is expanding the image and not actually changing the Focal-Length
    and what you are seeing is an enlarged image of the original Prime-Focus image size … and the more PowerMates or Barlows you use …. the more the
    enlargement of the image 'object' . This sounds confusing that the actual physical mathematical properties of the original Prime-Focus reality
    of the Telescope never changes and a PowerMate or Barlow is only enlarging the existing Prime-Focus image . The enlargement would be like
    a slide projector on a screen near the front of the projector and if you move the screen farther away … then the image is enlarged and is dimmer ….
    but with a camera you would use a longer exposure to get a better image that's less dim .x

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