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  1. #1
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    Default What is an autoguider?



    Somehow this one escaped me.
    What is an autoguider?
    I see it looks like a ccd camera but sounds like it does not connect to the camera.
    The mount I'm about to purchase(cg-5) says it has a "port" for an autoguider.

    Obviously it's used to track objects more accurately but what does it connect to?

    Example.
    The [ame="http://www.amazon.com/Orion-StarShoot-AutoGuider/dp/B001EPND18"]Orion starshoot autoguider[/ame]


    Looks like a ccd camera to me.

    ???

  2. #2
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    Default

    On some mounts there is an auto guider port for allowing the guider to plug into using a USB cable to make correction to the telescope tracking.Its usually connected to a finder scope on top of the main scope and tracks a guide star more precisely then the mount drives. But it only guides the scope, it does not take images.

    Check out the link below for more precise information.

    Equipment - Autoguider
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  4. #3
    HeXploiT's Avatar
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    Default

    So an autoguider can actually control the motor that is powering the scope to make corrections.

    Can software apps such as guidedog and a simple webcam improve upon the tracking of a quality mount/guiding system or would this only be beneficial to low end systems?

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    Default

    Quote Originally Posted by HeXploiT View Post
    So an autoguider can actually control the motor that is powering the scope to make corrections.

    Can software apps such as guidedog and a simple webcam improve upon the tracking of a quality mount/guiding system or would this only be beneficial to low end systems?
    An auto-guider feeds TTL (transistor-transistor logic) level pulses to the ST-4 compatible input port on the mount. The TTL pulses are "east", "west", "north" and "south", and follow a protocol originally devised by Santa Barbara Instruments Group (SBIG), who manufactured one of the original auto-guiding CCD cameras. ST-4 has become the defacto standard interface/protocol for auto-guiding.

    These pulses emulate what a human user would be doing with a hand-control attached to the mount, except that the pulse width/duration and frequency are better controlled.

    Auto-guiding is (or should be) one of the last things you do as an imager. One generally extracts all the performance capable from the mount first, by balancing the equipment load, planning the pointing and movement, learning to drift polar align, and through improving mechanical precision (reducing friction, motor stalling, gear lash), and PEC training.

    Auto-guiding is best used to improve tracking when the inherent tracking in the mount error has been reduced to less than 10 arc-seconds.

    It can only correct for so much error - a poorly aligned mount, or one that hasn't been PEC trained will not track accurately, even with auto-guiding.

    Auto-guiding is also "seeing dependent", and can create more problems that it solves by causing the mount to track and correct to seeing condition problems. It also adds complexity and cost to the equipment and set-up.

    It generally isn't necessary, beneficial, or cost-effective in conditions where exposure duration is limited by other factors, like light pollution. If your exposure duration is for example limited to 90 seconds due to heavy light pollution, there is no sense investing in auto-guiding to improve the mount's tracking to allow two minute or longer exposure.
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  7. #5
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    Quote Originally Posted by AustinPSD View Post
    An auto-guider feeds TTL (transistor-transistor logic) level pulses to the ST-4 compatible input port on the mount. The TTL pulses are "east", "west", "north" and "south", and follow a protocol originally devised by Santa Barbara Instruments Group (SBIG), who manufactured one of the original auto-guiding CCD cameras. ST-4 has become the defacto standard interface/protocol for auto-guiding.

    These pulses emulate what a human user would be doing with a hand-control attached to the mount, except that the pulse width/duration and frequency are better controlled.

    Auto-guiding is (or should be) one of the last things you do as an imager. One generally extracts all the performance capable from the mount first, by balancing the equipment load, planning the pointing and movement, learning to drift polar align, and through improving mechanical precision (reducing friction, motor stalling, gear lash), and PEC training.

    Auto-guiding is best used to improve tracking when the inherent tracking in the mount error has been reduced to less than 10 arc-seconds.

    It can only correct for so much error - a poorly aligned mount, or one that hasn't been PEC trained will not track accurately, even with auto-guiding.

    Auto-guiding is also "seeing dependent", and can create more problems that it solves by causing the mount to track and correct to seeing condition problems. It also adds complexity and cost to the equipment and set-up.

    It generally isn't necessary, beneficial, or cost-effective in conditions where exposure duration is limited by other factors, like light pollution. If your exposure duration is for example limited to 90 seconds due to heavy light pollution, there is no sense investing in auto-guiding to improve the mount's tracking to allow two minute or longer exposure.
    Very informative post Austin thank you.
    Sounds like it may bridge the gap between ones pocketbook and that equatorial mount that is financially just out of ones reach.

    Time for some due diligence on the details of error correction.

    I guess the next question that immediately comes to mind is whether it would be wiser to spend an additional $500 on a better quality mount(over a say...a CG-5) or whether spending $500 on an autoguider could more effectively bridge that gap?

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    Default

    Quote Originally Posted by HeXploiT View Post
    Very informative post Austin thank you.
    Sounds like it may bridge the gap between ones pocketbook and that equatorial mount that is financially just out of ones reach.

    Time for some due diligence on the details of error correction.

    I guess the next question that immediately comes to mind is whether it would be wiser to spend an additional $500 on a better quality mount(over a say...a CG-5) or whether spending $500 on an autoguider could more effectively bridge that gap?
    I guess it would depend on weather or not the more expensive mount would carry more weight ...and of course , track better ...
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