Using Forced Flip GoTo's

Using Forced Flip GoTo's

GoTo's and Mount flip

A GEM mount operates with the scope either on the west side of the mount or the east side. When you initiate a GOTO for an object east of the meridian, the mount will slew to the object with the counter-

weights in the “down” position with the scope/camera on the west side of the mount. If you then initiate a slew to an object west of the meridian, the mount will reverse its position or “flip” so that the scope/camera is on the east side of the mount.

In the normal scheme of things a “flip” only occurs for GOTO's/slews as described above. If you select an object east of the meridian and the object crosses the meridian, the mount will not flip and will continue to track the object. With this situation, the mount will end up in the counter-weights up position. It also poses collision risks that are potentially different from the counter-weights down position so close monitoring of mount movements is essential. EQMOD has a feature that allows control of a “flip” in a non-standard way.

When would non-standard flip be appropriate.

Here are a couple of examples:

  • If your observing setup favours primarily west of the meridian with limited view of objects just east of the meridian and you would like to start tracking an object, east of, but close to the meridian.
  • If you use something like a SkyPOD observatory where the roof tends to block access to the Zenith and would like to position the mount so the scope/camera is offset from the roof.

In general, this flipped movement is really only to be attempted as a last resort. It is much better, if you can, to track through the meridian rather than used “Forced Flip GoTo's”. In addition, flipped gotos may not be as accurate as normal goto as the alignment model was not designed with them in mind. Fir this reason, the user must not create a model that includes a mixture of points added from normal and flipped positions.

It is important that anyone considering flipped gotos also reviews the meridian limit functionality and the associated movement strategies that EQASCOM applies. See the youtube presentations at
http://www.youtube.com/watch?list=PLBB117AE85EB6BF04&v=TExsfjt8aro

How to use non-standard flip feature.

  • You must be prepared to monitor the mount movements to avoid any collisions. This is always good practice even when this feature is not utilized but is particularly important when using the “Forced Flip GoTo”.
  • Slew the mount so that the scope/camera is on the same side of the meridian as the object.
  • Click the {Display} button (located just below the ASCOM logo) until the “Mount position” panel is displayed.
  • Tick the “Force Flipped GoTo” option

  • Initiate the GoTo for the object
  • Fine tune the position with the slew controls

When the mount moves it will follow the strategy outlined in the Mount Movement Strategies topic.

Caution:

  • The “Force Flipped GoTo” option will be deselected after the GoTo, so you must be careful with the next GoTo. If you don't reset the option, it will be a standard GoTo and may flip the mount. If you intend to keep the mount in its current orientation, you will have to reset the option each time before initiating a GoTo.
  • If you start with the scope/camera on the opposite side of the meridian to the object, the “Force Flipped GoTo” will flip the mount.
  • The orientation of the mount using the “Force Flipped GoTo” poses significant collision hazards. Direct supervision of the mount is essential. Remote control of the mount is not recommended.
/home/welshdra/public_html/eqmod/data/pages/using_forced_flip_goto_s.txt · Last modified: 2012/06/27 22:59 by jon
 
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