OLDER IMAGES

M13 Imaging example with cge and off-axis guider

M27 Imaging example with cge and guidescope

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MetaGuide is a web-cam based tool for precise collimation of the in-focus diffraction pattern of a star. MetaGuide also provides novel "proactive" autoguiding by locking onto a frequency in the guide error and correcting for it in real time after seeing effects have been reduced. MetaGuide can provide insight into both the optics of your telescope, and the tracking behavior of your mount.

MetaGuide is free, easy to use, works with any type of telescope, and most web-cams.

For the guiding component of MetaGuide, a parallel port or USB cable such as available from Shoestring Astronomy must be provided.

What does MetaGuide do?

• Allows a high power view of a star and its diffraction pattern even when seeing is bad
• Compares the observed diffraction pattern with theory, including secondary obstruction effects
• Provides a simple "dump" of the raw and steady images of the star, along with a plot that shows how the stellar profile compares to theory, plus numeric values for the actual and theoretical FWHM's.
• Automatically re-centers the telescope during collimation so you can concentrate on the collimation adjustments and not have to re-center manually after each change
• Acts as an autoguider with seeing effects partially removed from the error, so the "chasing of the seeing" is directly reduced
• Locks onto a user-specified error frequency and corrects for it proactively, acting like a new level of periodic error correction that does not rely on indexing and can work at higher frequencies
• Provides graphical output and logs of drift and periodic error in your mount, including the "noise" that can be hard to remove with PEC (Periodic Error Correction).

How does it work?

• MetaGuide uses realtime image processing of the video stream to process each frame, find the star centroid, and output a realtime stacked version of the recent frames
• Bad frames are automatically culled from the stack without user intervention
• MetaGuide is written in DirectShow/C++ for maximum performance since the amount of realtime computation is significant
• The stacked view is magnified 4 times and aligned with sub-pixel resolution
• This stacked view is also used as to determine guide corrections. Since this view has bad frames removed, the resulting error signal is a truer representation of the error due to the mount. This reduces the "chasing of the seeing."
• The radial plot is calcluated based on the stacked image, allowing direct comparison to theory and calculation of FWHM
• See a screenshot here

What are its requirements?

• MetaGuide requires only a web-cam and Windows XP or 2000 computer (not Win98, ME, NT, Mac, or Linux) with recent DirectX installed to perform the core diffraction analysis of a star
• New in version 2.2.6, most web-cams are supported - as long as they can output a 640x480 format. In addition, it has been tested with inexpensive video2usb converters, allowing most any video camera also to work
• Modified web-cams are not supported; MetaGuide relies on high speed streaming video to correct for seeing
• For the guiding features of MetaGuide, a parallel port or USB guider cable is needed, along with a mount that supports ST-4 style corrections
• A view of the diffraction pattern requires high power and a stable mount, so a Barlow and good tracking may be needed. The guiding aspects of MetaGuide will work with any f/ratio

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Download

NEW! version 2.2.6, June 10, 2006

• Support for most web-cams
• Some cleanup of the user-interface
• Additional tuning of the proactive MetaGuiding

MetaGuide 2.2.6 Installation, with documentation (1.9MB)

MetaGuide documentation alone, in pdf format, for perusal without doing the install. Instructions and many examples, including a comparison of an SCT with a Maksutov. This manual is included with the installation.

Support

For support, please send feedback and questions to the AstroGeeks Yahoo group.

Back to AstroGeeks main site

Questions, comments, and feedback contact Frank Freestar8n at the spam encoded address, freestar8n att yahoo ddoott com