Sunday, January 18, 2009

Autoguiding: By Glen Regan

After you have selected your object and slewed the telescope to it, I would do an "autofocus function" (usually defaults to the Clear filter). Also do a Center function to make sure you have the right target.

Then I would start the Tzec Maun autoguiding. First click on the "inactive autoguide" to start the function. Select an exposure time of 8 or 10 sec, then an aggressive setting of 6 with 0 sec delay. Make sure the "Clear" filter is selected. Start exposure. When the guide window opens after exposure, select a bright star for guiding with your cursor. When that star has been centered for guiding, close the window. The telescope is now being guided.

You can now take images individually or with the series function. Determine what filters you will use and select for each exposure. ALL image exposures will also switch the filter for guiding to the selected filter as well. Therefore what star appeared bright in the Clear filter usually appears bright in the RGB or RGB-Bissell filters. On the other hand the narrow band filters (Ha, OIII, SII) can make the guide star appear faint and the guider may not be as accurate in its function. This is the reason I choose a longer initial exposure time (say 8-10 sec) for the guider.

Attached is a quickly-processed H alpha image of IC 443 (Jellyfish nebula) taken tonight which had a 10 min exposure time using the BigMak Tzec Maun telescope.

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