Techniques
Home Dew Heater Image Processing Focusing

 

 

  

Telescope guiding etc 

 My observatory is conveniently located in my back garden and my control room is attached to my garage only a few metres away. I first open the control room and power up the PC. Using the PC I can remotely turn on the power to the telescope, dew heaters, cameras and lights. While the cameras are cooling down, I open the roof of the observatory .  

I  have my scope permanently mounted, so that a simple one star alignment is all that is required. The SXV-H9 and HX516 cameras require only a few minutes to cool to operating temperature, and this can be done while the rest of the equipment is being prepared. As soon as it's dark enough, I turn on the telescope and synchronize on a known star..  The finder, guidescope and APO refractor are already aligned with the main telescope so that all four optical systems are centered on the same object. 

    The CCD cameras are left attached to the scopes so that focusing is a simple affair. Although the LX200 is supposed to be an f10 instrument, it appears to be working at f12 normally. I usually use an f6.3 or f3.3 focal reducer for deep sky imaging and add a 2x Barlow to the scope to give me a measured f25 for planetary imaging.

For deep sky work, most of my integrations are 600 seconds.  I would take a series of maybe 8-10 of these which would then be stacked to produce the required total exposure. Guiding is done by using the separate 80mm guidescope.

 For wide angle imaging, I attach the CCD camera to a 300mm or 500mm camera lens and this is piggybacked on the main scope.

 For focusing, I use FocusMax software which operates via a RoboFocus system to produce very accurate focusing in a short time. This RoboFocus is temperature compensated to allow for slight changes in focus as the temperature of the air changes during an imaging run.  

I usually use AstroArt for imaging although I also have MaxIm DL/CCD.

I use a home made lightscreen to produce flat field images. It is a simple matt white screen, evenly illuminated and attached to the wall of the observatory and seems to give me acceptable results. I take multiple flats, and then average or median combine them, before storing the Master Flat as a file for use in the image processing