The Night the Earth Stood Still.......
It's not very often that you get a chance to carry out long exposure CCD imaging with a stationary telescope, and the night of the 14th/15th March 1999 presented just the right conditions. Comet Linear (C/1998 M5) was passing very close to Polaris, and I took the opportunity of imaging it with a stationary 10" Dobsonian telescope and SX CCD. At closest approach to the pole (which in fact occurred later at 10h U.T. on March 15th) the comet's motion was just 2 arc seconds/hr!
Under these circumstances a Dobsonian telescope performs better than one mounted on a German Equatorial, since it is difficult to orientate the scope at such high latitudes and almost impossible to image Polaris. For this reason I brought the small 10" Dob into the dome within reach of the CCD. Using a Megastar chart with the comet's position plotted I soon found the small circular glowing patch of Linear just over one eyepiece field of view away from Polaris.
This is a 4 x 40 sec exposure showing the small almost circular coma of the comet, with the stars just showing slight evidence of trailing. These images were all registered on the brightest star in the image. During the second image I used the comet itself for registering each image. This has resulted in showing the stars as short trails. Finally in this image below I took a single exposure of 160 sec, which now shows the comet itself showing a short trail. Not to miss out on a good opportunity I also imaged Polaris - something that I had never done before. This short 1.6 second exposure reveals its 9th magnitude companion. Observing details: 10" Meade Starfinder Dobsonian + SX CCD. Telescope undriven and stationary in all images.
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