Monday, December 7, 2015

OR: Comet C/2014 Q2 Lovejoy, 7 January 2015

Equipment: Edmund Astroscan, 4-1/8” aperture f/4.2 reflector; RKE 28mm eyepiece = 16x magnification, 6.6mm exit pupil, 2.8 deg. TFOV.

Conditions: Seeing: 5/7; Transparency 2-3/5 (some high clouds after 9:00pm PST). Red zone light pollution.

Summary: I made hourly observations of the comet to note its progress relative to background stars. The comet’s movement was obvious when seen at this interval. The comet was barely visible naked eye, and through the telescope appeared as a bright point within a large ~15’x15’ round coma; no tail was observed. It looked like an unresolved globular cluster, very faintly bluish green. I first located slightly to the SW of star HIP19800. The comet progressed NW through the evening and occulted a magnitude 9.5 star to the NW of HIP19800, as noted in the drawings below. More stars were visible in the FOV but I only drew the brightest for reference (however the magnitude 9.5 star was 50% held with direct vision, 100% held with AV). Based on my sketches and use of Aladin, I estimate the comet traveled 35 arc minutes in the 4 hours I observed it, or 8.75 arc minutes per hour.

West in the following sketches is to the left, north down to show a consistent position of the background stars and better illustrate the comet’s movement. However my logbook rough sketches, in which I marked West at the point where the comet drifted out of the field stop, West actually started in the “8:00” clock face position of the field stop and progressed up to “11:00” by the end of the session. This was a unique demonstration of the sidereal motion of the sky as seen through the eyepiece.

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