Comet 21P/Giacobini-Zinner

Mike Olason
Location of photo
Denver, Colorado
Date/Time of photo
15 April 2018, 1017UT
11" SCT f/6.4 and STF-8300M CCD Camera
In this 300 second image 21P/Giacobini-Zinner is magnitude 18.1 and 170 million miles from Earth. 21P will be at perihelion in its 6.54 year orbit on September 10 when it will be 94 million miles from the Sun. 21P will also makes its close approach to Earth on September 10 when it will be 36 million miles from Earth. 21P may reach magnitude 7.
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Mike Olason

About Mike Olason

I started imaging comets in 1994 with an ST-5 CCD Camera and an 11" SC Telescope. Since then the CCD cameras have changed (ST-7, ST-402ME and STF-8300M), but I am still using the 11" SC Telescope. Naturally I have used a lot of smaller telescopes to obtain larger fields of view. I live south of Denver at an elevation of 6150 feet which allows me to image comets down to almost magnitude 21 on a perfect night. Unfortunately ChemTrails have turned Denver cloudy and dry. I use the camera software CCDOps to process my images. All I do to each image is dark subtraction and flat field, stack images as required to show faint comets, contrast/bright adjust the final image and maybe use a median filter to reduce the image noise. The result is an image that reflects reality and will never win any picture of the day award. If you would like to use my images for a project or ask a question send me an email to "".
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