Comets 219P/LINEAR and C/2015 ER61 PANSTARRS together in Earth’s Night Sky

Mike Olason
Location of photo
Denver Colorado
Date/Time of photo
26 October 2017, 1001UT
11" SCT f/6.4 and STF-8300M CCD Camera
Comets 219P/LINEAR and C/2015 ER61 PANSTARRS were both moving at about 1/4 degree per day to the WSW in this image. They are 1/4 degree apart with 219P 175 million miles from Earth and ER61 163 million miles from Earth. Both comets were at perihelion earlier this year. 219P has a 7 year orbit and ER61 has a 7,807 year orbit. Interestingly, both comets tails point in the general direction that they are moving. ER61 is about 100 times brighter than 219P which made it a little difficult to make either comet look good in this image.
Astronomy Pictures: Sky & Telescope's Online Gallery, Meteor, Comet & Asteroid Pictures
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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