Comet 117/P Helin-Roman-Alu

Comet 117/P Helin-Roman-Alu is a faint periodic comet that has relatively circular orbit with a perihelion distance of over 3 AU. As a result, the comet is visible at any portion of its orbit. However, the brightness variation is quite assymetric, with the comet being at its brightest several months after preihelion passage.


Comet 117/P Helin-Roman-Alu. January 29, 2001.
Combination of 5, 3 minute images, SBIG ST-9XE CCD.
300mm f/6 newtonian at prime focus.


Comet 117/P Helin-Roman-Alu. 15 March, 2003.
Combination of 5, 3 minute images, SBIG STL-1001E CCD.
20" f/6.8 cassegrain at prime focus.

The comet was about magnitude 14.8 when the above image was taken, and it should peak at about magnitude 13 in mid-2014.