Comet Section        




Saturn isn’t the only solar system body at its best this month. Comet Johnson is also at its best and is well placed as soon as it gets dark after sundown.

C/2015 V2 (Johnson) was first spotted by Jess Johnson of the Catalina Sky Survey back in November of 2015. It is a dynamically new comet with an original orbit almost indistinguishable from a parabola. Perturbations by the major planets have transformed its orbit to hyperbolic so this will be Johnson’s only trip through the inner solar system. Perihelion was only a few days ago (Jun 12) at a rather distant 1.64 au. Closest approach to Earth was earlier in the month (Jun 5) at 0.81 au.

Johnson is currently located over a dozen degrees south of Arcturus as it moves south through Virgo (finder charts can be found here and here). There has been some inconsistencies in its reported brightness. Binocular users are reporting it around magnitude 7.5 while telescope users are reporting it around magnitude 8.0 to 8.5. The plot below shows visual magnitudes submitted to the Comet Section. For the most part, those points above the green curve were made with binoculars while those below the curve were made with larger aperture telescopes. Regardless of what instruments you use, how bright do you think Johnson is?

The scatter in magnitudes may be due to Johnson’s bright broad dust tail. The tail is obvious in the below image taken by Chris Schur on June 15 with a 10″ Orion F/3.9 astrograph + SBIG ST10XME. It is possible that binocular observers are including some of the tail in their brightness estimate resulting in brighter magnitudes.

John D Sabia used a Canon DSLR and telephoto lens to image the comet on June 13. The image gives a good impression of what Johnson looks like in small apertures. The tail is also visible in this image.

So far the Comet Section has received 34 magnitude estimates from Salvador Aguirre, Carl Hergenrother, John Sabia and Willian Souza and 38 images from Charles Bell, Denis Buczynski, John Chumack, Carl Hergenrother, Manos Kardasis, Gianluca Masi, Richard Owens, Efrain Morales Rivera, John Sabia, Chris Schur and Michael Schwartz.

If you are out this weekend observing, please give Johnson a look. Whether you image it, make a magnitude estimate or just take a quick peek, submit your observations and impressions to the Comet Section.

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