117p 20210530 tlehmann

Comet 117P/Helin-Roman-Alu has shown a prominent dust tail for the last few
months. On images taken May 11th I have noticed a faint glitch of a very
long tail but the images were taken using a green filter primarily for
photomtry. So i decided to get much deeper images but had to wait until
end of May.

And here it is. I managed to get exposures for 1/2 hour using a fast 8 inch
scope (with L filter) remotely from Namibia. The dust in the orbital plane of
the comet is clearly visible and extends beyond image border. The visible
length of 1.8 degrees corresponds to ~8 Mio Km (projected on the sky sphere).

Earth has been crossing the comets plane around May 20th.