Comet 2009 R1 (McNaught) is by far the brightest comet in the sky right now. There is a good chance observers under very dark skies will even be able to see it without the help of binoculars or telescopes. Recent visual estimates place it as bright as 5th magnitude.
Over the past few nights I have been observing the comet with a remotely operated 0.32-m (12.5″) telescope (part of the LightBuckets network [www.lightbuckets.com]). The images below are from the morning of June 5th. Each image is actually the same only displayed with a different ‘stretch’. The top image shows more detail in the inner coma while the bottom image shows more of the faint tail.
The comet currently displays 2 tails. A gas, or ion, tail seen extending a little north of due west (little bit up from due right). A shorter, stubbier dust tail is seen extending to the southwest (lower right). The sky was already getting bright when this image was taken so some detail may have been washed out.
With the Moon quickly fading and soon to be leaving the morning sky, brightness estimates will start rolling in again. Already a few estimates have been made. The comet appears to have experienced a small increase in brightness. Only a few days ago observers were reporting the comet around magnitude 6.0 to 6.5. In the last day or so, reports placed it at magnitude 5.0 to 5.5.
The lightcurve below still shows a rapidly brightening comet which will peak at minimum brightness off 3rd to 4th magnitude early next month.