Two Green Comets!

Added: 2026-05-12

[00:00:05]This month, comet chasing shifts southward and leaves observers in the north green with envy, a shade none unlike our comets.

[00:00:14]C 2025 R3 pan stars remains within binocular range, while 88P Howell is now accessible in 4 in or 10 cm telescopes.

[00:00:26]Both comets favor observers in the equatorial and southern latitudes where they become our primary comet targets for May.

[00:00:34]This image of 2025 R3 is awesome in so many ways, but in particular, I love how it shows the comet in relation to the horizon rather than a close-up view. It gives you a good idea of what it might look like on your horizon.

[00:00:50]This comet has been putting on a nice show in binoculars since last month and has even been glimpsed by the unaded eye. It passed closest to the sun on April 19th at a distance of.5 AU splitting the distance between the Earth and Sun as it did so. It's been fantastic in pictures showing off its unusually bright ion gas coma and tail, which gives us a bright green coma and a beautiful blue tail.

[00:01:18]Had this comet released heavy dust, it would have been much brighter and even obvious to the naked eye. But this is the great thing about comets. They're like people. One may remind us of another, but no two are truly alike.

[00:01:31]Dustless comets have an appeal all their own. The comet's distinctive blue green color is attributed to the presence of diatomic carbon C2 and cyanogen CN gas.

[00:01:45]What causes the gas to glow is called resonance fluoresence. Those gas molecules in the coma absorb solar ultraviolet light becoming electronically excited and then release that energy as light at other specific wavelengths or colors. It's kind of like money laundering but with light. This is similar to how neon bulbs work in that both involve gas molecules emitting light at characteristic wavelengths when excited. The key difference is the excitation mechanism. In a neon bulb, an electrical discharge excites the gas rather than photon absorption as in the comet. Diatomic carbon produces green light. Cyanogen contributes to the blue violet. The diatomic carbon gas fluoresing in sunlight produces the coma's green color. This gas is abundant close to the nucleus, but doesn't survive for long. is quickly destroyed by the solar ultraviolet light. As a result, the green is usually confined to the coma, not surviving to be blown into the tail by the solar wind. The cyanogen survived longer, producing the blue violet colors in the tail.

[00:02:56]These colors are not generally obvious in the eyepiece, but the tint of the green coma can sometimes be glimpsed, especially with large aperture telescopes and at low powers.

[00:03:08]2025 R3 will continue to put on a nice show in binoculars as seen from the southern hemisphere and equatorial regions. It also makes an easy target for smart telescopes as seen from equatorial and southern latitudes. 2025 R3 will be obvious in 7x50 binoculars through the evening of May 10th and easy through May 19th.

[00:03:33]After that, it will be perceptible through May 24th.

[00:03:40]88P Howell was discovered by Ellen Howell in 1981 at Palomar Observatory when she was an undergraduate at Calte.

[00:03:50]88P is a short period comet returning to the sun every 5 and 1/2 years. It passed 1.4 AU from the sun on March 18th and is now on its way out again. It'll swing out to almost 5 AU from the sun, then begin its journey back toward the sun once again. From equatorial and southern latitudes, 88P hull will be perceptible in 4 in or 10 cm telescopes from the morning of May 6th through May 29th, a little after 5:00 a.m. By the way, perceptible means it will be readily visible, but not easy. So, it may take a moment or two to spot in the eyepiece.

[00:04:31]Look for a small round fuzz ball. To be sure you found it, note its position against the nearby stars. Come back in 20 minutes and it should have moved noticeably.

[00:04:43]People become interested in comets because of the hype.

[00:04:47]>> GREAT.

[00:04:52]>> But that hype isn't what comets are really about. In fact, the hype usually sets people up for disappointment.

[00:05:00]Once you let that hype go and begin to know comets routinely, that is when you become a comet chaser.

[00:05:08]Comets are slow wanderers, best appreciated with a relaxing sunrise or sunset or as a remarkable little fuzzball in your eyepiece, bringing you to a starfield you might never have otherwise seen.

[00:05:24]>> Be sure to come back next month to see what comets June has in store.

[00:05:29]Comets.

[00:05:31]Comets drifting through the void.