APOD: Introducing Comet Leonard (2021 Nov 21)

[APOD Robot]

Introducing Comet Leonard

Explanation: Here comes Comet Leonard. Comet C/2021 A1 (Leonard) was discovered as a faint smudge in January 2021 when it was out past Mars -- but its orbit will take the giant shedding ice-ball into the inner Solar System, passing near both Earth and Venus in December before it swoops around the Sun in early January 2022. Although comets are notoriously hard to predict, some estimations have Comet Leonard brightening to become visible to the unaided eye in December. Comet Leonard was captured just over a week ago already sporting a green-tinged coma and an extended dust tail. The featured picture was composed from 62 images taken through a moderate-sized telescope -- one set of exposures tracking the comet, while another set tracking the background stars. The exposures were taken from the dark skies above the Eastern Sierra Mountains, near June Lake in California, USA. Soon after passing near the Earth in mid-December, the comet will shift from northern to southern skies.

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[Joe Stieber]

It's Sunday, but today's picture isn't an encore presentation! However, the subject, comet C/2021 A1 (Leonard), is certainly a current topic. I had my first view of it during the lunar eclipse on November 19, 2021, from the New Jersey Pines. I was able to detect it initially about an hour before maximum eclipse with my 15x56 binoculars and then confirmed the sighting in my 88 mm apo spotting scope at 25 to 60x. The latter instrument showed a vague tail. I'm looking forward to new moon on December 4, 2021, to see Leonard in a fully dark sky (and it should be distinctly brighter then).

[Ann]

It's Sunday, but today's picture isn't an encore presentation! However, the subject, comet C/2021 A1 (Leonard), is certainly a current topic. I had my first view of it during the lunar eclipse on November 19, 2021, from the New Jersey Pines. I was able to detect it initially about an hour before maximum eclipse with my 15x56 binoculars and then confirmed the sighting in my 88 mm apo spotting scope at 25 to 60x. The latter instrument showed a vague tail. I'm looking forward to new moon on December 4, 2021, to see Leonard in a fully dark sky (and it should be distinctly brighter then).

Well done Joe!

Ann

[orin stepanek]

Nice!

[neufer]

Comet Leonard started out at aphelion of ≈3700 AU
with an angular velocity of just 9 m/s

when its Oort Cloud neighbors all had
angular velocities of hundreds of meters per second

What caused Leonard to be such a laggard

[orin stepanek]

Oh! BTW; mustn't forget our puppy!

[Fred the Cat]

Comet Leonard started out at aphelion of ≈3700 AU
with an angular velocity of just 9 m/s

when its Oort Cloud neighbors all had
angular velocities of hundreds of meters per second

What caused Leonard to be such a laggard

Cometary physics?

[neufer]

Click to play embedded YouTube video.

Click to play embedded YouTube video.

[neufer]

Click to play embedded YouTube video.

Comet Leonard started out at aphelion of ≈3700 AU
with an angular velocity of just 9 m/s
when its Oort Cloud neighbors all had
angular velocities of hundreds of meters per second

What caused Leonard to be such a laggard

Cometary physics?

Engine design difficulties

[she11back@hotmail.com]

I probably missed it, but best time to see the comet in the USA or Florida, please.

[alter-ego]

I probably missed it, but best time to see the comet in the USA or Florida, please.

Early morning. From Jacksonville, FL, C/2021 A1 (Leonard) is almost due East at 5am EST, and today is at an altitude of 40°. Unfortunately, as the comet brightens between now and into December, it will move closer to the Sun, and by Dec. 8th it's altitude will drop to ~15° at 5:am EST, heading into dawn very quickly. Assuming the comet is bright enough, you can look just before dawn (maybe as late at 6am to 6:30am EST). On Dec 8, the altitude will be ~35°at 6:30am EST. At 6:30am, Dec 10, it will at 22° altitude due East.

So bottom line, your best viewing window will be between now and Dec 8th to 10th depending on Leonard's brightness and your local horizon (assuming clear skies, of course)
 

View from Jacksonville, FL, Dec 10, 6:30am
You can explore views at the above link.

[Keyman]

OK, maybe it's just me but...
When they say

passing near both Earth and Venus

shouldn't we include at least an approximation of "near"?

[johnnydeep]

OK, maybe it's just me but...
When they say

passing near both Earth and Venus

shouldn't we include at least an approximation of "near"?

Take a look at the orbit link in the description. Here's a snapshot illustrating the "nearness" to both Earth and Venus on Dec 10, 2021:

Comet Leonard "near" Earth and Venus on Dec 10, 2021

EDIT: oh, and if you use The Sky Live site to step forward to Dec 18 in the comet's orbit, it verily seems to IMPACT Venus! If it really gets so close, I would think that Venus' mass would greatly affect its orbit!?

EDIT #2: ok, on zooming in, it clearly doesn't impact Venus , but it does seem to get awfully close.

EDIT #3: well, actually, it will still be several million miles away according to Forbes - https://www.forbes.com/sites/jamiecarte ... nother-one

A paper has just been published that describes how close Comet Leonard will get to Venus—and it’s really close!

On December 18, 2021, the authors predict that Comet Leonard will pass just 2.6 million miles/4.3 million kilometers from the second planet from the Sun. It will then graze Venus with its dust trail less than two days later.

It’s the closest known incident of a long period comet coming so close to any planet save for the 2014 encounter of Comet C/2013 A1 Siding Spring and Mars, which produced a meteor shower on the red planet that could be seen by NASA spacecraft.

[Keyman]

Thanks. Figured it wasn't "too" close or we'd have seen it on TMZ. *L*

[johnnydeep]

Thanks. Figured it wasn't "too" close or we'd have seen it on TMZ. *L*

See the edit in my prior post. It seems to get REALLY close to Venus on Dec 18.

[neufer]

When they say

passing near both Earth and Venus

shouldn't we include at least an approximation of "near"?

EDIT: oh, and if you use The Sky Live site to step forward to Dec 18 in the comet's orbit, it verily seems to IMPACT Venus! If it really gets so close, I would think that Venus' mass would greatly affect its orbit!?

EDIT #2: ok, on zooming in, it clearly doesn't impact Venus , but it does seem to get awfully close.

EDIT #3: well, actually, it will still be several million miles away according to Forbes - https://www.forbes.com/sites/jamiecarte ... nother-one

A paper has just been published that describes how close Comet Leonard will get to Venus—and it’s really close!

On December 18, 2021, the authors predict that Comet Leonard will pass just 2.6 million miles/4.3 million kilometers from the second planet from the Sun. It will then graze Venus with its dust trail less than two days later.

It’s the closest known incident of a long period comet coming so close to any planet save for the 2014 encounter of Comet C/2013 A1 Siding Spring and Mars, which produced a meteor shower on the red planet that could be seen by NASA spacecraft.

Comet Leonard will pass 4.3 million kilometers from the second planet from the Sun.

In 1910 Halley's Comet passed 22.5 million kilometers from the third planet from the Sun (at magnitude: –5).

Comet C/2013 A1 passed just 0.14 million kilometers from the fourth planet from the Sun (at magnitude: -6).

[Keyman]

Thanks. Figured it wasn't "too" close or we'd have seen it on TMZ. *L*

See the edit in my prior post. It seems to get REALLY close to Venus on Dec 18.

I don't think they have TMZ on Venus.