APOD: A Triple View of Comet ZTF (2023 Jan 31)

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APOD: A Triple View of Comet ZTF (2023 Jan 31)

Post by APOD Robot » Tue Jan 31, 2023 5:05 am

Image A Triple View of Comet ZTF

Explanation: Comet ZTF has a distinctive shape. The now bright comet visiting the inner Solar System has been showing not only a common dust tail, ion tail, and green gas coma, but also an uncommonly distinctive antitail. The antitail does not actually lead the comet -- it is just that the head of the comet is seen superposed on part of the fanned-out and trailing dust tail. The giant dirty snowball that is Comet C/2022 E3 (ZTF) has now passed its closest to the Sun and tomorrow will pass its closest to the Earth. The main panel of the featured triple image shows how Comet ZTF looked last week to the unaided eye under a dark and clear sky over Cáceres, Spain. The top inset image shows how the comet looked through binoculars, while the lower inset shows how the comet looked through a small telescope. The comet is now visible all night long from northern latitudes but will surely fade from easy observation during the next few weeks.

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Re: APOD: A Triple View of Comet ZTF (2023 Jan 31)

Post by daddyo » Tue Jan 31, 2023 7:42 am

Nice. Just wondering if any of you has seen any green through a telescope? I still barely see a white fuzzball in a 10” scope, and nothing naked-eye, but I'm in somewhat light polluted skies. I noticed a few green stars in the middle image…

DRN

Re: APOD: A Triple View of Comet ZTF (2023 Jan 31)

Post by DRN » Tue Jan 31, 2023 2:26 pm

I've been tracking the comet for a few weeks with binoculars every available break I get in the clouds. But even in a 6" refractor, I've never seen the green color. I live within Madison county of Alabama so there is a major source of light pollution nearby. If you can't see any color in M42, don't expect to see color (visually) in ZTF. I'm guessing the color is very distinctive in any photographic system except the normal human eye in a populated area. Darker skies than mine must be needed if it is visible to the eye.
I wish the media wouldn't hype the color since the majority of the world's population lives in or near conditions that make such observations impossible.

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Re: APOD: A Triple View of Comet ZTF (2023 Jan 31)

Post by Chris Peterson » Tue Jan 31, 2023 2:29 pm

daddyo wrote: Tue Jan 31, 2023 7:42 am Nice. Just wondering if any of you has seen any green through a telescope? I still barely see a white fuzzball in a 10” scope, and nothing naked-eye, but I'm in somewhat light polluted skies. I noticed a few green stars in the middle image…
No. I don't think it's bright enough to stimulate color vision.
Chris

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Re: APOD: A Triple View of Comet ZTF (2023 Jan 31)

Post by orin stepanek » Tue Jan 31, 2023 2:52 pm

I love APOD; especially for color and their descriptive views!
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Re: APOD: A Triple View of Comet ZTF (2023 Jan 31)

Post by orin stepanek » Tue Jan 31, 2023 2:59 pm

TripleCometZTF_Caldera_3574.jpg
TripleCometZTF_Caldera_960.jpg
My favorite of the three photos!
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Re: APOD: A Triple View of Comet ZTF (2023 Jan 31)

Post by VictorBorun » Tue Jan 31, 2023 7:10 pm

a naive question:
the nucleus and the "tail & anti-tail", what's in front and what's in the background in this APOD?

I think I know the answer, I'm asking just to amuse the public

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Re: APOD: A Triple View of Comet ZTF (2023 Jan 31)

Post by Chris Peterson » Tue Jan 31, 2023 10:04 pm

The caption is a little misleading. None of these images are equivalent to what we'd see with our eyes. In either binoculars or a telescope all we can see is a fuzzy gray spot with a hint of elongation. The scales are accurate, but the color and contrast certainly are not.

This comet reminds me a little of Holmes a few years ago. Its coma and inner dust tail have greatly expanded over a short time.

Below is an image of the comet (about 1/3 degree wide field) from 17 Jan. Below that is a pair of images from 28 Jan. The first is processed about the same as the earlier one. You can see that the coma largely fills the field. The second is processed using a very nonlinear transfer function that allows the coma structure and faint ion trail to show better. Basically, the inner half degree or so of the comet is now so bright that the ion trail is nearly lost in the glow.
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C_2022E3_20230117_1252.jpg
lrgb_ca_bright.jpg
lrgb_ca_stars.jpg
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