Astroblog

Track of comet C/2022 as seen from Adelaide at astronomical twilight (an hour after sunset) when the sky is fully dark (21:53 ACDST). The positions of the comet from 6-14 February are shown. Click to embiggen. Similar views will be seen elsewhere in Australia at astronomical twilight. Simulated in Stellarium.	Location of comet C/2022 on 6 February 20:04 as seen from Brisbane at astronomical twilight (an hour after sunset) when the sky is fully dark . Click to embiggen. Simulated in Stellarium.	Location of comet C/2022 on 6 February 21:32 as seen from Melbourne at astronomical twilight (an hour after sunset) when the sky is fully dark . Click to embiggen. Simulated in Stellarium.
Black and white guide map suitable for printing (use with a red light torch to keep your night vision intact). Click to embiggen and print.	Black and white binocular spotters map with guide stars identified, suitable for printing (use with a red light torch to keep your night vision intact). Click to embiggen and print.	Black and white binocular map for the night of February 6 with guide stars identified, suitable for printing (use with a red light torch to keep your night vision intact). Click to embiggen and print. The circle is the approximate field of view of 10x50 binoculars.

You have probably heard of Comet C/2022 E3 (ZTF), described some what breathlessly in some media outlets as "a rare green comet last seen by the neanderthals". The wording is a bit unclear, but it is not rare for a comet to be green, as comets (variously described as "dirty iceballs" of "Icy dirt balls") come close to the sun their ices start to vaporise, comets not only have water ice but also organic ices such as ethanol and methane.

The ultra violet light from the sun causes these molecule to break down and form dicarbon, two carbon atoms bind together, which fluoresces green in ultraviolet light. Of course this is rather dim, and can usually only be picked up by long exposure images, you are not likely to see any colour with the unaided eye, even in telescopes.

The comet appears to have come from the Oort Cloud, and last passed earth around 50,000 years ago, if any curious proto-humans had looked at the patch of sky were the comet was all those eons ago, it is unlikely that they would have taken notice of the faint fuzzy patch. Whether C/2022 E3 (ZTF) will return to the Oort cloud is still unclear. ZTF stands for Zwicky Transient Facility, which normally looks for things like supernova.

Currently people in the norther hemisphere are reporting that it is just unaided eye visible. With binoculars its looking like a fuzzy blob with a central condensation and the hint of a tail. While you may have seen some stunning images of the dust tail and ion tail, these are telescopic images with extended exposure times, so what you see in a telescope is likely to be much less dramatic. 

Black and white binocular map for the night of February 6 with guide stars identified. Almaaz in the stellarium map is epsilon (ε) Aurigae on the black and white map. The circle is the approximate field of view of 10x50 binoculars.	Approximate binocular sky view or the night of February 6simulated in stellarium for a comparison to the black and white map to give you a feel fro how they translate to the sky. Click to embiggen

Northern Australia has the best views with Places like Darwin and Cairns potentially seeing the comet from the 3rd, Brisbane, Perth and Sydney from the 5th and Adelaide and Melbourne have to wait for the 6th.

While the comet is theoretically unaided eye visible under dark sky conditions when it enters Australian skies, the fact that it will be low in the horizon murk and with the full Moon on the horizon (6th, waxing Moon earlier) will likely make it a binocular only comet.

Over the coming days conditions get better as the moon leaves the evening skies and the comet gets higher, but it is also fading, so there is a good chance that it will remain binocular only. This does not that it will be unworthy of following, comet C/2021 A1 Leonard was basically binocular only, but was a lovely little comet with good binocular features and a significant out burst that produced a nice tail than spanned almost an entire binocular field. So do not despair and have a look.

We are also lucky that that we have good guidepost stars and that the comet will be one of the brightest objects in most of the fields aside from the guide stars. 

On the 5th the comet is a binocular field below Capella, alpha (⍺) Aurigae, the brightest object almost due north above the northern horizon (see charts above). On the 6th it is within a binocular field of Capella, close to the brightish star epsilon (ε) Aurigae (Almaaz in Stellarium). It should be obvious as a fuzzy blob with a central condensation.

As always let your eyes dark adapt for around 5 minute before searching, a bit longer if you have been looking at bright computer/TV screens. Start looking when the sky is fully dark for the best results (and hour and a half after local sunset).

In general, to find the comet sweep up from Capella in a line towards mas and Aldebaran (again, see maps above) .

On the 7th the comet is a binocular field above  epsilon (ε) Aurigae, just above a distinctive triangle of stars with epsilon (ε) Aurigae as its apex.

On the 8th it is a binocular field below iota Aurigae, then on the 9th within a binocular field above the star, in a line with Mars. On the 10th it is within a binocular field of Mars.

On the 11th it is a finger width from Mars,  and although no longer unaided eye visible, the sight of the pair together should be really nice.

The comet then continues up towards the Hyades and Aldebaran on the 14th and 15th the comet is within a binocular field of Aldebaran and should still be obvious in binoculars.

The positions for the comet from the  Minor Planet & Comet Ephemeris Service are below. It can also format the output for various astronomy programs. put C/2022 E3 in the search box (note the capitalisation).

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 C/2022 E3 (ZTF)

Perturbed ephemeris below is based on elements from MPEC 2023-BF4.

    CK22E030
Date       UT      R.A. (J2000) Decl.    Delta     r     El.    Ph.   m1     Sky Motion
            h m s                                                            "/min    P.A.
2023 01 28 000000 13 59 04.4 +73 52 24   0.325   1.139  110.5  54.1   5.6   12.73    322.9
2023 01 29 000000 12 57 41.9 +77 42 40   0.310   1.143  113.2  52.3   5.5   13.99    307.8
2023 01 30 000000 11 05 40.0 +80 09 13   0.298   1.147  115.9  50.6   5.5   15.13    280.2
2023 01 31 000000 08 44 28.4 +79 19 14   0.290   1.151  118.3  48.9   5.4   16.04    245.2
2023 02 01 000000 07 08 06.5 +75 19 56   0.285   1.155  120.2  47.5   5.4   16.60    221.5
2023 02 02 000000 06 16 27.7 +69 50 45   0.284   1.160  121.6  46.4   5.4   16.72    209.0
2023 02 03 000000 05 47 18.0 +63 50 49   0.287   1.164  122.3  45.7   5.5   16.39    202.1
2023 02 04 000000 05 29 12.6 +57 48 35   0.294   1.169  122.3  45.4   5.5   15.66    198.0
2023 02 05 000000 05 17 06.2 +51 59 46   0.304   1.174  121.7  45.6   5.6   14.63    195.3
2023 02 06 000000 05 08 31.6 +46 33 26   0.317   1.180  120.6  46.0   5.7   13.42    193.5
2023 02 07 000000 05 02 11.5 +41 34 11   0.333   1.185  119.2  46.6   5.9   12.15    192.2
2023 02 08 000000 04 57 21.7 +37 03 29   0.352   1.191  117.6  47.2   6.0   10.90    191.2
2023 02 09 000000 04 53 35.5 +33 00 42   0.372   1.197  115.8  47.9   6.1    9.72    190.4
2023 02 10 000000 04 50 35.4 +29 24 03   0.395   1.203  114.0  48.6   6.3    8.64    189.7
2023 02 11 000000 04 48 10.2 +26 11 07   0.419   1.209  112.2  49.1   6.4    7.68    189.2
2023 02 12 000000 04 46 11.8 +23 19 22   0.443   1.215  110.4  49.6   6.6    6.83    188.6
2023 02 13 000000 04 44 34.6 +20 46 15   0.469   1.222  108.7  49.9   6.7    6.08    188.1
2023 02 14 000000 04 43 14.3 +18 29 30   0.496   1.228  107.1  50.2   6.9    5.44    187.6
2023 02 15 000000 04 42 08.0 +16 26 59   0.523   1.235  105.5  50.4   7.0    4.87    187.1
2023 02 16 000000 04 41 13.1 +14 36 55   0.551   1.242  104.0  50.5   7.1    4.38    186.6
2023 02 17 000000 04 40 27.8 +12 57 42   0.580   1.249  102.5  50.6   7.3    3.95    186.0


MPEC one line format
    CK22E030  2023 01 12.7851  1.112249  1.000327  145.8156  302.5557  109.1685  20230225   7.5  4.0      C/2022 E3 (ZTF)

Labels: binocular, C/2022 E3, comet, unaided eye

# posted by Ian Musgrave @ 9:39 am