C/2022 E3 (ZTF) Naked Eye Visibility in Late January 2023

[PMSchu]

The LONG period(?) comet C/2022 E3 (ZTF) is predicted to become visible to the naked eye in late January - early February. ST4v currently estimates the brightness at 7.1 magnitude in Corona Borealis in the morning. Some estimates have the period as ~50,000 years. The NASA JPL Small Body Database lookup page lists the eccentricty (e) as 1.000270488706647±7.7609E-7, so a slightly hyperbolic orbit & not really periodic.

Here's ST4v's description of the naked eye visibility of the comet:

"C/2022 E3 (ZTF) will reach perihelion in mid January. On January 12 this comet will pass within 0.3 AU of the earth. It is predicted to reach maximum brightness of magnitude 5 in late January. The best visibility from Darby Creek 2 near maximum brightness is predicted to be in late January when it will be approximately magnitude 5. On February 1 this comet will be moving quickly across the sky at a peak rate of 16.6 "/min PA 211.2°. Note that future predictions of magnitude and visibility are subject to the unpredictable nature of these objects."

This is a northern hemisphere object as it will pass through Draco & Ursa Minor. Information about this comet is in the Current Comets Observing List for 2023 January.

Good hunting,

Phil S.

[obrazell]

I think the naked eye predictions are a bit loose. It may (or may not ) make 4.7 from very dark skies. It is most likely to be a binocular object after the end of next week when the moon gets out of the way. It was periodic as this is not its first visit to the inner solar system but planetary perturbations have moved it to hyperbolic so this will be its last visit.

[PMSchu]

Thanks for the additional information Owen. I saw an article that said that this comet last appeared 50,000 years ago, but they didn't mention the perturbations of the orbit to hyperbolic. This is another comet that's getting chucked out of the solar system instead of being drawn into an elliptical orbit. Binoculars would certainly make spotting this comet easier. You could probably photograph it with a good camera on a fixed tripod too.

Phil S.

[theskyhound]

My predictions are based on my model, not just the magnitude, and it has proven to be accurate in the past. It looks solidly like a naked eye object for my location. It won't be obvious, or even easy, though, and certainly not from a location with light pollution.

   

[PMSchu]

Sure does Greg, but you're in one of the best locations in the USA at 9000 ft.  . 

Those interested should try taking images. ST4i predicts that even a DSLR with a 100 mm f/4 lens can capture decent images with 10 minutes worth of 10 second exposures. This might work on a fixed tripod too.

Phil S.

[theskyhound]

The high Declination of this comet means it is going to be observable at unusually high altitudes in a dark sky, which is the main thing that makes it a viable naked-eye object. This is no horizon hugger.

But here's the real point: SkyTools can tell people whether or not it will be naked eye for them, personally, given their own pupil diameter and location, and it will also tell which dates to look on and at what time to have the best chance. Most people rely far too much on general predictions, and general statements, IMNSHO. This is the whole point of having SkyTools. You can make very specific predictions.

The SkyTools ephemeris will always calculate the true optimum time period. The optimum time is the optimum time, so you can't really apply a filter to it to say, "how about the next-best "sub optimum time" in the evening instead?" But that's ok. I'm not wild about getting up before dawn for this one.  I noticed that, for me, the Begin time starts in the evening later in the month, which is weird for a comet. So I turned to another tool to figure out what's going on. I picked a night late in January on the Nightly Planner, selected the comet, and had a look at the NightBar. I discovered that comet was very strongly a morning object at that time. But as the nights went on, it became quickly available in the evening too, only the moon starts to interfere. Here is what the night of January 28 looks like for me:

   

Note the green "Best Quality" period. It runs for most of the night, despite the moonlight. What that means is that there is little difference in how visible the comet is going to be to the naked eye for nearly the entire night. I can even try in moonlight, provided I can find a spot to view the comet where the moon isn't shining in my eye. 

Here is the very next night, with the moon later and brighter:

   

Now my chances of seeing the comet naked eye are less before 1 AM, but it may still be possible.

This comet is interesting to plan for, regardless of how you are going to view or image it. I hope this example helps someone out there make better use of SkyTools for planning for this comet.

[theskyhound]

Another useful thing to do is to plot the ephemeris on a chart via the Ephemeris menu. This will plot the position of the comet at the optimum time to view it each night. This can be a great way to have all the info you really need in one place. It tells you where the comet is on each night, and labels it with the best time to observe it.

Here is the default view plotted on a Naked Eye chart.

   

I changed the time on the chart to 10 PM, and this is what I got:

   

[PMSchu]

Yea, the darn thing really seems to like 5AM doesn't it? It's so close to the pole that its altitude doesn't change much during the night after Jan 25. Being here at 40°N makes the comet easier to see when it's at a less favorable time. The 11x80s will certainly help. Hopefully the weather will cooperate.

Phil S.

[PMSchu]

I ran the Nightly Observing Ephemeris for C/2022 E3 (ZTF) from 2023 Jan 6 - Feb 6 here:     

The addition of the Begin & End times in addition to the Optimum observing time are very helpful. I haven't run this ephemeris variation in a while.

Phil S.

[bigmasterdrago]

It took me a good bit of experimenting to get a similar IA with the right dates in it. I just was not able to follow Greg's method. But I have it now.... Thanks Greg.