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Comment by rtpg | Hacker News Reader

Is there a website with more info about where and when I should look?

https://theskylive.com/c2023p1-info

If you plug in your location you can see when it rises and sets, and the "online planetarium" can help you to orient yourself.

Thanks for the link. I'm typing this at 11:43pm in Cupertino, CA.

I plugged in Cupertino as my location, and it says Rise is 5:02, which I assume means 5:02 am, which makes sense. However, it also says

VISIBILITY RIGHT NOW C/2023 P1 (Nishimura) is above the horizon from California, United States edit_location_alt. Right now it is placed in the East-North-East direction at an altitude of 23° above the horizon.

How can it be visible and above the horizon right now if the rise time is 5:02am?

Honestly I don't know. My guess would be some kind of bug resulting from integrating different, conflicting data sources? But I'm mostly responding so that someone who knows better sees their bat sign and doesn't wait to see if I respond.

In general, you can only expect the interval between the rising and setting of a celestial object to be similar to that for the sun on that day if the object is near the ecliptic. Perhaps the most obvious counter-example is the pole star, which, being closely aligned with Earth's axis, never sets on Cupertino.

According to the same site, however, the comet is currently in Leo, which is close to the ecliptic and is currently setting before the sun, so I cannot see this being the explanation here.

Good morning from Germany, where the sky is clear and sunny, local time 9:15 am.

I guess the message:

> Given its current magnitude, C/2023 P1 (Nishimura) is barely visible to the naked eye, easily visible with the help of a small binocular.

does not take the spectator's location into account, it is just based on the object's magnitude.

But for my location, C/2023 P1 (Nishimura) is reported to be above the horizon.

So I had a look, and: the problem is that the comet's current location is vertically above the sun, and so close to it, it is not visible to the baked eye, and it would certainly fry your retina trying to locate it with a binocular.

And here is the orbit diagram. https://theskylive.com/c2023p1-info#orbitdiagram

My interpretation from the orbit: the issue with the comet's visible closeness wrt seen from earth will remain until the comet leaves again.

But maybe if a crazy-big coma and tail develops on the perihelion/maximum closeness to sun can help with visibility

> it is not visible to the baked eye, and it would certainly fry your retina trying to locate it with a binocular.

Baked eye indeed.

On iOS I use Sky Guide

Me too. And via this app it appears that the comet will be visible just after sunset on Sep 12/13/14/15.

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