Recently I found a fantastic website in-the-sky.org, from here we can simply pick up any astronomical event and check its visibility in any part of the Globe. For occultations, for example, we have very nice maps like this below:

enter image description here

There are a lot of conjunctions, occultations, eclipses, and so on described fairly in detail. I think it's the best website so far for people making Astro calendars.

The problem is, that if I checked some conjunction i.e. Mercury with Mars on August 19, 2021 I spent quite a lot of time checking which located around the Globe is the best for watching this event. I took into consideration the solar depression, not lower than 6 degrees (end of civil twilight), and an altitude of these 2 bodies above the horizon (not lower than 3 degrees due to atmospheric extinction). Finally, my hand-sketched maps are looking like this:

Day and Night Map Timeanddate.com

plotted in the Day & Night Map at timeanddate.com

enter image description here

sketch plotted in Google Maps

enter image description here

Circumstances checked with stellarium-web.org

So basically is quite a lot of work by checking which location is the most appropriate to watch the moment of conjunction ideally (I mean the moment of biggest approach these 2 planets, which lasts maybe...30mins or so). Concluding I would like to ask about the possibility of auto calculate stuff like this. If for example, I would put in one column the min solar depression, in another column the min altitude of these planets, some tool would bring me the map as presented above?

Is it possible i.e. with Python or other (I am only basic with soft)?

Or do you know web services, which do the calculation such as this for you?

I fund some query here:

How to calculate conjunctions of 2 planets

but it applies to calculate the dates and geometrical circumstances of the conjunctions. I would like to have something in the map as presented above.


1 Answer 1


Partial answer to

Is it possible i.e. with Python or other (I am only basic with soft)?


Use Skyfield.

As long as you can muster a little Python you can search for events, make topographical maps of event times and elevations, or even put it in a loop and find optimized locations.

The nice thing about learning to use Skyfield is that you can then do all your event searches, plots, predictions etc. this way in the future, and it's a great way to improve Python skills as well.

Skyfield also has a Github page where there are discussion and issues pages that are both very active.

You can also view other Stack Exchange questions tagged with Skyfield here and in Space Exploration SE.

See also:


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