Stellarium Date System Mistakes

This is a tutorial on how to avoid the #1 mistake made when using Stellarium for archaeoastronomy investigations. Is the summer solstice on June 21st? Well it depends on the date system. Watch to find out more, and if you find this content useful, please like, subscribe, share, and donate if you can to help in the production of more content for the community. Thanks!

Many thanks to the wonderful developers of Stellarium, available as a free download here:

Video on how to enable Stellarium Plugins, including Archaeolines:

Video on the Motion of the Sun along the Ecliptic:

Another Visualization of the Ecliptic:

⚙️ Turn up YouTube streaming quality to display labels more clearly.

🌓The Archaeoastronomy Database facilitates the gathering of crowd-sourced data relating to archaeoastronomy.

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🌒 Form to submit an archaeoastronomy question for future videos:

Sky Simulation & Logo: Stellarium
Music: Ambient String Quartet by LuxeXx

[apa]

An even more accurate way is to see when the solar disk is centered on the 0, 90, 180 and 270 degree markings in RA. To get the "official" value, we need to set the system to geocentric.

[DeDunking]

I've watched your tutorials on using Stellarium, I have had trouble setting it up to drop an image as an overlay and look for alignments that way, although I see it's possible, I can't figure it out. If you have time could you cover that in a future video? Thanks so much :)

[Lalu-lrqd]

Very informative 👏 keep it up and share more informative videos

[TheNarrowPathisnoteasy]

Excellent videos! Where did you find this landscape zip file?

[michaeldamolsen]

Interesting video! When I convert the proleptic Gregorian date 3000-06-21 BC to the Julian calendar I get 3000-07-15 BC, but the solstice seems to be early morning on 3000-07-18 BC. (I tied to fuzz by a few years and got the same result, so it is apparently not due to leap years and whether year -0 is counted or not.) Do you happen to know what accounts for this small difference?

[scottsullivan]

Hi, I wanted to post a quick question. I'm looking at first century solar eclipses in Jerusalem for the obvious reasons. NASA lists an April 3, 33 partial eclipse in Jerusalem. Which made no sense to me because there is a full moon on that day. NASA also claims to use Julian calendar pre 15 whatever. I did a bunch of back and forth scrolling like you do in the video. But my question is this actually:

How could NASA and Stellarium be completely opposite phase of the moon if both are on Julian calendar?

I presume NASA's eclipse database is correct. But I don't know what about Stellarium could be off by a full fifteen days on the phase of the moon. I know we lost eleven days in the Gregorian switchover. But that should not be showing up in Stellarium if it uses Julian by default before 15 whatever. (And of course, there's the two hundred years until England accepted Gregorian...).

My concern is that Stellarium would be useless for archeoastronomy if I don't know why they are off by a half cycle of the moon without an explanation; because I don't know why, or how or which way to correct it.

I was getting ready to do a review of NASA first century eclipses versus STellarium. I expect all of them to be wrong (and would be even more troubled if some of them are right). So I found your video and thought I'd ask first in case you've already encountered this. IOW, I know it's all math, so there is an answer that I can figure out eventually. But I assume that actual astronomers and people with more experience with Stellarium have encountered this already.

[oliverargires]

Is there anyway using stellarium to project the form of a constellation on the ground?
For example how someone can see the Orion belt been projected on the top of the three Egyptian pyramids?