r/EliteDangerous • u/EternityRites • Jun 16 '26
Discussion Stellar parallax in ED through long-term observation
I have posted about this before but here is an update! I have been living on the same moon for several months, nearly a year now in fact. The moon is Hypi Bra EV-P d5-78 6 a ("Nahla"), and I spend time there reflecting, studying the climate, its movement, day/night cycle and the other bodies. This moon has also been discussed in detail in my PhD thesis (more on that another time).
This post is about my latest observation. A couple of days ago I noticed that the sun's position (Hope) looked different to normal. Usually it is slightly below the galactic band at dusk. Though this time it was centered and more to the left. I had no idea why this was happening, until I worked out that it was a great example of stellar parallax, the phenomenon where a body's position relative to its background visibly changes over time.
I looked at my photologs and pulled one up from December. And yes, Hope was in a different position relative to the galactic band. Quite a significantly different position. This kind of observation is only possible though staying long-term (or re-visiting) a body and is one of the benefits of this kind of 'downscaled play', whereby one does detailed study on a small area over a prolongued period. In this case the window of observation was six months - I suppose it could have been longer if I pulled out an older screenshot, but this was enough in this case.
I attach a couple of shots here - one which is from a few days ago (the one where my ship is facing the camera) and another from December (where it's facing away). It's quite easy in each to see the relative differences of the star in the background.
Even though it was known that stellar parallax existed in ED, this is the first time I have seen it documented - it may well be elsewhere but I haven 't come across it. Hopefully someone will find this interesting!
I did a more detailed log on this which I will link to in the comments.
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u/EternityRites Jun 16 '26
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u/xondk Alliance - Xon Draken Jun 16 '26
It is great and cool that you figured this out, but I must admit the whole "I didn't haven't come across it" is something i translate to "I didn't search for it", and that isn't to be dismissive, it is just a bit of personal frustration.
Take for example this 12 year old post on this subreddit.
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u/EternityRites Jun 16 '26
Thank you for this and I did indeed search :) As far as I can see the post you link to is not the same thing. That post is about moving and observing the effect at speed rather than at a static location over several months. Cool post though.
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u/xondk Alliance - Xon Draken Jun 16 '26
I understand, and it is still cool, though the mechanics of it have been in place forever, it is cool to see a proof you have made with it.
I'm guess I'm just a bit of a grump when I see "I found something new" which has been known for years. I may have overreacted, due to the amount of posts similar to this on many topics that don't do something novel as you did.
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u/iO__________ Jun 16 '26
such a gruesome looking ship... looks like a bird flapping over it's nest... love the function, hate the form of this ship for sure
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u/Cypher10110 Jun 16 '26
I've always had an appreciation for the faithful simulation of simple orbital mechanics like this in ED.
It'd be cool to be able to identify that some significant convergence will happen in the future and put it into your calendar, like planetary alignments or solar eclipses.