Thanks for the animation, which is amazing to see, and for your responses!
> Indeed the video is almost entirely “fabricated” by motion smoothing and interpolation between images taken a year or two apart.
That's fine but you might say that in your post (and maybe you did and I overlooked it). There's nothing wrong with it - the animation is great, just be open. In a world of misinformation and disinformation, it's more essential than ever.
The professional space community publishes so much artistically enhanced media that for me, it's guilty until proven innnocent. When I do trust it, like in this case (yes, I didn't really stop to think about the number of actual frames), I feel a bit deceived.
And the vast public less experienced in these matters already has doubts about science, the space program, conspiracy theories, etc. When they learn something is 'faked', we lose them.
Good spot! It’s an error in the primary mirror segment phasing.
The observatory has to phase the mirror segments periodically, and it’s a bit of an art as well as a science. For a while, something was happening with their algorithm and procedure that was leaving those spots. Some of us (hi) did complain and it was fixed for the most part. It did come back a couple times though….
The slightly incorrect phasing produces those spots. It’s conceptually like a diffraction spike.
But I doubt they’re outshining other planets — other planets on the same orbit would be unstable, and most likely be ejected from the system very quickly. The system is about fifty million years old, so a good guess is that the orbits have been stable for about fifty million years.
The main reason, is why bother? We know there’s four planets, we know they orbit according to Keplers laws, we know how bright they are. The public outreach is reasonably well handled by this motion smoothed video. Better to use that telescope time to look for new planets instead!
That said yes there is something about earths orbit. There’s a few month window that gives the best observation of this star. We time the observations to be roughly June- November most years.
Not stellar activity — a flare wouldn’t be visible on this scale of image.
The main concerns are the observatory —- how aligned all the many dozens of optics are — and the earths atmosphere on the nights the target was observed.
In 2017 we captured five nights worth of images and averaged them. Some early years only had one night.
Around 2019 we also figured out some better observing strategies— all the later data is taken without a coronagraph. Turns out the coronagraph was hurting more than it helped, close in. Not to say coronagraphs aren’t useful, but some aspects of the observatory control software aren’t in place to get the benefits out of the coronagraph.
The creator of the GIF above used a data from a range of different telescopes and wavelengths, whereas I made this with using data only from same telescope (Keck), instrument, and wavelength (3.5 microns; near infrared).
That’s right. We only have images take every year or so, so I did a motion interpolation between the images using Keplers laws. Diffraction close in gets pulled around by the interpolation.
This is maybe not the place, but we did some apples to apples comparisons between PyMC, Dynesty, and the Julia Turing.jl package.
A little to my surprise, despite being a Julia fan, Turing really outperformed both the Python solutions.
I think JAX should be competitive in raw speed, so it might come down to the maturity of the samplers we used.
I visited the Large binocular telescope just a month or two ago. A very impressive facility, and one can only imagine the image quality if they were captured using both mirrors coherently.
Indeed the video is almost entirely “fabricated” by motion smoothing and interpolation between images taken a year or two apart.