Glenn C Newell:
@Gary and all,Just wondering if you have seen the 3D "fly though" etc. work by J-P METSAVAINIO?
https://www.youtube.com/watch?v=fZz9Com0piEhttps://www.smithsonianmag.com/smart-news/amazing-astrophotography-lets-you-see-nebulae-in-3d-25351639/
https://astroanarchy.blogspot.com/
Beautiful and amazing stuff, but he has not shared the actual details of creation (only at a very high level, at least not enough for me to follow).
Based on the ideas presented by JP and ideas presented in Chris Woodhouse's book "The Astrophotography Manual" (pp. 356-61), I was able to create this:
https://astrob.in/340905/0/It's not as good as JP's work because I didn't use a volumetric model for the nebula like he does. I just used over a hundred layers of 2d data.
I have tried to get myself to create more, but the way I did it was so time-intensive that I haven't gotten around to it. Although I do have some data that I think would lend itself well to this treatment.
Here was my workflow (this again may be too high level, but if you need any assistance, I would be happy to help):
Prep
In PixInsight:
ImageSolver (under Scripts->Utilities)Solve the image in PixInsight. If you have trouble, make sure all the info like pixel scale, and focal length are correct.
AnnotateImage (under Scripts->Render)Annotate the image with named stars, hipparcos, and tycho catalogsTurn on grid and tweak to taste. Create image and text file (“write objects to text” from this dialog)
Data wrangling
In Excel:
Open the text file from PI in excel and use the import options to get everything into columns
Visit VizieR and download the Tycho and Hipparcos star catalogs
Make a formula to match the catalog numbers and grab the parallax data from the VizieR download. I also grabbed the stellar classification info which was good to double-check star color, etc.
Alternatively, use Stellarium, Sky Safari or other full-featured planetarium to look up distance info for the stars.
Manipulating the Photo to prep for 3D
in Photoshop:
Separate out and label the stars with stellar distances
This step takes forever!
Open the original image and the annotated image in layers. Start with the top left star. Separate it by cutting it out of the image, filling it in with fill->content-aware and then “paste in place” on a new layer, name that layer with the distance in light years from spreadsheet, and name of star.Repeat hundreds of times. (I did not do every star, but did do most of the bright ones, where I could make it out any color information, and I had parallax data for).
Separate out bright and dim parts of the nebula and put those on their own layers as well. Make slightly fuzzy selections.
Finish prepping photoshop file. There should be a sky background layer, nebula layers, and many star layers, any unnamed stars should go on their own layer with transparency too. Save as PSD.
Animating the prepped PSD
Open PSD in After Effects as “composition” and retain layer sizes.
Select all PSD layers in After Effects, and click on the 3D column to make them 3D layers.
On each layer, click “P” (for position) and add the distance (in layer name) to the Z-value (they will all start at 0).
If anything in the nebula, looks weird, change the opacity (“T”) until it blends a bit better.Add a camera (Layer->New->Camera), and keyframe the “Z” position of the camera over a few seconds.
I think I also changed some of the other camera properties like “zoom” until it looked right. For some reason, everything got flipped (L to R), so I also flipped it back to proper orientation at this point.
Render a video, I was still working at high quality (4k) at this point. The nebula looks a bit weird since there is no volumetric data, but I knew I was going to downsample to make the gif.
Open video in PhotoshopExport->Save for WebGif, loop forever, perceptual, 256 colors, dither at 85%, change size, everything else full quality
Upload Gif to astrobin
