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4:52 AM
@uhoh I see! I have just been updating my Earth gravity potential model to use GGM05C instead of GGM03S, so have been able to get back into looking into the details of what normalization I'm using.
To be precise, I'm using the normalization described here download.csr.utexas.edu/pub/grace/GGM05/GGM05_Notes.pdf , which seems to match the same used in this IERS note iers.org/SharedDocs/Publikationen/EN/IERS/Publications/tn/… (described in page 1)
This seems to be the so-called "4pi", "geodesy", or "Kayla" normalization, which makes the squared spherical harmonics yield a value of 4pi when integrated over a sphere, as stated for example in the paragraph at the end of page 52 and beginning of page 53 here books.google.co.jp/books?id=4o92DwAAQBAJ&pg=PA53
The GGM0X models seem to use this normalization of the Legendre polynomials together with what they call "fully normalized" coefficients (as can be inferred by the fact that, in the header of their files, e.g. GGM05C.ICGEM.gz from download.csr.utexas.edu/pub/grace/GGM05 , they state "norm fully_normalized"
This document by the same authors of the CERES dataset www-geodyn.mit.edu/konopliv_dawn_ssr11.pdf states, by the end of the page that has Fig. 6, that the coefficients are chosen such that the integral of the squared harmonics equals the surface of a unit sphere (4pi), so I'm assuming that the same normalization for Legendre functions used with the GGM0X models should be used with this dataset ...?
 
5:44 AM
@Rafa This is absolutely wonderful! It will take me some time and coffee to digest, but I'll let you know where it takes me. thank you!
 
6:37 AM
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Q: Same area, different shape. pro's & cons

BukPure speculation about a future replacement for the JWST that I almost certainly won't live to see. The JWST's mirror (and then some) would fit unfolded and flat into the Starship's 8m diameter payload volume. In the following image that is shown by the 18 grey 1.5m AF hexagons, giving a 7.5mØ a...

Cool telescope optics question, but also involves "fairing packing"
 
 
9 hours later…
3:16 PM
Guest Post on January 17, 2022
An essential part of requirements analysis is understanding which quality characteristics are the most important so that designers can address them appropriately.
 
 
6 hours later…
9:05 PM
posted on January 17, 2022 by Adrian Beil

China successfully kicked off 2022 with the launch of the classified Shiyan-13 payload from the… The post China launches Long March 2D with Shiyan-13 to start busy year appeared first on NASASpaceFlight.com.

 

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