Re: Happy 25 years, Mailing List :)

On 2026-08-25 20:43, Glen Langston wrote: > Hey Marcus, > > Your paper, "Determination of Earth’s Orbital Parameters Using Doppler Measurements” is > a very nice paper. It’s good to see how well your measurements > fit the model. You really put a lot of work into your experiment. > > My understanding is that Jupiter’s contribution to the Earth’s motion is > the next biggest effect on the otherwise elliptical motion of the Earth’s orbit. > > Wonder if Jupiter is contributing to your residuals. > > Thanks > > Glen It was a combined effort between me and Daniel Marlow (emeritus at Princeton, and a member of the CCERA crew). My guess is that Jupiter's effect would be very small, and thus very much in the noise.  Jupiter's orbital period is about 11.8 years,   so you'd need a LOT of this data to be able to see any effects with enough SNR to be confident.... We're actually spending "idle time" on the telescope to measure the Doppler of the H1 *absorption* feature in M8.   Since it is very close   to the plane of the ecliptic, there's less uncertainty due to coordinate rotation, and the feature is very narrow compared to emission features,   leading to less Doppler-determination uncertainty.   This was the technique used by Stephen Knowles in 1969 using the Navy dish at NRAO Green Bank.   New paper on that in the next few months probably. > >> On Aug 25, 2026, at 3:36 PM, Marcus D. Leech <patchvonbraun@gmail.com> wrote: >> >> On 2026-08-25 13:08, Glen Langston wrote: >>> Dear Marcus and all SDR Aficionados, >>> >>> Thanks for all your contributions over a quarter century! >>> >>> Cheers, >>> >>> Glen >>> >>> PS John Makous and his student used GR radio to map distance >>> to the Milky Way's spiral arms. Here’s the link to his very short, >>> very interesting (free) paper. >>> >>> See: https://www.researchgate.net/publication/412208740_Determining_Galactic_Structure_Using_a_Student-built_Horn_Radio_Telescope#fullTextFileContent >>> >>> In retrospect GR radio needed more acknowledgement… >> I should have posted this here a few weeks back, but: >> >> https://arxiv.org/abs/2607.21812 >> >> In retrospect, Gnu Radio should have been highlighted a bit more. We use GR exclusively at our observatory for all kinds of >> observations. We basically just build observation-specific "instruments" as we need them. >> >> We had U of Toronto undergrad students last year use milky-way Doppler observations to measure the rotation curve and infer the existence >> of Dark Matter (because the rotation curve deviates from a strictly-Newtonian/Keplerian model by enough that it implies that either there's >> more mass there than we can see "dark matter", OR gravitation doesn't work on large scales the way we think it does). >> >> >>> >>> >>>> On Aug 25, 2026, at 8:03 AM, Marcus Müller <mmueller@gnuradio.org> wrote: >>>> >>>> Hi, dearest and most enduring Mailing List in the world of SDR, >>>> >>>> I just noticed the mailing list archives stretch back to July 2001, so that marks a quarter century of history! >>>> >>>> In fact, activity on the mailing list doesn't even seem to start at that point; the first "proper" email in the archive is already a reply, but we just don't have any history before that. >>>> >>>> So, looking forward to the next three quarters of witnessing FOSS SDR be successful, >>>> Marcus >>>> >>