Re: IPDA Geometry Project White Paper

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Mitch Gordon

May 22, 2012, 10:30:40 AM5/22/12
to Dick Simpson 650-723-3525,,,,,,,,, Showalter, Mark R (4500-Affiliate)
Hi Chuck,

Here is the draft 'terminology' paper to which Dick refers. We are
currently working with members of the CASSINI UVIS, VIMS, and RSS teams
who are separately preparing submissions of derived ring occultation
radial profiles. Our discussions with them and review of the
corresponding Voyager data products lead us to producing the draft
document to establish all of the key (from a ring's perspective)
occultation parameters. This is still a draft - I'll send you the final
version when it is done.


On 5/21/2012 4:00 PM, Dick Simpson 650-723-3525 wrote:
>> 1. Let me know if you plan to participate in this project. (Maybe with any
>> caveats.)
> Chuck:
> I’m in. The next two weeks aren’t bad, but then I’m traveling most
> of the first two weeks in June, so the schedule is a little tricky.
>> If you will work on the project‚
>> 2. Let me know if you think focusing on this white paper is the right
>> approach. And if not, what approach do you recommend?
> I agree with your general approach. I’d feel a bit better if
> there were more than two months to complete the white paper ...
> but deadlines do provide motivation (for everyone).
>> 3. If you do agree the group should focus on this white paper, shall we
>> begin by having everyone send back to me either general comments, or
>> specific changes, or both? Or do you have a suggestion for a better way
>> to move ahead with revising this document?
> Given the time, I don’t think receiving comments in June, when
> the completion deadline is mid-July, is practical. Some immediate
> thoughts after a very quick reading of the white paper ...
> The focus in the white paper is heavily toward image-like data and
> the associated ‘geometry.’ I’m not sure where in situ geometry fits
> in – for example, the information needed to interpret magnetometer
> data, where the instrument is immersed in the magnetic field.
> There’s also a problem with distributed instruments, such as in radio
> propagation observations, where the transmitter and receiver are at
> different locations and looking in different directions and the ‘target’
> is somewhere else.
> From the radio science perspective, it’s also useful to distinguish
> between geometry as a research topic (astrometry, ephemeris development,
> etc.) and geometry as a context within which to consider other data.
> These are old questions; it would be nice to see them acknowledged,
> even if a comprehensive discussion is beyond the scope of the project.
> I follow the reasoning behind your distinction of ancillary data from
> observation geometry; but I’m not digesting it very well. From a PDS
> perspective, ‘ancillary data’ cover more than geometry; and I think
> that’s true in the wider world as well. It might be better to talk
> about geometrical archives (e.g., a set of SPICE files, documentation,
> tools, etc.) and geometrical parameters (specific values that appear in
> PDS labels and can be used for searching).
> My initial reaction to the white paper was to try a second draft –
> not so much to refine draft 1 as to see how the issues could be
> addressed from a different starting point. But I don’t know very
> much about how IPDA functions, what the sensitivities are, or even
> what the original geometry project charter requested. A second draft
> could be a complete waste of time. On the bright side, it could be
> something I might complete before 1 June. In the two month time frame
> you have, a revised draft before 1 June might be more useful than a
> ton of conflicting suggestions received two weeks later.
> RINGS just distributed a ‘terminology’ white paper, which I will
> tackle next. There might even be some text relevant to the
> geometry project. Let me know what you think. If you’d prefer to
> phone, I expect to be at 650-723-3525 through tomorrow (traveling
> Wednesday-Friday).
> Dick

Mitch Gordon
PDS Rings Node
Deputy Manager
Ring Occultation Terminology DRAFT 2012-05-17.pdf
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