Questionnaire
NFA/A on “Terminology choices”
The purpose of this
questionnaire is to provide information to the WG so that it can determine the
opinions of the astronomical community regarding the terminology needed to
implement and promulgate the IAU 2000 resolutions, including those on nutation
and the new origin. There is a complementary questionnaire NFA/B for the
Almanac Offices.
Please read all the
questions, and look at Annex 1 (Table of Terms) to obtain the full picture: the
first five questions, I-V, of this questionnaire are about your personal
concerns relating to the issues, and questions 1-10 concern the terminology
choices.
We realize this questionnaire is
long and covers many topics, not all of which might be important to you. Please
answer only those questions about which you are knowledgeable and have a
definite opinion. It is not necessary to complete the entire questionnaire. We
appreciate all ideas, opinions, and concerns we receive, and we thank you for
your time.
Please make amendments. Note that those words, phrases highlighted in blue are those that come directly from the IAU 2000 resolutions, suggestions are in green, those marked in red correspond to suggestions or terms used in this questionnaire and have not been recommended by the IAU. Finally, those in black are in regular use. Recall that at present the terms that are defined in the IAU 2000 resolutions are Celestial Intermediate Pole (CIP), Celestial Ephemeris Origin (CEO), Terrestrial Ephemeris Origin (TEO) and Earth Rotation Angle (ERA).
For each terminology
choice, please provide wherever you can, the corresponding name in French
and/or comment on possible problems of compatibility with your language.
IAU
WG
QUESTIONS ABOUT YOUR PERSONAL CONCERNS ON THE ISSUE
What is your field of research or area of work?
I. List the publications
and software products that you use, and believe will be affected by the IAU
2000 precession-nutation theory and the celestial ephemeris origin. For each
publication and software product, indicate (i) if you
have control over it, and your views on (ii) the IAU 2000 precession-nutation
theory, and (iii) introducing the celestial ephemeris origin (a few examples are provided).
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Publication/Software Product |
Type of Product |
(i)
Con-trol |
(ii) Updating to IAU 2000
precession-nutation * |
(iii) Introducing the celestial ephemeris origin * |
Comment |
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A
few examples |
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Astronomical Al. |
Book |
Yes |
Yes 2006 |
2006 – few tables |
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Connaissance des temps |
Book |
Yes |
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MICA |
Software |
No |
Necessary |
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AsA |
Book |
No |
Necessary |
x, y, s, theta |
As soon as possible please |
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CalC |
Software |
No |
Necessary |
desirable |
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To be filled |
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* If the answer to both is
‘NO’ then enter N or No. If the answer
is positive for either (ii) or (iii) please indicate, if possible, the year of
product that will see the changes.
II. Considering the items listed above, please indicate what problems you think you will have. Either with implementation, or if those items used are updated or not updated:
a. the IAU 2000 precession-nutation
b. the Celestial
Ephemeris Origin
III. E-mail address
IV. Signature and date
1.
Do you think it
better to re-use an existing term, such as
Yes/No, give reasons
2.
Do you agree
that, in general, all the words for origins, systems, poles, should have the
first letter as a capital? At present,
for example,
Yes/No: comment
Note
that the rest of this questionnaire uses capitals only when necessary.
3.
In the general
case, how do you wish to refer to the pre IAU 2000 paradigm using the equinox, and the paradigm recommended by the IAU 2000
resolutions using the celestial ephemeris origin (CEO)? Some suggestions
are conventional /classical / classic / old or new / modern / polar / CEO-based or
something else
4. Consider the system defined by the IAU 2000 resolutions that consists of the celestial intermediate pole (CIP) and either the celestial ephemeris origin (CEO) or the terrestrial ephemeris origin (TEO) on the true equator of date.
a. Is it useful to name the system containing (i) the celestial ephemeris origin (CEO) and celestial intermediate pole (CIP) and (ii) that containing the terrestrial ephemeris origin (TEO) and celestial intermediate pole (CIP)?
Yes/No
b. Suggest a suitable name/phrase for these systems:
for (i) the
(1) celestial intermediate system (CIS), or the
(2) celestial ephemeris origin and the true equator of date (CEO and ted), or
(3) celestial intermediate origin and the true equator of date (CIO and ted), or the
(4) celestial intermediate origin and intermediate equator (CIO and ie), or
(5) non-rotating equatorial system (NES), or
(6) celestial equatorial system (CES),
and for (ii) the
(1) terrestrial intermediate system (TIS), or the
(2)
terrestrial ephemeris origin and the true equator of date (TEO and ted), or
(3) terrestrial intermediate origin and the true equator of date (TIO and ted), or the
(4) terrestrial intermediate origin and
intermediate equator (TIO and ie), or the
(5) rotating equatorial system (RES), or terrestrial equatorial system (TES),
or not formally named, or something else?
for b(i)
for b(ii)
c. What would be the corresponding name for the equatorial system defined by the true equinox and the true equator of date: e.g. true equinox and equator of date (ted), equinoctial equatorial system (EES)
5. Should the name of the pole and origin be as specified by the IAU 2000 resolutions - celestial intermediate pole (CIP), celestial ephemeris origin (CEO) and terrestrial ephemeris origin (TEO), or would you prefer to harmonize the name of the pole and the origin, or choose a new one:
a. harmonized to the celestial intermediate pole (CIP), celestial intermediate origin (CIO) and terrestrial intermediate origin (TIO) or something else?
b. if you are not in favour of the harmonized use of ‘intermediate’, should the name of the celestial intermediate pole (CIP), be changed to reference pole, conventional pole, celestial ephemeris pole, or something else?
c. something else
6. Consider the names of the geocentric equatorial coordinates, right ascension and declination. The following terms are currently in use, right ascension, apparent right ascension, right ascension with respect to the true equinox of date, right ascension with respect to the mean equinox of date:
a. In the IAU 2000 paradigm, should the name of the coordinate other than declination be completely new?
Yes/No
b. Consider the following phrases and comment in which system they should be used, i.e. classical, modern, both, neither, or make a suggestion/comment.
i. right ascension
ii. equinox right ascension
iii. apparent right ascension
iv. apparent equinox right ascension
v. intermediate right ascension
vi. apparent intermediate right ascension
vii. right ascension with respect to the equinox
viii. right ascension with respect to the CEO
ix. longitude coordinate
x. equatorial azimuth
xi. celestial (equatorial) longitude
xii. or something else/comments:
c.
When you read the
words, right ascension, without
amplification as to its reference origin or direction (e.g. apparent) would you
expect that it is measured from the true equinox,
the mean equinox or the celestial ephemeris origin, or do you think it is
undefined? Please comment
7. Origins and Meridians of the terrestrial system.
a.
What should the
name of the terrestrial origin be; the terrestrial
ephemeris origin, the terrestrial intermediate
origin,
b. There are now several prime meridians; should they all have special names? Please suggest names and comment. The meridians are:−
(i)
The
(ii) the meridian through the ITRF origin, (the WGS84 origin, longitude zero),
(iii) the meridian through the terrestrial ephemeris origin (TEO), (or TIO) _
(iv) the ephemeris meridian, the meridian such that GAST(UT) - ae(TT+DT=0) = 0, or ERA(UT) – ai(TT+DT=0) = 0 (see AsA E43)
8.
What name/phrase
do you wish to give to the quantity that gives the difference between
9. In the context of the pre and post IAU 2000 resolutions, please comment on the use of the following phrases. In particular, should the distinction between just applying frame bias, precession and nutation, and including light-time, light deflection etc., be kept when dealing with places generated using the modern paradigm.
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Phrase |
Short Meaning |
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apparent place, implies RA with respect to the equinox, (mean or true), and a declination with respect to the true equator of date. |
geocentric, including light-time, light deflection, aberration, frame bias, precession and nutation – classical paradigm. |
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mean place, implies RA with respect to the mean equinox and declination measured from the mean equator of date. |
geocentric, frame bias and precession – classical definition. |
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intermediate place, implies RA with respect to the CEO and declination measured from the true equator of date (i.e. intermediate equator) |
geocentric, including frame bias, precession and nutation only – modern paradigm. |
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apparent intermediate place, implies RA with respect to the CEO and declination measured from the true equator of date (i.e. intermediate equator) |
geocentric, including light-time, light deflection, aberration, and frame bias, precession and nutation – modern paradigm. |
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astrometric place, implies RA with respect to
the ICRS origin, declination with respect to the ICRS equator (star-like
position). |
geocentric, including light-time – both paradigms. |
a. apparent place
b. mean place
c.
intermediate place
d.
apparent intermediate place
e.
astrometric place
f.
proper (virtual) place
10. Any other comments?