vertex angle, TiPS
Walter Nissen (dk058@cleveland.Freenet.Edu)
Wed, 24 Jul 1996 18:53:38 -0400
There seems to be a lack of agreement between surveying and astronomy on
the name of the angle and the definition (see appendices). Therefore, I
suggest this convention. Assume that the observer is able to distinguish
Ralph from Norton. If the orientation is, e.g.:
n n R n
| \ | /
| \ n--------R | R---------n /
| \ | /
| \ | /
R R n R
then the vertex angle is:
0 45 90 180 270 330
and the observer should report a vertex angle between 0 and 359.99
degrees. I.e., the vertex angle (see appendix) of Norton with respect to
Ralph. If the observer cannot distinguish Ralph from Norton, then the
angle reported should be a vertex angle, determined in the same way,
between 0 and 179.99 degrees.
Modelled after PPAS, I suggest this format:
Walter I. Nissen, Jr., CDP, dk058@cleveland.freenet.edu, 55 Barrett RD #808,
Berea, OH 44017-1657, USA, 216-243-4980, -81d 51.823', 41d 22.413', 256m
yy-lllpp yy-mm-dd hh:mm:ss.ss NN d->d al v.a UML m1 sp RN mag apur Comments
96- 29 ? 96-07-11 4:43 WN N->S 50 140?LML 6 xx 7x35 steady angle
96- 29 ? 96-07-12 3:35 WN N->S 65 45?LML xx 11x80 TiPS
96- 29 ? 96-07-12 3:38 WN N->S 40 45?LML xx 11x80 TiPS
96- 29 ? 96-07-16 2:39:30 WN N->S 40 0 V 5 xx 11x80 TiPS
96- 29 ? 96-07-16 2:40:30 WN N->S 30 0 V xx 11x80 TiPS
96- 29 ? 96-07-21 2:18:52.08 WN N->S 57 150 LML xx 11x80 TiPS
96- 29 ? 96-07-21 2:24:39.53 WN N->S 14 175 LML xx 11x80 TiPS
96- 29 ? 96-07-23 1:50:00 WN N->S 58 sp? 11x80 TiPS
96- 29 ? 96-07-23 1:51:30 WN N->S 46 10 UML xx 11x80 TiPS
96- 29 ? 96-07-23 1:53:30 WN N->S 28 5 UML xx 11x80 TiPS
The pp is the piece number in the COSPAR ID (apparently no agreement yet)
UTC data and time are given (give local time and zone also if your clocks are
not set to UTC, or if you have any doubt about the conversion)
NN is the observer's initials (from PPAS)
al is the altitude, if the al's you provide don't suggest the maximum
you are encouraged to provide a record to give the max altitude
d->d is the direction of motion
v.a is the vertex angle (norton above = 0, norton left = 90, etc.)
UML is Upper Mass Leading, Lower Mass Leading or Vertical
m1 is total visual magnitude
sp is blank if no sparkles are observed, sp if 1-5 are observed,
SP if more than 5 are observed
RN is blank if the orientation could not be observed, xx if Ralph could not
be distinguished from Norton, and RN if it could.
mag is image magnification
apur is aperature in mm
Comments are encouraged to run into paragraphs if you have things to say
Do we need left->right also?
Azimuth also?
Anything else?
The dashes(-) in the date and the colons(:) in the time are an unnecessary
affectation.
Cheers.
Walter Nissen dk058@cleveland.freenet.edu
---
David Dunham writes:
... vertex angle in occultation predictions ... is measured like
position angle, but 0 is the local vertical direction, rather than north.
Hence, 0 deg. is up, 90 is to the left, 180 is down, and 270 is to the
right.
--
In
http://www.auslig.gov.au/geodesy/astro/definiti.htm - size 8K
we find this:
AUSTRALIAN SURVEYING & LAND INFORMATION GROUP
Scrivener Building, Dunlop Court, Fern Hill Park, Bruce ACT 2617
PO Box 2 Belconnen ACT 2616 Phone: +61 6 201 4201 Fax: +61 6 201 4366
COMMONWEALTH OF AUSTRALIA 1995
Zenith Distance
The zenith distance is a vertical angle measured from directly overhead, down
to the required point. An ideal horizon has a zenith distance of 90 degrees.
Vertical angle
The Vertical angle is the angle measured in a vertical plane, from the horizon
to the required point. Directly overhead would have a vertical angle of 90
degrees.