TiPS OBS, vertical angle?, new Mir elset

Walter Nissen (dk058@cleveland.Freenet.Edu)
Fri, 19 Jul 1996 15:22:37 -0400 

I picked up TiPS as it passed Altair about 960716 023930, or so, well past 
culmination, and followed it for a minute or so.  I looked carefully and 
could not discern any departure from the vertical.  It was about mag 5 or 
so, maybe, though I find it difficult to make magnitude estimates for 
extended objects.  I didn't defocus my binoculars as if I were gauging a 
comet; after all, I was trying to see the orientation of the line. 
Haven't seen any sparkles. 
 
I made two earlier OBS with oblique orientation, but I have to say that in 
both cases the orientation occurred to me as an afterthought and when I 
wrote down slashes, back at my desk, which, upon comparison were found to 
be different, I thought maybe I was confused.  I now suspect maybe I 
wasn't confused.  Anyway, at 960711 0443, I recorded mag 6 or so, and 
"didn't seem to be tumbling, maintained steady diagonal /" which would 
translate to a vertical angle of about 40 degrees (if I recall correctly 
how to express vertical angle; it's been many years; I think you measure 
clockwise from straight up??).  The orientation was not so easy to see in 
7x35s, so then I began using 11x80s for this object.  At 960712 0335 I 
recorded "\" with a vertical angle of -45 degrees, at least assuming my 
recollection of how to measure vertical angle.  I am sure that neither 
earlier observation was of a vertical line; both were oblique, to the best 
of my recollection. 
 
Now that I know about the interest in the orientation I will focus on 
that.  I'm always amazed how much more data I get when I focus. 
 
I think LML, UML is an easy way to express the orientation, but perhaps we 
should use an already established concept, vertical angle?  Perhaps early 
discussion of the pros and cons would be appropriate?  Position angle, I 
use frequently.  That's easy to do from a sketch of a comet on a sky 
chart, measured East from North.  Maybe not so easy for this purpose? 
 
Has anyone answered Jay's question as to the point along the line to use 
for astrometic position measurements? 
 
Cheers. 
 
Walter Nissen                   dk058@cleveland.freenet.edu 
approx. -81.86371, 41.37355, 256m 
 
P.S.  Here is the latest Mir elset from OIG: 
Mir 
1 16609U 86017A   96201.43700708 +.00001081 +00000-0 +18478-4 0 06136 
2 16609 051.6518 321.6828 0009975 319.1986 040.8243 15.61517459595012