Re: [re: Frequencies of Iridium passes/flares]

BJORN GIMLE (b_gimle@usa.net)
29 Aug 98 23:23:52 MET DST

dk058@cleveland.Freenet.Edu (Walter Nissen) wrote:
> Thanks for posting your response (twice!). 
Once to you, once to SeeSat.

>  
> > No, MM is anomalistic (perigee-to-perigee), and the precession rate for 
> > operational Iridiums is about 3.4 deg/day, or 0.237 deg/orbit, or .066 % 
>  
> > This gives P = 100.469 minutes.  Actually I think it is 100.465116, which 
>  
> I was mulling this over in my mind (i.e., thinking about it), and had 
> calculated that the precession rate (precession of what?) would have to be 
> about 3.2 to give 100.465116, when I turned to a file of many elsets for a 
> suitable object, what I've proposed calling Ir P19 = Ir 25: 

....
> and can't find anything precessing at either 3.4 or 3.2 degrees/day.  So I 
> am unable to follow your argument. 

The AOP should precess 5.00(5 cos i * cos i - 1 ) ( a(1-e^2) )^3.5
degrees/day, but in reality this seems to vary with AOP, and is very
difficult to determine for near-circular orbits.

If it really varies, I can't find a physical possibility that nodal
period varies, so I assume anomalistic period varies with AOP and
its precession.

> Your message arrived blotched by many unwanted equal signs, "=".  I attach 
> a copy of the complete message so you can see this.  If you know why this 
> occurred, I'd be very interested to know also.  If you don't know, you 
> needn't apologize especially to me.  It seems to happen for a distressing 
> number of correspondents and rather irregularly. 
>  

This is the MIME encoding of characters that may possibly get lost on
the net. The middle letter of my first name is ASCII code 246 (hex F6)
and is encode (equal sign)F6. Since the equal sign is a kind of ESCape,
it by itself must be encoded (equal sign)3D. Trailing spaces are
(equal sign)20.

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