BAA Comet Ephemeris Vixen Sky Sensor 2000

[Merkhet]

Hello All.

I would like to try out my Vixen Sky Sensor 2000 in the Comet program mode.

It requires the following entering into the hand set.

T/TT .....time of passage in perihelion

q .....perihelion distance in AU

e .....eccentricity

w .....argument of perihelion

omega .....longitude of ascending node

i .....inclination of orbit

From the British Astronomical Association Comet Ephemeris for C/2014 E2 Jaques, available on line.

I can fill in the handset requirements for .......T/TT......I.......q.......e

omega has two values in the ephemeris. Lower and upper case............omega/OMEGA

Which omega value should I use.

Also do I have to work out a value myself for w longitude of ascending node?

If so how?

I am located in Merseyside UK, just in case it makes any difference to my required values.

Can anyone please tell me how to get a value for w and which omega value to use?

Cheers All.

From Merkhet

[Merkhet]

On the Vixen 2000 PC handset the parameter w is actually a small omega sign  ω . 

Instead of a curvy character it is drawn with straight lines.     Hence to somebody that is new to comet co-ordinates it is very confusing.

The BAA ephemeris has values for omega in small, lower case letters and OMEGA in capital letters.

The small omega ω uses the values of the lower case omega in the BAA tables.

The capital OMEGA Ω uses the values of the capital OMEGA in the BAA tables.

The time of passage in perihelion that is given in the BAA ephemeris is entered into the handset.   Not the date that you are observing on. 

e.g.   from the ephemeris        T=2014  July   2.5158

This is entered as 140702.5158    yymmdd

Using these values, my telescope head points roughly in the correct position whilst trying it out in doors. .  I cannot tell for sure if I am 100% correct until the next clear night.

Cheers