(IAAC) Double Star Observation


I have been observing double stars for around three years, during which 
time I have been making visual estimations of separation and position 
angle.  (The methods I use are described in the double star section of 
my site, given below).  However I think I am now in a position to start 
actual measurement using a micrometer, which is where I need help.

I understand I would be able to obtain a filar micrometer from a 
supplier called Retel in England for around #400 - #500, but is it 
really a filar micrometer that I want?  This sort of money is an 
enormous amount to me as I am only 18 years old.  I currently observe 
with a 220mm f/5 Newtonian which, although equatorial, has to be 
transported out whenever I observe.  I have plans to permanently mount 
the telescope soon.  Would the discrepancies each time I set up the 
telescope have a serious impact on the sort of results I obtain with a 

Alternatively, I could use a CCD camera instead of a micrometer, 
although I would seriously doubt that it would provide the sort of 
accuracies required.  Besides, I like the idea of actually being at the 
eyepiece making the observation.  

I understand that there are certain other sorts of micrometer available, 
such as eyepiece reticles etc.  Has anyone had any experience with these 
sorts of things?  Are they cheaper, but do they provide the same sort of 
accuracy as a micrometer?  Is there another method of double star 
measurement which has completely slipped over my head, which would be 
the wisest path to follow.  Being young, I would be quite interested to 
follow an experimental path, perhaps refining new techniques.

I would be very grateful indeed if anyone could help me with any of 
these matters.  I am keen to start to post observations on the 
netastro-catalog, and I shall post the visual estimations made by the 
Brit. Astron. Assoc. Student Group over the past 3 years (a project I 
co-ordinated) very soon.

Once again, thanks in anticipation.

Clear skies,   Paul Haworth.

PS. Please CC: any replies directly to paulhaworth@hotmail.com as I am 
not yet fully on the list.

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