Re: (IAAC) Double Star Observation

At 02:00 18/02/98 PST, you wrote:
>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 
Paul I would suggest you do two things. 

1) contact Bob Argyle of the Webb Soc Double star section on
rwa@ast.cam.ac.uk as he will be able to answer all your queries about the
Retel as he uses one

2) if you do not have a permantly mounted an ligned scope then I do not
think you will be able to do much in the way of visual double star work

3) you might try and get a second hand copy of the Webb societies double
star section handbook. We are out of new copies and there will be no more

If you are with the BAA student group then I suggest you get in touch with
Bob anyway as he will be able to give you a hand in this direction

>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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