[AZ-Observing] Re: Estimating size and brightness

Thad,
Maybe you could submit this technique as a note in an appropriate 
publication. It seems to me worthwhile.
Stan

Thad Robosson wrote:

>Hey All, 
>Forgive me if I've already said some of this in an earlier thread, but it's 
>pertinent again.  Anyway, 
>Brightness is obviously going to be subjective unless there's some ready 
>comparison at hand, but size 
>can be relatively accurate with a few items.  Here's what I do.....First, 
>determine the FOV for your various EP's.
>Then, set up some sort of drawing form, or at least a circle of an easy 
>diameter, say 3".  From there, you can determine what some arbitrary distance, 
>say 30', appears like in a 3" circle.  ie...given a 2* FOV and a 3" circle, a 
>line 30' long is 3/4 an inch long in the circle.  You could set up 
>transparency with various length lines on it to slide over your circle to help 
>determine various angular measures for your EP's.  I took this a step further 
>by milling some notches in aluminum sheets so I could draw a distance line 
>right into my sketches, a'la Skiff & Linganbuhl (sp?).  You don't necessarily 
>need to sketch, just the printed circle with a transparency would be a big 
>help in judging angular size.
>
>Another aspect I've "helped" myself with is ratio as in comes to play with 
>galaxies.  I used a CAD program to print up ellipses of various ratios, 2:1, 
>3:1, 4:1, etc.  That really helps my descriptions along and makes this 
>judgement quite a bit easier.
>
>
>  
>

--
See message header for info on list archives or unsubscribing, and please 
send personal replies to the author, not the list.

Other related posts: