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Old 28-09-2011, 09:52 AM
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Paddy (Patrick)
Canis Minor

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Join Date: Jun 2007
Location: Strangways, Vic
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Originally Posted by orestis View Post
Hi guys,

A very interesting thread and great tips.

I have a question though not deep sky related I hope this is okay.

In a lot of observing reports I see mentions of Apparant size of an object and was just wondering how to do this myself is it plainly estimations on your knowledge of your Eps TFOV or is it more complicated than that.

Thanks in advance
reagrds Orestis
The way I mostly do it is mentally divide the FOV. So my 13mm Nagler gives me a TFOV of 28', I find the centre of the field to get 14' to the edge, then half way from there to the edge is 7' etc. It's a bit hit and miss - sometimes I'm close to what's recorded in my books and sometimes a long way off. I did buy an illuminated reticle eyepiece, but find that the red light is so bright even on lowest setting that it blots out whatever I'm trying to see. I cope with this by shining a faint red light on the secondary (benefit of a truss scope) to faintly illuminate the reticle. But it's so much mucking around that I mostly just go back to my mental reticle method with my usual eps. I like Rob's idea of comparing size to distances between close stars.

I'd love to hear Steve Gottlieb's approach...
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