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jhors
Riddle me this
Reged: 07/16/07
Posts: 978
Loc: Tempe, AZ
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I posted this in the beginner forum where it has sunk below the horizon, so to speak, and never received a definitive answer. This is my first post here and I guess it reveals my deep-seated fear of art that I didn't post it here in the first place. 
I searched for a thread discussing this, but to no avail.
One of the requirements of the AL Double Star Club is that the objects must be sketched and cardinal directions must be indicated. So, I've been trying to use directions in my descriptions of objects -> seems a tad more precise than "over a little bit to the right" and I've been trying to sketch. I've found it to be very rewarding so far. One question I have though is how do you tell N, S, E, and W at the eyepiece?
I thought I had a good system that I read about, but I've found that sometimes my descriptions don't match what others report. Sometimes they are right on and sometimes they are exactly opposite.
Here is the method I read about from another person using a reflector:
* center the object
* allow the object to drift
* the direction it drifts is west
* north is 90° counter-clockwise from west
Is that correct for a reflector? Which system do you use?
Forgive me for opening another can of worms, but how do you measure distance in ' and " in the eyepiece?
Incidentally, boy am I learning to respect the art of sketching even more since I have begun attempting it myself! 
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-Josh
Boyce Thompson Arboretum:
10" f/4.7 Dob
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Adam S
sage
Reged: 12/21/05
Posts: 361
Loc: Gunnison, Colorado
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You are correct if the optical system has an ODD number of mirrors (ie/ SCT, MCT or refractor-each with diaganol). If an even number of mirrors (ie/ a Newtonian) than North is 90 degrees CW of West. Steve Coe (also a CN member) gave the best explantion for finding direction within the ep in the book he wrote I've ever read-I would suggest sending him a pm for better.
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Adam S.
AP 130 GT
Televue Pronto
Orange C8
Coronado SM 60
Tak EM 200
Denk II
Van Slyke Turret
CN Gallery: http://www.cloudynights.com/photopost/showgallery.php?cat=500&ppuser=14004
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 Special Ed
Post Laureate
Reged: 05/18/03
Posts: 4306
Loc: Greenbrier Co., WV 38N, 80W
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Quote:
Here is the method I read about from another person using a reflector:
* center the object
* allow the object to drift
* the direction it drifts is west
* north is 90° counter-clockwise from west
Is that correct for a reflector? Which system do you use?
Josh, this is correct for a reflector. (I'm afraid Adam S had a bad remembering day and got his otherwise excellent info reversed). 
Quote:
Forgive me for opening another can of worms, but how do you measure distance in ' and " in the eyepiece?
Incidentally, boy am I learning to respect the art of sketching even more since I have begun attempting it myself!
First, you must determine the field of view for your ep/scope combination. Look here for info on finding the true field of view.
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Michael Rosolina
8" f/10 Orange Tube SCT
4.25" f/4.2 Astroscan Reflector
SVP 3.6" f/13.6 CA Reflector
40mm PST f/10
APM Germany HD 15x70 binoculars
Canon 12x36 IS II binoculars
Mark I Eyeball
My CN Gallery
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rodelaet
Post Laureate
Reged: 04/28/06
Posts: 3063
Loc: 50°56' N - 4°58' E (Belgium)
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Josh,
I have a simple solution for finding north. Move the scopes tube a little towards Polaris. The starfield in the eyepiece will move from north to south. The edge were new stars appear is north.
Clear skies,
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Rony
My Astronomical Sketches
My Binocular Sketches
Callibrate your Monitor with this little strip.
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Adam S
sage
Reged: 12/21/05
Posts: 361
Loc: Gunnison, Colorado
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I did have a bad memory moment-thanks for catching it.
Odd # reflections (refractor, SCT, MCT each with diag)
-North is 90 deg CW of West
Even # reflections (Newt)
-North is 90 deg CCW of West.
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Adam S.
AP 130 GT
Televue Pronto
Orange C8
Coronado SM 60
Tak EM 200
Denk II
Van Slyke Turret
CN Gallery: http://www.cloudynights.com/photopost/showgallery.php?cat=500&ppuser=14004
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Erix
Toad Lily
Reged: 12/25/04
Posts: 22358
Loc: Ohio, USA
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Thanks for the great responses. Rony, that really makes it easier for me to remember, thanks! I do ok until it comes to star fields and DSO's. Then I can never remember north orientation. West is easy...I just turn off tracking. 
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Erika
Automatic doors make me feel like a Jedi. 
Zhumell 16", 10" LX200 Classic,Orion ED80, ETX70-AT, DS Maxscope 60mm
My CN Gallery * 2007 July - tracking NOAA10963
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jhors
Riddle me this
Reged: 07/16/07
Posts: 978
Loc: Tempe, AZ
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Thank you for your responses!
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-Josh
Boyce Thompson Arboretum:
10" f/4.7 Dob
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rolandlinda3
Carpal Tunnel
Reged: 01/24/06
Posts: 2233
Loc: Crozet VA 22932
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one addition to what Rony says if your scope is being driven, give it a jiggle or slight nudge toward North but don't move it, unless you want to re-do alignment.
Roland
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Roland
Sketches in members galleries: rolandlinda3
Inspirational stories/sketches at:
www.christworksministries.org
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