Re: (IAAC) Obj: Alpha Ori - Inst: 10" F4.8 Equatorial Mount GP/DX

It's unlikely that you would split such as close a star as 0.5" with that 10mm eyepiece Barry, as far as I can work out it only gives you 120X mag, I would guess that to split a star that close you would need near perfect seeing (Steady air, no stars "twinkling" ) your scope collimated perfectly and cooled down as well, and about 500x + magnification, I could be wrong but  I don't think I'm far out with that estimate.
for you to get 480X you would need either a 2.5mm or a 5mm with a barlow. In reality though (as perfect conditions etc are so rare) Splitting of tight doubles is a job for a Refractor rather than a reflector, that's not to say that you cannot attempt it, or enjoy Double stars with a reflector!
Kim Gowney
----- Original Message -----
From: Apache User
To: Internet Amateur Astronomers Catalog
Sent: Thursday, January 03, 2002 3:06 PM
Subject: (IAAC) Obj: Alpha Ori - Inst: 10" F4.8 Equatorial Mount GP/DX


Observation Poster: Barry Sharpe <barry.sharpe@btinternet.com>

Observer: Barry Sharpe
Your skills: Beginner (< one year)
Date/time of observation: 29th December 2001 22:54UT
Location of site: Welwyn Garden City (Lat 53:27:00, Elev 02:31:00)
Site classification: Suburban
Sky darkness: 5 <1-10 Scale (10 best)>
Seeing: 7 <1-10 Seeing Scale (10 best)>
Moon presence: Great - full or very near object
Instrument: 10" F4.8 Equatorial Mount GP/DX
Magnification: 25mm @ 10mm
Filter(s): None
Object(s): Alpha Ori
Category: Other.
Class: Star
Constellation: Orion
Data: mag 0.50  size
Position: RA :  DEC :
Alpha Ori with it's deep red colour makes this a gem, which is why i have left
it until last. I am unable to split this double with 25mm or 10mm eyepiece. In
the FOV to the south i see 2 stars very close together pluas a further 8 stars
on the edge of my vision. i can make out if i concentrate really hard a star so
faint but just noticiable just above the halo of Alpha Ori to the south this
this could be the companion?
Optional related URLs:
** This observing log automatically submitted via the Web from:
To stop receiving all 'netastrocatalog' lists, use the Web forms at: