[AZ-Observing] Re: Eridanus Goodies


Ran into the same problem... Big, small, bright, dim.

All very subject to the scope, magnification and conditions.  But I am
using an 18" scope, the same as Hershel used for most of his
observations.  I know! speculum mirrors only reflect about 60% of the
light on a good day, with degredation as they tarnished.  His scope also
had a 20 foot focal length compared to my two meters.  My magnification
is comparable, I use 174x for almost all of my descriptions, compared to
WH's 157x.  But our real advantage is Arizona skies, I lived in England
for three years!

One has to consider these things when you follow in the footsteps of 
discovery...

Andrew



Steve Coe wrote:
> 
> Joe;
> 
> Over the years I have always tried to use about the same power as the
> original observations in the NGC.  William Herschel used a power of 157X for
> his observations so that he would be consistent.  My observations have been
> with several telescopes, so I can't be that consistent, but I can say that I
> have always made those observations at something between 100X and 200X.  I
> was internally consistent with each scope.  So that, with the 13 inch it was
> always at 100X, and with the new Nexstar 11 inch it has been at 125X, same
> as with my old 17.5 inch Dobsonian.
> 
> I know it is an opinion, but it seems to be a pretty repeatable opinion and
> I have found it to be helpful as a method of being able to compare my
> observations to previous observers.
> 
> Hope that helps;
> Steve Coe
> 
> Author "Deep Sky Observing--The Astronomical Tourist"
> Saguaro Astronomy Club website
> www.saguaroastro.org
> 
> --
> See message header for info on list archives or unsubscribing, and please
> send personal replies to the author, not the list.

-- 

Andrew Cooper
Tucson, AZ
mailto:acooper@xxxxxxxxx
http://www.whitethornhouse.com
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