[Chaos-l] Wil Tirion's _The Cambridge Star Atlas_

[BOBI and Mike GALLAGHER]

Neat stellar adventure, Jon!

The comparison of the star atlases, got me thinking. Is there any handy 
software (maybe free:) where one could specify a rectangle in the sky and a 
limiting magnitude for a handy map of territory to explore with the scope? 
It seems that a box 5 degrees on a side down to 8th mag, for example would 
be helpful to bring along.

----- Original Message ----- 
From: "Jon Stewart-Taylor" <joncst at earthlink.net>
To: <chaos-l at rtpnet.org>
Sent: Thursday, August 05, 2010 1:18 PM
Subject: [Chaos-l] Wil Tirion's _The Cambridge Star Atlas_


> Hi all.  During my observing session last night at Farrington Point, i 
> was using a copy of Wil Tirion's _The Cambridge Star Atlas_ (which i'd 
> checked out of the library) to hunt things down.  I currently use 
> Tirion's _Bright Star Atlas 2000_ as my main atlas, and was curious  how 
> the two compare, especially since _BSA_ was out of print for some  years. 
> The first obvious difference is that _TCSA_ has a  moon map,  listing 
> about 250 craters as well as the various mares.  The map is  inverted as 
> per Newtonian 'scopes, but at a scale perhaps more suited  to binoculars. 
> The monthly whole-sky maps are divided per-hemisphere  in _TCSA_, as 
> opposed to the one-chart-fits all approach in the _BSA_,  and are are a 
> pretty blue with the Milky Way in a lighter blue.  More  importantly, 
> there are 12 in _TCSA_, intended for use from 9 to  midnight, compared to 
> 7 in _BSA_ labeled with  the 16 month//time  combinations each of the 7 
> charts cover.
>
> The most important differences between _BSA_ and _TCSA_ are limiting 
> magnitude and scale.  _BSA_ is a  mag 6 atlas, and covers the sky in  10 
> full-page charts. _TCSA_ is a mag 6.5 atlas, and covers the sky in  20 
> full-page charts.  _TCSA_ also lists fainter objects, some as faint  as 
> 12th mag, in contrast to the usual mid 10th magnitude limit for  BSA. 
> These differences mean that BSA is a better unaided-eye,  binocular, and 
> Telrad reference, while _TCSA_ is a better finder-scope  and telescope 
> reference.  Using _TCSA_, i sometimes had to flip back  and forth between 
> pages to get the layout of the bright stars used for  Telrad hopping. 
> Conversely, the extra half magnitude, and especially  the finer detail, 
> helped in using the finder to close in on the targets.
>
> The _BSA_ has a set of tables at the front, one listing all the  Messier 
> objects and one each for the double stars, clusters, galaxies,  and nebula 
> shown in the whole atlas.  Both atlases (atlasi?) have  tables for each 
> chart listing the objects on that particular chart.   _TCSA_ has 4 charts 
> at the end showing the distribution of each kind  of object over the whole 
> sky: kinda fun, but not something you'd refer  back to all that often.
>
> Bottom line is that you probably don't need both of these.  If you  want 
> to do primarily unaided eye or binocular observing, _BSA_ is  probably 
> better, especially given you can usually get it for under $12  including 
> shipping.  For telescopic purposes, _TCSA_ has better  charts.  It also 
> costs about twice as much, on the order of $24 in  hardback.  Either is a 
> good choice to pair up with _Turn Left at Orion_.
>
> Hope this was useful.
>
> J.
> -- 
> Jon Stewart-Taylor:  joncst at earthlink.net
> Chapel Hill Astronomy: http://www.rtpnet.org/chaos
>
>
>
>
>
>
> _______________________________________________
> Chaos-l mailing list
> Chaos-l at rtpnet.org
> http://rtpnet.org/mailman/listinfo/chaos-l