Re: [guide-user] Multiple apertures/colored stars/.BMPs/level 7 button

Chris Marriott Nov 30, 2001

----- Original Message -----
From: "Bill J Gray" <pluto@...>
To: <guide-user@yahoogroups.com>
Sent: Friday, November 30, 2001 8:52 PM
Subject: [guide-user] Multiple apertures/colored stars/.BMPs/level 7 button


> Chris, you're right; it's a Good Idea to draw bright stars using
> Tycho data at all levels, dropping back to the lower-quality GSC only if
> necessary. Guide does exactly that, which ensures that the stars are
> shown with consistent magnitudes and positions at all levels. As you
> say, the consistent numbering scheme makes this reasonably simple to do.
>
> It would therefore also be simple to do as you suggest, and show
> a mix of colored stars from Tycho and "plain white" stars from GSC. I
> figured that such a mix would be more annoyance than help, and rigged
> Guide to show "all or nothing"... everything colored by spectral type
> (or B-V, if there's no spectral type available), or shown in plain
> white. Maybe I'll have to re-think that. Or at least provide an option
> for those who don't mind mixing spectrally-colored Tycho with colorless
> GSC stars.

If it's of any help to you in making a decision, the feedback from my
customers has been extremely positive in this area - since the "non Tycho"
stars on the chart are generally the fainter ones, the fact that they aren't
coloured doesn't really matter so much. Personally - and this is purely a
personal opinion! - I'd find *losing* all the colours from the Tycho stars
merely because of a change in limiting magnitude much more annoying than
*gaining* some faint stars with no colour.

As you may recall, some time ago you and I discussed at some length the
various ways of colouring stars from the B-V colour index. Before I added it
to SkyMap I had thought that it would be a bit of a "gimick", but now the
program has it I think it's one of the most useful features it has. I'd hate
to lose all the star colours simply because I wanted to display additional
stars which didn't have colour info available!

Regards,

Chris
---------------------------------------------------------------
Chris Marriott, SkyMap Software, UK
e-mail: chris@... Web site: http://www.skymap.com
Astronomy software written by astronomers, for astronomers