Re: GSC 748-1618 period

[Tom Droege <tdroege2@earthlink.net>]

Well, if the data had error bars we could see if there was a significant 
difference.  Don't know why astronomers do not seem to like to put error 
bars on plots.

OK seems to me like this might also be explained by filter 
differences.  The peak could be sitting on a filter edge and this would 
give you both a gain and a possible color term to explain the apparent 
shape difference.  Arne could explain what a big project it would be to 
match up the data from the two filters.  Sigh!  This is a tough business.

Coming from physics, I am used to things not matching up.  Some of the 
curves will have 50 orders of magnitude range.  Possibly exaggerating, but 
not by much.  If the error bars overlap, you just don/t let it bother you.

Tom Droege

At 12:44 PM 2/15/03 -0600, you wrote:
>Chris Lloyd and Paul Bartholdi were both kind enough to provide periods. 
>The difference between them was less than 5 seconds, so I split the 
>difference and used 0.7774. I gave different symbols to the TASS data, 
>which is about a year old, and my data, which begins right at the end of 
>December 2002 and into 2003. The new plot is here:
>
>http://www.lolife.com/astronomy/gsc748-1618/7481618_phase_3.jpg
>
>I want to go back and double-check the TASS data. Even if you dismiss the 
>the stuff at phase 0.1 as cloudy or something, it's impossible to make the 
>ascending and descending parts match up with my data. Even if you adjust 
>the zeropoint, there is something funny about the difference between the 
>two data sets.
>
> From the databases this appears to be a K-type star with B-R=1.4 
> (USNO-B1.0) and B-V=0.97 (Tycho-2) and probably a Cepheid of some sort.
>
>Michael Koppelman
>