Re: GW Lib - best exposure time?

From: Joe Patterson <*jop_at_astro.columbia.edu*> Date: Tue, 06 Jul 2010 20:10:15 -0400 · jop_at_astro.columbia.edu

Hi Tom,

GW Lib potentially has some fast signals (just potentially - they 
haven't definitely shown up in 2005).  But they've always been low 
amplitude, not likely visible in the light curve (strictly 
power-spectrum material).

GW Lib should now be at ~16.6, and I'd have thought 58 s (I assume >40 
of that is integration, yes?) was sufficient to yield a good light 
curve.  In particular, the slow waves on a 2-4 hour time scale should be 
easily visible.

If the data's implausibly noisy, I really don't think it's the star 
(though that's certainly for some other fast variables, e.g. RX0704+26).
A somewhat longer integration time might help... but I'm really puzzled 
- you usually handle 16.6 no sweat.  Is there other data on the same 
night (on a different star) that looks normal?

BTW, OT1625+12 looks like a pretty interesting new transient - at least 
based on the first night.

joe

Tom Krajci wrote:
> I just submitted last night's data for GW Lib.  Looking at an X-Y plot 
> of JD vs. Mag...it's a messy jumble to the eye. 
> 
> Two night's ago I used a cycle time of about 58 seconds.  Last night I 
> used 38 seconds.  Both look like I'm not capturing the fast 
> behavior...instead, it looks like I've got aliasing.
> 
> What image cycle time is desired on this star?
> 
> Thanks in advance.
> 

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