[Aavso-photometry] Landolt error bars

[Michael Newberry]

Ben,

Why do you need to know Landolt's exposure times?

I don't think the original Landolt paper (AJ vol. 78, p. 959) mentions the 
exposure times. And I don't think I've ever seen or heard about them 
anywhere else. You can download the paper here:
http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?db_key=AST&bibcode=1973AJ.....78..959L&letter=.&classic=YES&defaultprint=YES&whole_paper=YES&page=959&epage=959&send=Send+PDF&filetype=.pdf

Michael Newberry

----- Original Message ----- 
From: "Ben Davies" <b3davies at gmail.com>
Cc: <aavso-photometry at mira.aavso.org>
Sent: Monday, July 21, 2008 11:13 AM
Subject: Re: [Aavso-photometry] Landolt error bars


[...]

> Good point about the S/N, but I have to think more about the exposure
> time consideration.  I am doing instrumental magnitudes in adu/sec which
> gives me big negative magnitudes, but it saves  a lot of downstream
> futzing about with exposure time corrections.
>
> I'm getting a little fuzzy here, but I *think* that since I am plotting
> my instrumental magnitudes as flux rates I wouldn't have to care what
> Landoldt's exposure times were.  And it sure seems like adding,
> squaring, etc logarithms as if they were regular numbers would not be
> the thing to do.  I am probably all wet here but, straighten me out.
>
> Ben
>
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