[Aavso-photometry] Landolt error bars

[Ben Davies]

Hi Michael.

I don't need to know the exposure times.  The question is, how to 
extract Berr through Ierr values for the standard stars.  Arne answered 
that.  The residual issue is me being too thick to understand why it works.

Ben

> 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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>
>
>