[Aavso-photometry] VSX Searching

Fri Apr 6 09:31:58 EDT 2007

Is there a way to search VSX by the Delta between min and max magnitude for
the variable? For example suppose I want stars with min mag > 12 (brighter
than) and Delta mag > 0.5, I don't think using the max range and min range
values will do that. The search would have to be constrained to look only at
the differences between the two "upper" value boxes and the two "lower"
value boxes. From the number of results I get, that doesn't seem to be what
it is doing.

If there isn't a way to include delta mag as a search criteria wouldn't it
be a good idea to add it?

Also in the min and max mag criteria selections the instructions say

"Supply both an upper and lower extent for a magnitude range in order to
include objects with maximum and/or minimum magnitudes between and including
those given. Enter only an upper (brightest) value to locate magnitudes
equal to or fainter than that value. Enter only a lower (faintest) value to
locate magnitudes equal to or brighter than that value."

I have two questions:
1. Which of the two boxes for each criterion is lower and which is upper? 
2. I tried entering a value in only the right hand box for min mag (I
assumed that would be the lower box(dimmest)and a search error resulted.
Specifically when I left the left and box blank and entered  the number 10
in the right hand box, I received an error. When I entered -2 in the left
and 10 in the right the search worked. This seems to be at odds with the
instructions. 

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Today's Topics:

   1. Finding targets for a class.... (Roland Roberts)
   2. Re: Finding targets for a class.... (Michael Koppelman)

----------------------------------------------------------------------

Message: 1
Date: Wed, 04 Apr 2007 22:33:46 -0400
From: Roland Roberts <roland at astrofoto.org>
Subject: [Aavso-photometry] Finding targets for a class....
To: aavso-photometry at mira.aavso.org
Message-ID: <4614600A.8010707 at astrofoto.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I've just finished looking at _Variable Star Observations in an 
Introductory Astronomy Course_, (Gaskell, JAAVSO 20, p41) and am looking 
for my own small set of variables I can use for a similar purpose but 
doing CCD photometry.  I'm having a bit of trouble trying to search 
through catalogs to find suitable objects....

The criteria are *similar* to those of Gaskell.  The star should show 
variability with a period of 20-60 days, should be visible in a small 
scope (I'm using a 120mm f/5 achromat with an ST-7XE and BVRI filters), 
and have enough magnitude variability that it is easily detectable even 
with modest errors (say 0.05).   I can find things on the AAVSO site if 
I know the designation.  I can find things at the GCVS site if I know 
the type or designation.  But I'd really like to be able to filter the 
list quite differently than any of the searches I've found. 

Oh, and every time I think I found one on the GCVS site, I can't seem to 
find any data or charts at the AAVSO site :-(  These are the best as 
they are short period Cepheids, but they're examples of stuff I found at 
the GCVS site that I can't find in the AAVSO database: GV AUR, GT AUR, 
AM CAM.

Is there some way to search objects using period and variability?

roland

-- 
                       PGP Key ID: 66 BC 3B CD
Roland B. Roberts, PhD                             RL Enterprises
roland at rlenter.com                            6818 Madeline Court
roland at astrofoto.org                           Brooklyn, NY 11220

------------------------------

Message: 2
Date: Wed, 4 Apr 2007 21:51:02 -0500
From: Michael Koppelman <lolife at bitstream.net>
Subject: Re: [Aavso-photometry] Finding targets for a class....
To: Roland Roberts <roland at astrofoto.org>
Cc: aavso-photometry at mira.aavso.org
Message-ID: <284C2D2D-94B6-41FE-AAD0-955EC65DACFB at bitstream.net>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed

http://www.aavso.org/vsx/

A quick search on stars 20 < P < 60 days and max mag brighter than  
V=10 gave 2864 results.

Some of these will have AAVSO charts linked off of them (look in the  
Link-outs section). You can, of course, look at a star that lacks an  
AAVSO chart and just use magnitudes from another source.

M.

On Apr 4, 2007, at 9:33 PM, Roland Roberts wrote:

> Is there some way to search objects using period and variability?

------------------------------

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