Final Reduction

Excel Reduction: Introduction

This page is for varios Excel reduction techniques.  Upload your Excel sheet and give a breif (one-paragraph) introduction to how it is used.  Just plug in the general formulas, don't lock any cells (yet), and make it easy to use by someone with a little Excel experience.

We'll evaluate which we think is best for the general public and whichever we think is best will be used as our "standard" reduction sheet.  Brian will modify the worksheet to include the equations for full uncertainty analysis before the sheet is added to the general CS website.

Please name the files by your username without spaces (i.e. bkloppenborg.xls) and add a new section to this page following the examples below (note, you'll need to rename your file on your computer before attaching it to this page).

Heading 2 (filename.xls)

Description:
A one-paragraph description of how to use your Excel sheet.  Ideally the user should just plug in magnitudes and standard deviations from one of the reduction packages and calibrated magnitudes should be exported.

Discussion:
Others will comment here.

(TomPearson.xls)

Description:
This spreadsheet computes the transformation coefficent because photometric V isn't the same as the Green Bayer array.  The areas highlighted in yellow represent data that is entered for each observation session.  Areas in green are for tabluated data that are entered only once for a specfic star.  The (single) variable in the example is epsilon Aurigae with Lambda Aurage as the comparision star.  Six other stars in the vicinity of eps Aur are used for determining the TC.  The user needs to look up the (B-V) of a star, possibly using SIMBAD or some other similar service.

Discussion:
Others will comment here.

(Bikeman.xls)

Description:
This spreadsheet was done "stealing" many ideas of Tom's spreadsheet and by editing Brians latest reduction Excel sheet. It allows to perform the TC calculation and the variable star magnitude estimations in basically one go. You have one data entry area (in yellow) at the top of the sheet where you can put all the instrument magnitudes, e.g. cutting and pasting from AIP4WINs data log. Next you will specify whether the sheet should compute the TC itself or whether it should just use a TC that you enter manually (for those who measure the TC only once in a while). The sheet will the do the rest of the calculations automagically.

(Photometry4.xls)

Description:
This is the spreadsheet I have used for all my observations. Now translated to english and completed with an Instruction page. This sheet automatically computes both the Tc (color-index) and k' (air mass) coefficients and calculate corrected magnituds for both epsilon and the compairsion stars used.

It is also possible to see the error between the compairsion stars calculated and their catalog magnitudes. This give an indication how good data you have in the image. You can for example discover if you have hidden clouds on part of the image.

The sheet have data for 20 compairsion stars. If you don't want to use that many you simply remove the rows on each sheet that correspond to the stars you don't plan to use. I recommend to use not lesser than 5 compairsion stars or if possible 8 or more. (The more stars you use the the more confident you will be that your result is correct).

For calculation of airmass the altitude of epsilon and the compairsion stars has to be entred, this is a data that easily can be found in a planetarium software as Stellarium or Cartes du Ciel/SkyCharts. Other than the altitude the only thing that has to be entered is the stars instrumental magnitudes.

Thomas Karlsson

Discussion:
Others will comment here.