![keck nirspec zemax file keck nirspec zemax file](https://www2.keck.hawaii.edu/inst/nirspec/images/spec_highres.png)
It uses the method of least-squares with a single value decomposition tofit the parameters (a, b, c, d, e, and f). The list of wavelengths and refined pixel coordinatesgenerated is input into a least squares routine to fit the parameters of thebivariate quadratic (or cubic, or quadratic) equation described above.
![keck nirspec zemax file keck nirspec zemax file](https://support.zemax.com/hc/article_attachments/1500007446522/KA-01443_6_Sample_Image.png)
All IDLprocedures written for this analysis can be found in an adjacent directory. The x-coordinate of this list (rememberthat we rotated the image before doing GetLambdas) were refined by a4-parameter Gaussian fit to improve the center position (usingrefinelines.pro). We identified ~5 positions along each line. It usesa lower level function called GetClix.Pro which returns the coordinates of apixel that you click on. This procedure allowsyou to enter the wavelength for a line, the click on the line in another windowdisplaying the lamp image. We used the IDL procedure GetLambdas.pro to generate of setof (wavelength, x, y) triplets for least-squares fitting. L (x, y) = a + b x + c y + d x y + e x 2+ f y 2 + gx 2y + hxy 2 + ix 3 + jy 3 This is automatically done in therectification procedure used later.įor the polynomial relating x and y to wavelength, we used acubic: Therefore, before doingthe wavelength calibration or later the rectification of the raw images, werotate the image by 270°, using the command rotate(data, 3) in IDL. Ultimately we would like our rectifiedimages to have the wavelength axis correspond to increasing columnnumbers. Now that we have identified the lamp lines, we can establishthe transformation from pixel space to wavelength space. Thelist of Neon lines and our Neon image. For the other case, themiddle line of the three blended lines used.įigure 2. For two of the occasions, the two linecenters were averaged – a reasonable solution as the lines had similarstrengths. Three times, multiple lamp lines were not resolved. Figure 3 shows the image of the Neon lamp (on the left) andthe list of lines from the NIST database. Once we knew the approximate spectral range, we couldvisually identify the lines on the Neon lamp image. The purple text is ourestimate of line locations:
Keck nirspec zemax file simulator#
This is how the simulator looked forour setup. Wevisually identified lines on this NIST list in the 2-D image of the Neon lamp.In order to have an initial guess as to the location of the lines in our image,we used the NIRSPEC Format Simulator. We used an image of a Neon lamp for this calibration and alist of Neon lines from the NIST database. The first step is the wavelength calibration to determinethe mapping from pixel space to wavelength.
![keck nirspec zemax file keck nirspec zemax file](https://www2.keck.hawaii.edu/koa/public/nspec/Image6.gif)
This web page describes the reduction of spectroscopicobservations of Pluto from 2.8 to 3.7 mm recorded on Keck II(with the NIRSPEC instrument(The data were recorded on Augby Eliot Young andWill Grundy. Reduction of Keck-NIRSPECobservations of Pluto Section 1 Introduction