Differences

This shows you the differences between two versions of the page.

--- arces [2026/01/30 04:23] – holtz
+++ arces [2026/01/30 04:34] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 ===== ARC Echelle Spectrograph (ARCES) =====
+The ARC echelle was constructed for the 3.5m at the University of Chicago in the 1990s.
+[[https://www.apo.nmsu.edu/mainpage/arces/arcesguide/|ARCES instrument manual on APO website]]
 ==== Features / issues ====
 * the traces and ThAr lines can move around over the course of a night. The reason has never been completely understood.
-  * This leads to issues with conventional flat-fielding since it is possible that pixels with flux in an object spectra will not have pixels with a lot of flux in a flat-fielded image.
+  * This leads to issues with conventional 2D flat-fielding since it is possible that pixels with flux in an object spectra will not have pixels with a lot of flux in a flat-fielded image.
   * This also affects the ability to get precision velocities. More frequent ThAr frames may be required, or you may wish to try to use telluric absorption to correct for wavelengths; see {{:wiki:arces:echelle_dispersion_note.pdf|note by Patrick Gaulme}} with his conclusions about the nature of the shift.