TL_SUMER is an interactive program which asks the user questions needed to design a SUMER study. The program then writes an idl save file (with suffix .rst) which can be used as input for the SUMER command language (SCL) program (available in [wilhelm.contrib.scl]) which will write a program in SUMER command language to perform the observations. TL_SUMER also writes the parameters of the observational program into ascii files (.dat) and can write a postscript file (.ps) showing the focal plane arrangement. To start the program start IDL, place the directory with all the programs here in your idl path and type tl_sumer