fitscopy: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/fitscopy - from package: libcfitsio-bin

You may install the required package with command apt-get install {package}
Error in other languages:
fitscopy: bevel nie gevind nie
fitscopy: comandă negăsită
fitscopy: comando não encontrado
fitscopy: commande introuvable
fitscopy: command not found
fitscopy: käsku ei ole
fitscopy: không tìm thấy lệnh
fitscopy: komanda nerasta
fitscopy: Kommando nicht gefunden.
fitscopy: kommandot finns inte
fitscopy: komut yok
fitscopy: nie znaleziono polecenia
fitscopy: níor aimsíodh an t-ordú
fitscopy: no se encontró la orden
fitscopy: no s'ha trobat l'ordre
fitscopy: opdracht niet gevonden
fitscopy: parancs nem található
fitscopy: perintah tidak ditemukan
fitscopy: príkaz nenájdený
fitscopy: příkaz nenalezen
fitscopy: команда не найдена
fitscopy: командата не е открита
fitscopy: 命令找不到
fitscopy: コマンドが見つかりません