SKYCAT(1)

okay bestie, pull up a chair because this is skycat, page 1 of the User Commands manual, and she is that girl 💖 (astronomy edition, obviously)

✨ NAME ✨

skycat — a tool for displaying astronomical images and catalogs. yes literally both. images AND catalogs. she contains multitudes. 💅

🎀 SYNOPSIS 🎀

skycat filename -option value ...

🦋 DESCRIPTION 🦋

So the ESO Skycat tool is a whole collaboration: it takes the image display capabilities of the RTD (Real-Time Display) and pairs them with a set of classes for accessing astronomical catalogs — both locally and over the network using HTTP. And the vibe? You get to view FITS images from files, or straight up from the Digitized Sky Survey (DSS). no cap, she's serving ✨

💅 OPTIONS 💅

• -file filename — name the FITS file you want displayed. A '-' means read the file from standard input. And plot twist: the '-file' part is optional, so you can literally just hand her a file name and she gets it. Image compression and decompression happen automatically, based on the file name suffix: .gzfits or .gfits for GZIP compression, .hfits for H-compress, and .cfits for UNIX compression. she just knows 🫶
• -cat bool — if bool is 1, the 'Data-Servers' menu gets included in the menubar (and yes, that is the default, periodt). The 'Data-Servers' menu is your backstage pass to the ESO Archive extensions — browsing astronomical catalogs, plotting objects in the image window, and pulling images over the network from image servers like the Digitized Sky server.
• -rtd bool — if bool is 1, the Real-Time menu gets included in the menubar (default is 0, so it's off unless you ask). That Real-Time menu unlocks the VLT Real-Time Display features — camera control, rapid frames, the works. Lowkey important: to use any of this, the rtdServer daemon has to be running on the local host. Then a client application, linked with the Rtd image event library, can send images via shared memory to be displayed in rapid succession. iconic behaviour 🔥
• -float_panel bool — if the option value is 1, the skycat info panel gets yeeted into its own separate popup window, which leaves more space for the image window. (Default is off, so she stays docked.)
• -panel_layout <saoimage | reverse | default> — this one reorders the zoom and pan windows in the layout. The default layout is: zoom window on the left, info panel in the center, pan window on the right. Say "-panel_layout saoimage" and you get a layout similar to saoimage (info panel, pan window, zoom window). Say "-panel_layout reverse" and the window order is the reverse of the default. pick your fighter 💜
• -remote bool — if "-remote 1" is specified and a skycat process is already running, the existing skycat process gets sent a message asking it to open a new window, and the brand-new skycat process exits immediately. Perks: sharing the image colormap and using fewer system resources. The catch: it depends on being able to use the Tcl send mechanism. And for security reasons, Tcl send will not work if you're using "xhost" based X security — you need to use X-auth security instead. See the "Tcl/Tk Tools" book from O'Reilly for more on this topic. ⚠️
• -min_scale n — (she and her sister below share one whole personality, keep reading)
• -max_scale n — these two specify the min and max scale values for the Magnification menu. Negative values shrink the image, positive values zoom in closer. The default values are -10 and 20. 🌈
• -port portnum — specify a port number to use for the remote RTD socket interface. See the Rtd User's Guide for details on this socket based interface. By default, a port number is chosen automatically and written to the file ~/.rtd-remote. 🍓
• -disp_image_icon bool — if bool is 1 (default), display a miniature version of the image in the tool's icon window. tiny image. tiny. 🥺
• -default_cmap <cmap> — specify the default colormap. This should be one of the names listed in the 'Colors' popup window (default is 'real').
• -default_itt <itt> — specify the default intensity transfer table. This should be one of the names listed in the 'Colors' popup window (default is 'ramp').
• -colorramp_height <pixels> — use this to change the height of the color bar (the widget at the bottom of the screen displaying the image colors).
• -with_colorramp bool — if bool is true, display the color bar (this is the default).
• -with_zoom_window bool — if bool is true, display the zoom window (default).
• -with_pan_window bool — if bool is true, display the pan window (default).
• -dozoom bool — if bool is true, turn the zoom window on automatically (default).

👑 MENU ITEMS 👑

📁 File menu

• Open... — open and display a (FITS) image file.
• Reopen... — reload the image display after the image has changed on disk. (she noticed. she always notices.)
• Save as... — save the current image to a file.
• Save region as... — save a section of the current image to a file.
• Print... — print the current image to a file or printer.
• Clear — clear the image display. bye bye pixels 💀
• New Window — display up a new main window.
• Close — close the main window and exit if there are no more windows.
• Exit — exit the application.

👀 View menu

• Colors... — display a window for manipulating the image colormap.
• Cut Levels... — display a window for manipulating the image cut levels.
• Cuts... — display a graph of pixel values along a line drawn interactively over the image.
• Pick Object... — select an object or star in the image and display statistics. main character selection energy ⭐
• Fits Header... — display the FITS header for the current image.
• Pixel Table... — display a table of pixel values surrounding the mouse cursor.
• Magnification — set the magnification factor of the image display.
• Hide Control Panel — toggle the visibility of the upper control panel
• Hide Popup Windows — toggle the visibility of the popup windows.

🎨 Graphics menu

• Toolbox — display the line graphics toolbox.
• Mode => — select the drawing mode.
• Width => — set the line width for drawing.
• Arrow => — select the arrow mode for lines.
• ArrorShape => — select the arrow shape for lines. (yes that's the spelling, i don't make the rules 🙈)
• Fill => — select the fill color for drawing.
• Outline => — select the outline color for drawing.
• Stipple => — select the stipple pattern for filling objects.
• Font => — select the font to use for labels.
• Smooth => — set the smooth option for drawing polygons
• Clear => — delete graphic objects.
• Delete => — delete selected graphic objects.
• Hide Graphics — toggle the visibility of the image line graphics

🌐 Data-Servers

• Catalogs => — select a catalog from the menu.
• Image Servers => — select an image server from the menu.
• Archives => — select an archive from the menu.
• Local Catalogs => — select a local catalog from the menu.

⚡ Real-time menu (displayed when -rtd 1 is specified)

• Attach Camera — attach the real-time camera - start receiving images.
• Detach Camera — detach the real-time camera - stop receiving images.
• Set Camera... — set the real-time camera name.
• Rapid Frame — create a rapid frame by interactively drawing a rectangle on the image.

🫶 Help menu

• About Skycat... — display a window with information about this Skycat version.
• Help... — display information about Skycat in netscape (if netscape is available).

🌿 ENVIRONMENT VARIABLES 🌿

• $SKYCAT_CONFIG — if set, this is used as the URL to access the skycat configuration file, which contains the list of available catalogs and how to query them. By default, the configuration file is also searched for in $HOME/.skycat/skycat.cfg, and if that is not found, in the ESO default URL: http://archive.eso.org/skycat/skycat2.0.cfg.
• $SKYCAT_PLUGIN — if set, this variable should be a colon separated list of files or directories containing skycat plugins. A skycat plugin is a Tcl script that defines a Tcl proc to be called for each instance of the main window. The script is sourced before any windows are created and can also load shared libraries dynamically to add new features. See the Skycat User's Guide (ftp://ftp.archive.eso.org/pub/skycat/docs) for more information. plugins?? we love an extensible queen 🧚

🗂️ FILES 🗂️

• http://archive.eso.org/skycat/skycat2.0.cfg - default configuration file.

🔗 SEE ALSO 🔗

rtd(1)

and that's the whole page bestie!! this one's the SKYCAT page, straight from March 2009, and it lives in the SKYCAT(1) slot of your manual. now go look at some galaxies 💖✨🌌