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Hubble Space Telescope
WFPC2 Linear Ramp Filter Calculator

This form will calculate (x,y) target positions, POS TARGs (distance, in arc seconds, from the -FIX position of the chip), and wavelengths for WFPC2 Linear Ramp Filter observations. The (x,y) position calculator can be used to check where your target should be. The wavelength calculator can be used to determine effective filter wavelengths for objects in your images.
(Note: you do not need to use this tool in preparing your Phase II proposal; the proposal software does this automatically from the central wavelength.

Information on calibrating Linear Ramp Filter data is now available.

Calculate The X And Y Pixel Co-Ordinates And POSTARG Positions:

Please give the wavelength: Å.

Please be sure that the wavelength is between 3710.00Å and 9762.00Å.

Calculate The Wavelength:

Please give the x and y pixel co-ordinates (x,y):


Filter: Chip:

This page was created and is maintained by Matt McMaster ( and John Biretta (