Tools Required:

• 3/32 allen wrench
• Palm grip handle tool found in the LRIS storage area on the Keck 1 Nasmyth deck or in the instrument lab LRIS cabinet (bin marked special tools).
• Gloves
• facemask
• hairnet or cap

Procedure

1. Locate new filter and old filter storage boxes. These are located on the bottom shelf of the cabinet located next to the laminar flow bench.

   

2. If you need to remove the grism cell from the instrument first please follow the instructions Remove Grism
3. Insert palm handle into grism cell top plate if not already installed.
4. Place the Grism cell in the laminar flow bench with the retaining baffle face up as seen in the picture below.

   

5. Remove the four socket head screws securing the square filter retainer
6. Remove the square filter retainer. .

   

7. Remove the filter and the delrin frame from the grism cell. You may have to use a small screw driver to lift from the filter frame from the corners. You also may have to wait until the cell is at room temperature.

   

8. Pack filter in appropriate storage box.
9. Unpack new filter which should be already installed in a delrin frame.
10. Install filter+frame into the grism cell. It is a tight fit so you have to drop it in almost vertical. The local lore is shiny side up, but it should not matter.
11. Install and secure the square retainer.
12. Re-install in instrument if necessary. See Remove Grism