1. Put on the latex gloves
2. Set the filter position on the TCS to 1, so the clear filter is in place, and make sure the telescope is in the zenith position, or close to it.
3. Go upstairs, notice next to where the CCD camera is located there is a dial with a little handle on it; this is the dial to manually change the filters.
Directly above that is a black rectangular box with two thumb screws holding the cover in place.
4. Remove the thumb screws and take off the cover inside is the filter wheel. If the filter position is set to 1, then the filter seen is in the 4th position.
There are numbered position labels on the filter wheel.
IF REMOVING A WIDE-BAND FILTER
5. Use one hand to push the filter up through the hole at the bottom of the GAM assembly (below where the cover was) while you use your other hand to hold it and remove it.
6. Bring the filter downstairs and put it away (see Filters guide for location of wide-band filters)
IF REMOVING A NARROW-BAND FILTER
5. Screw the end of the tool(silver cyclinder with a screw end) into the open hole on the metal filter holder of the filter you want to change
6. Pull out the filter, you may have to wiggle it around a little. This is okay — it is a tight fit. The filter will not break.
7. Bring the filter downstairs, replace in its case and box (the filter information is printed on the side of the filter as well as the box — match it).
IF INSTALLING A WIDE-BAND FILTER
8. Install the new filter by hand, holding it by the sides as much as possible. You will have to put in one side and then push down to snap in place.
IF INSTALLING NARROW-BAND FILTERS
8. Pick up the new filter using the tool. Place the filter reflective side up.
9. Put the filter in the wheel. This is sometimes tricky, if having difficulties the metal sides of the holder can be pushed down. Just remember not to touch the actual filter.
10. When finished changing the filters, manaully return the filter wheel to the 1st position (the 4th position will be seen), replace the cover on the filter wheel.
IN ALL CASES
11. Go down to the control room and make up a table of the filters currently in use (if different from the default arrangement).