* Optimum focus varies with temperature, typical summer values are ~2200 while cold winter nights may be closer to 2270 units.
===Focusing the acquisition /guide camera===* Having focused the telescope as described above, one needs to focus the acquisition /guide camera.
* The star used to focus the telescope may be too bright, so aim for something fainter (e.g. a guide star that needs a ~1 sec exposure).
<!--* Adjust the acquisition camera focus with the up/down buttons in the lower right corner of the TCS GUI to get the stars as sharp as possible.* With the new autoguider (installed Oct 2023), a focus value of 5300 is a good starting point.--> In February 2024, an instrument selector was installed on the telescope to allow SpUpNIC and SHOC to be mounted simultaneously. Prior to this, the guide mirror was used for SpUpNIC acquisition while in the beam, and for guiding when out of beam. Now, the guide mirror stays "out of beam" at all times and is only used for guiding, and a pick off mirror is slid in front of it (covering the slit) for acquisition. The same camera is used for both procedures, and is therefore at a different distance from the two mirrors, so the camera focus must be adjusted between acquisition and guiding:* During acquisition (fold mirror in beam), camera focus ~29000.* When guiding (fold mirror out of beam), camera focus ~6000. Adjust the camera focus by entering the value into the "Camera Focus" box toward the lower right of the TCS GUI, and pressing "Enter" on the keyboard.
==User's Troubleshooting Guide==