clarify centering procedure in checklist.md

Author: ojf

_pages/checklist.md

@@ -50,7 +50,7 @@ Weather data for wind speed and humidity are available from the wireless station
 
 8. **Take flats.** Take sky flats pointed approximately 20 degrees east of the zenith (west for morning flats). Take dome flats in Cover Position using the incandescent desk lamp pointed down to the floor. 
 
-9. **Fine tune the telescope pointing on a bright star.** Vega is a fine target for much of the summer. Select your target in *SkyView* (Ctrl-f), and slew by (left-) clicking and choosing GoTo. It's likely that your target will not appear in the ccd's field of view, in which case you should change the paddle's speed to *Pan* (yellow light on F1), and use the finder to center the star. Once the star appears in the ccd, ensure you're zoomed out and use SiTech.exe to center the star. Finally, update the telescope's pointing by selecting it again, but this time choose Sync.
+9. **Fine tune the telescope pointing on a bright star.** Vega is a fine target for much of the summer. Select your target in *SkyView* (Ctrl-f), and slew by (left-) clicking and choosing GoTo. It's likely that your target will not appear in the ccd's field of view (But did you remember to zoom out?), in which case you should change the paddle's speed to *Pan* (yellow light on F1), and use the finder to center the star. Once the star appears in the ccd, use SiTech.exe to center and update the telescope's pointing by selecting it again, but this time choose Sync.
 
 10. **Focus the telescope on a faint star.**  Move the telescope to a dimmer star in the finder, then take images and adjust focus to minimize the PSF. 9000 is a reasonable move for donuts, 3000 is best when you can see stars. 1500 is the smallest reasonable move, only for fine tuning. Note that the focus position will change as the temperature changes over the course of the night, which may necessitate refocusing.