Troubleshooting guide

7. Variation of focus with temperature and airmass. The telescope changes focus due to temperature
variations; the focus value will increase with decreasing temperature. Similarly, the focus value will
decrease as the airmass increases:
• Temperature Variation: ∆T(+1 C) = -75 focus units
• Airmass Variation: ∆X = -130 focus units
It's advisable to watch the temperature every 30 – 60 minutes, and if necessary adjust the focus.
8. Check the display orientation. A raw FLAMINGOS image on the nominal ds9 display (no image flip or
rotation) has earth parity (E is cw from N), with the instrument position angle (0º) at the bottom of the
display (Figure 3).
Figure 3: Orientation of a raw FLAMINGOS image on the ds9 display at the 2.1-m (PA = 0).
9. Other Useful Bits:
The snowflake icon on the second-1 and second-2 desktops will display the truss temperature.
The windsock icon on the second-1 and second-2 desktops will display the current weather at the 4-m
telescope.
You are now ready to start observing!
FLAMINGOS@2.1-m, Ver. 2.39, 2011 May 13 Page 18 of 46