Changes

SPUPNIC

1,677 bytes added, 22:07, 21 August 2016
/* Dome Flats */
====Dome Flats====
 
* Go behind the control room desk and check that the black rheostat is dialed down to zero
* Flip the switch next to it to On
* Dial the rheostat up to 220 V (do not exceed that value as you will blow the lamps)
* The lamps on the top end of the telescope should now be on
* Open the mirror cover
* With the telescope vertical, rotate the dome to 127 degrees, so that the white flat-field screen is just to the east of the south pier
* Set the telescope RA to HA = 0
* Slew the telescope in Dec to the south pole (-90 degrees), while keeping an eye on the spectrograph cables
* The cables will look like snagging, but they will not if you are at HA ~ 0
* Slew Through the pole, to -86.5 degrees (on the other side of -90)
* Try not to overshoot as the pointing limit is at -85 on that side
* If you run into the limit, an alarm will sound and the telescope will stop moving
* To recover: turn the over-ride key next to the console while backing the telescope out towards the north in Dec
* With the telescope at HA ~ 0/12 & Dec ~ -86:30, the telescope should be quite well centred on the flat-field screen
* In the control room, take some trial exposures to check the count level, aim for ~40k counts
* The lamps are quite red, so blue settings (e.g. G4) struggle for counts
* In that case, it is fine to crank the slit wide open to let more light in (you do not care about resolution here)
* Take as many flats as you like (say, 11?) once you have established an appropriate exposure time
* When you have the flats, slew the telescope back to the zenith (again keeping an eye on the cables)
* Dial the rheostat down to zero
* Flip the switch to Off
* Close the mirror cover
====Focusing The Spectrograph - running a Hartmann sequence====
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