Spectrograph operation at Kitt Peak

1. Setting up a new folder for the data

2. Setting the photometry camera

This can be useful to take images of the current field of view to find the spectroscopic target. The field of view of the photometry camera is larger than that of the ASCOM camera used to locate the target on the fiber. 

I like to set the filename root to simply PhotImg, as all of the information (RA, DEC, time, etc) is included in the header of the file. 

Note: the photometry camera and the ASCOM camera do not have the same optical path, thus the telescope focus is different. When we take a quick image of the photometry field to orient ourselves, don't be surprised to see donuts. 

3. How to fix DS9 is the photometry camera image does not automatically show in DS9 on the camera computer

4. Connecting the spectro camera (FLI) and the fiber camera (ASCOM)

Typical setpoint temperature for the FLI is -40°, but the cooler power needs to be below 90%.

IF MAXIM CRASHES: you need to restart the coolers AND often reset the cooling set point -- make sure you note what your setpoint was, as the calibration (especially the darks) are temperature-dependent. (The temperature is recorded in the fits headers worse case worse, but it's much shorter to have it on a piece of paper)

5. Using the autosave function and taking bias calibration frames

6. Using the spectrograph and the calibration arm to open the ThAr lamp. 

7.  Using ThAr frames in continuous mode to focus the spectrograph.

I use a subframe of 100x100 pixels, centered at x=1000 and y = 250. A moderately bright spectral line will have a FHWM of ~2.7. 

8. Taking ThAr calibration frames with the autosave

I usually take ~ 30 ThAr images

9. Taking flat calibration frames

Note: make sure to do this either during day time/twilight, or with the dome closed.

Make sure the peak of the flats are below the saturation point. With a too long exposure of the flat, there is a lot of scattered light that is difficult to remove. Better to have more flats to build up the signal-to-noise. I usually take at least 40 flats.

10. Focusing the fiber camera (ASCOM)

This is easier to do at twilight, with the dome and telescope cover open. It is also doable during day time, with the dome closed and the telescope covers open. 

The "moon" mode in the image "View > screen stretch window" is the best to see the seams of the mirrors.

11. Loading and modifying a target catalog. 

Also, how to use the Go To Target button to see the current airmass of a target (no worries, the telescope won't move until you confirm. 

12. Using a bright star to focus the telescope. 

On the ASCOM, the FWHM will be around 10'' (this is not the real seeing -- the scale plate is set for the photometry guiding camera)

13. Target acquisition, and verifying the field with the photometry camera.

To get the photometry camera in North up and East left, DS9 needs to be in Invert X with rotation 90°, amplifier C. 

The field of view of the photometry camera is ~15". The field of view of the ASCOM is half that. Note that the ASCOM is tilted at ~45° with respect to the photometry camera. 

The focus of the telescope for the photometry camera is not the same as for the ASCOM. But I usually don't bother to change the focus, I can still check the field of view with donut. 

14. Putting the target on the fiber and starting the autoguiding.

The position of the fiber on the ASCOM is x = 658 and y = 548.