MAESTRO Characterization checklist.

QUESTIONS TO ANSWER:

1. is the spectrograph collimated and in good internal alignment?
2. does the collimation and focus hold with changes in elevation?
3. where are the light leaks?
4. do we get the spectral resolution we expect?
5. what is the spectral line profile?
6. what is the end-to-end throughput?
7. how does flexure affect the spectrum -- how often do you have to take th-ar? Can we use night sky lines to derive small linear offsets?
   
8. what level of scattered light do we have?
9. what is the dark current
10. what is read noise of the CCD on the telescope?
11. what is the spectral resolution on the sky, using a star
12. is the focus derived from th-ar the best focus for the star?
13. what is the longest exposure time feasible: flexure, cosmic ray rate
14. what is the best scheme for pixel to pixel flat-fielding
15. what is the best observing strategy for sky subtraction
16. what is the best scheme for de-fringing
17. what limits s/n -- on the bright end
18. what limits s/n on the faint end.
19. how well does the ADC work
20. what limits observing efficiency?
    

MEASUREMENTS TO MAKE:

Take focus run with very small hole, CCD unbinned.
Use sextractor to measure astigmatism and focus.
Adjust CCD position until no astimatism.
does best focus line profile agree with what we expect?

Repeat at large airmass.

2. CCD measurements on telescope

0. control light leaks
1. read noise
Does RMS in average of biases reduce like sqrt(N)
2. linearity
3. gain
4. bias stability
5. dark
6. does bright light leak onto overscan?
7. traps, cosmetics

3. Throughput On sky, use echelle standard star and big slit or holes.

4. Spectral resolution On sky, use Dave Meyer's star and .4 arcsec slit

repeat at large airmass

5. Spectral resolution,
Observe Vega with tiny hole to compare to Coude atlas.

6. Spectral resolution as a function of slit width Take th-ar through different slits, see how FWHM
changes with slit width

Repeat with dave meyer star

7. Flexure Use th-ar to measure shifts as function of
(1) elevation
(2) rotation

8. Compare on-board Th-ar and f/5 th-ar

9. Compare on-board quartz/leds with f/5 quartz

10. S/N Observe Vega, 0.4 arcsec slit,
dither spectrum with PZTs to attempt s/n=500

11. Sky subtraction, Scattered light

Observe star with very saturated lines, or quasar with dlya
to see if bottom of line is black after sky subtraction
and scattered light corrections. Use ABBA two hole method.

12. Velocity standard Observe a few velocity standard repeatedly, at different airmasses,
different nights. This checks stability of illumination of slit by
comparason box.

13. Fringing Take comp lamp exposures with different elevations. Repeat.
Develop strategy for fringing correction.
Take twilight flats.
Take two standard stars to see if fringing can be removed with
(1) twilights, (2) internal flats, (3) f/5 flats, (4) dividing by
a star.

14. Red sky subtraction. Compare tilted slit, ABBA, single slit.

Requires fringing to be controlable.

15. Blue wavelength solution: Take series of Th-Ar's to get very deep blue spectrum

16. How well does the ADC work? Take a standard star at different airmasses, using small hole.

Almanac

July 25:
Sunset 19:25

LST at midnight: 19h 51m

18 degree sunrise: 4:02am
LST at 18 degree sunriset: 01h 51m

MOON

VEGA:
Right ascension 18h 36m 56.3s
Declination +38d 47' 01"
Apparent magnitude (V) 0.03

Dave Meyer's star: HD 157787, V=8.6
Interstellar Na D line has two components, separated by 8 km/s
Observed at Coude resolution (1.3 km/s) the blue component is
unresolved, so b-value < 1 km/s

Echelle photometric standards

Object with black lines:

PHL 957, V=16.6

J2000:
01:03 11.3
+13 16 18

Velocity standard

-- Main.jill - 03 Jul 2007