A survey of Quest data after extinction and calibration

1
A survey of Quest data after extinction and
calibration

• A single nights calibration is applied to
  extinction corrected data
• Quest will be compared to Sloan on several areas
  of the sky
• Quest color diagrams will be presented which show
  the effectiveness of requiring multiple
  independent detections in each filter(unforced
  detections)

2
Forced detections
Pipeline applies a blind Measurement at the
position Of the missing star
B
R
3
Johnson 180 to 190 ra 0Dec
4
Sloan Quest on 0Dec
R
I
B
All measurements 10 error
5
BRI 0Dec
B-R
Sloan matches to Quest gt3 of 7 nights combined
per filter 10 error cut
From Sloan Star catalog
R-I
6
BRI 0Dec
Cutting forced detections 3 nights (of 7) per
filter at least
B-R
R-I
7
Johnson 340 to 360 ra -9 Dec
8
Sloan Quest at -9 dec
All measurements 10 error
9
Johnson 340 to 360 ra 22.5 Dec
10
BRI 22Dec
B-R
Measured in every filter at least 3 of 4
nights With forced detections
At least 2 of 4 nights Column 26 creates the
halo Without forced detections
R-I
11
Gunn 180 to 190 ra 0 Dec
Note, cloudy on January 27,2004
12
Sloan-Quest 0Dec
z1
z2
i
r
13
0Dec, lower quality extinction
14
Gunn 350 to 360 ra 4.5 Dec
15
Sloan-Quest 4.5Dec
16
RIZ 2 nights at 0Dec
Allowing for forced detections, Matched to sloan
r-i
i-z
17
Gunn 350 to 360 ra 22.5 Dec
18
22Dec RIZ
Unforced detections At least 3nights of 6 per
filter
Histogram of errors on measurements
r-i
i-z
19
Sloan - Quest
Sky level
20
Conclusions

• Johnson zero points off by order 10
• Forced detections add noise 14 error in B
• Gunn zero points are good
• Gunn color diagrams are a bit wide
• TBD effect of sky brightness on zero points in U
  and B.