Typical Dome flat-field exposures for each filter are given below. These exposures should produce pictures having 5,000-10,000 ADU per pixel to stay within the linear regime (note that each ADU represents ~3 electrons, so there is plenty of signal with these recommendations. To minimize thinking at the telescope, we tried to use the maximum voltage settings when possible (4m: 53V; 0.9m: 100%).
|
Filter |
4meter |
0.9m |
||
|
|
Lamp Setting |
Exposure Time |
Lamp Setting |
Exposure Time |
|
U |
High 53V |
8s |
High 100% |
10s |
|
B |
Low 53V |
18s |
Low 100% |
18s |
|
V |
Low 53V |
12s |
Low 100% |
8s |
|
R |
Low 53V |
12s |
Low 100% |
5s |
|
I |
Low 53V |
15s |
Low 100% |
6s |
|
Halpha |
High 20V |
9s |
Low 100% |
6s |
|
Halpha +4 |
High 20V |
8s |
Low 100% |
60s |
|
Halpha +8 |
|
|
Low 100% |
60s |
|
Halpha +16 |
High 20V |
9s |
Low 100% |
60s |
|
OIII |
High 53V |
2s |
High 100% |
3s |
|
OIII+29 |
|
|
Low 100% |
28s |
|
g' |
Low 53V |
10s |
Low 100% |
4s |
|
r' |
Low 53V |
12s |
Low 100% |
5s |
|
i' |
Low 53V |
18s |
Low 100% |
6s |
|
z' |
Low 53V |
22s |
Low 100% |
11s |
|
Wash M |
Low 53V |
|
Low 100% |
3s |
|
DD051 |
High 20V |
35s |
Low 100% |
18s |
|
VR |
Low 53V |
8s |
|
|
|
Bw |
Low 53V |
15s |
|
|
|
wh |
Low 53V |
3s |
Low 50% |
5s |