Fan Mountain Observatory Instrumentation: Filters

40" Astrometric Reflector

The 40" telescope has a number of filters for many uses. We have two sets of broad band photometry filters, a set of 4-inch standard UBVRI filters and a set of 6-inch Washington C,M,T1,T2  filters. We also have a 6-inch DDO-51  filter that is used with the Washington set.

We have a matched pair of 4-inch H-alpha line and red continuum filters. We also have a set of 2-inch H-alpha filters at various redshifts, which unfortunately cause vignetting when used with the SITe 2048×2048 chips.

Filter
Size
QE(%)
Johnson U
4-inch
30%
Johnson B
4-inch
70%
Johnson V
4-inch
80%
Cousins R
4-inch
80%
Cousins I
4-inch
50%
Washington C
6-inch
 
Washington M
6-inch
 
Washington T1
6-inch
 
Washington T2
6-inch
 
DDO-51
6-inch
 
H-alpha Line
4-inch
 
H-alpha Red Continuum
4-inch
 
H-beta Line
4-inch
 
[O III] Line
4-inch
 
[N II] Line
4-inch
 
[S II] Line
4-inch
 

31" Tinsley Reflector

The 31" telescope has a broad range of filters spanning the near-infrared region.
These filters are primarily for use with FanCam.
Filter
Size
Transmittance
(% Average)
2MASS Prototype J
1-inch
75
2MASS Prototype H
1-inch
92
2MASS Prototype Ks
1-inch
78
2MASS Prototype K
1-inch
70
2MASS Prototype Br-γ
1-inch
50
NicMASS Ks
1-inch
82
ThrillCam J
1-inch
85
ThrillCam H
1-inch
65
ThrillCam Ks
1-inch
78
ThrillCam K
1-inch
62
ThrillCam Br-γ
1-inch
55
FanCam Pa-β
1-inch
60
FanCam Fe-II
1-inch
70
FanCam Br-γ
1-inch
63
FanCam Y
1-inch
93
Polarizer 1
1-inch
North-South
33" separation
Polarizer 2
1-inch
NW-SE
33" separation