Blocking filters for use with TTF/TAURUS
[Narrow band] [Intermediate band] [Broad band]

Here is a summary of the available TTF filters. You can download this figure from here. You can download a text file of the transmission curve by clicking on the filter links below.

Newsflash: There is a neat trick which allows us to "invent" a BTTF blocker centred at 450nm, 80nm width when using the MITLL3 detector. This works well at low resolution. The B filter cuts sharply to the red, the MITLL3 cuts out in the blue as shown here. This
was used to good effect in Feb 2000 runs. Note that the peak transmission for the pseudo-filter is at least 80%. What is shown here is the product of filter and CCD.

Narrow band (3.0 inch diameter; there are many more at the WHT  web site which can be used with the TTF. Note that these filters can be tilted for off-band use. Contact JBH for details. These filters provide almost full field coverage at the AAT.)

AAT  HeII          4686/20
AAT  OIII           5007/30
AAT  HeI/NaD   5890/40
AAT  OI             6300/40
AAT  Ha/NII       6570/40
AAT  SII             6730/40
AAT  CI             8727/4
Intermediate band (The R0...R8 filters used to be refereed to as the I0...I8 filters. The naming was changed to bring into line with the TTF names. The filters are 4.80 inch diameter to permit the full field to be used with the WHT TAURUS-2; a 3.5 inch filter is big enough for the AAT TAURUS-2 field.)
WHT f098       4670/320
WHT f099       4770/320
WHT f101       4880/100  (Aug 99: currently resides at AAT)
WHT f107       5000/350  (May 99: currently resides at AAT)
WHT f126       5220/380  (May 99: currently resides at AAT)
WHT f133       5700/450
WHT f135       5960/470
WHT f136       6240/540

AAT  B0    3750/190
AAT  B1    3900/170
AAT  B2    4110/150
AAT  B4    5000/320
AAT  B6    5820/190
AAT  R0    6680/210  (this filter can be used with the BTTF or RTTF)
AAT  R1    7070/260
AAT  R3    7580/280
AAT  R4    7820/405
AAT  R5    8140/330
AAT  R6    8570/400
AAT  R8    9090/400

Broad band (always use the 4" filters for full field work)

2" diameter 4" diameter
WHT users have access to a wide list of intermediate blockers: see