Filters

A common system of filters is available for use with the CCD cameras at Moore, Mt. Kent and Mt. Lemmon observatories. With some exceptions, noted below, all filters are mounted in wheels that may be changed on request.

Sloan Photometry

There is a set of Sloan filters for each of the ULMT, MORC24, CDK20N, CDK20S, and CDK700 telescopes. Each set excepton ULMT is in a wheel with 6 openings assigned serially.

• (1) g' (400-530)
• (2) r' (530-700)
• (3) i' (700-825)
• (4) z' (825-1100)
• (5) blue block (500-1100)
• (6) Open

Currently the ULMT wheel has 10 openings including the Sloan filters, color imaging filters, H-alpha and [OIII]. That wheel is scheduled to be replaced with a 7-filter wheel that has Sloan, plus others to be determined.

Transformation from Sloan to UBVRI Filter Bands

Transformation coefficients are discussed on the Sloan Digital Sky Survey Sloan Digital Sky Survey website

UBVRI Photometry

There is one UBVRI filter wheel at each observatory to be used as needed an any telescope with an IFW3 filter wheel.

• (1) U (340-390)
• (2) B (375-490)
• (3) V (490-580)
• (4) R (570-690)
• (5) I (725-1025)
• (6) Open

BGRC Color Imaging

There is one color imaging wheel at each site.

• (1) C (350-1100)
• (2) R (590-700)
• (3) G (490-575)
• (4) B (390-510)
• (5) Open
• (6) Open

Narrowband

There are three narrowband filter sets available. The wheels at Mt. Kent for CDK20S and CDK700 use Astrodon filters:

• (1) [SII] (3/671.6)
• (2) H alpha (3/656.3)
• (3) Red continuum (5/645)
• (4) [O III] (3/500.7)
• (5) UV blocked clear
• (6) Open

A wheel for the CDK20N is

• (1) He I (5/1083.0) (Custom Scientific)
• (2) [SII] (3/671.6)
• (3) H alpha (3/656.3)
• (4) Red continuum (5/645)
• (5) [O III] (3/500.7)
• (6) UV blocked clear

A wheel for use at the RC24 is

• (1) [SII] (Custom Scientific)
• (2) H alpha (Custom Scientific)
• (3) Red continuum (Astrodon)
• (4) Na D (590) (Custom Scientific)
• (5) [OIII] (Custom Scientific)
• (6) UV blocked clear (Astrodon)

SBIG STL Filters

The SBIG STL6303 cameras take 50 mm diameter filters in a 5-filter wheel. Moore and Mt. Kent observatories have the standard UBVRI set installed in the STL cameras used on the wide-field FSQ telescope for student projects:

• (1) U (330-390)
• (2) B (375-490)
• (3) V (490-580)
• (4) R (570-690)
• (5) I (725-1025)

Additionally, at both locations there is a set of color imaging RGBC filters in spare wheels. STL cameras require disassembly to change wheels.