Nasmyth 2 Guider - Old (outdated) Information

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This page last updated: June 28, 2006 - JMD
This page last checked: October 27, 2004 - JMD

Contents

Warning all information in these pages is considered out dated but presented for those needing historical information or for reduction of older data!

Roper Scientific Camera

Reference

Information relating to the Roper Scientific NA2 Guide Camera in operation from pre 1998 to Summer 2004

NA2 (Roper) Guider Information & Specifications

NA2 (Roper) Guider Quick  Information

• CCD is a SiTe back illuminated 1024 x 1024 CCD

• CCD pixel size = 24 µm

• CCD gain = 10.5 e^-/ADU

• CCD read noise = 22.5 e^- / pixel

• Quantum Effeciency ~70%

• Dark Current: <1 e- / second

• Pixel scale = 0.137"/pixel binned 1x1

• Full well depth: 150k e^-

• Linear up to 64k, Saturation at 64K

• Installed filters (User selectable): R, I, B, Red + ND2, Clear, U, V (all filters are Johnson-Cousins)

• Available gratings (Observing Specialist installable): N/A

• Grating resolution: N/A

• Spectral Coverage: N/A

• Field of View: 143.4"

• Minimum Exposure:

NA2 Guider for Beginners: Basic Usage Information

• Filters There are 7 filter positions, containing the following filters from Custom Scientific. For a plot of all filters, click here.

• 0 - Bessell R
  1 - Bessell I
  2 - Bessell B
  3 - Red + 1% ND (ND2) (See below for specs)
  4 - Clear
  5 - Bessell U
  6 - Bessell V

• These are the numbers used in the [set gfilter=#] command. The filter file that describes these filters is found in the tdat. To get to that filder type [move tdat]. The file that you want to edit is [ip_na2.dat]. The center wavelength and FWHM values are not used by the TCC, but the focus offsets are. The offsets are based upon the clear filter being a 0 offset. Since the CLEAR, U, B, V, R & I filters are all the same thickness, there is no offset betrween them. The only filter requiring a focus offset is the ND2 + R filter which will be measured on the sky.

• The Red Filter Used With the ND2

• • 645 nm central wavelength

• • 70 nm FWHM

• • peak transmission 80%

• The red filter attached to the ND2 in position 6 is not the same as the Bessell R. Number 6 is an RG610 red glass filter (Rolyn 65.1355) for the 610 nm cut-on. The interference filter absorbs 20% at 650 nm; the red glass filter doesn't seem to absorb much in the 610-680 nm range

• Neutral Density Filters (Position #6)

• • 1% transmission (Rolyn 65.0110)
    

• Focus

• Focus ranges from 0 to > 75,000 microns. Nominal focus is at approximately 45,000 microns. 0 is defined by a high quality limit switch; the other limit is not--the focus stage just runs into a physical limit and the motor stalls.

• Camera

• The guide camera is currently a SpectraSource HPC-1/TK512, which uses a SITe 512x512 CCD with 24 µm square pixels. The camera is fixed to the instrument rotator (it has no independent motion). The image scale is approximately 7 pixels per arc-second, so binning 3x3 is normally used. A more detailed listing of chip characteristics is available on the detector characteristics page.

• Guide Image Controller

• The guide image controller is a Macintosh. Commands are issued via the modem serial port, which is connected to the TCC via a terminal server. It is accessed on the TCC as logical name tcc_Cam. Images are served via ftp to gcam35m.apo.nmsu.edu (an account and password required) or via AppleTalk to Guider.

• Guider Mechanical Controller (filter and focus)

• This is one of Charlie Hull's hardware controllers. Control is via the serial port, connected to the TCC via a terminal server. It is accessed on the TCC as logical name tcc_GMech.

• Additional Information - available on Eric Deutsch's APO Guider page