MagIC
The Raymond and Beverly Sackler Magellan Instant Camera
New Manuals (2010 Aug 04)!
Table of Contents
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0. MagIC Current Status
2. Performance
3. Observing
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3.0 The LOIS data acquisition systems
3.1 MagIC User Manuals
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3.1.1 LOIS version 4 (installed 2006 August)
PDF
PS
3.1.2 LOIS version 1 (less capable but available if needed) PDF PS
3.3. Things to Watch Out For
Appendix C. Responsible Individuals
0. MagIC Current Status
MagIC Location
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Folded Port of the CLAY 6.5-m telescope. |
Availabe Camera Operating Modes
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Quad, dual and single-amp readouts. Binning 4x4, 2x2 or 1x2. Readout time: ~20 seconds (quad amp 1x1). Output file contains serial and parallel overscans for each quadrant for bias calibration. |
Filter Status
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Filters installed: Filter positions recorded in lookup table. |
Folded Port Guider Status
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Operational: MagIC is permanently mounted on one of the three folded ports, allowing the rapid switching between MagIC and other scheduled instruments. |
1. Introduction
MagIC (the Magellan Instant Camera) is a high throughput CCD camera system built as the first facility instrument for the Walter Baade telescope, one of the two Magellan telescopes. Personnel from the MIT departments of Earth, Atmospheric and Planetary Sciences and Physics and from the MIT Kavli Institute for Astrophysics and Space Research and the Harvard-Smithsonian Center for Astrophysics contributed to its construction. MagIC consists of four components; i) an instrument rotator, ii) a dual-probe guider/wavefront sensor, iii) a filter wheel and shutter mechanism, and iv) a high quantum efficiency, wide spectral coverage, cryo-cooled, back-illuminated, thinned CCD camera and associated electronics. The camera is run from a single science workstation via a custom software package (LOIS) developed in collaboration with colleagues at Lowell Observatory. The instrument was initially deployed at the Baade telescope in March of 2001 and has undergone several upgrades and refinements since then. MagIC is currently mounted at a folded port of the Clay telescope, always ready for observations and rapidly accessible by rotation of the tertiary mirror. The combination of optimized scheduling and a highly efficient, instantly accessible camera allow the Magellan partners to pursue science programs not possible or practical elsewhere. MagIC was conceived to tackle such programs as optical follow-up of gamma ray burst sources, monitoring of the light from gravitationally lensed quasars, occultations of stars by solar system bodies, high precision photometry of microlensing events in the Magellanic Clouds, physical studies of recently discovered near-earth asteroids, optical follow-up of supernovae in distant galaxies, and exploration of the Kuiper Belt.
1.1 Design Goals
- High efficiency and throughput
- Minimal optics (only optics introduced are the filter and dewar window)
- High quantum-efficiency detectors
- Fast data readout
- Instantly accessible
- Mounted on folded port
- Cryo-cooler
- Low power consumption
- Low maintenance
- Easy to use
1.2 MagIC Technical Characteristics
The current MagIC focal plane houses a grade 0 SITe 2048 x 2048 pixel CCD array. The MagIC dewar is always kept cold, cooled by a closed cycle CryoTiger to a detector temperature of 120 C.
SITe SI424a Specifications
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Detector Size | 2048 pixels x 2048 pixels |
Pixel Size | 24 microns |
Focal Plane Scale | 2.89 arcsec/mm = 0.069arcsec /pixel |
Field Of View | 2.35 arcmin x 2.35 arcmin |
Quantum Efficiency | 85%-400nm; 82%-700nm; 48%-900nm (SITe lab measurements) |
Output | 4 output device @ 50 +Kpix/sec |
Readout | 4 amp, full frame = 20 sec |
2. Performance
2.1 Gain, Read Noise, Saturation, and Linearity*
Camera Mode: Unbinned, 4-amp readout
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Amplifier
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Gain (e-/DN)
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Read Noise (e-)
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Saturation Level (ADU)
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Linearity
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A/aka 1
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1.94
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5.9
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65k
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linear to saturation
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B/aka 2
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1.92
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4.6
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65k
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linear to saturation
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D/aka 3
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1.91
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5.3
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34k?
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linear to saturation
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C/aka 4
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2.05
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5.2
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34k?
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linear to saturation
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* Results from June 2001 Engineering data at the Baade
Amplifier C/aka 4
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Amplifier D/aka 3
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Amplifier A/aka 1
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Amplifier B/#2
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2.2 Throughput*
Filter
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Transmission Curve
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Absorption Curve
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Throughput
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mag for 1 e-/sec
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extinction coefficient
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B
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27.13
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0.21
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V
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27.17
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0.12
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R
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27.42
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0.10
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I
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26.79
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0.04
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u'
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25.09
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0.49
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r'
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27.51
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0.09
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g'
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27.44
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0.16
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|||||||
i'
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27.17
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0.04
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z'
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26.21
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0.04
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VR**
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* Results from June 2001 and March 2004 Engineering data.
**custom filter for KBO observations, see Jewitt, D., Luu J., & Chen J. 1996 Astron. J., 112, 1225.
Filter Slide Drawings — View1.PDF, View2.PDF or View1.PS, View2.PS
3. Observing
3.0 The LOIS data acquisition systems
LOIS, the Lowell Observatory Instrument System, is versatile data acquisition software used with optical and infrared detectors. MagIC was initially installed with version 1 of LOIS, but was upgraded to version 4 in August 2006. Version 4 runs on a the computer named "magic2." Version 1 runs on a the computer named "magic1," and serves as a backup system in the event of difficulties.3.1 MagIC/LOIS User Manuals
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3.1.1 LOIS version 4 (installed 2006 August)
PDF
PS
3.1.2 LOIS version 1 (less capable but available if needed) PDF PS
3.2 Star Charts
If you need a star chart, note that a five-second exposure through the Sloan r' filter goes to about the same depth (at full moon) as the Digital Sky Survey. To download a DSS chart, go to the web site http://stdatu.stsci.edu/cgi-bin/dss_form. Select the second generation red survey and an appropriate size to use is 3' x 3', which is a bit larger than MagIC's full frame field of view.
3.3 Things to Watch Out For
The most recent topics of discussion concerning MagIC can be found on the news and forums webpage
Each filter wheel is set independently, so do not forget to have one of the wheels set to the open position. If not, you will be exposing through two filters at once! Both filter names will be written in the FITS header.
In version 1 scripts could not (and still can not) be aborted or interrupted short of quiting the running LOIS session. This represented a major shortcoming. In version 4 scripts can be aborted when the camera is exposing or reading, but NOT when the filter wheel or telescope is moving.
When operated in single amp mode (available only in version 4) two phantom pixels are inserted at raw row number 1991. The last 4 arcseconds of data are therefore shifted by 2 pixels. All of the data are present and can be recovered, but many users may just choose to ignore the last 4 arcseconds.
Appendix A. MagIC Analysis Scripts and Reference Material
Appendix B. Magellan I Schedule
Appendix C: Responsible Individuals
Point of Contact at MIT: Jim Elliot
Point of Contact at LCO: David Osip
"MagICians" can be contacted through our mailing list: magic@lco.cl
Any problems should be documented and sent to the mailing list.