MROI.Tip-tiltSystems History
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March 16, 2007, at 05:00 PM
by John Young -
Changed lines 10-26 from:
to:
- Detector choice: EMCCD or conventional CCD
- If EMCCD, do we ever need to use photon-counting mode?
- How to handle dispersion offset between TT band and science/FT bands, e.g.
- Does subframe need to move on TT detector during an observation?
- How do we determine the colour of the target?
- Is dispersion significant when determining a pointing model?
- What ratio sample rate/bandwidth is needed?
- How do we measure the temporal seeing with the TT system?
- How do we choose the bandwidth for a particular observation?
- How to manage range of target magnitudes 0-16, e.g.
- Do we need ND filters?
- What detector parameters need to be varied
- Do we always use the full aperture?
- Centroiding algorithm
- Can we achieve the required stability of reference direction?
Tasks:
Deleted lines 27-28:
- Stability of reference direction
- Sample rate/bandwidth
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* At what level is the interface to RTC?
March 16, 2007, at 03:44 PM
by John Young -
Changed lines 4-6 from:
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- Answer questions in requirements doc.
- Insert values from new system error budget.
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March 16, 2007, at 03:38 PM
by John Young -
Changed lines 1-16 from:
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Original tip-tilt memo: Attach: INT-402-MIS-0034.pdf
Requirements document: Attach: INT-403-ENG-0003.pdf
Specifications of tip-tilt secondary mirror: XXX
Open questions:
- Derived requirements
- Stability of reference direction
- Sample rate/bandwidth
- ROM cost
The expression for the control system error factor from the tip-tilt memo is
\gamma = \left[ \frac{2}{\Omega} \tan^{-1} \left(\frac{\Omega}{2}\right) \right]^{1/2} ,
where \Omega is the ratio of sampling frequency to 3dB bandwidth.
March 16, 2007, at 03:00 PM
by John Young -
Added line 1:
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