Re: cluster obs requirements

From: Marc Postman (postman@stsci.edu)
Date: Fri Jan 27 2006 - 12:02:00 PST

  • Next message: Henk Hoekstra: "Re: cluster obs requirements"

    OK then we should correct the proposal text on page 6 which currently
    states:

    (each orbit contains four ACS/F850LP dithered cosmic-ray splits plus
    one ACS/F775W exposure)---

    That looks like 4:1 to me. So the four in the above sentence should be
    three! Good catch!

    Marc

    On Jan 27, 2006, at 2:54 PM, marek kowalski wrote:

    > Hello Marc,
    >
    > I just want to make sure we phrase it consistently. In the SNe
    > observing requirement section we say 515 seconds exposure in I and
    > 340 seconds in the four z-band exposures. That makes a ratio of
    > 1:2.64. The waek lensing section says 25% to 75% which is close enough
    > to this ratio but different from 4:1.
    >
    > Cheers,
    >
    > Marek
    > On Jan 27, 2006, at 11:43 AM, Marc Postman wrote:
    >
    >> Here are our expected photometric errors in i775 and z850 - as Henk
    >> knew, the 4:1 exposure ratio for z850:i775 yields comparable errors at
    >> each AB mag interval. these are based on scaling our Lynx (z=1.27)
    >> mosaic exposures to the exptimes we will have in our co-added data. I
    >> am modifying the cluster obs reqs section accordingly and making the
    >> CMR slope/scatter measurements the main drivers.
    >>
    >> <SNeHST_photerr_vs_mag.eps>
    >> On Jan 27, 2006, at 2:07 PM, Saul Perlmutter wrote:
    >>
    >>> ...and of course, show that our new F775 exposures (515 sec times ~7
    >>> or 8 orbits co-added) is exactly what we need!
    >>>
    >> -----------------------------------------------------------------
    >> Marc Postman Email: postman@stsci.edu
    >> STScI - CMO Phone: +1-410-338-4340
    >> 3700 San Martin Drive Fax: +1-410-338-4424
    >> Baltimore, MD 21218 U.S.A. http://www.stsci.edu/~postman
    >>
    >>
    >
    > --------------------------------------------------------------
    > Marek Kowalski Lawrence Berkeley National Laboratory
    > mpkowalski@lbl.gov 1 Cyclotron Road, MS 50R5008
    > (510) 486 4652 Berkeley, CA 94720-8160
    > --------------------------------------------------------------
    >
    >
    -----------------------------------------------------------------
    Marc Postman Email: postman@stsci.edu
    STScI - CMO Phone: +1-410-338-4340
    3700 San Martin Drive Fax: +1-410-338-4424
    Baltimore, MD 21218 U.S.A. http://www.stsci.edu/~postman

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