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Re: Pan-STARRS 1 Telescope Begins Science Mission

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  • Steve McCluskey
    {Moderator s note. I just found this one in stuck in the pipeline, which explains it s late distribution] Once again, the press office seems to be a bit ahead
    Message 1 of 29 , Jun 17, 2010
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      {Moderator's note. I just found this one in stuck in the pipeline, which explains it's late distribution]




      Once again, the press office seems to be a bit ahead of the astronomers. This June 9 Status Report <http://ps1sc.org/Status_Reports.shtml> seems much more tentative.

      Steve
    • Richard Kowalski
      Hey Tommy, I d first like to congratulate you and the PS-1 team for becoming operational. It s good to see a lot of the hardships your team has endured have
      Message 2 of 29 , Jun 19, 2010
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        Hey Tommy,

        I'd first like to congratulate you and the PS-1 team for becoming operational.
        It's good to see a lot of the hardships your team has endured have been
        overcome. I know from what my team mates have told me, CSS had a lot of trying
        years before we took over from LINEAR as the most productive NEO survey,
        including getting up and running under the threat of being shut down entirely.

        I's also like to say that my personal opinion about the current discourse on
        MPML about PS is a bit of schadenfreude over the trouble you have had over the
        past several years. Uncalled for in many respects, but I can understand some of
        the posts when much of the public face and information about the project comes
        from PR people who don't work on the team instead of the team itself.



        I do have a few questions for you though. Keep in mind that I am asking because
        of personal interest and are not "official" in that they are coming from CSS.
        Our PI Ed Beshore speaks for the program, not me.

        You mentioned a limiting magnitude of 23.5R under very good conditions. Is that
        for stationary or moving objects? Last night at G96 I have very good conditions,
        high transparency and sub arcsecond seeing and for at least one NEO candidate at
        21.8V, which if I'm not mistaken translates roughly to about 23.5R, so both
        systems seem to be matched in that case, if your limiting magnitude was for
        moving objects. I have found objects fainter than 22.0V using 30 second
        exposures, but those are rare.

        At CSS its no secret that we work at ~1.2 sigma, so we are scrounging in the
        dirt for the fainter objects. I'm just curious as to the sigma you are expecting
        to work at for your operational NEO detections

        Though PS1 has a slightly larger aperture, your obstruction is larger than ours,
        so my estimate is your light gathering power is about the same or even a little
        less than ours. Also, since PS1 is on Haleakala, the conditions are not optimal,
        so I'd be curious as to how many nights of sub-arcsecond seeing you enjoy? I'd
        estimate that these things combined make PS-1 & G96 well matched, in reach. You
        clearly have the advantage in a larger field of view, so that will help find
        more NEOs per exposure.

        Sorry, I don't see it at the moment, but I believe you said that two nights per
        lunation will be dedicated to NEO surveying. Just comparing the two systems head
        to head, knowing we discover on average about one NEO per night per telescope,
        with a slightly higher percentage going to G96, it seems to me we should expect
        6 to 10 NEOs from PS-1 per lunation. It'll be interesting to see if this holds true.

        As you no doubt already know, the Catalina Real Time Transient Survey is one of
        the most productive, (if not the most productive) optical transient surveys
        currently in operation. It will be interesting to see how PS-1 supplants or
        supercedes this position in the coming months and years as you get into full swing.

        I look forward to your responses.

        --
        Richard Kowalski
      • Richard Kowalski
        Oops. I was corrected privately. I went the wrong way on the conversion, V to R. 21.8 V = 21.4R Thanks and sorry for the mistake. Richard
        Message 3 of 29 , Jun 19, 2010
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          Oops.

          I was corrected privately. I went the wrong way on the conversion, V to R.


          21.8 V = 21.4R


          Thanks and sorry for the mistake.


          Richard
        • Dave Tholen
          ... Kron-Cousins V-R of the Sun is 0.365, so a typical asteroid, which is slightly redder than the Sun might have V-R = 0.5 or thereabouts, which means that
          Message 4 of 29 , Jun 19, 2010
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            > Last night at G96 I have very good conditions, high transparency
            > and sub arcsecond seeing and for at least one NEO candidate at
            > 21.8V, which if I'm not mistaken translates roughly to about 23.5R

            Kron-Cousins V-R of the Sun is 0.365, so a typical asteroid, which
            is slightly redder than the Sun might have V-R = 0.5 or thereabouts,
            which means that V=21.8 corresponds roughly to R=21.3. I have no
            idea where this R=23.5 figure is coming from. That was the figure
            being bandied about for a full four-telescope system.
          • Tommy Grav
            ... The hard work has and are being done by Larry Dennaeu, Robert Jedicke, Mikael Granvik, Andrea Milani and others. Personally I help where I can, but WISE
            Message 5 of 29 , Jun 20, 2010
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              On Jun 20, 2010, at 12:13 AM, Richard Kowalski wrote:

              > Hey Tommy,
              >
              > I'd first like to congratulate you and the PS-1 team for becoming operational.
              > It's good to see a lot of the hardships your team has endured have been
              > overcome. I know from what my team mates have told me, CSS had a lot of trying
              > years before we took over from LINEAR as the most productive NEO survey,
              > including getting up and running under the threat of being shut down entirely.

              The hard work has and are being done by Larry Dennaeu, Robert Jedicke, Mikael Granvik,
              Andrea Milani and others. Personally I help where I can, but WISE takes most of my
              time these days :)

              > I's also like to say that my personal opinion about the current discourse on
              > MPML about PS is a bit of schadenfreude over the trouble you have had over the
              > past several years. Uncalled for in many respects, but I can understand some of
              > the posts when much of the public face and information about the project comes
              > from PR people who don't work on the team instead of the team itself.

              It is a fine line to walk. PR is unfortunately necessary to keep the funding agencies
              happy.

              > I do have a few questions for you though. Keep in mind that I am asking because
              > of personal interest and are not "official" in that they are coming from CSS.
              > Our PI Ed Beshore speaks for the program, not me.
              >
              > You mentioned a limiting magnitude of 23.5R under very good conditions. Is that
              > for stationary or moving objects? Last night at G96 I have very good conditions,
              > high transparency and sub arcsecond seeing and for at least one NEO candidate at
              > 21.8V, which if I'm not mistaken translates roughly to about 23.5R, so both
              > systems seem to be matched in that case, if your limiting magnitude was for
              > moving objects. I have found objects fainter than 22.0V using 30 second
              > exposures, but those are rare.

              As you corrected yourself V of 21.8 is more like r~21.5 or so. Pan-STARRS has
              a limiting magnitude of 22 - 22.5 on average for the images that I have seen.

              > At CSS its no secret that we work at ~1.2 sigma, so we are scrounging in the
              > dirt for the fainter objects. I'm just curious as to the sigma you are expecting
              > to work at for your operational NEO detections

              We are expecting to be working at the 5 sigma level (that is the limiting magnitude
              quoted above). As the project gets more comfortable we might try to go to fainter
              sigma levels.

              > Though PS1 has a slightly larger aperture, your obstruction is larger than ours,
              > so my estimate is your light gathering power is about the same or even a little
              > less than ours. Also, since PS1 is on Haleakala, the conditions are not optimal,
              > so I'd be curious as to how many nights of sub-arcsecond seeing you enjoy? I'd
              > estimate that these things combined make PS-1 & G96 well matched, in reach. You
              > clearly have the advantage in a larger field of view, so that will help find
              > more NEOs per exposure.

              I am not sure what the number of nights with sub-arcsecond seeing there are on
              Halakela, sorry.

              > Sorry, I don't see it at the moment, but I believe you said that two nights per
              > lunation will be dedicated to NEO surveying. Just comparing the two systems head
              > to head, knowing we discover on average about one NEO per night per telescope,
              > with a slightly higher percentage going to G96, it seems to me we should expect
              > 6 to 10 NEOs from PS-1 per lunation. It'll be interesting to see if this holds true.

              We have on the order of 12 nights of observing in the 3pi cadence that we search for
              moving objects. I am not sure where this 2 night misunderstanding comes from. We
              will be surveying thousands of sq. degrees per lunation. We do loose a fraction of NEOs
              due to the area-loss in the chip. As for the number of NEOs per lunation I don't want
              to speculate until we start producing.

              > As you no doubt already know, the Catalina Real Time Transient Survey is one of
              > the most productive, (if not the most productive) optical transient surveys
              > currently in operation. It will be interesting to see how PS-1 supplants or
              > supercedes this position in the coming months and years as you get into full swing.

              I think it will be a healthy and friendly competition :)

              Tommy
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