1. I am less than thrilled with full CSV format for Fabienne's tables - most of our users, I thought, preferred simple, fixed width, plain ascii tables without the comma delimiters or the " " around each ascii field. Since the table really is fixed width and since the ascii string character columns do not contain any blanks except leading blanks, I don't see any real advantage to the CSV format. For the users who want to use EXCEL, EXCEL can happily read either format. I hope that there is a real reason for wanting delimiters in a fixed-width table. 2. Plotting the results in a useful way almost certainly requires scaling by the inverse square of the distance for many of the points (to get rid of the big increase in the last days). I think a column that has the spacecraft-comet range in some units would make the product far more useable. I should have thought about this before since when I used the early version of these data I had to go in and generate such a column. The range is already in the PDS label and the FITS header of all images, so it should be easy enough to extract it. 3. I think that we also need to go through and eliminate the cosmic rays manually. The plots show in which images they occur and, by comparing different-sized apertures, tell you approximately how far from the center the cosmic rays are. For studying variations in activity, whether outbursts (for me) or rotation (for Belton), the cosmic rays are a time-consuming distraction. N.B. Per Mike's email dated 22 Dec 2008 below, he agreed that CR removal can wait until version 2.0 of this data set because this task will very labor intensive, and it will change the analysis process and the photometric results. --sam 4. The table of nav data is not in chronological order, for no apparent reason. In particular, the images for June 14 at 21h UT come before the other data for that day (at 5, 9, 13 UT). Since times are given, this is not a major problem but it will scare users into thinking that the times are wrong. 5. There still seems to be an offset between the science data and the nav data around JD 2453510. 6. The photometry writeup says that the times have been corrected both for stellar aberration and for the Earth-comet light travel time. I do not understand what correction there should be for stellar aberration - this should be primarily a correction to the RA and dec of the pointing but not for the exposure timing (at least not at the level that we care about - there should be only a small term). As I look at the numbers and compare them with other sources of information on my laptop, it looks to me as though the values correspond more or less, but not precisely, to time at the comet, which is essentially the same as time at the spacecraft. I have a few images on the laptop so I can look at the PDS label and I find that the label for the science image taken Jul 2 at 5:51 UTC, has 5:51:06 for the mid-time whereas the photometry table has 5:51:48 and the PDS label gives the Earth receive time as 5:57:57. In other words, it does not look to me as though these have been corrected for transit time to earth but they have been corrected for something much smaller (is the aberration correction that big? The sign is wrong for correction from spacecraft to comet.). The fact that they have not been corrected is not a problem. I am happy having them be time at the spacecraft, or even better, time at the comet (which for this image must be about 20 sec earlier than the time at the spacecraft if I have done the arithmetic correctly for the range at that time) but we do have to explain things correctly and be entirely self-consistent. Here is another image where I was able to dig out more data and this implies that the time is at the spacecraft. Image # MV0173123422_8000008_001_RR.FIT PDS Label Mid-Time = 2005-06-27T05:53:09.670 PDS Label Earth Receive Time = 2005-06-27T06:00:00.881 Your Photometry Table = 2005-06-27T05:53:09.670 Range to comet from PDS label = 6222235.4445 Light Travel Time = 21 sec (approximately) Mid-Time at comet = 5:52:48 ---------------------------------------------------------------------------- Date: Mon, 22 Dec 2008 22:38:52 -0500 From: Michael F. A'Hearn To: Stephanie McLaughlin Cc: Michael F. A'Hearn Subject: Re: Fabienne's data Hi Stef, I agree that the CRs can wait for version 2. Mike On 2008 Dec 22 09:55, at 21:55 , Stephanie McLaughlin wrote: > > Hi Mike, > > I actually started working on one of the liens for the DI Photometry > data set weeks ago, for about 2 hours but have since been distracted by > tasks for the EPOCh archive... > > One of the items you noted in your pre-review list mentions eliminating > the cosmic rays manually (item #3 at http://pdssbn.astro.umd.edu/holdings/ > dif-c-mri-5-tempel1-photometry-v1.0/NOTES/ma_notes.txt). I expect this > task will be very time consuming and recommend pursuing it as version 2.0 > of the data set. Otherwise, most of the liens are not that difficult to > resolve. I'll send an estimate of the effort involved next week. > > Enjoy the Holidays! > stef > > > On Mon, 22 Dec 2008, Michael F. A'Hearn wrote: > > > Hi Stef, > > > > Could you please let me know when you are working on the liens for > > Fabienne's dataset? And the approximate amount of effort involved? I > > should pay you from my DDAP grant, instead of either PDS or EPOXI, > > when you are doing that. Thanks. > > > > Mike ----------------------------------------------------------------------------