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Hi Arne, I was a little surprised by your reference to 'using the latest version' in this context. Does this imply that earlier versions were less than reliable? My own experiences with AIP4WIN have been less than satisfactory. The CBA circulated a book in which this came as an included disc with a recommendation that this might be a standard CBA reduction package. But I couldn't get the programme to run in any useful manner. Many images it rejected, others close to the edge it wouldn't look at. Compared to the DAOPHOT derivative, MUNIDOS, that I was using at the time it appeared very poor. Perhaps the disc was faulty but where is the quality checking? At that time I had also been offered a couple of other reduction packages also written by amateurs, or people with little experience in the field. All seemed much less effective when compared to MUNIDOS. Perhaps AIP has improved in later versions. But can it yet be compared to software produced by professionals at a major observatory where the performance was subjected to extensive practical checking by people working in the field? DAOPHOT has extensive documentation and apparently the source code is available - see TK's comments about complexity. AIP was presumably written to take advantage of a commercial opportunity and is still, if your comments are correct, being developed. Perhaps none of this matters in reality as most users are doing unfiltered photometry in which the 'errors' arising from other sources probably outweigh any faults in these newer software reduction packages. No two CCDs are alike and scale factors and zero point corrections are essential if two datasets are compared. Perhaps an ideal solution would have been if the AIP people had built their more user friendly? package around DAOPHOT? Regards, Stan From: "Arne Henden" <aah@nofs.navy.mil> To: "Taichi Kato" <tkato@kusastro.kyoto-u.ac.jp> Cc: <vsnet-campaign-ccd-discussion@ooruri.kusastro.kyoto-u.ac.jp>; <vsnet-chat@ooruri.kusastro.kyoto-u.ac.jp> Sent: Monday, July 14, 2003 5:30 AM Subject: [vsnet-chat 6685] Re: (fwd) problems with AIP4win > > Taichi Kato wrote: > > I know how complex DAOPHOT is, and I even > >read the "extremely complex" source code of DAOPHOT -- a modern > >software engineering would have resulted a much simpler solution...). > > > The American saying goes: "If it ain't broke, don't fix it." > Once you produce a software package that does better and is > available in full source code and in public domain, you may > have a right to say this, but not before. > > There is no software package that I know of, including my own, > that does not have problems when you are dealing with low signal/noise > situations. This is a very tricky regime and I am willing to bet > that what works for one case will not work for another. You should > avoid low signal/noise regimes until you are experienced. If > it is important to use the low signal/noise data, then it is > best to have an expert, such as Kato-san, reduce all of the original CCD > frames rather than using results from many different observers and > reduction procedures. > Arne > > > > > >
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