Re: Poor DRA Observations

Bart De Pontieu (BDP@MPEPL)
Mon, 24 Jun 1996 18:32:06 +0100 (CET)

RB Minton wrote:

>I have looked at each video snippet many times and I would be trying to pull
>the wool over someones eyes if I claimed any higher accuracy than what I have
>already reported.  All 3 satellites had flat maxima and minima.  Believe me,
>the data is recorded accurately enough to give you 0.1 sec. times if the 
>satellite had a nice spike in its flash pattern - but they did not.
>How do the visual observers handle these flat maxima & minima?  Could their
>technique be applied to a video recording?

I wonder whether using video to record the brightness somehow makes maxima
or minima less pronounced. Maybe the response function of your video 
compresses the amplitude of the flashes? I have no experience in this area. 
I will try to take a look at your previous images (that you sent in April) 
again to see whether there's any truth in this. 

Visual observers do not do anything special. If the maxima is really flat,
they're having trouble coming up with accurate data too. I lack recent
observational experience to determine whether the sats you observed suffer
from flat maxima for visual observers too. Can anyone who's been observing
(visually) these objects recently fill us in?

>I am hesitant to continue observations (of this type) if you don't think they
>are accurate enough (or depend on future efforts).  Ideas?

Maybe someone who has experience with recording flashes on video can tell us
more about the problems connected to this kind of observations. Paul ?

I also wonder whether digitizing the video and extracting a light-curve may
not solve the problems. Maybe the maxima are compressed by the response 
function of your video so much that the human eye can't detect the maximum
anymore, but it might still be there. Maybe you could send me a copy of the
videotape. I'll try to digitize it when I get it.


Bart De Pontieu --  Max-Planck-Institute for extraterrestrial Physics, Garching --
BWGS-coordinator -- Flash editor -- SeeSat-L administrator -- would-be-observer
         "Nous sommes quand-meme tous des Europeens" -- TC Matic