RE: fun with coadding images on Disk Set 19

["Creager, Robert S" <CreagRS@LOUISVILLE.STORTEK.COM>]

Hey Tom,

Software wise, I can quite easily do this, as I'm already matching stars to
stars in V vs I band now.  So I'll start scripting away, hopefully tonight.

I'm betting that Michael might have this data already though...

Later,
Rob

> -----Original Message-----
> From: Tom Droege [mailto:tdroege@veriomail.com]
> Sent: Tuesday, October 16, 2001 4:15 PM
> To: Stupendous Man
> Cc: tass@listserv.wwa.com
> Subject: Re: fun with coadding images on Disk Set 19
> 
> 
> Many thanks to Michael for looking at co-adding.
> 
> It was my thought that adding them in fours would be about 
> right.  This 
> should get a near factor of two in signal to noise.  At least 
> it did when I 
> checked some frames.
> 
> The best data is always that which you have not yet looked at.
> 
> There are some problems with DS-19.
> 
> 1) There are only 49 V images on DS192.  At least when I counted them.
> 2) There are only 44 I images on DS193.
> 
> I have no idea of how I did this.  I took 50 (I think).  But 
> the source 
> files have been erased.  I have only the copy directories.  
> Sigh!  Somehow, 
> I did not transfer all the files when copying them to the 
> CDs.  Then I 
> copied the original CD into a directory on another machine 
> for making the 
> copies.  Not a good practice, but it is what I did.
> 
> I have made a small improvement in alignment since DS19.  It 
> is now of 
> order 3 arc seconds per minute N-S and still <1 arc second per minute 
> E-W.  This gives some improvement in star shape.  Since DS-19 
> I have gone 
> to 56 frame sets.  This is about as far as I can go without 
> running into 
> the stops.
> 
> How good does it need to be?  The present slide out mount 
> will not do much 
> better, I think.  The Mark IVs in the dome can probably be 
> aligned more 
> accurately, but I have not tried it yet.
> 
> Here is something to study:  Look at the drift between 
> frames.  i.e 1-2, 
> 2-3, ... 48-49.  This in the E-W direction.  This should be 
> constant.  Look 
> for variations, particularly at the end of the ranges to 
> check how well the 
> RA drive is working.  If anyone wants to do this, I can send 
> a later data 
> set which has more frames and goes closer to the limit.
> 
> Tom Droege
> 
> 
> 
> At 12:14 PM 10/16/01 -0400, you wrote:
> 
> >   Check out my quick'n'dirty analysis of coadding frames
> >from disk set 19:
> >
> >        http://a188-l009.rit.edu/tass/markiv/michael/coadd/coadd.html
> >
> >   People who are working on DS 19 may find the shift in
> >position from frame to frame, even in the "follow" frames,
> >of some interest ...
> >
> >                                      Michael Richmond
> 
>