[Aavso-photometry] RE: BZ UMa - 18/19 Jan

[David Boyd]

Hi Dave,

I use AIP4WIN for multi-image photometry and it seems happy to run through as 
many images as you give it as an automatic process. I've processed several 
hundred in one run without problems. It does about 2 images per sec. This is on 
a 1.7GHz PC with 512 MB RAM running XP. You just tell it on the first image 
which stars you want to measure (limit 3 with current version), set the 
photometry radii and off it goes. It does calibration on the fly if you've given 
it the dark and flat. I always monitor what its doing closely however to check 
for problems which might occur due (eg) to drive errors causing a jump between 
frames. I also visually inspect every image as a quality check before doing the 
photometry and measure the star image profile on an image if in doubt. You can 
get spoilt images from wind, etc and you need to identify them and remove them 
before running the photometry routine. Otherwise the GIGO rule applies.

Regards,
David Boyd

----- Original Message ----- 
From: "Tandy, David" <DAVID.E.TANDY at saic.com>
To: "Aavso-Photometry" <aavso-photometry at mira.aavso.org>
Sent: Wednesday, January 19, 2005 2:03 PM
Subject: RE: [Aavso-photometry] RE: BZ UMa - 18/19 Jan


> I got about 1 hr 30m of data last night from 0245 UT 19 Jan to 0415 UT but
> I haven't had a chance to run the numbers.  BZ UMa has definitely fallen off
> in magnitude.  On Sunday I was able to shoot 20 sec integrations and have a
> good S/N.  I had to jump up to 60 sec last night and I was still getting
> lower counts than on Sunday.  I'll submit my observations from Monday night
> and Tuesday night this evening.  BZ UMa sure was a fun introduction to
> photometry!  Unfortunately, the forecast is calling for clouds so I may be
> shut down for a while.
>
> On another note, I was wondering which software package is the most
> efficient at photometry data reduction.  I use Maxim DL/CCD and I can only
> work with around 100 images (ST-10XME binned 2x2) before my computer gags.
> I have a 1 GHz system with 384 megs of RAM running Windows XP Home.  If I go
> above about 100 images, I get a low virtual memory warning and the machine
> starts to run very slowly.  Plus, Maxim DL/CCD starts to get weird.  Even if
> I do work with less than 100 images at a time, my machine gags after I've
> ran about 300 images.  Obviously a faster processor and more RAM would help
> but is there also a more efficient software package available to analyze the
> raw data?  Maybe this is Windows XP memory issue??
>
> - Dave
> Huntsville, AL
>
> -----Original Message-----
> From: aavso-photometry-bounces at mira.aavso.org
> [mailto:aavso-photometry-bounces at mira.aavso.org] On Behalf Of lou krajci
> Sent: Wednesday, January 19, 2005 1:01 AM
> To: cvnet-discussion at yahoogroups.com; Aavso-Photometry; 'Cba-Chat'
> Subject: [Aavso-photometry] RE: BZ UMa - 18/19 Jan
>
> I started on BZ UMa at about 06:45 UT.  I have scattered, thin cirrus, but I
> think it will improve over time tonight.
>
> A quick, eyeball comparison of my first CCD image to
> http://www.aavso.org/cgi-bin/shrinkwrap.pl?path=/charts/UMA/BZ_UMA/BZUMA-F.J
> PG
> shows that BZ UMa is now about 1/4 magnitude fainter than the 13.7 mag.
> comparison star...so let's say it's about 13.9 - 14.0 (unfiltered CCD) right
> now....but if you consider that my unfiltered CCD is sort of like R...and
> the comparison star has a B-V color index of about 1.0...then BZ UMa is
> perhaps around 13.1 - 13.2 in R.  (I am not submitting this paragraph as
> data...just a quick and dirty comment.)
>
> I'll submit my data tomorrow morning via webobs.
>
> Tom Krajci
> Albuquerque, New Mexico
>
>
>
>
>
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