[Aavso-photometry] Aavso-photometry Digest, Vol 52, Issue 7
Russ Garrett
russ at russgarrett.com
Sat Mar 8 17:24:53 EST 2008
This is short notice but my skies may clear. Can any one suggest an easy
eclipsing binary or CV to observe tonight for a novice? I have a C14 and a
ST 10. I need the so called formula such as number and length of exposures.
I will try to keep the counts at about 30,000 for this camera and use a B
filter although I have UBVRI. Should there be a delay between the exposures?
I would like to keep it simple with no AutoGuiding. I will take the flats
and darks and combine later. If you can point me in another direction that
would be great to.
Thanks in Advance.
Russ
-----Original Message-----
From: aavso-photometry-bounces at mira.aavso.org
[mailto:aavso-photometry-bounces at mira.aavso.org] On Behalf Of
aavso-photometry-request at mira.aavso.org
Sent: Friday, March 07, 2008 11:00 AM
To: aavso-photometry at mira.aavso.org
Subject: Aavso-photometry Digest, Vol 52, Issue 7
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Today's Topics:
1. Re: Aavso-photometry Digest, Vol 52, Issue 6 (Kate Davis)
2. Alternates Photometric Growth curve fitting (Brad Walter)
3. Re: Aavso-photometry Digest, Vol 52, Issue 6
(hudsonjk at astound.net)
----------------------------------------------------------------------
Message: 1
Date: Thu, 06 Mar 2008 16:40:08 -0500
From: Kate Davis <kate at aavso.org>
Subject: Re: [Aavso-photometry] Aavso-photometry Digest, Vol 52, Issue
6
To: hudsonjk at astound.net
Cc: aavso-photometry at mira.aavso.org
Message-ID: <47D064B8.90001 at aavso.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi Jerry,
If you send an email to aavso at aavso.org your request should be directed
to the correct staff member. In the case of WebObs' issues, that is me.
So feel free to email directly as I check that email more frequently
than I see discussion group messages.
I am sorry for the inconvenience. The Feb. 29 Bug is now fixed. Let me
know if you have any other questions.
Best,
Kate
aavso-photometry-request at mira.aavso.org wrote:
>
> Today's Topics:
>
> 1. Feb 29 Bug (hudsonjk at astound.net)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 5 Mar 2008 22:22:03 -0000
> From: <hudsonjk at astound.net>
> Subject: [Aavso-photometry] Feb 29 Bug
> To: <aavso-photometry at mira.aavso.org>
> Message-ID: <001501c87f0f$56aa7db0$64dcea42 at LittleDevil>
> Content-Type: text/plain; charset="Windows-1252"
>
> Hi -
>
> I just tried to submit some observations via WebObs for CCD obs.
>
> I tried entering the dates
> 2008/02/29/...
> and also
> 2008/03/00/...
>
> and got error messages. In the first case, the complaint was that
February only has 28 days (!), the other wanted me to use a number in range
1..31 for March.
>
> Don't know if this is the forum for airing this, so forgive me if it
isn't. I tried sending to
> observations at aavso.org
> but that obviously isn't the right place.
>
> Don't worry about the problem, I was able to use J.D. format to get around
the problem.
>
> - Jerry Hudson (HJA)
>
>
> ------------------------------
>
> _______________________________________________
> Aavso-photometry mailing list
> Aavso-photometry at mira.aavso.org
> http://www.aavso.org/mailman/listinfo/aavso-photometry
>
> End of Aavso-photometry Digest, Vol 52, Issue 6
> ***********************************************
>
>
------------------------------
Message: 2
Date: Thu, 6 Mar 2008 16:40:28 -0600
From: "Brad Walter" <bswalter at hughes.net>
Subject: [Aavso-photometry] Alternates Photometric Growth curve
fitting
To: <aavso-photometry at mira.aavso.org>
Message-ID: <4794C3EA00E840A3 at n016.sc0.he.tucows.com> (added by
postmaster at bouncemessage.net)
Content-Type: text/plain; charset="US-ASCII"
When doing (or at least trying to do) millimag time series photometry
(exoplanet light curves, for example), I have been manually picking the
inner-most aperture on every individual image so that my measurement is
always at the same point on the growth curve. This is exceedingly time
consuming and exceptionally tedious. I have tried a "short cut" of analyzing
the images with the smallest FWHM, the median FWHM and the largest FWHM in
the time series; then finding the ratio of the measurement apertures to
FWHMs that accomplishes the following:
1. Puts all three sets of measurements as close as possible to the same
point on the growth curve of the target star measured as a percentage of the
maximum net counts obtained with an aperture that slightly exceeds the
radius needed to reach the second minima inflection point on the horizontal
and vertical line profiles through the centroid of the star;
2. Falls on or near the maximum SNR point on the growth curve of the comp
star;
3. If using ensemble photometry, I will adjust condition in #2 to pick an
aperture that falls near some weighted average of the highest SNR points of
the ensemble stars (usually using a weighting that is the square of the
ratio of each star's best SNR to the best SNR of the "brightest" star, i.e.
the one with the highest overall SNR).
Once I have found these three Aperture to FWHM ratios, I average them and
set the inner apertures for each image in the series at the FWHM (or
weighted average FWHM, in the case of ensemble photometry) times this ratio.
This is faster than making growth curves of each image, but it is still
pretty tedious stuff, and I am not convinced it is rigorous. Does anyone
know a faster, less labor intensive method that is rigorous? I would like to
avoid as much of this drudgery as possible, since I am basically lazy, and I
find it hard to carve out the time to do all of the spreadsheet work this
process takes. On the other hand, the process allows you to achieve
precisions of a few millimag standard deviation even with a 10 inch
telescope as long as you have reasonable consistent skies, even when the
seeing isn't great (e.g. 3.5-5.5 arcsec FWHM).
------------------------------
Message: 3
Date: Thu, 6 Mar 2008 23:07:35 -0000
From: <hudsonjk at astound.net>
Subject: Re: [Aavso-photometry] Aavso-photometry Digest, Vol 52, Issue
6
To: "Kate Davis" <kate at aavso.org>
Cc: aavso-photometry at mira.aavso.org
Message-ID: <001f01c87fde$dde811a0$05f75540 at LittleDevil>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
Kate -
Thanks for the info. I'll know better where to send problems.
"Observations" was obviously not the place! And I probably shouldn't have
used the discussion group to mention it. As I said, it wasn't really much
of a problem, but thanks for fixing it. Now, I'll have to be sure to
observe on Feb. 29, 2012 to check out your fix!!!
I don't know whether it is your project or not, but I think the chart-maker
is a work of art. I like being able to say which way North is, and
prescribe the exact field of view. The web site as a whole is pretty
friendly.
Thanks again,
Jerry Hudson (HJA)
----- Original Message -----
From: "Kate Davis" <kate at aavso.org>
To: <hudsonjk at astound.net>
Cc: <aavso-photometry at mira.aavso.org>
Sent: Thursday, March 06, 2008 9:40 PM
Subject: Re: Aavso-photometry Digest, Vol 52, Issue 6
> Hi Jerry,
>
> If you send an email to aavso at aavso.org your request should be directed to
> the correct staff member. In the case of WebObs' issues, that is me. So
> feel free to email directly as I check that email more frequently than I
> see discussion group messages.
>
> I am sorry for the inconvenience. The Feb. 29 Bug is now fixed. Let me
> know if you have any other questions.
>
> Best,
> Kate
>
>
> aavso-photometry-request at mira.aavso.org wrote:
>>
>> Today's Topics:
>>
>> 1. Feb 29 Bug (hudsonjk at astound.net)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Wed, 5 Mar 2008 22:22:03 -0000
>> From: <hudsonjk at astound.net>
>> Subject: [Aavso-photometry] Feb 29 Bug
>> To: <aavso-photometry at mira.aavso.org>
>> Message-ID: <001501c87f0f$56aa7db0$64dcea42 at LittleDevil>
>> Content-Type: text/plain; charset="Windows-1252"
>>
>> Hi -
>>
>> I just tried to submit some observations via WebObs for CCD obs.
>>
>> I tried entering the dates
>> 2008/02/29/...
>> and also 2008/03/00/...
>>
>> and got error messages. In the first case, the complaint was that
>> February only has 28 days (!), the other wanted me to use a number in
>> range 1..31 for March.
>>
>> Don't know if this is the forum for airing this, so forgive me if it
>> isn't. I tried sending to observations at aavso.org
>> but that obviously isn't the right place.
>>
>> Don't worry about the problem, I was able to use J.D. format to get
>> around the problem.
>>
>> - Jerry Hudson (HJA)
>>
>>
>> ------------------------------
>>
>> _______________________________________________
>> Aavso-photometry mailing list
>> Aavso-photometry at mira.aavso.org
>> http://www.aavso.org/mailman/listinfo/aavso-photometry
>>
>> End of Aavso-photometry Digest, Vol 52, Issue 6
>> ***********************************************
>>
>>
------------------------------
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