[Aavso-photometry] AE Aqr

[Michel Bonnardeau]

I observed too AE Aqr with a 20cm telescope, B and V filters,
and a BVBV... sequence.
But my exposures were only 200s with the B filter and 60s with the V.
This gives a fairly good SNR and allows the observation of
nice ~30mn flares.

To compute B-V, I transform with coefficients I measured from
a Landolt field and I also interpolate, my B and V measurements being
done alternatively and not simultaneously. The results are here:
http://mbond.free.fr

So, I observed B-V around 0.7 but it can jump to 0.3 during a flare.

Also, next to AE Aqr, there is a suspected eclipsing star, HX Aqr.
I observed no variation and Sebastian on his web site writes it is probably
constant. May be the good coverage for AE Aqr could be used to
firmly establish it as such?

Michel (BZU).

----- Original Message -----
From: "Tomas L. Gomez" <tomas.l.gomez at gmail.com>
To: <Aavso-photometry at mira.aavso.org>
Sent: Friday, September 02, 2005 12:03 PM
Subject: [Aavso-photometry] AE Aqr


> On the night Aug 31/Sep 1, I made a 4 hour time series observation of
> AE Aqr, with B filter (as well as V filter, to be able to transform to
> the standard system). I will send the observations as soon as I reduce
> them.
>
> Tonight (Sep 2/3) I am planning to do another times, but I have a
question:
> To get the data transformed to the standard system, I use the usual
formula:
>
> B = b + T (b-v)
>
> where b and v are the instrumental magnitudes, and T is the transformation
> coefficient. Therefore, I need to get data also with the V filter, but
> then I will loose time resolution. I guess that the standard way to do
> this is  to take
> frames following the sequence
>
> B V B V B .....
>
> and then calcultate the b-v color index for each B-frame by interpolation.
> To get better time resolution,  last night I took the frames using the
following
> sequence:
>
> V B B B V B B B V B B B  ...
>
> i.e., I took one picture with V for every three pictures with B. Then
> I calculate the
> color index b-v for each B-frame by interpolation. Is this OK?, or is it
better
> to use the sequence B V B V B .... to get a more precise interpolation of
> the color index?.  Or is it better to take frames only with the B filter,
and
> report the instrumental b magnitude?
>
> The aperture of my telescope is only 20 cm, so to get a good SNR I need to
give
> exposures of 20 min for B and 10 min for V.
>
> -Tomas L. Gomez (GOT)
>   Madrid, Spain
>
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