[Aavso-photometry] Re: [cvnet-discussion] VV is one lonely Pup!

Fri Feb 11 11:17:17 EST 2005

 What we ask is for a SNV>20. So do what you need to reach that  level
of signal. It can be extra long guided images, stacked images, etc.
Once you have enough for a SNR of 20 then start another round of
observations. I agree that good time resolution will not be possible
with the majority of scopes (but some of our observers do have acccess
to quite large apertures and may be able to do it).
   It is very important that we stick with filters here. Steve Howell
was very specific in his e-mail in how the filters should be used so
he has specific reasons for wanting them.

Aaron

On Fri, 11 Feb 2005 12:51:03 +0200, Berto Monard <lagmonar at csir.co.za> wrote:
> Dear Aaron,
> 
> Recent 'unfiltered' observations show VV pup evolving around 17.5CR. I
> wonder if, at this faint level, any precise timeseries photometry via
> filtered observations can be done by the usual amateur instrumentation.
> 
> But if VV Pup is a polar, it will give a reasonably good signal over
> the unfiltered CCD band while measurements in the different bands will
> likely show a similar light curve.
> 
> At decl -19, VV Pup is very much equatorial, which means that longer
> exposures (more than 30 sec) will produce significant star trailing on
> most of the images with the commercal type telescopes. This will firmly
> reduce the magnitude reach in filtered photometry.
> 
> If someone were (in addition to unfiltered runs, produced by others
> perhaps) to make (by means of stackings) 'deep' snapshot observations in
> the different filters, the overall information can still be had. From
> past experience I am not a strong believer in the quality of timeseries
> derived from stacked images...
> 
> I hope that Arne (in his capacity as expert astro-photometrist) has
> comments on all this.
> 
> Good luck with the campaign. I will definitely apply a dense coverage
> with snapshot observations, probably even with filters, weather
> allowing.
> 
> Regards,
> 
> Berto Monard / #MLF
> 
> Bronberg Observatory / CBA Pretoria
> 
> >>> aaronp at onceler.org 10/02/2005 21:47:56 >>>
> 
>  Hey all. We really need CCD observations of VV Pup during the next
> week. If you can observe it please make it your #1 priority target. We
> have no recent data at all. Below is a copy/paste from the recent
> announcement in CCD Views #330:
> 
> http://www.aavso.org/publications/ccdviews/330.shtml
> 
> ---------------------------------------------------------------------------
> 3. VV PUP CAMPAIGN IN SUPPORT OF KECK OBSERVATIONS
> Dr. Steve Howell, WIYN Observatory & NOAO, has requested observations
> of the polar VV Pup to coincide with observations being done at the
> Keck Observatory on February 16, 2005 (UT). Time series observations
> for as long as possible in BVRI are requested from 00:00 UT February
> 15 - 23:00 UT February 17, 2005. VV Pup is quite faint and also near
> the quarter Moon during the observing window. So we recommend the
> following observing plan:
> 
> 1) Observe it in one filter instead of alternating between filters.
> Set your exposure time to get an SNR > 20. You may need to stack
> images to reach this SNR.
> 
> 2) Small and moderately sized telescopes should observe in Ic first
> and in Rc if you don't have an Ic filter or someone else is currently
> observing in Ic. This will lessen some of the effects of the Moon and
> also lower exposure time (this is a field with heavy extinction).
> Those with larger apertures should go for V and B photometry.
> 
> 3) Post to the aavso-photometry discussion group and tell us what
> filter you are using and the expected start and end time of your
> observation run. This way someone else can use a different filter if
> they are observing at the same time.
> 
> We currently have very few observations of VV Pup. So baseline
> observations prior to and immediately after the observing campaign
> would be very useful.
> 
> The AAVSO Chat Room will be open for this event! Join us during the
> campaign at http://www.aavso.org/aavso/chat.shtml .
> 
> The VV Pup chart is here:
> http://www.aavso.org/cgi-bin/searchcharts3.pl?name=vv%20pup
> 
> Our observations of VV Pup are minuscule!! We desperately need some
> photometry. Our latest observations of VV Pup:
> VV PUP JAN 01.4960 <15.3 SRX Visual
> VV PUP DEC 31.8280 17.2 CCD MLF Unfiltered
> VV PUP DEC 28.4424 16.305 CCDI CTX ERR: .03
> VV PUP DEC 23.4785 18.38 CCDV CTX ERR: .027
> SRX - Rod Stubbing, Australia
> CTX - Tim Crawford, Oregon, USA
> MLF - Berto Monard, South Africa
> -------------------------------------------------------------------------
> Aaron
> 
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-- 
Aaron