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THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
25 Birch Street, Cambridge, MA 02138 USA
Tel. 617-354-0484 Fax 617-354-0665
http://www.aavso.org
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C C D V I E W S
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June, 2001 Vol 2 No 1
Table of Contents
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1. Introduction to the New CCD Views
2. Rare Superoutburst of AL COM
3. SU UMa Campaign
4. Rare GU Sgr Fading
5. Comments on Faint LPVs by J.A.M
6. Recently Published CCD Charts
7. Appulse Data
8. Extrasolar Planetary Transit Monitoring of IL AQR
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1. INTRODUCTION TO THE NEW CCD VIEWS
This is the first issue of a new electronic edition of CCD Views.
This newsletter is published by AAVSO Technical Staff (Aaron Price) and
the AAVSO CCD Committtee Chair (Gary Walker) for variable star
observers with an interest in CCD observing. Both Aaron and Gary are
avid CCD variable star observers. Our goal is to support your observing
program with lists of new targets, new observing program ideas, summary
of recent activity of faint variables, and the publication of other
issues important to CCD observing. I will add comments on stars (mostly
LPVs) and other news from time to time. We want to provide the initial
ideas for observing programs.
CCD Views will be published bimonthly and as needed. It will be
distributed primarily via e-mail and will be archived on our WWW site.
To receive CCD Views send a message to majordomo.at.aavso.org with
"subscribe ccdviews" in the body of the e-mail.
This is a new format for CCD Views so we anticipate some tweaking
and minor changes over the first few issues. Newsletters like this
normally do not hit their stride for a few months, so please bear with
us. We are eager to receive any feedback about what you may like, don't
like, and what you would like to see in future editions. Please send
your comments to ccdviews.at.aavso.org.
Thank you and we hope you find this new publication useful and
informative!
Good observing!
Janet Mattei (JAM)
Director
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2. RARE SUPEROUTBURST OF AL COM
The SU Ursae Majoris-type dwarf nova AL Comae Berenices is
undergoing a rare superoutburst. CCD observers are urged to search for
superhumps (small-amplitude periodic oscillations), making observations
every 5 minutes for as long as possible during the night and recording
the time to four decimal places while this star is in superoutburst.
Please use an I filter if you have one, otherwise use V filter. For
more information consult AAVSO Alert Notice #283 at the URL below:
http://www.aavso.org/alerts/alert283/alert283text.stm
This star has a very interesting behavior and superhumps during
superoutburst. We had excellent CCD coverage during its 1995
superoutburst and we published the results in a collaborative paper
(Howell et al 1996, Astr. Journal,.. ). We would like to do it again
with this superoutburst if we have enough coverage.
Please submit your observations to the AAVSO as soon as possible
so that we can began working with the data and coordinate further
observations.
Here is an example of good photometry in I by Doug West:
MAY 25.1167 2452054.6168 13.50 WJD CCDI
MAY 25.1203 2452054.6204 13.82 WJD CCDI
MAY 25.1214 2452054.6214 13.63 WJD CCDI
MAY 25.1277 2452054.6278 13.62 WJD CCDI
MAY 25.1313 2452054.6313 13.51 WJD CCDI
MAY 25.1345 2452054.6346 13.51 WJD CCDI
MAY 25.1381 2452054.6382 13.50 WJD CCDI
MAY 25.1419 2452054.6419 13.55 WJD CCDI
MAY 25.1455 2452054.6455 13.42 WJD CCDI
MAY 25.1491 2452054.6492 13.61 WJD CCDI
MAY 25.1510 2452054.6511 13.55 WJD CCDI
MAY 25.1548 2452054.6548 13.53 WJD CCDI
MAY 25.1584 2452054.6584 13.36 WJD CCDI
MAY 25.1620 2452054.6621 13.52 WJD CCDI
MAY 25.1656 2452054.6657 13.34 WJD CCDI
Here are some recent observations of AL COM:
MAY 30.1882 2452059.6882 13.8 SXN Y
MAY 30.7354 2452060.2354 13.7: BTH M
MAY 30.9325 2452060.4326 13.9 JCN K
MAY 30.9402 2452060.4402 14.04 SMI CCD
MAY 30.9459 2452060.446 13.7 MGH KY
MAY 31.9375 2452061.4375 13.9 JCN K
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3. SU UMA CAMPAIGN
Please remember to monitor SU UMa closely through the end of the
month. A colleague from The University of Leicester has been awarded
time on RXTE to observe the dwarf nova SU UMa regularly through
June. Please keep a close eye on this star and report your observations
regularly to the AAVSO as our colleague is checking the Quick Look File
often. We are also periodically sending him data files so that he can
correlate his x-ray data with the optical data. Please use the SU UMA
visual charts to make your estimates.
SU UMa belongs to a subclass of dwarf novae which has frequent,
faint, and narrow outbursts along with infrequent, long, and bright
superoutbursts. Superhumps appear during such outbursts at periods of
2%-3% of the orbital period. In fact, these superhumps are important
because scientists often use them to determine the orbital period of
the system.
For more information read "Outburst Characteristics in the Dwarf
Nova SU Ursae Majoris" by P. Rosenzweig, et. al. in P.A.S.P Volume 112,
Issue 771, pp. 632-641. The abstract is available via ADS at:
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000PASP..112..632R&db_key=AST&high=39ad50824503046
(URL should be on one line)
SU UMA was featured as the February 2000 Variable Star of the
Month available at http://www.aavso.org/vstar/vsotm/0200.stm .
In addition, SU UMa recently underwent another outburst as
reported in News Flash #791 with the following observations:
UT Mag. Initials UT Mag. Initials
MAY 29.9380 14.2 PYG MAY 30.9270 11.8 GUN
MAY 30.1430 <13.9 SXN MAY 30.9485 12.2 RMQ
MAY 30.8950 <13.4 GUN MAY 30.9687 12.08 CCD SMI
MAY 30.9270 11.8 GUN MAY 31.2784 11.9: LMK
This campaign was originally reported in News Flash #772.
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4. RARE GU SGR FADING
As originally reported in IAU Circular #7619, GU SGR (1818-24), a
R CrB star which doesn't fade often, is beginning to fade quickly after
being at maximum light for about 8 years. As of the end of May the star
has faded from 10.4 to 16.6. During the last minimum in 1988 it reached
mag 16.4.
Thanks to the following observers for notifying us of this fading
via their observations:
S. Otero, Buenos Aires, Argentina
S. O'Connor, Montreal North, QC
R. Stubbings, Druin, Victoria, Australia
A. Pearce, Nedlands, W. Australia
Recent observation of GU SGR:
MAY 20.2938 16.6 OCN CCDV
MAY 20.3014 <15.7 OCN CCDR
MAY 22.6480 <14.6 PEX
MAY 26.8580 <14.6 PEX
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5. COMMENTS ON FAINT LPV'S BY J.A.M.
Below is a list of mostly faint LPVs that may be of interest to
CCD observers next month. This list combines elements of the AAVSO
Bulletin, Quick Look files, and long term data. Stars listed are
generally faint and either in need of more observations or show some
strange behavior that needs to be studied. We realize that many of
these objects have charts that need improvement. Please continue to use
these charts until we are able to release new ones. It is important for
these long term variables that new charts and comparison stars are not
issued haphazardly.
0045+33 RR AND <9.1-15.1>
Minima need to be better monitored to determine behavior and to
predict future minima. Use AAVSO f scale chart and comp stars.
0159+12 S ARI <10.9-15.2>
Cycles in 2000 and 2001 are not well monitored. Go for
early morning coverage to reduce the seasonal gap.
0212+81 Z CEP <10.8-15.4>
Although circumpolar, large gaps exist around minima. Next
predicted minima is June 18.
0242+37 AI PER 11.0-15.5
Large gaps exist in the light curve, particularly around minima.
CCD charts with B-V and V-R values are available on the AAVSO FTP
site.
0452+56 TX CAM 8.1-(15.3
Another northern polar very poorly monitored in 2000.
0513-16 X LEP 8.8-15.6
Needs predawn observations as it is fading to minimum.
0728-20B Z PUP <8.1-14.5>
Very poorly monitored in 2000. Presently fading to a minimumin
July.
1353-04 SY VIR
Maxima in 2000 was about 1 magnitude fainter at 10.5. Minima
poorly observed. Use AAVSO e-scale chart that has well measured
and faint comp stars.
1405-12A Z VIR
Needs more data around the minimum and on the ascendancy branch
of the light curve. Use e-scale standard chart.
1853+16 EU AQL
In need of more observations throughout the entire light curve.
Use e-scale chart even though it may need a better comp star sequence.
1855-12A ST SGR
Very poorly monitored around minimum. Go for it now. Predicted minima
is July 5. Use f-scale preliminary chart to make the estimate. An
e-scale standard chart is available for finding the field.
1906+43 ST LYR
For several years it has been poorly observed near minima making
predictions very difficult.
1909+31 EL LYR
Needs more observations around minima on June 13. The e-scale preliminary
chart unfortunately is inadequate for it needs fainter magnitudes, do the
best you can.
1922+01 TU AQL
Needs more observations near minima in order to determine the true
minima brightness. Beware of close by magnitude 11 star. Use e-scale
preliminary chart.
2003+57 S CYG
Needs positive observations around minima. Use e-scale standard chart.
2008-22 W CAP
Badly in need of more observations, particularly around minima
predicted for June 26.
2011-39 RT SGR
Very badly in need of observations at all phases of its light curve.
CCD observers may be able to get positive observations better than
visual using the poor sequence on our d-scale chart. Go for it.
2012+09 RU DEL
Needs more positive observations around minima.
2022-40 U MIC
The star is in desperate need of more observations at all phases. Only a
few observatiosn exist since 1999. Presently it is fading to minimum
predicted for August 7.
2042-15 U CAP
Another LPV in desperate need of observations at all phases. Has a
good e-scale standard chart.
2056-27 RR CAP
Needs more observations around minima, predicted for early July.
This is only meant as a guide and should not be considered a
comprehensive list of LPV CCD targets. Please let us know whether you
find this list useful by sending comments to ccdviews@aavso.org.
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6. RECENTLY PUBLISHED CCD CHARTS
Please remember that over 40 new CCD charts were released in
January on the AAVSO FTP site. Of these 40, 19 are Miras, 10 are CVs
and the rest belong to a wide variety of types. This brings the total
number of CCD charts to above 70. We expect to be releasing many more
in the next month or so. All of these charts are available at the URL
below:
[URL REMOVED -- see http://www.aavso.org/vsp for modern charts]
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7. APPULSE OBSERVATION EXPERIMENT
An "appulse" is the near approach of one heavenly body to another.
We would like to conduct an informal experiment to observe CVs close to
the full Moon. These are CVs that cannot be observed by visual
observers because of lunar interference.
Below is a list of five CVs that will be around 20 degrees from the
full Moon on June 6. Please observe these stars, at least once per
night, on every possible night between June 2 and June 10 UT inclusive.
There may be a large background gradient or glints in the CCD field; do
your best to get good photometry. We are only asking for observations
at the 0.1mag level of accuracy; anything more precise will be
difficult because of such sky gradients and the probable faintness of
the CVs. If at all possible, use an R or an I filter to decrease the
scattered moonlight. For any filter, go ahead and report your data
based on the chart magnitudes, but indicate what filter was used.
Designation Name Distance(deg) Range(1)
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1542-42 AB NOR 26.2 13.9p-<19.0j
1633+08 V544 HER 29.6 14.5p-20p
1751-14 MU SER 16.1 7.7v-<21p
1805-14 UZ SER 19.2 11.9v-16.0v
Please report your results and comments to ccdviews@aavso.org,
even if you catch a CV in outburst. This e-mail address will be checked
many times per day so such an outburst will make it into the News
Flash. These can be informal reports and do not need to be in the
official AAVSO format. If we find that it is possible to perform .1 mag
level photometry this close to the full Moon then every month we will
publish a list of CVs to observe for the 4 days prior to and after the
full moon.
Charts for these stars are available on the AAVSO Variable
Star Chart CDROM or at http://charts.aavso.org.
(1) From "A Catalog and Atlas of Cataclysmic Variables" by Ronald
Downes, et. al. available at http://icarus.stsci.edu/~downes/cvcat/
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8. EXTRASOLAR PLANETARY TRANSIT MONITORING OF IL AQR
In June, 2 windows of opportunity exist for the possible detection
of planetary transits around IL AQR. 5 minute integrations should be
made during the observing windows. Transits could last 2-4 hours and
could dim the star by as little as a few hundredths to a few tenths of
a magnitude.
Planet Predicted Transit Time(UT) Full Window
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Gliese 876b 2452079.97 (11:17 June 19) Jun. 14-26
Gliese 876c 2452080.9 (09:36 June 20) Jun. 14-26
The position of IL AQR/Gliese 876 is:
R.A. = 22h 53m 16.7s Decl. = -14 degrees 15' 49" (2000)
For much more detail about this possible event consult AAVSO Alert
Notices #281 & #282 at the URLs below:
http://www.aavso.org/alerts/alert281/alert281text.stm
http://www.aavso.org/alerts/alert282/alert282text.stm
CNN & Wired.com also covered this subject at these URLs:
http://www.cnn.com/2001/TECH/space/05/22/planet.search/index.html
http://www.wired.com/news/print/0,1294,43865,00.html
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CCD Views is published bimonthly and when circumstances warrant
via e-mail. An archive is available at http://www.aavso.org/ccdviews/ .
Please send comments and suggestions to aaronp.at.aavso.org.
To receive CCD Views via e-mail send a message to
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The AAVSO has many free online publications including "Eyepiece
Views", a similar newsletter intended for visual observers. To learn
more and subscribe visit: http://www.aavso.org/mailinglists.stm
Good observing!
Aaron Price, AAVSO Technical Assistant (PAH)
Gary Walker, Chairman of the AAVSO CCD Committee (WGR)
Copyright 2001, American Association of Variable Star Observers
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THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
25 Birch Street, Cambridge, MA 02138 USA
Tel. 617-354-0484 Fax 617-354-0665
http://www.aavso.org
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