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Variable stars close to deep sky objects

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As a follow up a prevoius thread on the [AAVSO-DIS] list I'll regularly list some interesting variable stars can be found close to deep sky objects.

Recently I started to create a spreadsheet for my planned article "When the visitors come..." in our mountly Meteor. In this preadsheet I list the expected maximum brightness of possible type Ia supernovae in nearby galaxies.

My recent take is: CV Vir. This is a nice mira just 5' from the M87 galaxy, with an amplitude 12.5 - <14.6v and a quite short period: 149.3 days according to VSX. I recommend a chart "e" printed with DSS images via VSP.

One month ago Thom Gandet wrote me "FH Sct is in M26, a very nice looking but small open
cluster.  It may be too far south for yourlocation.  FH Sct is not very active, but I really like looking at the cluster anyway!" -
FH Sct is an RCB star with an apmlitude 13.4-13.8p. Chart "e" is recommended.

(To be continued...)

Clear skies,

Robert Fidrich (FRF)

thanx
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Thanx for the staff for the fast correcting of my typo in the title of the topic!

SN 2012cw in NGC 3166 + a drawf nova and an EW: variable
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SN 2012cw, a 16.3 mag type-Ic supernova, has been recently announced in CBET 3148:
http://www.cbat.eps.harvard.edu/iau/cbet/003100/CBET003148.txt

The host galaxy NGC 3166 is a 11.3 magnitudes bright galaxy in Sextant.  There is another bright galaxy NGC 3169 in the field (just 7.5' from NGC 3166), and a fainter one, NGC 3165 too (just 4.5' from NGC 3116). In NGC 3169 two supernovae has been already visible (SN 2002cg at 14.4 mag and SN 1984E at 15.0 mag).

In 2009 the CSS team discovered a bright dwarf nova just 30' east from NGC 3166: CSS 090429:101546+033312. The maximum brightness of this dwarf nova can be 15.23CV, the amplitude is 4.85 mag - according to VSX.

For those who like eclipsing variables I can recommend ASAS J101420+0309.9, an EW: star with an amplitude 12.87 - 13.22V, period 0.320376 days. According to the remarks of Sebastian Otero in VSX: "Light curve and period changes. Spotted EW or DSCT?"
Worth to make time series for this star while imaging SN 2012cw. 

Clear skies,

Robert Fidrich (FRF)

WW Vul (UXOR type variable)
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WW Vul (UXOR type variable) is not only close to the Coathanger (Brocchi's cluster), but also close to the nice small cluster NGC 6802.

AN Dra (a forgotten MIRA) is close to NGC 6340.

Maybe we can make an online list of variable stars close to deepsky? I still think this can help convince deepsky observers to look (or even estimate) a variable star...

re: online list
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Yes, I'm considering to put my list online when I've finished -- if it can be finished ever... :O

Until then I'm gonna introduce some interesting object here from time to time.

* * *

I've 'discovered' NGC 6802 last year when comet Garradd passed the Coathanger. It was clearly visible on my photos too. With a 25cm Dobsonian it was not too bright from Budapest, but from countryside it can be an interesting target too.

Thanx for mentioning AN Dra here to. I'll check her during the summer...

Variable Stars Near Deep-Sky Objects
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Perhaps I missed something, but I saw no mention of: R and S Sco near M80; AL Com near M88; several M supergiants in or near NGC 869&884; and numerous irregular variables in or near the Orion Nebula. The 2009 nova KT Eri has two dim but distinct galaxies near it. If you count active galaxy nuclei as stars, some (e.g. 3C 66A) are seen among nearer but still dim galaxies. 

Since this is not a full,
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Since this is not a full, complete list, no wonder R Sco and Sco was not mentioned yet. Althoug they are included in my list, but not mentioned them in my post on [AAVSO-DIS]. On the other hand AL Com was mentined there.But ot least we can leave space for others to mention further intersting deep skye/variable targets.

vs near deep sky objects cont.
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V778 Cyg is a little-studied Carbon star in the extreme north of Cygnus.  It is near the galaxy NGC6946 (which is so extended, it's half in Cygnus and half in Cepheus!) I actually observed V778 tonight (Sun-Mon 24-25 June) and saw a bright star near the galaxy, which was invisible (It's very diffuse) - what? Not a supernova surely! Because NGC6946 is quite productive of SNs.

Not far away is an open cluster, NGC6939.

 

Staying in the Summer milky way, I used to observe W Vul and remember that it's in a neat and bright little open cluster.

V778 Cyg
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[just typo corrected today]

Yes indeed, V778 Cyg was on my list posted on  [AAVSO-DIS] in may. As I can recall first I've learns about V778 Cyg was when a chart of this star with the sketch of NGC6946 was published in on of the BAA/VSS Circulars - it was probably in the 80's.

"I actually observed V778 tonight (Sun-Mon 24-25 June) and saw a bright star near the galaxy, which was invisible (It's very diffuse) - what? Not a supernova surely!"

Sorry, but it's not clear for me. Have you seen a new star - SN or a nova - or just 'discovered' V778 Cyg tonight?

Actually I regularly make DSLR images of the field V778 Cyg. On the next clear night I'll make a new one of this field too.

Variable Stars near Deep Sky Objects
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Actually in 2004, before APASS, I was motivated to find foreground Mira stars near southern globular clusters. Most globulars have well constructed calibration V sequences which , I thought, could be used to observe these neglected Mira stars. Not all sequences could be used , as no suitable Mira stars lay nearby, but a short list of stars, for which I prepared charts, is given here. TV Ara NGC 6208 V639 Ara NGC 6397 V720 Oph M107 SS, SU Lup NGC 5986 RZ Mus NGC 4833 FI Hya M68 This is really doing things in reverse - knowing a sequence exists, then looking and hoping that a suitable Mira star lies nearby. Of course, the list is far from complete. The listed stars are only few examples that I deemed capable of being observed visually. Other types of variables were ignored.

UV Per, TZ Per, S Per and the khi/h Persei double-cluster
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Since John Bortle recently mentioned the rare outburst of UV Per, this is the time to write about some variables close to the famous Double Cluster (khi and h Persei).

UV Per is a nice dwarf nova, just 1.2 degrees west from the Double Cluster. Although it is a circumpolar object, there are almost now observations made during the last two month :( At least because of the ongoing outburst she deserves some more attention.

TZ Per is one of the target of the ZCAMpaign, located 1.4 degrees NW from the Double cluster. More observations needed.

S Per is a nice SRC variable, 1.4 degrees north from the Double Cluster. It seems she usually lacks observations in the April-June periods, despite being circumpolar object too.

For binocular observers there are plenty other bright LPVs in/near the double cluster: T Per, SU Per, AD Per, BU Per, FZ Per, KK Per, PP Per, PR Per too.
 

DY Per and Trumpler 2 cluster
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Since I mentioned the Duble Cluster and some under observed circumpolar variables in Perseus, it is worth to call the attention to DY Per. This RCB variable is a prototype of a subclass of RCB variables. DY Per is lies just 18' NW from the beautiful open cluster Trumpler 2. The  brighness of DY Per changes in the range of 10.6-16.0v.

Clear skies,

Robert Fidrich (FRF)

M13 and M57
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Mike Simonsen in the past may have mentioned Mira W HER being with a degree or two of M13 in Hercules and Mira RX LYR being close to M57.  If not, I will.  Another reason to observe Miras !!!  Kevin - PKV

M57 and FF Lyr
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There is another mira near M57: FF Lyr (only 24' distance). Unfortunately there is no sequence for this star in VSP, but some old chart (based of AAVSO sequence from 1978) can be downloaded from the AFOEV site:

http://cdsarc.u-strasbg.fr/afoev/cartes/cartes/Lyr/lyrff-d.gif

and http://cdsarc.u-strasbg.fr/afoev/cartes/cartes/Lyr/lyrff-c.gif

I hope with the next release of APASS we'll be able to produce uptodate sequence for FF Lyr.

FF Lyr Chart
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I have an old AAVSO f-scale chart for FF Lyrae, dated 6/84 that I use (see attached).

re: FF Lyr chart
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Thanks, Walter! It seems this is the same sequence as it was used for the AFOEV chart.

NGC 404 + FN And, CY Lyr + the "Necklace" asterizm
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Since Andromeda is rising on the morning sky it is worth to observe NGC 404 (Mirach's ghost), a bright galaxy next to beta And and the dwarf nova FN And just 40' SE from the gx. FN And is an UGSS type dwarf nova with a range 12.9-19.3V.

Another interesting dwarf nova is CY Lyr, wich lies in an asterizm described an "Necklace with a Gem" by Gerry Dick in his article published in the Sky and Telescope somewhere in the 1980's. CY Lyr varies between 13.2-17.0p and produces an outburst mostly every 2dn week.

IC4665 and V380 Oph
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The campaign to monitoring of V380 Oph in support of HST observations has been recently announced in AAVSO Alert Notice 466. This variable lies around 1 degrees NE from the bright open cluster IC 4665. Nice target for those who like open clusters!

Vend44 (VSX J003518.1+404547) and M31
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One of our recently discovered new variable Vend44 (VSX J003518.1+404547) , and EA/RS star can be found ~1.5 degrees from the center of M31.

http://www.flickr.com/photos/26731206@N05/8032026057/sizes/l/in/photostr...

and

http://www.flickr.com/photos/26731206@N05/8032028439/sizes/l/in/photostr...

The next predicted eclipse of Vend44 can be observed (in Europe) around 23.35 UT on 1/2 October 2012.

Clear skies,

Róbert Fidrich (FRF)

CP Dra
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The Dwarf Nova CP Dra lies in the same 30' field as NGC 3147, which I believe has had at least three type 1a Supernovae detected (maybe more?).  I always make a visual check for SNe whenever I visit CP Dra.

Gary

PYG

Nova Cep 2013 and NGC 7510, IC 1470 and other nebulae
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The recently discovered Nova Cep 2013 (
PNV J23080471+6046521) lies only 25' distance to the open cluster NGC 7510 and only 38' to the diffuse nebula IC 1470. Another nebula NGC 7838 can be found only 59' from the nova. The famous Bubble nebula (NGC 7635) is located around 1.6 degrees distance from the nova. DSLR observers with larger FOV can hopefully image the open cluster M52 too while observing the nova, since it is around 2.6 degrees distance.

Other interesting variables in the surroundings of the nova:

- QT Cep: a mira star with period of 460 days, 6' from IC 1470;

- OQ Cep: an SR variable 14' to NGC 7510;

- V563 Cas: a mira star 44' to NGC 7510.

Clear skies,

Róbert Fidrich (FRF)

Nova Cep 2013 and NGC 7510 photo
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Nova Cep 2013 and the open cluster NGC 7510.
03/04 February 2013, Pesterzsébet, Budapest, Hungary.

http://www.flickr.com/photos/26731206@N05/8443071713/

Canon EOS 1000D, 300mm (zoom) telephoto lens, 12x30 stacked images, G channel.


The brightness of Nova Cep 2013 was around 11.5TG.

re: UV Per, TZ Per, S Per and the khi/h Persei double-cluster
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Some of these stars are visible on my DSLR image:

http://www.flickr.com/photos/26731206@N05/8454033747/in/photostream

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