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PQ And in very rare outburst

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PQ And in very rare outburst

I just sent out a BAA email alert on this important and rare event:

The dwarf nova PQ And has been reported to be in outburst at mag 10.5 on May 28.776 by Kenji Hirosawa (Aichi, Japan). This means that it is some 9 magnitudes above its usual quiescence of 19.5.

PQ And has only been seen in outburst once before when Dave McAdam discovered it as Nova And 1988. So this is its first appearance for 32 years.

Gary Poyner managed to catch PQ And in the dawn sky this morning: May 29.088 at a visual mag of 10.5 using a 22cm Dobsonian on a wobbly table. Eddy Muyllaert of Belgium also observed it visually this morning at mag 10.3, May 29.080.

All observations of this rare outburst are urgently required, both visual and CCD. Time resolved CCD photometry would also be very helpful. It’s of course tricky to observed given the location in the dawn sky.

Dwarf novae are compact binary stars and as they evolve their orbital period gets shorter until it reaches a minimum around 75 to 80 minutes. The orbital period of PQ And is 80.6 mins. There is some speculation that this might be a rare example of a “period bouncer” in which the system has evolved through the minimum and is increasing.

PQ And is located in Andromeda at RA 02 29 29.55 Dec +40 02 40.0 (J2000.0). A finder chart is available from the AAVSO website. Do try to observe this very rare event. At 10th mag it is visible in a small telescope You might have to wait 32 years for the next one!

Jeremy Shears

Director, BAA Variable Star Section

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PQ And at last

I've never waited 32 years to see a star for the second time before - but it was worth the wait.  On 1988 March 28 I made my first observation of PQ And, detected by my fellow BAAVSS observer and friend Dave McAdam a week before.  Tried from the BAA Winchester weekend at Kings Alfred's college without luck on the 26 & 27, although the skies were very clear - no scopes about!  My mag on the 28th was 11.6.  By April 13 it had faded to mag 13.0 when I lost it in the NW evening sky. 

Three decades later and here I am at 3am in the morning, balancing my trusty old 22cm dobby on a garden table, peering over the hedge to pick out this 10th mag dot low in the NE sky, and hoping the local cat doesn't jump up, knock everything over and wake up the neighbours - and worse, my wife!!!  I have to admit I was beginning to wonder if I'd ever see it again, yet there it was.   Couldn't sleep when I eventually got to bed - too excited.   VS are brilliant things to observe.

Gary

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Dave McAdam

I remember Dave from the old TA days. A great guy. I chased up a few of his suspects back in the late 80s. I remember discussing the TA/VSS computer archive with him when computers weren't quite what they are today.

I'll have a go at getting some images from here tomorrow morning but it will have to wait until the sky is quite bright.

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Exciting!

How long will is likely remain mag 10 for? 

James

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PQ And

Hi James,

Well we only have the historic outburst to go on, which wasn't that well covered.  However looking at the light curve it faded by a magnitude in just 5 days or so, and then two weeks to lose a further magnitude.

UGWZ type stars (if it is indeed one of these) can do wonderful things once they have faded - like re-outbursting a number of times after the primary outburst.   They don't do this every time though, just to keep us on our toes.  

It's going to be very frustrating due to it's poorly placed position, but must remain hopeful that someone will get some good photometry and or spectroscopy during this outburst - but I'm not holding my breath.

Gary

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spectroscopy

A tough one. I've put out an alert on the main spectroscopy forums. It is (just) circumpolar for me and I although I do have a decent (though currently bright)  horizon directly north, I lose it behind a tree as it climbs in the dawn sky

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Maybe a saw, Robin?

Maybe a saw, Robin?

Good luck, though. It would be great to get some spectroscopy.

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DSLR

Gary / Jeremy, I’ve never made a meaningful observation of anything the VSS is interested in. What sort of settings would you recommend For a DSLR at prime focus? I think the FoV will be too wide with my 80mm refractor  so May have to jump right up and use my C11 and Canon 6D. I think I can get to a site with a low northerly horizon that isn’t too light polluted; but 3am though, whose idea was that?!?!?! :)

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DSLR

James, it’s difficult to say as it’s so dependent on your specific set-up, plus we have a brightening sky to contend with. If we are going to extract photometry from images, the star and its comparisons should not be saturated. This will result in shorter exposures than you might normally consider to get a “pretty picture” (but a pretty picture would also be nice as this is such a rare event!). Thus it’s best is to bracket with a range of exposures. Also avoid saving as a file type that compresses the image, like jpg, as that will involve loss of data.

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pretty picture

The first pretty picture I see I'll put on front of VSS web page.   I've just put the 1988 light curve on there too.

Gary

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Thwarted again

Pity it didn't occur later  in the year, I live in a valley and have a big hill covered with trees and houses when it clears the hill!!

I hope there will be a report on this later

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Response

No chance of me observing it yet, put I've put out a call for help. Let's see what happens, if anything.

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TA e-circular 137

I'm sure Guy won't mind me posting this here. This is from my archive as downloaded using a 1200 baud modem...

THE ASTRONOMER Electronic Circular No 137 1988 Mar 24 19.04UT.

Telecom Gold 72:MAG60138
Ed:Guy M Hurst, 16, Westminster Close, Kempshott Rise, Basingstoke,
Hants, RG22 4PP, England. Telephone:(0256)471074.Int:+44256471074
Telex:265871(MONREF G) Quote"72:MAG60138 ATT G.HURST"in FIRST line.
-------------------------------------------------------------------
VARIABLE OBJECT IN AND= Q1988/18
D.McAdam, Telford, reports his discovery of a variable object in
And. The stellar object, of mag approx 10.5pv is present on two
photos taken on 1988 Mar 21 at 21.36UT and 21.55UT for the UK
Nova/Supernova Patrol. The position is:
RA 02h26.5m DEC +39 50'(1950)
The object was not present on photos of Jan 22 and to date no
variable or asteroid candidate has been found.
Observers with a clear sky tonight are urgently requested to check
the field and report their findings by e-mail using 'EXPRESS'.
Guy M Hurst

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And TAEC 138

THE ASTRONOMER Electronic Circular No 138 1988 Mar 26 14.32UT.
Telecom Gold 72:MAG60138
Ed:Guy M Hurst, 16, Westminster Close, Kempshott Rise, Basingstoke,
Hants, RG22 4PP, England. Telephone:(0256)471074.Int:+44256471074
Telex:265871(MONREF G) Quote"72:MAG60138 ATT G.HURST"in FIRST line.
-------------------------------------------------------------------
TAV0226+39 = VAR OBJ IN AND
M.Mobberley and G.Hurst report confirmation of the new object
announced on E137. Available magnitude estimates (some re-reduced):
1988 Feb 12.802UT,(11.5pv M.Mobberley 85mmFL f2 Tri-X
Mar 15.835UT,( 9.0pv N.James 55mmFL
1988 Mar 21.900UT, 10.0pv D.McAdam 305mmFL f4 K2415
21.913UT, 10.0pv D.McAdam 305mmFL f4 K2415
25.844UT, 10.8pv M.Mobberley 0.36-m f5 refl. Tri-X
25.844UT, 10.6v G.Hurst 0.44-m refl.
N.James, Chelmsford, reports the object is not present on patrol
photos with the following limiting magnitudes:
1986 Dec 6, 10; 1987 Feb 20, 10; Oct 17, 11; Nov 14, 11;
1988 Jan 20, 11; Feb 12, 11.
G.Hurst reports a revised position from analysis of the discovery
photos:
RA 02h26.3m DEC +39 50'(1950)
There is no candidate on Atlas Stellarum to an approx limiting
magnitude of 13.8B. (1969 Aug 9).
Preliminary sequence:
Comp RA(1950) DEC(1950) mv Source
A 02 27.6 +39 57 6.8 CSI
B 02 26.3 +39 47 8.7 M34 Transfer
C 02 25.7 +39 39 9.3 do.
D 02 25.9 +39 39 10.2 do.
E 02 25.6 +39 43 10.6 do.
F 02 26.2 +39 47 10.8 do.
G 02 26.3 +39 49 11.2 do.
The discovery has been communicated to the Central Bureau by telex
and as yet, no independent results have been announced.
Guy M Hurst

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Not a pretty picture

Here it is in the spectrograph guider a few minutes ago (at 5 deg altitude !)

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And the spectrum

And the spectrum against the bright sunlight, strong telluric lines and auroral and atmospheric sodium emission lines.

Note how the spectrum curves down towards the blue end due to the strong atmospheric refraction. Not sure if I can extract much of use from it but it was fun trying !

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PQ And

Taken at 01:34 UT 30.05.2020 with Canon 6D at prime focus on Celestron C11 (15 second exposure, ISO 800); excuse the hot pixels; a cropped version with brightness stretched to show it easier. Have the raw files.

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I had to wait until it was

I had to wait until it was almost daylight for it to clear my house roof but here it is. I'll need to dig out my nova patrol films from 1989 to see the last time I got it this bright.

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PQ And - Dave McAdam interview

I filmed Dave talking about his discovery one year later, at the 1989 TA AGM on 1989 June 24 at Basingstoke. I've just uploaded the short clip to youtube. No smartphone videos then... A huge shoulder mounted camera and a heavy VHS recorder slung around my neck! Nick conducted the interview. You'll find it here:

https://www.youtube.com/watch?v=bxfzpvN3oF0

Seems like yesterday!

Regards,

Martin

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Blimey, it really was a long

Blimey, it really was a long time ago. I had some hair then.

Nick.

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PQ And page

There is now a short and pretty basic PQ And page residing on the BAAVSS website   https://britastro.org/vss/PQAnd.htm

Hopefully I'll add to it as the outburst progresses, so if you have anything you'd like to share (spectrum, time series photometry etc.   I'm not asking for much am I) then please send it to me and I'll add it.   

And please don't forget to add your observations of PQ And to the BAAVSS database

Gary

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Observations

Good to see people overcoming the odds and securing successful observations of PQ And. I managed to see it this morning at about 02.25 BST. I decamped with my 12 cm refractor to a field a mile away and it's far too low from my obsy as you can see from the angle of my telescope in the dawn sky.

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Dawn

"this morning at about 14.25 BST."

I hope you mean 04:25 BST, or dawn comes remarkably late where you live ;-)

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PQ image

Obtained this rather 'noisy' image in the predawn sky, using a 102mm refractor mounted on top of my 10" SCT.

Rob Januszewski

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PQ And

Hello Rob,

Good to see you've finally got to it after all these years!  Quite something isn't it!

Gary

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Hello Gary,

Hello Gary,

Yes, great to catch a rare event like this. After 18 clear nights during May most of which have been exceptionally good quality I'm absolutely exhausted but just had to give it that extra half an hour to observe this.

Rob

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wobbly table

Further to my #2 post above, our VSS director suggested I post a photo of my scope in PQ And mode.   Well here it is.  My trusty 30 year old battered 22cm dobby doing a balancing act on a table, but it does get me to view over the hedge.  I often do this for stars low in the north which my 51cm in the observatory can't get at.  In the past it's been on milk crates, house bricks etc. and even poked out of the bedroom window - much to my wifes' disgust on a cold winters morning :-)

The cat didn't show up this morning, so this is one I made earlier...

Gary

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That doesn't look very stable

That doesn't look very stable Mr. Poyner. The cat looks to be a Brummie relative of bagpuss.

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stable

No it isn't very stable Nick, but with careful handling it works fine - you just have to be patient!  Without it I wouldn't have seen PQ And at all! 

And if these pesky NLC's keep away from Brum, I'm hopeful of continued use for a while longer yet!

Bagpuss is a Brummie.  Thought everyone knew that.

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Reduced spectra

OK  here are the spectra for 2020-05-29 and 30.   

Apart from the hot continuum there is nothing common between them so unfortunately  the details are probably just noise. They were taken at 5 deg altitude (air mass 10) in a bright sky though so to be honest it was a surprise to get anything

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Spectra

My goodness, Robin! You have certainly given this your best efforts. As you say, remarkable that you got anything given the circumstances!

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pq And on May 30

PQ was at alt 8deg, and managed a sequence of FITS from 1.30 to 3 am BST.  BUT I dont know what to do with the data.    However i have a memamsured image giving a R mag of 10.5 using UCAC4. I dont know how one gets V mag with a filter. Where do you get the ensemble photometry data for V (or G)?   My image is attached (single image in Astrometrica).. I hope
The browser is not playing ball.

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image i hope

Here goes. Ah! it seem to take a long time before its available to insert.   I may have made a second comment...sorry

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V-band comparison

Nice work, Tim! Looks like you solved your problem, but just to say I use V-band comparison star data from the AAVSO VSP. Comps for PQ And are listed here. If you used a V-filter on your camera (which I assume is monochrome?), the resulting mags are quoted as CCD-V. If unfiltered they would be CCD-CV.

Thanks for tackling this star!

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No chance for me!

Someone (ahem...) years ago decided to build the observatory due south of my wife's office - not sure she'd be happy with a demolition job to have half a chance of an observation of this one! (I think even then, there's a large ash tree that might get in the way!)

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Same problem

I have poor horizons from my obsy, Graeme. But I'm lucky enough to have a second, portable, set up with an AZEQ6 mount which enables me to decamp to more favourable observing locations for special events like this.

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New spectrum

An Astronomer's Telegram, ATel #13776, from the Kyoto group publishes a spectrum taken on June 2. This "showed Balmer absorption lines with emission cores, which are typically seen in dwarf nova outbursts. There are no signals of O III, which were reported in the 1988 outburst", although they question the 1988 conclusion.

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With the help of Thomas Bayes

With the help of Thomas Bayes perhaps I can now claim to have previously detected both the Balmer H beta absorption with emission core and H alpha emission ;-)

My rectified spectrum from 2020-05-30 (red) overlaid on the spectrum published in the Atel

(I also see the problem of not being able to insert images. I had to press "preview" before I got the "insert"  option)

Robin

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PQ And spec

This implicit reference to posterior probability in Bayesian statistics is just the sort of intellectual high-brow stuff one would expect on our forum :)

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PQ And rebrightens

PQ And is undergoing it's first rebrightening today after fading to 16.6CV on June 25.  Latest observations reveal 13.45V on June 26.45 (M. Mobberley).  This could be the first of several rebrightenings (or the only one), so please stick with it for the next few weeks if possible.

The field is getting slightly easier in the morning sky now, so any observations made please report them to the VSS.

Thanks and good luck,

Gary

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PQ And still active

After 41 days since it's first outburst for 32 years, PQ And is still active with the fourth rebrightening commencing on July 7.

All except number three have been short duration events of ~1d.  The third has been long in comparison ~3d. (see light curve from my own observations below)

I can't recall the system which has had the most post outburst brightenings, but we have a way to go yet with four,  so please stick with PQ And for the foreseeable future.

Gary

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Fourth rebrightening Gary? It

Fourth rebrightening, Gary? It's hardly out of the stalls, yet! 

I think the record holder is EZ Lyn, which showed 11 rebrightenings during its 2006 outburst.

Maybe we should have a VSS sweepstake on how many PQ And will undergo. I'll say 6, but I hope there are more.

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EZ Lyn

That's it.  Thanks Jeremy.  I knew it was more than 10, but couldn't recall the object without cheating and checking in my records ;-)

I'll have a bob on eight!

Gary