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Hello Cam,
those are great images: a nice range of star colours in the Double Cluster and a wealth of detail in M42. I always think M42 is one of the toughest objects to image, given the range of contrast – but you have done a very job job.
You seemed to have tamed your HEQ5 – it’s certainly giving you good results.
Keep up the imaging.
Go well!
Jeremy
I have begun the analysis of the CSS photometry data from the campaign, so I thought a quick update might be helpful. We have 6552 data points from the BAA VSS, AAVSO and CRTS databases, covering the 2013 and the 2014 observing seasons. You can view the 100-day plots for the recent season (data up to 2015 Jan 2) here: http://www.britastro.org/vss/CSS%20plots%202014.pdf
The red dashes are “fainter than” measurements. The blue data are CV or V.
You can see that coverage got better as the campaign took off. The light curve is typical of an SU Uma system (not an ER UMa as once postulated) with frequent outbursts and in my mind is quite beautiful. There are 4 superoutbursts visible, plus many normal outbursts. Analysing the superoutburst times gives a fairly consistent ephemeris, with a period of 66.4 days, taking into account the 4 supers in 2014 and an additional 2 in 2013; or 68.7 days if I only include the 2014 supers. Of course, superoutbursts are only quasi-periodic and it is a mug’s game to try and predict the next. But for a bit of New Year fun I’ll have a go anyway: sometime between Jan 18 and Jan 25, depending on several assumptions – most likely around Jan 23 if I were a betting man. You heard it here first, as they say….
However, given the field is slipping into the west, it will be a challenge to spot the next superoutburst, but it would be fun to try – and would help to update the ephemeris before the seasonal gap. So single shot imaging of the field would be helpful (as would short photometry to look for confirmatory superhumps). The supers last about 13 days.
Of course, this analysis makes use of the hard-won data submitted by many observers – hats off to them! I have used data kindly contributed by: David Boyd, James Boardman, Juan-Luis Gonzalez Carballo, Ian Miller, Ken Menzies, Roger Pickard, Gary Poyner, Richard Sabo, Pavol Dubovsky, Richard Sargent and Denis Buczynski. If you have observed this star and your name is not listed, please contact me as it probably means I have not seen your data.
Good luck and go well! Jeremy
Great work, Bill. Fascinating to see the results you are obtaining. Hopefully we’ll soon get some multi-station captures of the same event, to tie in with your spectroscopy.
Go well!
JeremyThat’s an interesting project, Mike. And nice images. Hope you will continue to extend the gallery.
Go well!
Jeremy
Hello Cam,
good to hear from you. I am afraid that I do not have experience of that telescope, but perhaps somebody else does.
Personally I have always found small refractors to be good for wide field imaging, given their compactness, no need for collimation and ability to use relatively small mounts. I recall from your previous postings that you have used an ED80, which was giving you excellent results.
Anyway, I hope to see some further results from you with whatever telecope you use.
Go well!
JeremyTime for a brief update. In my previous note I mentioned there was a long outburst from Sept 7 to 19. The star was then in quiescence until earlier this week, when it was found on Oct 8 at mag 16.3C. This was one of its brief outbursts, lasting no more than 2 days. Last night (Oct 9) it was back at quiescence again. I still expect a long outburst in early November, but this is by no means certain. Further monitoring is still requested to see if this materialises “on time” and how many brief outbursts there are in the meantime. We need dense coverage (preferably nightly) to be able to discern the brief outbursts and to spot the beginning of a long outburst – an event which would prompt time-resolved photometry. I would like to thank the people who have contributed data so far. I review data in both the BAA VSS and AAVSO databases regularly, which include observations by Ian Miller, Roger Pickard, Kenneth Menzies, Juan-Luis Gonzalez Carballo, David Boyd, Richard Sargent and Richard Sabo. Apologies if I have missed anybody. Go well! Jeremy
It’s time for an update on this target – a little overdue as I have been on hols for the last couple of weeks.
In the previous update I reported that at the end of August we had a short outburst. During the first week of September the star was in quiescence. Then a long outburst started on 7 September, lasting at least 12 days. Ian Miller valiantly carried out time-series photometry on several nights during the outburst. This again revealed hump-like features, with a period near 0.0807d, although there was a significant alternative around 0.0881d. Observations during the previous long outburst, in July, suggested a period near 0.0882d, with a significant alternative around 0.0810d. In each case the runs were rather short, introducing the uncertainty in the period. The upshot of all this is that further observations are needed!
So far we have observed long (>10 day) outbursts in late April/early May, early July and mid September, which might point to a ~2 month supercycle. Will we see the next one in early November? Of course there are short (~3 day) between the long outburst that we need to track too.
Many thanks to everyone who has contributed to the campaign so far.
Go well!
Jeremy
In my previous note, I mentioned the brief outburst of CSS from Aug 2 to 5. Since then the star has been languishing at minimum of about ~19 or lower. That is until last night (Aug 22), when it was again in bright outburst. Ian Miller conducted a 2 h time series photometry run in the early hours of today (Aug 23) which showed the star at ~16.0, with a pretty flat light curve. What will tonight bring? A fade or the start of a long outburst? Only further observations will tell!
These notes are based on observations in the BAA VSS Database and the AAVSO International Database by Juan-Luis Gonzalez Carballo, Kenneth Menzies, Ian Miller, Roger Pickard, Richard Sabo and myself. Further observers are welcome.
Go well!
JeremyHah! The old “to calibrate or not to calibrate” debate! My view: calibration is needed on scientific images, where one intends to extract data, such as photometry. But if it’s purely for images, then the choice is yours. The proof of pudding is in the eye of the beholder (to mix two sayings). I have seen many wonderful images which were not calibrated, which also convey the beauty of the night sky. I also think that for beginners, who may be keen to get their first results, then there is no real issue in not calibrating – they can move onto that later.
A similar debate has run in CCD photometry on the use of photometric filters (he ventures, not really wishing to trigger another subject of debate). There is certainly a place for using these, depending on the objective of the work. But I have noticed that some beginners have been put off even starting CCD photometry because they are worried about getting V filters etc. I say: have a go unfiltered to start with and select you targets with that in mind. If you find you like the work, then by all means invest in filters later.
Go well!
JeremyA slightly better night last night: clear(ish) from 2115-0030 and 0210-0320.
The 2 cameras caught a total of 90 meteors, of which 34 appear to be Perseids.Hope others had some luck.
Go well!
JeremyA bit of a frustrating night here at Bunbury, with drifting cloud banks, although some breaks between 21.40-00.00 and 02.30-03.15 UT. I shouldn’t complain as the wx forecast was for complete cloud cover. In total, the 2 video cameras (3.8 mm f/0.8 pointing SSE and 12 mm f/0.8 pointing N) caught 61 meteors of which 19 were Perseids.
I fared a bit better the previous night (Aug 11/12), although again there were many cloud banks moving through. A total of 106 meteors, of which 25 were Perseids.
Go well!
JeremyThanks for the tip Callum. I have fixed some of the links, but the page keeps crashing when I try to Edit – will try and fix the others soon.
In the meantime I can report that the current outburst of the dwarf nova was a normal outburst of ~3 days as Juan-Luis Gonzalez Carballo had it fading to mag 17.1 last night.
Go well!
Jeremy
This dwarf nova was in bright outburst for about 13 days from July 1 – a light curve with observations by Ian Miller, Roger Pickard, Richard Sabo, Jeremy Shears can be seen on the VSS web site here: http://www.britastro.org/vss/css_121005.htm
At the peak of the outburst it was mag 15.9, ~4 to 4.5 mags above quiescence. Time series photometry revealed humps in the light curve, but the runs weren’t really long enough to draw definitive conclusions about their period. The humps certainly looked like superhumps, although intriguingly there appeared to be more complex structure in them towards the end of the outburst
The most recent observation was on Jul 19.957 when the star was at mag 19.2 (Ian Miller).
We are now eagerly awaiting the next outburst of this frequently outbursting dwarf nova. It will almost certainly be a short, or “normal”, outburst lasting a couple of days. Continued monitoring is needed to determine how often the system goes into outburst, so please feel free to join it (you can upload your data to the VSS and/or AAVSO databases – and do let me know how you get on). In addition, further time series photometry during future long outbursts will be required.
For more details go to: http://www.britastro.org/vss/CSS%202126%20campaign_20140511%20(1).pdf
Go well!
Jeremy
Thanks Nick. Whenever I try and paste the link it cuts off the .pdf extension. Let’s try again in plain text: http://www.britastro.org/vss/CSS%202126%20campaign_20140511%20(1).pdf
…that doesn’t work either. So for those wanting to look at the doc I suggest either of the following options:
1. cut and paste the complete url (including the .pdf extension) into your browser, or
2. Use the link in my original posting to the BAA VSS web page and then click on the link to the campaign note that you will find there.
Go well!
Jeremy
The dwarf nova CSS 121005:212625+201948 continues to be active. As previously reported, it was in bright outburst during the first half of July, fading towards quiescence on July 13. There was then a brief outburst (<3 days) around July 20. Recent data from Ian Miller and Juan-Luis Gonzalez Carballo have it currently in outburst (Aug 2, 3, 4) at ~16.4. It will be interesting to see how long this outburst lasts.
Further observations are welcome. For more details go to: http://www.britastro.org/vss/CSS%202126%20campaign_20140511%20(1).pdf
Go well!
JeremyI can watch all the videos online with good sound – Chrome, Vista
Great meeting, by the way. I was unable to attend this one, so have really appreciated the facility to be able to catch up via the videos.
Go well!
Jeremy
This Dwarf Nova has been in outburst since last Sunday (6 July) and was still at 16.9C this morning (Richard Sabo, Bozeman, US).
Time-series photometry conducted on several nights this week by Ian Miller (Swansea, UK) and Richard Sabo has shown superhumps with superhump period, Psh ~ 0.088 d. There is some uncertainty on the period and significant aliasing associated with the short runs that are necessitated by the short nights at these 2 observatories at this time of year. These data are consistent with the dwarf nova being a member of the SU UMa family. The measured value of Psh suggests is is probably not an ER UMa system.
The campaign will continue as we still need to determine the outburst and superoutburst periods. In addition, further photometry during future superoutbursts will help to confirm the Psh of this frequently outbursting dwarf nova. Further info on the BAA VSS website.
Go well!
Jeremy
The star was once again in outburst last night (Jul 6.941 16.0C). Ian Miller carried out time series photometry which reveals what may be a (super)hump, although runs at this time of year are necessarily short. Further photometry encouraged.
Go well!
Jeremy
Great to hear the latest developments in your variable nebula project, Mike. (For some reason the image attached in your last Mr G posting didn’t come across, although the link to it you gave shows the image)
The short-term changes in NGC6729 are especially interesting.
Keep up the good work and sharing your results of this worthwhile venture.
Go well!
Jeremy
