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Hartl-Dengel-Weinberger 3 (HDW 3)

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About this observation
Observer
Peter Goodhew
Time of observation
08/12/2019 - 17:55
Object
Hartl-Dengel-Weinberger 3 (HDW 3)
Observing location
Fregenal de la Sierra, Spain
Equipment
APM TMB 152 LZOS refractor
QSI6120wsg8 camera
Exposure
HaOIIILRGB 71.5 hours total integration
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In another of his "long exposure of faint stuff" series, Peter has produced this stunning image of Hartl-Dengel-Weinberger 3 (HDW 3, PK149-09.1, PNG149.4-09.2) which is an extremely faint ancient planetary nebula in the constellation of Perseus. the object is so faint that it is very rarely imaged.  The progenitor star is the small blue star at the 5 o-clock position just below the large yellow star in HDW 3. The progenitor is not, as one would expect, in the centre of the nebula, which is because it is moving rapidly in a north-westerly direction through a dense area of interstellar medium (ISM). This ISM is slowing down HDW 3, creating a shock front and the unusual "braided" appearance. As the star isn't slowed by the ISM it has continued to move and is thus no longer at the centre of HDW 3 and is slowly overtaking HDW 3. This causes the shock front to be brighter as it's getting more ultraviolet radiation, whereas the opposite side of HDW 3 is receiving less UV radiation and has become invisible. This movement of the star causes differential excitation of the shell. OIII emission, which requires higher energy of the ionizing radiation than HII emission, only happens close to the star.

Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.
BAA Articles

Is Betelgeuse about to go supernova?

Have you noticed that the constellation of Orion looks slightly odd at the moment and that Betelgeuse (alpha Orionis) looks a little dimmer than usual? Well, that’s because Betelgeuse has been fading slightly for the last few weeks. It’s now fainter than it’s been for quite a few years, but not unprecedently so.

This has promoted speculation that Betelgeuse is about to go supernova. Could that be the case? Probably not, but read on….

The variability of Betelgeuse was first noticed by Sir John Herschel in 1836 and it has been followed ever since. When at maximum it can rise to magnitude 0.4 when it can rival Rigel. At minimum brightness, as in 1927 and 1941, the magnitude may drop below 1.2. In the late 1970’s it reached magnitude 1.5. Recent observations put it at a similar level, between 1.3 and 1.5.

Betelgeuse is a pulsating red supergiant. Its diameter varies between the size of the orbit of Mars and at maximum diameter may equal the orbit of Jupiter. Its brightness varies in a complicated way as there are multiple periods. The main variation takes place over about 420 days.

Betelgeuse is in the last stages of its evolution and it is expected to explode as a supernova within the next million years. Some recent sources estimate a supernova event from today to 100,000 years. So will it go off tonight? Probably not, but keep looking! When it does explode, it will be visible in the daytime sky.

It certainly provides a great opportunity to take friends and family outside over the Christmas and New Year period to view Orion and Betelgeuse.

A chart can be downloaded from the VSS website.

 

Thumbnail image: Betelgeuse, as seen by the Atacama Large Millimeter/submillimeter Array (ALMA)

Images by Paul Whitmarsh and Nick James

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The planet Uranus

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About this observation
Observer
Martin Lewis
Time of observation
03/12/2019 - 22:16
Object
Uranus
Observing location
St Albans, UK
Equipment
444mm Dobsonian
ASI290MM camera
Bader 610nm LP filter
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Martin comments that this was his best view of the planet Uranus since 2015 Oct 31.  The planet on this occasion was imaged on the night of very good seeing using 8.6msec exposures for planet at gain of 500x using an ASI290MM camera and 610nm long pass filter. The image is a combination of the best 15% of 14 minutes of video data, combined in Winjupos using image derotate function.

The moons were imaged separately at a longer exposure (100msec), processed separately and then combined with planetary image.

The data are currently being analysed for possible light spots at the border of the lighter polar region.

Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.
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Sun_Samworth b_151219 g11_46_35

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About this observation
Observer
Roger Samworth
Time of observation
15/12/2019 - 11:46
Object
Sun
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Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.
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Sun_Samworth b_111219

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About this observation
Observer
Roger Samworth
Time of observation
11/12/2019 - 09:50
Object
Sun
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Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.
BAA Observing Sections Deep Sky

Deep Sky Update – December 2019

J900

I was reading a new paper in Monthly Notices of the RAS about the planetary nebula Jonckheere 900. I must admit it was an object I had quite forgotten about, though I did write a short item about it a few years back. Although it is listing in Phil Harrington's Cosmic Challenges, as a challenge object for a small scope, it should be within easy reach for those with a medium or larger scope. It is very small, though, which makes resolving it as much more than just a star a bit tricky. It lies in Gemini and so is well placed in the coming months. If you get a chance to get out and observe it I would appreciate reports and images.

Sky & Telescope - Hubble's Variable Nebula

The February 2020 issue of Sky & Telescope arrived in my in-box (I take the digital version) and I found an excellent article by Howard Banich on observing Hubble's Variable Nebula. It is well worth a read. Observations of variable nebula are always worthwhile, so please do get in touch with Nick Hewitt or me if you want to find out more.

There have been a few attempts by myself, Nick Hewitt, Mike Harlow, Grant Privett and Paul Whitmarsh to follow up on McNeil's Nebula - but it still appears to be 'not there'. It will be interesting to see when this object 'turns on' again.

DSS Meeting 2020

Arrangements for the section meeting in 2020 (March 14) in Sheffield progress. The programme is firming up now, and places can now be booked either on-line or via the BAA Office. The price is £7 for BAA members and £14 for non-members. Visit https://britastro.org/deepsky2020 for updates and a link to the booking page.

Meade in trouble (again)

I expect most people will now be aware that Meade has got into financial difficulties, and filled for Chapter 11 protection in the USA. Although this may be worrying to those that have recently purchased a Meade telescope, I expect they will be bought out and continue business.

Also in trouble is my own Meade LX200 - it is a very old (around 1996) 10" Classic and it seems like the RA board has packed up. However, I might take the opportunity to upgrade to something more current...

Newsletter

With the Christmas break coming up I hope to get the 2018 Newsletter out by the end of the year. Shortly to be followed by the 2019 Newsletter at the end of January. If you have observations made in 2019 that you have not sent me yet, or if you would like to write a short note or article, then please send to me by mid-Jan.

Highlights from Members Pages

There are some fantastic images being posted on the BAA Members Pages. Here is a selection of a few recent ones that caught my eye.

Graham Winstanley 
Jones 1
LDN 1164
Clive Nanson
M31
Simon Dawes
NGC 6960
Callum Wingrove
Horsehead and Flame nebulae
Rosette Nebula

And Finally

I hope you have a merry Christmas and a Happy New Year, and if you are having a break over the festive period a chance to get some observing in.

Clear, dark skies.

Callum

If you would like to join the Deep Sky Section and subscribe to deep sky news as soon as it comes out visit https://britastro.org/node/18641

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BAA Observing Sections Comet

Follow a comet through the northern sky

A relatively bright, circumpolar comet

Comet C/2017 T2 (PanSTARRS) was discovered by the PanSTARRS telescope on Haleakala, Hawai when it was 9.3 au away from the Sun and 20th magnitude. It is moving inwards towards a perihelion which will be at a distance of 1.6 au from the Sun in 2020 May. Comets are often difficult to follow since they are usually at their best when they are close to the Sun in the sky and so can be low down in the dawn or dusk. C/2017 T2 is different. For those of us in the far northern hemisphere it is circumpolar throughout the winter and spring months and it will make a great target for observation from now until perihelion. It is not particularly bright but it is within the range of small telescopes and cameras and since the comet is high up in familiar norther constellations it should be relatively easy to find.

The path of the comet over the next few months is shown in this finder chart (2017t2.pdf). It starts December moving along the Perseus/Camelopardalis border not far from the bright star Mirfak. It continues moving north in Perseus until it crosses the border into Cassiopeia in mid February, finally moving back into Camelopardalis again in April. At present (mid December) the comet is around 10th magnitude and it will continue to brighten slowly through the winter and spring possibly reaching mag 8-9 in April. It may be visible in binoculars from a dark site but small telescopes should definitely provide a good view. The latest lightcurve is here. The comet currently has a short tail about a quarter of a degree long although you will need a dark site to see this.

This is an unusual opportunity to follow a comet for a long period over the long nights of winter and spring to see how it develops as it moves in to perihelion. Observe it whenever you can but the best conditions will be when the Moon is out of the way. There are good Moon-free periods in the last two weeks of December, January and February.

Wide field imaging

While it is not spectacular the comet is bright enough to show up in images taken with small instruments. It also passes close to some nice deep sky objects and so it will be a great target for driven cameras with fairly long telephoto lenses or small telescopes. Of particular note is a close approach to the famous Double Cluster (NGC 869/884) from January 25-30. The path is shown in the figure below. There will be plenty of opportunites to get nice images of the comet and the cluster over that week and the Moon is conveniently New on January 24th. Please submit any images that you get to the Section following the instructions here.


The Double Cluster is the most prominent object that the comet passes but thre are many more pairings that can be imaged with rather longer focal lengths. A list of of the more interesting ones is in the following table. In late May the comet will pass a degree from the galaxy pair M81/M82. The Moon is new on May 22 and the comet will be high in the sky as darkness falls.

Date Object
2019-12-23 Crossing Sh2-205
2020-01-21 South of NGC 957
2020-01-26 North of NGC 884
2020-02-23 1 deg E of NGC 743
2020-03-02 2 deg W of IC 1805
2020-03-13 Passes NGC 886
2020-04-12 1 deg S of NGC 1343
2020-05-24 1 deg from M81/M82

Visual observing

Despite all the modern technology involved with comet observing visual observers are still the main source of accurate total magnitude estimates. Estimates of brightness (magnitude), coma diameter and tail length are all important and details of how to make these estimates are given in section 3.7 of the Comet Section Observing Guide which is available for download from here. If you are a new observer please submit estimates that you make to the Comet Section. More experienced observers are encouraged to submit estimates directly to the COBS database. If you are a BAA member registered with COBS please ensure that the BAA is set as your group so that we can download all BAA observations for analysis.

Sketches of the comet are a good way to keep a record of your visual observation. You can submit these to the section by followin the instructions here.

Estimating total magnitudes using imaging

This is a great opportunity to follow a reasonably bright comet for several months as it approaches perihelion and to compare total magnitude estimates from images with those obtained  by visual observers. At present there is a quite a large scatter and visual observers at dark sites are seeing the comet rather brigher than imagers. This all comes down to how much of the coma is detected. The section has developed some software called comphot which can be used to estimate comet total magnitudes from images. You can download it from here. Be sure to read the instructions on that page. Doing comet photometry can have a steep learning curve so please contact me if you need any advice. More details are in section 7.3 of the Observing Guide. Images taken for photometry can also be used for measuring the comet's position. This is called Astrometry and most of our observers use a software program called Astrometrica to do this. Astrometry is covered in section 7.1 of our Observing Guide.

Let's hope for some good runs of clear, Moonless skies over the next 6 months which will allow us to follow this comet all the way to perihelion. Comets are always interesting to observe since you never know quite what you will see when you go out to observe one. This one is particularly well-placed in our northern skies so don't miss this opportunity.

Nick James. Comet Section Director.

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