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Bulletin Board
****The Webb Deep-Sky Society 2012 AGM will be held at the Institute of Astronomy (IoA) in Cambridge on Sat 16th June 2012**** Click here for directions to the IoA Confirmed Speakers so far: Paul Clark - Title still to be confirmed, Jeff Young - Experimental Visual Observing, Dave Adshead - Deep Sky Imaging from the Kingfisher Observatory, Bob Marriott - Title still to be confirmed.
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January 2012 - Picture of the Month Simeis 147 and its Surroundings Image Courtesy of Rogelio Bernal Andreo, California
Click on image for a larger version (4MB image file) Rogelio's Observation Notes: "Simeis 147, a supernova remnant also known as Sharpless 2-240, is an object typically photographed with narrowband filters, because under visible light it just appears too "poor" in comparison, mainly due to the fact that this object is extremely faint when imaged through RGB filters - and not too bright when using narrowband filters either! Narrowband data however deprives us from viewing the many other things happening around it. Most narrowband + broadband compositions I've seen (usually H-Alpha + RGB or H-Alpha + LRGB) haven't been able to "fix" that, so I decided to give it a try, also expanding the typical already-wide FOV, to hopefully capture and visually document more of what's around. The image being presented above includes the entire field I photographed, in a 3x1 mosaic, but here you can see a composition that focuses on the supernova remnant itself: Successfully combining narrowband data (H-Alpha in this case) and (L)RGB data can be tricky. One of the usual results is that, since H-Alpha data tends to produce very small stars, when combined with broadband data, the resulting image often presents a rather severe ringing around the stars. Also, some conventional techniques rely on mixing H-Alpha with the red (R) and blue (B) data, but in this case, my RGB data was rather poor so I couldn't rely on just this technique. Therefore, for this particular image I followed a number of conventional as well as non-conventional methods that proved to be rather successful in producing an image that visually documents this area of the sky. Also, as usual in many of my recent images, a multi-scale approach dominated post-processing, in particular to bring out the fainter details that hide behind the swarm of stars. My daughter says this supernova remnant looks like a Christmas tree ornament, although I kind of see a piggy's head instead! :-) " For more images from Rogelio please visit his website |
January 2012 - Galaxy of the Month NGC 2775 Image Credit/Copyright -Adam Block/Mount Lemmon SkyCenter/University of Arizona
Click on image for a larger version Winter is never the best time for trying to persuade observers to look at galaxies as most deep sky observers are focusing their attention on the star clusters and nebulae of the Milky Way. There are however some galaxies to be found in unexpected places. The constellation of Cancer is perhaps best known for its two open clusters M44 and M67 but the third brightest deep sky object in this constellation is the galaxy NGC 2775. First discovered by William Herschel in 1783 NGC 2775 is a face on spiral galaxy of an unusual type. The core of the galaxy is very prominent and has a very smooth light distribution and unlike most spiral galaxies the arms seem to start from a long way out from the centre. The spiral arms themselves are very tightly wound and appear on images at least to be discontinuous with a large number of HII regions dotted along them. The spiral arms show a very curdled appearance on deep images. NGC 2775 is the largest galaxy in a small group which includes NGC 2773 and 2777, both of which are very much fainter than 2775. They were both discovered by Marth with Lassell’s 48” reflector, presumably from Malta. The NGC 2775 group is part of the larger Virgo cluster, much like our own Local group. With a blue magnitude of 11 the core of NGC 2775 should be visible with quite small telescopes, of the order of 10cm, however to see much detail in the spiral arms will require a telescope with a much larger aperture. Some sources suggest that NGC 2775 has been home to five supernovae in the last 30 year so it is obviously a good target for supernova hunters. I can however only find information on one in SN 1993z. NGC 2775 appears to be at a distance of about 17 Mpc. There are some suggestions that NGC 2775 maybe interacting with one of the smaller galaxies in the field from radio observations but this is not yet certain. NGC 2775 is also of interest because it does not seem to have a significant dark matter halo. Click here for The University of Arizona Mt.Lemmon SkyCenter |
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The Webb Deep-Sky Society Star Atlas This is the most detailed and accurate Atlas in its class! The Atlas comprises of 44 star charts (inc. Notes and Measuring Guide) covering the whole sky to magnitude 7.1 Two Versions are Available - Colour and Monochrome For details on how to order the Star Chart click the 'Price Lists' button at the top of this page
Click on image for a larger version of Chart No. 26 |
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Tenerife - An Observer's Log An Article by Andrew Robertson Tenerife 22nd Nov to 29th Nov 2011 "This was my 6th trip to the Parador, Teidi, Tenerife for a weeks observing with Rod Greening’s 25” Dobsonian (actually its 24.5”) but my first outing in the Autumn, all previous ones being in the Spring. Just the three of us went this time - myself, Mark Turner from Norwich AS and the man himself, Rod Greening. We made use of the 25” Dob and the hotel’s 10” F6 Dob after giving the optics of both a clean and collimation. There are two main advantages to this location: 1) you’re at 7,000 feet altitude, which means transparent skies. 2) The latitude is 28 degrees which means that not only can you see objects totally unobservable from the UK you can observe objects that whilst technically visible from the UK are poor but from Teidi superb! For example, the Skull Nebula, NGC 246 in Cetus, invariably poor from the UK, absolutely awesome visually from Teidi, beats any image I’ve seen! I first went to this location over 10 years ago and I have to admit that the light pollution in the SW due to holiday apartment development has got worse but this has to be put into perspective. It is about 10 miles away and below the observing site to the tune of 7,000 feet. Frequently there is cloud around the mountain cone of the island, which peaks out about 5,000 feet keeping the light pollution at bay. When it is like this you don’t see the light pollution and you can observe objects with little atmospheric extinction close to the artificial horizon afforded by the caldera. Unfortunately for me but fortunately for my wife who was staying at a coastal resort, there were largely clear skies over the coast and we only had a couple of periods giving really transparent skies low in the SW but not a problem. We just changed our observing tactics concentrating on objects to the East of the Meridian or above 30 degrees altitude in the SW. Another example here is that I had the best ever views ever of M33 and the NGC 206 region in M31 – just because you have views to the South doesn’t mean you can’t enjoy mega views overhead. There was a bit of high level stuff around this time and I would say that generally our skies were only about mag 6.5 but still better than the best skies I enjoy from the UK. Mark and I arrived about 4pm on Tuesday 22nd. Got settled in our room, set the 25” up ready for observing then got a couple of hours sleep in. We were out by 9pm. Rod who’d arrived by a separate flight at 8pm was already out there but he was flagging by 11.30pm whereas we went until 3am after our top up sleep. I did bring a Dictaphone with me but didn’t use it on the first night choosing just to have a look around to get a flavour. Mistake really – should always record ones observations as we did a lot of objects in the SW that we never re-visited and I had to try and do some notes from memory. All observations refer to 24.5” F4.5 Dobsonian (FL 2756mm) with fully inverted views unless otherwise stated." Click here for Andrew's detailed observations. Latest Deep-Sky Observer - DSO155
Experiences at the Texas Star Party - Faith Jordan NGC 246 in Cetus - Wolfgang Steinicke NGC 4485/90 - Wolfgang Steinicke Hickson Galaxy Groups Project - Owen Brazell Hickson 15 - Ronald J Morales Ercole Dembowski - A Life Dedicated to Astronomy Robert Argyle and Domenico Gellera Autumn Doubles - Andrew Robertson Cracking Cassiopeia Star Clusters -Martin Griffiths Book Reviews Viewing the Constellations with Binoculars Bojan Kambic - Reviewed by Melvyn Taylor Advancing Variable Star Astronomy Thomas R Williams & Michael Saladyga Reviewed by Gary Poyner
Hickson Project Article by Owen Brazell Hickson 44 Image Courtesy of Sheldon Faworski and Sean Walker
Click on image for a larger version In 1982 Paul Hickson published a paper containing a set of compact groups of galaxies numbering 100 that he had found whilst studying the POSS prints. The Atlas was also produced in book form in 1993 by Gordon and Breach with images for all the galaxies. Although this has been long out of print second hand copies can still be found on Amazon. These galaxy groups have been much studied by professionals because of the fact that they have a rigorously defined set of parameters which makes them useful for looking at the dynamics and evolution of galaxy groups. The catalogue also contained a number of well known objects, such as Stephan’s Quintet which made it interesting for amateurs looking for new challenges. Hickson himself wrote a review of the status of these objects in 1997. As this catalogue became more well known to the amateur community various people produced guides to observing them including Alvin Huey and Reiner Vogel. There are also fine webpage's which include observations of various members of this catalogue. Bearing this in mind, and that there is a limited range of 100 objects, Stewart Moore and I thought that Obser ving the alt="The Webb Deep-Sky Star Atlas" alt="The Webb Deep-Sky Star Atlas" Hickson catalogue might make a nice joint observing project for the British Astronomical Association Deep Sky Section and the Webb Society galaxy section to collect observations and images of as many of these groups as we can with the intention of putting a paper together for DSO and /or the BAA Journal. The galaxy groups here range from challenges for small telescopes (here we define small as 20-22cm) where you may be able to see the brighter members of some of the groups down to challenges which will probably require very large telescopes from dark sites to see at all visually. However because of the rise of CCD imaging I would imagine that most of these objects should be gettable with relatively small instruments, although image scale may be an issue as some of these groups are quite small in angular size. In the past observing projects have not proved very popular in the Webb Society, certainly amongst UK based observers, and the fact that the catalogue was generated from the POSS prints means that a number will not be visible for southern hemisphere observers and means that we may yet be relying on our North American colleagues for some of these observations. As a helping hand for those observers who have either SkyTools 3 or AstroPlanner V2 (beta) I have included a couple of plan files one for each package (The SkyTools one contains images for each group) You should be able to download these and import them into the programs. The .stx file is for SkyTools and the .apd file is for AstroPlanner. Click here to download the files. Owen Brazell - Galaxy Section Director |
January 2012 - Double Star of the Month 35 Cam (06 04 29.10 +51 34 24.2) was observed by Madler in 1843, and became number 128 in the Pulkovo Catalogue of Otto Struve, although it had been discovered by John Herschel in 1830. Later authorities including Aitken in the ADS added the word rejected because the separation was too wide for the pair to be a likely binary system. The rejected tag seems to have been removed in the current WDS but there is no evidence that the two bright stars are connected. The pair is a fine sight in a small telescope - the primary appears white and V = 6.4, whilst a V = 9.26 mag. bluish companion sits about 40 arc seconds away in PA 14°. For the user with say 30-cm there is the additional interest that the companion is a close pair - HU 559 which appears to be moving in retrograde binary motion - some 30 degrees since the discovery by Hussey in 1902. The WDS gives magnitudes of 9.6 and 10.6 and the current separation is 0".6 so this is as much of a test of the atmosphere as it is of the telescope. The constellation of Columba lies to the south of Canis Major and a triple star worth seeking out is HJ 3858 (06 25 30.01 -35 03 50.5). It forms an isosceles triangle with kappa and delta Col and is exactly 5 degrees south of zeta CMa. This is both an easy binocular pair and a fine triple in the small telescope. The brightest stars have magnitudes 6.4 and 7.6 and are separated by 131" a distance which is slowly increasing. The primary star, of spectral type K3 appears deep yellow to Gould with 175-mm, whilst the companion appears white, reflecting its spectral type of A4. When John Herschel noted it on sweep 663 at Feldhausen, he described its three stars as 'Fine object. A star 6 mag precedes to the south'. The close pair (BC) is currently 3".8 apart and also slowly separating with little change in position angle, and the magnitude of C is 8.2. Bob Argyle - Double Star Section Director Object of the Season - Spring 2012 & Summer 2012 The Webb Deep-Sky Society Nebulae & Clusters Section Director Wolfgang Steinicke has requested observations for the following deep-sky objects:- Object of the Season (Spring 2012): Galaxy pair NGC 4485/90 in Canes Venatici Details have been published in DSO155 and the results are scheduled to be in DSO 157 Click here for Object Details
Object of the Season (Summer 2012): Planetary Nebula NGC 6765 in Lyra Details will shortly be published in DSO156 and the results are scheduled to be in DSO 158 Click here for Object Details NGC4485/90 NGC 6765
Click on images for a larger versions The complete schedule, including further objects, is published in the Deep Sky Observer (DSO). Observations should be sent to: steinicke-zehnle@t-online.de Deep-Sky Observer (DSO) No 153 - Free Sample
The free journal is DSO 153 from 2010 You can download it as a PDF file onto your computer by right clicking the link below and choosing either 'Save Target As' or 'Save Link As'....
Download DSO 153 (2MB PDF file)
IC1848 aka the Soul Nebula in Cassiopeia Image Courtesy of Paul Brierley - UK
Click on image for a larger version Paul's Observation Notes: "Friday 25th of November the sky according to our metoffice, was supposed to be clear. Well it was for an all too brief period. From 8pm until shortly before 10:30pm. Then once again, cloud's rolled in to spoil my fun. During this period. I was successful in imaging the "Soul Nebula" aka IC1848. The image is a stack of Seven minute exposures, that total 1 hour and 15 minutes. I would have carried on, but that's when the cloud's rolled in. This image was captured using. William Optics Zenith Star 66sd Losmandy G11-Gemini L4 Atik16ic and Astronomik 13nm HA filter. Guiding Orion Optics 8" f4, focal reduced to 400mm f2 Q5 and PHD. IC1848 is a very huge cloud of nebulosity. But, because of the small Atik sensor, you can only see the central part of this huge nebula here." Regards Paul A Brierley. Observing Co-ordinator Macclesfield Astronomical Society |
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A Selection of Deep-Sky Sketches from Dale Holt Sketches Courtesy of Dale Holt, from his Chippingdale Observatory  Click on sketch larger versions and Dale's Observation Notes. |
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Sketches of NGC6572, NGC6535, NGC6765, NGC 6894 and M56 A selection of Sketches Courtesy of Jeff Young
Click on image for larger versions and Jeff's Observation Notes Further sketches from Jeff can be found at The Observatory at Rokeby Hall |
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Planetary Nebulae Sketches NGC 6720(M57), NGC 7293 and NGC 7662 Courtesy of Massimo Zecchin - Italy
Click on image for further Planetary Nebulae Sketches and Massimo's Observation Notes |
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.jpg "NGC 6765 - Image Courtesy of Stefan Binnewies, Capella Observatory")
