Bulletin Board

Latest Website Update [29 May 2016] >> DSO 171 is now out and available for download >> New Object of the Season: B86 / NGC 6520 in Sagittarius >> An archive observation of NGC 4111 >> Details have been finalised for the 2016 Annual Meeting >> Observations of NGC 4111 and surrounding galaxies >> New Double Stars and Galaxy (with a double star in the FOV) of the Month for May >> Observations from Kelling Health Star Party 2016

We have a date for your calendar! The 2016 Annual Meeting in Cambridge on Saturday the 18th June 2016.

The news section contains more detailed items. I try to post items that may be of interest to members there. If you have suggestions, please contact me.

Object of the Season (Spring 2016)

Dark nebula B 86 and open cluster NGC 6520 in Sagittarius

Dark nebula B 86 and open cluster NGC 6520 in Sagittarius will be announced in DSO 171, and the results will be published in DSO 173.

This interactive image of the NGC 6520 and B86 was provided by the Digitised Sky Survey using Aladin Sky Atlas.

NGC 6520
Position (2000)
18 03 25.0 -27 53 28 (Sgr)
Open Cluster (I2m)
Visual magnitude
7.6 mag
Other Designations
VII 7, h 3721, GC 4386, OCL 10, ESO 456-SC42
Barnard 86
Position (2000)
18 02 58.0 -27 52 06 (Sgr)
Dark Nebula
1950 ly
Other Designations
LDN 93

Wolfgang Steinicke - Nebulae and Clusters Section Director

May 2016 - Picture of the Month

M92 in the Constellation of Hercules

M92 - Image Courtesy of Bernhard Hubl Image was provided Bernhard Hubl. Please visit his website to see more of his work and for more details about the image.

Globluar cluster season is here and this is one of the best of these ancient objects in your web administrator's opinion. Bernhard has done a fantastic job of resolving this dense ball of stars and bringing out the colour in many of them.

It's not a difficult object to find, but worth the effort in any sized scope. Not too difficult to resolve a large number of stars in a large scope. More of a challenge in a small one though.

James Whinfrey - Website Administrator.

May 2016 - Galaxy of the Month

This interactive image of the NGC 4111 group was provided by the Sloan Digital Sky Survey using Aladin Sky Atlas. We also have a finder chart should help you locate these galaxies.

As the summer approaches and dark skies end from northern latitudes I thought I would give the bright galaxy NGC 4111 its turn as the galaxy of the month. Completely independently I found that it had already been chosen as object of the week on the Deep Sky Forum and also as the ESO/Hubble picture of the week, obviously a galaxy whose time has come.

On the border of Canes Venatici and Ursa Major, NGC 4111 was first discovered by William Herschel in 1788. NGC 4111 is a near edge on lenticular galaxy showing a boxy central core and tapering spiral arms. The galaxy is thought to be at a distance of about 50 million years.

Deep images from Hubble show a disk of dust and gas orbiting at right angles to the main disk, possibly forming a polar ring galaxy. These are often associated with the mergers of galaxies and this may be all that is left after a merger with a smaller spiral galaxy.

NGC 4111 itself should be visible in telescopes of 20-22cm in aperture but to see much detail will probably require 40cm. Night Sky Observer's Guide (NSOG) reports that with telescopes of 45cm aperture structure can be seen in the disk.

NGC 4111 is part of a group of galaxies but there seems to be some disagreement about how many and which galaxies it is associated with. The WBL catalogue lists it as group number 380 consisting of three galaxies NGC 4111, UGC 7094 and a third galaxy, whilst the LGG catalogue lists NGC 4111 as part of a group of 18 galaxies as group 269 but does not include UGC 7094 as part of the group.

There are also three other NGC galaxies in the immediate area. NGC 4117 was also discovered by William Herschel later in 1788 but the other two are much fainter and were discovered by Stoney in 1851 (NGC 4109) and Mitchell (NGC 4118) in 1854 using Lord Rosse’s 72” reflector at Birr.

If the NGC galaxies are not enough of a challenge then there are two edge on UGC galaxies UGC 7094 and UGC 7089 in the same field but I think these may require large telescopes in the 20” (50cm) category to see, especially from typical UK skies.

All the NGC galaxies will fit in the same field of a high power eyepiece as will NGC 4111 and the two UGC galaxies so before we lose the dark skies for the year try and chase down this small group. For double star fans there is also a nice coloured double star HJ 2596 in the same field.

Owen Brazell - Galaxy Section Director

Observations of NGC 4111 and the surrounding galaxies: Mike Wood and Andrew Robertson use their large reflectors. It appears that the UGC galaxies do require lots of aperture, but Patrick Maloney suggests that might not be as large as you think.

May 2016 - Double Star of the Month

Virgo straddles the celestial equator and this month two pairs are included from this constellation - one north and the other south of the zero line of declination.

The primary of STF 1764 (13 37 44.01 +02 22 56.5) is a K2 giant and the note in Sissy Haas' book says that the stars are yellow and blue and that the colours are vivid. This system has been left out of Hartung and the Rev. Webb dismisses it with the comment yellow and ash.

The pair can be found about 3 degrees north and slightly following zeta Virginis. It forms an equilateral triangle with 84 and 78 Vir. There has been very little change since discovery. The stars are mags 6.8 and 8.6 and last year the writer measured the pair and found PA 32° and separation 16".2. The distance of A has been measured by Hipparcos but the resulting large value (2038 light years) is very uncertain. There are two further and fainter companions 10.4 at 139° and 172" (C) and D 10.7 at 143° and 207" (D), which together form the pair STF 1765.

SHJ 162 (13 14 55.85 -11 22 07.3) misses the cut in both Webb and Hartung but Haas was obviously impressed by the colours of the two wide stars A and B - white and pale red. John Nanson, however, using a 6-inch f/10 lens and x84 in 2011, noted that they were yellow and white.

It was measured by James South on 1823 May 7 using his 5-foot equatorial when the distance of AB was 45". The writer has not observed this pair but apart from AB there is another star in the system, close to A which was discovered by Richard Rossiter from Bloemfontein in 1937 using the 27-inch refractor. This has turned out to be a binary of period 122 years and in mid-2016 the companion (a) is at 161° and 0".55. It is about 1.5 magnitudes fainter than A but might be seen in 30-cm on a good night. The rapid proper motion of Aa (0".37 per year - distance 128 light years) is leaving behind star B which is now 112" away. There is a star of mag 13.3 at 67". The system is 3 degrees directly preceding Spica.

Bob Argyle - Double Star Section Director