M85 a superb sight with a very bright core and an overall mottled appearance and hints of dark areas.  Even better at x180.  At x80 has NGG 4394 in same field, as an oval smudge but with no discernible detail.

FIREBALL

Date           1986 May 3rd

Time           22 hours 20 minutes

Conditions   steady hazy

Instrument  Naked eye

Observer     Angela Turner

Location      Southam Warwickshire.

Notes.

Appeared to come from the constellation of Coma Berernices, making a very distinct sound upon entering the atmosphere.  It lasted for no more than 3 seconds and finally broke up into about five separate components.  Each component was red with yellow surround.  The fireball was extremely bright perhaps -8 or more.

The above was also seen by Mr Barry Merrikin from his home in Rugby who just happened to look up from the eyepiece of his telescope whilst conducting a series of deep sky observations.

Interestingly enough Barry estimated the track of the fireball through a slightly different area of the heavens to Angela's drawing as the track was parallel to δ and β Virgo ie. the right hand arm of the Y of Virgo heading towards Regulus in Leo Major and no sound was heard.

However Barry relates "I was dumbstruck by the shear brilliance of it which made a magnitude estimate very difficult."  After destruction a faint remaining steak was noted just below Leo, heading towards Regulus.

OBSERVING DOUBLE STARS

By Rob Moseley

Multiple star systems are by far the most common class of celestial object available to the Deep Sky observer - and also the most neglected.  Many amateurs have relegated them to mere test objects.  This is a great pity, because they are intrinsically beautiful and far more readily found in urban skies than faint nebulae.

A casual glance at Norton's Star Atlas reveals hundreds of doubles within the range of amateur telescopes.  I must admit that for years those, strange ε's, σ's and β's captured my total neglect.  Of course I had looked at Albireo, Castor and a few other showpieces - but I was never motivated to look further.  Few other amateurs interested in Deep Sky observing seemed to pay them any heed, so I followed suit.  Whenever there was no Moon or favourable planet in the sky I frittered away my time in the largely futile hunt for elusive smudges of light.

And then a couple of years ago I had the good fortune to attend a lecture given by Frank Holden, a member of an almost extinct species - a professional double star observer.  As I listened to his reminiscences of solitary nights making measures with the Lick 36-inch, I became deeply impressed by his lifelong passion for double stars.  I left the meeting resolved to investigate further for myself.

My own telescope is an altazimuth 6-inch (f 1O) reflector - mainly used for Lunar studies.  I quickly realised that it was far better suited to double stars than to galaxies and nebulae.  I dug out my copy of Webb's "Celestial Objects for Common Telescopes" (virtually unused, I am ashamed to say) and set to work.

When I say "work" I really mean "play", as there is little scope for serious study unless measures can be made, and this is a different proposition entirely.  From the outset I regarded doubles as light relief from my preoccupation with the Moon.  My approach was, and still is when using my reflector, to select easy pairs from Webb's excellent lists that lay comfortably within its range.  These are mostly Struve (Σ) objects with separations above 5" and companions no fainter than mag 9.  I saw little point in being over-ambitious - having tasted the bitter cup of failure so many times with Messier and NGC objects.

I also decided to concentrate on handily placed constellations on or near the Celestial Equator.  For each constellation a list of achievable pairs is drawn up well in advance of any observing session.  There are two reasons-for this preparation.  Firstly, it gives enough time to forget the measures given in the catalogue (only the name of the pair is listed), and thus avoids estimates being compromised by fore-knowledge.  Secondly, it enables a constellation on or near the meridian to be utilised whenever an opportunity for an observing session occurs.  I normally limit myself to not more than ten objects in a session of around two hours.

Once the double has been located estimates of position angle and separation are made.  This is where the fun really starts!  At first I naturally found this operation difficult.  With an altazimuth mount it requires close attention to star drift in order to orientate for a PA estimate (with an equatorial its easier).  Judging separation by eye is simply a matter of practise and appreciation of your field diameters under different powers.  After my first 50 doubles I found that my estimates were getting towards average errors of 5" (for pairs separated by less than about 40") and 10 in PA.  I'm sure others could do better!

Its a good general rule in any area of observation not to over-press magnification, and this also applies to double stars.  I normally use a sweeping power of x60, as this will split most of my selections quite comfortably.  For closer pairs (under 5">  I use x120 - this will split down to 2.5" in good seeing.  For the occasional tough-nut I reserve my top power of x240, but T find that constant switching of eyepieces wastes a lot of time, particularly as mine have RAS threads.  For a   close pair my list will simply indicate "H.P." but will give no further clues.  A higher power can improve the accuracy of P.A. estimates because the drift of the pair across the field is more obvious.  If a companion is not seen, the fact is noted and the object re-checked at a later date. Its important not to get "bogged down" and frustrated.  For all pairs observed I make a field sketch at the telescope.

Estimates of colour are of no value in the scientific sense - and yet this is the part of double star observing I tend to enjoy most.  The subtleties of star coloration are only truly appreciated by the double star specialist.  Many are an aesthetic delight.  Once ray eye became used to perceiving colour at low light levels I found that Webb, Smyth and the other 19th century observers were not being that fanciful with their "garnets", "indigos" and "olivacea subrubicundas"!  Stars really do have the most gorgeous coloration's - if real attention is paid to them.  Colours are always more striking with complimentary pairs.  The yellow and lilac of Albireo is the most famous example of quite a common combination.  My favourite is the pair 32 Eridani (470).  The 4th mag primary is a rich yellow, with a 6th mag, comes I have noted as "emerald".  Webb describes the pair as "Topaz and Bright Green".  This companion is one of the few stars I've come across which is unmistakably green - it's a ravishing sight!  The red/green combination is best typified by Antares and its companion, but to British observers the 7th mag. attendant is a stiff test due to its low altitude and consequent poor seeing.

The expression "to my eyes" denotes the significant pitfall in colour estimates.  In its early years the BAA had a Star Colours Section, but it folded quite quickly (as did the Double Star Section!).   Colour appreciation is highly subjective and the physiological processes involved are still imperfectly understood. Colour blindness of various types is a relatively common handicap, especially in men.  Although the normal eye can distinguish thousands of colour gradations, putting a name to record each one is patently impossible.  For example, a random dip into my observing log produces the following terms to cover a close range of hues: Lilac, Pale Lilac, Purple, Purplish, Violet, Violet/Blue, Pinkish White, Pink, Rose, Reddish White etc.  Yet, allowing for etymological imprecision, I usually find reasonable and interesting comparison with the judgements of Webb and others.

But to complicate matters further there are other physiological gremlins at work.  With unequal pairs a fainter white star can "borrow" the complimentary colour of the primary.  There is also aspects of the infamous 'Purkinje Effect' (well known to VS observers) to contend with.  With my 6-inch aperture any star below 9th mag. appears a nondescript blue/grey.  This is because at low light levels the "rods" in the retina are operating alone, the colour sensitive "cones" having shut down.

Magnitude values are not really part of the double star observers province, but they are interesting to estimate and record.  When you go out to observe a Struve, Herschel or Burnham object you should bear in mind that you are very likely to he the only person to have locked at it closely for years.  You certainly won't see any dramatic changes in its configuration (most binaries have periods of hundreds of years, or it may be fixed) - but there is a very slight chance that one of the components may be variable and so far unrecorded.

When I have made my estimates of separation, PA, colour and magnitudes I have the added fun of comparing with Webb (Burnham's Celestial Handbook is another good source).  Its nice when I get it right - but there is always the occasional bizarre failure!

The doubles that teem on the pages of Norton's have come to life for me.  They are so little observed nowadays that many "one-to-one" relationships spring up.  As I sit at my telescope during the quiet watches of the night, watching those twin sparks of light floating through the field of view, my mind often conjures the vision of the Revd. Webb doing exactly the same on his vicarage lawn so long ago.  There is an indefinable tranquillity in observing double stars.  Grab yourself some.

Compilation of Close Doubles