MIRA 20
March 1988

M42


M42 A composite drawing of many nights detailed observation over the winter months.  Even so, a drawing can never reproduce the the subtleties of this wondrous object.

Instrument 8 ½ in. Reflector x80 (with greater detail picked out at x180.)
29' Field of view
Most nights can be described as reasonably clear and steady.
Observer Mr. Barry Merrikin


The following is a key of some of the features named by John Herschel in 1726 to which M42 resembled some kind of monstrous animal and depicted in Mr. Merrikin's drawing.


1 Regio Huygeniana  Named in the honour of Huygens whom Herschel mistakenly believed was the discoverer of M42. This area surrounds the Trapezium the multiple star Theta Orionis and represents the upper part of the head of the beast.

2 Rostrum               Represents the beak.

3 Proboscis Major     The greater trunk and first recorded in 1773 by Messier with a 3.3 refractor.

4 Regio Messieriann  The Messier region a dark lane.

5 Proboscis Minor     Only partly recorded.

6 Sinus Magnus      The Great Gulf, this area represents the open mouth of the beast.

7 Regio Fouchiana   Named after J.P. Grandjean, a assiduous observer of the Orion Nebula as are the following names below.

8 Regio Godiniana   L. Godin.

9 Regio Picardiana   J.Picard.




Jupiter Observations


Date         1987 November 2
Observer   Rob Moseley
Time         23.10 U.T.
Conditions Ant. Ill Transp. Fair
Instrument 12in. Reflector x 175

w1 341.6°
w2 014.6°

The drawing represents a typical view of Jupiter during the apparition now drawing to a close.
However, at the time of writing (10/2/88) several significant changes have occurred; the NTB having faded and the STB also becoming increasingly obscure.
Features to be noted on the drawing include the elongated dark spots on the NTB (which was sometimes seen as double near to opposition in October); the white rift in the NEB, the strong delineation of the Red Spot Hollow (but little evidence of the Red Spot itself); the appearance of a thin belt preceding the Red Spot Hollow in the STRZ throughout Sept-Dec, (after which it disappeared); and a rare view of the STZ ( which has been very obscure throughout).
Note also Europa casting its shadow just N of the STB.
37 drawings of the planet have been made and over 200 transits timed since 26/7/87



Date          1987 November 13th
Time          22h 00m to 22h 30m UT
Instrument 6in. Reflector F/10
Mag.         x120 and 180
Observer   Vaughan Cooper


The S.E.B. is approximately twice as broad as the N.E.B. and seemed to taper slightly as it approached the eastern limb.
N.E.B. fairly straight and even although a slight suggestion of a darker area on the southern edge preceding the C.M.
N.T.Z. well seen but not recorded on my drawing.
Satellite 1 — Io seen reappearing from Jupiter's shadow to the east of the planet at 22h 10m UT.



Date         1987 November 19th
Time         22h 15m to 22h 30m UT
Instrument 6in. Reflector F/10
Mag.         x60

Conditions Ant III to IV
I had the impression of a large feature occupying the southern edge of the S.E.B. preceding the C.M. with perhaps a slight undulation following it.
The N.E.B. again an impression at times of irregular edges to the belt, but not certain enough to record on my drawing, however a dark area around the northern edge of the N.E.B. following the C.M. was believed to be seen.

The above feature mentioned on the S.E.B. and hollow preceding the C.M. was clearly seen the following night approximately 20 hours later (two rotations of Jupiter) with Mr. Moseley's 12in reflector.





Interesting Astronomical Facts

In 1933 the Americans decided to utilise the light from Arcturus to switch on the lights of the World Fair in Chicago.  Forty years prior to that date in 1893 there was another World Fair in Chicago, and as the distance of the star is 40 light years away, it was thought to be appropriate to use the star light which started it's journey through space in 1893 to switch on the lights of the World Fair on it's arrival on earth in 1933.  The starlight was captured in a telescope which focused it onto a photo-electric cell where a tiny electric current was generated by the incident starlight. This small electric current was suitable amplified to make it powerful enough to switch on the lights of the fair.
Arcturus is about 20 million miles in diameter and is exactly 100 times brighter than the Sun, with a unique proper motion of 2.3 seconds of arc per year, mainly towards Spica in Vergo.  The angular separation between Arcturus and Spica is about 38°.  So at a rate of 2.3 seconds a year Arcturus will be close to Spica in 60,000 years time.  This is one example of the so called fixed stars which are far from stationary, as Arcturus shoots through space at about 75 miles an hour.

I would be most pleased if any member could contribute something of interest under this title for future issues of Mira it could be either astronomical or space flight related subjects.
Ed. V.C.





A Review Of The Star Party
On 13th November 1987
At Mr. G. Johnstone Residence

The early evening set in with patchy broken cloud moving quickly across the sky, by the time Rob Moseley and myself arrived at Geoff's residence, cloud totally covered the sky with just the small odd breaks in it, the observing session at this point looked over before it ever began, and the discussion, among the six members who turned up, either to go home or temperately retire to a pub and review the situation in an hours time, neither of those alternatives proved necessary as Geoff showed us his observatory and telescope equipment he has acquired and used over many years.  The present set up consists of a short focal length 10in. Newtonian reflector on a driven equatorial mounting made by Astro Systems Ltd., with I think a 6in. F/8 telescope attached to the 10in. in piggy back style.  The latest accessory is adjustable film holder which fits into the draw tube of the 10in. and has the advantage of accurately following moving objects like comets in P.A. without recourse to adjusting the telescope during the time of exposure.
The observatory, a 6 foot or so square building was converted from a summer house, Geoff acquired from a relative the structural design and available space within the observatory Geoff feels could be improved and a more convenient observatory to work in is being considered.
With the tour of the observatory over the clouds obligingly cleared, presenting us with a truly magnificent sky.  The 10in. was in heavy demand from the six of us that night as Geoff obliged us with our demands of wanting to see various objects.  I saw M33, a face on spiral in Triangulum, this can be a very elusive beast but with a 10in. of a short focal ratio it's an easy prey.  M36, 37 and 38 are three particularly interesting star clusters, although they are effectively of the same nature i.e. a cluster of stars and lie comparatively close to each other in the sky, they all have different qualities about them.  I meant to look for, but forgot, NGC 1907 which to me with my 4in. reflector appears as a faint tail to M38 of which I've only seen once before.
M81 and M82 the two galaxies with the greatest northern declination was well seen.  M82 the edge on galaxy of the pair I could see a slight mottling quality of it's image.  The double star cluster in Perseus was very impressive as the cluster of stars simple filled the field of view.  I had to miss my chance to see M31 the spiral in Andromeda and M42 the Orion nebula and Jupiter as I was occupied with firstly carrying out repairs to the mounting of my 4in. f/4 reflector I took along with me which decided to come apart as soon as I set the equipment up at the bottom of Geoff's garden, once operable again, I was intrigue to compare the views along the Milky Way through my 4in. reflector (a good proportion of which I made myself) to the newly acquired 8in. Celestron telescope donated to the society by Mr. A. Longbottom, although the 5in. Celestron has a slightly better advantage in reaching fainter stars and perhaps has a larger field of view theres precious little difference between them.
Towards the close of the evening I was fortunate enough to see M42, a view which left me with the deepest impression through Barry Merrikin 8 ½in. reflector.  Never before have I seen the gas clouds of the nebula broken up into isolated little clumps, like a Mackerel sky as a certain member would say this was quite unexpected, although I've naturally seen the nebula on many occasions with many different telescopes. The moral of the story is, the sky always has something new to show you, if only you took the trouble to look.
Between the visual observing Andy Johnson got to grips with some astro, photography with a ordinary commercial camera on a portable but equatorial driven mounting, the advantage with this set up is you can reach stars well below naked eye visibility and still retain sharp star point images without any trailing.
In some respects it's a pity more members didn't come along as I feel it's a fascinating business to compare the same views through different instruments! and generally improve ones knowledge by getting involved with the practical side of observational astronomy, but the benefits to be reaped with a small group in attendance we, didn't have to wait very long before it was your turn to look through a 8 ½in. or 10in. telescope.

Many thanks are due to Geoff for his general hospitality, the free use of his telescope and the coffee and biscuits.
V.C. Ed





Fra Mauro area


Fra Mauro area
Drawn by V. Cooper

Date          1987 Nov 14th
Time          5h 25m to 7h 00m UT
Conditions   Ant III to II
Instrument  6" F/10 Reflector x180 and 240
Co-long      188.50 to 189.30



Lunar Notes

Guerike  36 miles in diameter the walls are regular on the west and fragmentary on the east.
A wide valley traverses the interior north to south, it also contains on the south/west, ridges craterlets and clefts all requiring large aperture telescopes.
Bonpland 30 miles in diameter, the west walls are low and broken, while on the interior are crater lets hillocks and clefts.
Parry 25 miles in diameter, intruding into Bonpland.  The walls are broken in many places and one of the peaks rises to 4,900 ft.  The interior contains craterlets and a cleft which runs E.W. under the south wall, and another under the west and east wall which continues across Fra Mauro.
Fra Mauro 50 miles in diameter and in a ruined condition. The interior contains a number of parallel ridges, craterlets and large cleft running north to south from Parry, visible in telescopes of moderate aperture.
To the north of Fra Mauro, the LEM Antares landed on February 5th 1971 at 10.18 GMT, the landing point was only 87 feet off target and 75 seconds late from it's planned schedule.
50 minutes later the expedition commander A. Shepard, America's first man in space with a 15 minute space lob and only one of the original seven Mercury astronauts, finally stepped onto the lunar surface.  The prime objective of the mission was to visit Cone Crater lying nearly one mile away and 400 ft. above the touch down point which Shepard and Mitchell attempted during the second EVA, loading up their small hand towed cart, the second wheeled vehicle to be used on the moon, they set off for the rim of Cone Crater.
After 2 hours 10 minutes they were 50 minutes behind schedule and tiring and had to turn back before reaching the rim. If the astronauts had succeeded in reaching the crater they planned rolling stones down the inside of the 125 ft. deep crater.  Shepard made up for this by becoming the first lunar golfer.  He produced two golf bails and used the pole of the solar wind experiment to tee off.
The total stay time on the lunar surface 33h 30m, surface excursions 2, duration of the excursions 9h 17m, traversed a total distance by walking 3.3 k.m, collected and returned to Earth 43 kg of lunar rock and soil.