Observational notes for january 2005




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OBSERVATIONAL NOTES FOR JANUARY 2005

All observations were carried out from a suburban location of Bury, Lancashire, England, using a Meade ETX-125EC.

There were five decent nights that month, with about half-a-dozen others available for very quick views for the Moon.
Powers used:

Low Power: 48x (40mm Meade Series 4000 Plossl)

Standard Power: 73x (26mm Meade Series 4000 Plossl)

High Power: 146x (above + barlow) OR 173x (11mm TeleVue Plossl)

Maximum Power: 345x (11mm TeleVue + barlow)

Standard power used throughout all sessions unless otherwise stated.


SESSION 1

Date : 05 Jan 2005

Time (UT) : 21:40 – 00:15

Lim. Mag. (zenithal): 4.9

Seeing (out of 10) : 6

Weather : Showery, but with clear breaks, 3°C
The Met Office’s forecast was for clear spells with a risk of showers, and also rather windy. I revisited many favourite targets, but also took the opportunity to view some lesser-known deep sky objects and even a comet !
21.40 Aligned scope on Rigel and Alpheratz.
21.45 I aimed the ETX at two faint-companioned doubles in Orion, the wide all-yellow Tau and the orange and bluish 31 Ori. I also took a look at the open cluster NGC 2175, but could only make out an asterism shaped like an inverted ‘Scorpius’ with a faint background glow.
22.00 I continued my doubles hunt in Camelopardalis, but the windy conditions and mediocre seeing made it difficult to use high power. I could just about split the white pairs of STF 385 and 389.
It was more of a deep-sky night, so I tested the ETX on the galaxy NGC 2403. I could easily see the bright core flanked by two faint stars and surrounded by a fainter halo. I took another look at NGC 1502 in the ETX and the nearby star stream of Kemble’s Cascade in the finder, although I must admit that binoculars give a better view of the Cascade.
22.10 After all the previous weeks’ studies of Perseus, I went off the beaten track of galactic targets to see something unusual so close to the Milky Way plane, namely the external galaxy NGC 1023. I could see it as an oval patch, just framed within a triangle of 9th magnitude stars.
22.20 I took the opportunity of looking at a new triple in Auriga. 14 Aur was yellowish with two faint bluish companions, one to the north and the other to the southwest. Two other previously-unseen targets in the same group were the difficult planetary IC 2149, which I managed to locate and identify, but it only looked like an 10th-mag star. I had rather more success with the Flaming Star Nebula IC 405, which appeared as a misty patch involving a ‘Corona Borealis’ of bright and faint stars, the brightest being AE Aurigae. I then took a casual look at old favourites in the group, when the stars suddenly faded from view as the sky clouded over very quickly.
22.40 RAIN ! Time to park the scope and bring it home.
23.05 The rain had cleared quickly, but the region of the southern horizon was plagued by thin cloud and scattered skyglow. Re-aligned the scope on Betelgeuse and Hamal.
23.10 I took the opportunity to seek out some more new objects in Monoceros. They included two wide doubles, namely the red / white STF 1084 and the more disparate orange / white STT 146. I also spotted a third pair in the same field as the latter, the all-white STF 921.

I tried to spot Hubble’s Variable Nebula NGC 2261, but failed, and so I slewed the ETX back to the ChristmasTree Cluster NGC 2264, and to its leading star 15 Monocerotis. This time, after training my eye, I could see some faint nebulosity surrounding the star to the south. This was all I could make out of the Cone Nebula complex, with the dark ‘Cone’ to the south strictly off-limits.


23.25 Took another look at deep-sky objects in Puppis, hoping for an improvement from December 26, there being no Moon tonight.
M47 showed up rather more clearly, revealing some 25 stars, including the double STF 1121 near its centre. The richer but fainter M46 benefitted more from the absent Moon and revealed some 30 faint stars, but I could not positively identify NGC 2438 on the cluster’s north side. The southernmost of the three Messier objects in Puppis, M93, was plagued by more skyglow, and again only showed about 15 stars.
I went north again for two other open clusters; NGC 2423 (an arrowhead-shaped group of about 10 stars in a glow) and NGC 2539 (shaped like a poor man’s Praesepe involving about 10 stars), NW of a 5th mag star.
23.40 Aimed the ETX west to Canis Major to find NGC 2354 and NGC 2384, but again skyglow from Manchester killed those objects. I lifted my spirits with M41 and the Winter Albireo.
23:50 I slewed north to a ‘lost and found’ Messier object just outside Monoceros, but allocated to the monstrous group of Hydra. Messier had apparently catalogued his 48th object four degrees north of its true position, hence its ‘going missing’ until astronomers identified it with NGC 2548. The cluster itself was a large and showy gathering of some 40 stars with a tight triangular knot of brighter stars near its centre, better seen at lower power.
23.55 I slewed the ETX north to take advantage of a gap between walls, where Ursa Major was beginning to climb in the northeast. The target here was the galaxy pairing of M81 and M82, and the brighter cores of both were clearly visible in the 26mm eyepiece field.
00.00 The next challenging target for the ETX was the very faint globular cluster NGC 2419 in the obscure group of Lynx. It was easy to locate with Autostar, as two 8th-magnitude field stars pointed to it, but I needed averted vision to confirm its existence. (As an aside, this globular is 300,000 light-years, or six Milky Way radii, away from the galactic centre, leading several astronomers to dub it an ‘intergalactic tramp’ !)
00:05 Clouds gathering from the west, but I decided to end the evening on an unexpected note. I pointed the ETX to the Pleaides, and there, in the finderscope, SW of the cluster, was Comet Machholz ! Low power on the nucleus revealed a bright core with an almost uniform circular haze around it.

00.15 Turning overcast, with another rain shower in the air. Parked the scope and closed down for the night.


SESSION 2


Date : 10 Jan 2005

Time (UT) : 21:25 – 23:50

Lim. Mag. (zenithal): 4.8

Seeing (out of 10) : 7

Weather : Clear spells, 4°C
This session was a case of ‘the calm between two storms’. Northern England had already received a gale-force battering the previous Saturday morning, with more of the same predicted 24 hours on from this session.
21.25 Aligned scope on Betelgeuse and Alpheratz.
21.30 My favourite targets revisited, with particular emphasis on Orion and Monoceros, but the other important groups also got a look in, as did Comet Machholz.
22.40 There was too much humidity and sky glow in the south for me to bother trying for the fainter targets in Canis Major and Puppis, so I looked at four new doubles in Gemini:
STT 134, in M35, yellow and bluish

STF 889, orange and bluish

63 Gem, whitish and lilac, just in same field as Eskimo Nebula NGC 2392

STF 1140, orange and bluish, needed high power to split it


23.00 I took a few minutes to enjoy the high-power view of Saturn, with the Cassini division clearly seen during better moments. Titan was clearly visible east of the planet, with Rhea closer in, and to its west.
23.10 The ‘ghostly Orion’ of Cancer was beginning to come into view high in the southeast, and so I took a first look at its two Messier open clusters.
Praesepe, alias the Beehive (M44) was a fine sight in the finder, but perhaps too scattered for the ETX to do it justice, even at low power. It did, however, contain two attractive multiple stars. STF 1254 appeared at first to be a neat triangular grouping near the centre of the ‘beehive’ whose brightest member was yellow, but on closer inspection, there was a fourth 11th-magnitude star giving the group the appearance of the ‘Lozenge’ of Draco. BU 584 was another triangle to the southwest, but I could not split its brightest component, as it was too faint and close given the conditions.
The other Messier object in Cancer, M67, revealed some two dozen faint stars with a reddish one to the northeast of the main pattern, and another further to the west. Indeed, M67 was an example of an ‘old’ open cluster, where most of its stars had evolved into red giants.
23.20 I then aimed the ETX well off the beaten track of the winter constellations to focus on two non-Messier galaxies high in the east, approaching the zenith. NGC 2683 in Lynx was rather tough, in the same field as a quadrangle of 10th and 11th mag stars, and I needed averted vision to confirm it. NGC 2841, in western Ursa Major, was much easier, forming a right-angled triangle with a 9th and 11th mag field star.
23.55 Clouding all over and a Motor Unit Fault. Time to go home !
SESSION 3
Date : 13 Jan 2005

Time (UT) : 17:25 – 23:55

Lim. Mag. (zenithal): 4.8

Seeing (out of 10) : 7, improving to 8-9

Weather : Clear spells, 1°C
17.35 I set the ETX up roughly to take a quick look at the 3-day-old Moon, and was rewarded with a good view of the Earthshine, where I could make out several maria and a few brighter craters, particularly Aristarchus and Kepler. The main highlights near the terminator were, from north to south, Mare Crisium, the craters Langrenus, Vendelinus and Petavius, and Furnerius to the south of that trio. After viewing, I left the ETX outside to cool down, knowing that there was no rain expected that night.

21.25 Return outside after dinner for a mixed viewing session. This time I performed an accurate two-star align on Betelgeuse and Alpheratz.


I tested the night’s seeing with doubles in Cassiopeia, now at a more comfortable altitude. STF 3057 (all-white, large difference in mag), 6 Cas (white and blue, closer) and STF 3062 (yellow and blue, closer still) were all easily split at maximum power, suggesting a night of very good seeing. I then went for four previously-unseen doubles, all at maximum power. The first was a toughie on Clay Sherrod’s list, 36 Andromedae, said to be a test for the ETX 125 with its 0.9” separation. The best I could get at 345x was an elongation of the orange primary, but no black space. By contrast, STF 228, with a given separation of 1”, was just about split. My last search in the western sky was the yellow and blue pair of STF 285 in Triangulum, again cleanly split.

21.55 I decided to try something different, and look for a couple of variables near maximum in Sky and Telescope’s list, using low power.


R Ursae Majoris appeared roughly about mag 7.2 using two field stars to its southwest of mag 5.7 and 8.3 as comparisons, and a 5.0 mag star to its northwest. U Orionis was brighter, and I roughly estimated it as mag 6.5, compared to two field stars of mag 7.7 and 8.4 to its north, and 57 Ori (mag 5.9) to its south. Both of those Mira-type variables appeared strongly red in the eyepiece.
I continued where I left off to complete the survey of double stars in Camelopardalis. SAO 24169, SAO 14407 and STF 973 were all ‘mock-Albireos’, with the first two better seen at low power. I could detect the 9th-magnitude companion of Kuiper 16 at medium power, but could not see the closer companion even at maximum.
22.20 Cloud patches creeping in from the west, but with a trailing edge in sight, so I had a cup of tea and continued for a happy hour of dodging between clouds to revisit the usual favourites.
23.45 I decided to conclude the night’s session with a new showcase multiple system, Zeta Cancri. High power revealed it to be an all-yellow double, but barlowing to 345x just separated the A and B stars with a hint of black space during moments of best seeing. A splendid triple system for the ETX !
23.55 Work beckoning me for the morning – time to go home !

FOOTNOTE ON DOUBLE STARS.


Astronomers use two criteria of telescopic resolving power, the Dawes limit and the Rayleigh limit. The former defines ‘resolution’ as the ability to see the components as separated, but allowing about 15% overlap in Airy disk diameter. The latter, on the other hand, insists on clear black space.between the components.
To obtain the Dawes limit, you divide the aperture in millimetres into 116; for the Rayleigh limit, divide the aperture into 138.
The Dawes limit for the ETX 125 is 0.91” and the Rayleigh limit 1.09”. (I have used an aperture of 127mm).
The following four doubles were all close to the Dawes and Rayleigh limits (with altitudes given at the time of observation):
36 Andromedae, separation 0.9”, mag 6.2 and 6.6, alt. 30 deg FAIL

STF 228, separation 1.0”, mag 6.6 and 7.2, alt 60 deg PASS

Kuiper 16 (A/B), separation 1.1”, mag 6.2 and 10.5, alt 80 deg FAIL

Zeta Cancri (A/B), separation 0.96”, mag 5.7 and 5.9, alt 50 deg PASS


Of the four, Kuiper 16 was the most disparate in magnitude, so it is perhaps not surprising that it did not ‘perform’ to the resolution limits. 36 And was a failure since it was lower in the sky and more affected by seeing than the other three.
(The A and B components of Zeta Cancri have a short orbital period of 60 years, and the separation, which was 0.8” in 2000, had increased to 0.96” by 2005. )
LUNAR INTERLUDE
These nights offered only a brief viewing window for the Moon at various phases, including the option of looking through windows, both open and closed ! Weather conditions prevented the use of any power above medium, as it was generally very windy with poor seeing throughout the whole week. One can only hint at the detail that would have been visible under better conditions. Viewing through a closed window was the equivalent of looking through one of those dreaded ‘department-store’ scopes !
14 Jan – 19.00 Moon 4 days old.

From north to south, the new features on the terminator were the craters Endymion, Geminus, Cleomedes and Proclus. The whole of Mare Crisium was on view, as was the eastern half of the Mare Foecunditatis. Langrenus and its companions were still fairly prominent. (Viewed from the garden).


15 Jan – 19.45 Moon 5 days old.

I had to view the Moon through an open window inside, as it was too windy outside. The highlights of the terminator were the crater Posidonius, Mare Tranquillitatis, and a very dramatic-looking Theophilus chain, with Cyrillus and Catharina in especially deep shadow. Further south, Piccolomini and the Altai Mountains were equally prominent. This was an extremely short session, lasting only a few minutes in the fickle weather.


16 Jan – 18.00 Moon 6 days old.

This time the weather had calmed down enough for more than just a cursory glance, allowing a more rewarding viewing session, from the garden. In the north, the crater pair of Aristoteles and Eudoxus was striking, with the former’s floor covered in shadow and the latter’s eastern rim just receiving the sunlight. Further south, the small crater of Bessel on Mare Serenitatis stood out, as did the crater Menelaus and the Haemus mountains on the Mare’s southern edge.

Menelaus. I also detected a rill on the Mare. Other craters of note further south were the dilapidated Julius Caesar, along with the more regular Delambre and Descartes, as were many stellarform rim ramparts and moutain peaks. Two fine craters in the rugged south were Sacrobosco and Maurolycus, the latter particularly stunning in shadow. Away from the teminator, the Theophilus trio was still prominent.

17 Jan – 22.30

Moon 7 days old.

Viewing from the garden, the terminator had moved west to reveal new chains of craters and mountains. In the north, the Alps and the chisel-cut of the Alpine Valley were very prominent, as was the peak of Mount Piton. The Caucasus and eastern Apennine ranges were equally striking, with the crater pair of Aristillus and Autolycus adding to the scene. Further south, the Mare Vaporum was in view, as were Hipparchus and Albategnius, and the eastern wall of Ptolemaeus was just emerging into the sunlight. Another crater-pair coming to prominence was Werner and Aliacensis, with nearby Walter slap-bang on the terminator. Nearby, the eastern walls of Regiomontanus and Purbach were just emerging into sunrise.


18 Jan – 2100 Moon 8 days old.

(Viewed from the garden.)


The terminator had now reached Plato, Mount Pico and the western fringes of Mare Frigoris, with Archimedes well in sunlight but still prominent. Eratosthenes was right on the sunrise line and especially striking. Moving south, the chain of Ptolemaeus, Alphonsus and Arzachel was very impressive, with the long shadow cast by the Straight Wall very impressive. In the southern highlands, the craters of Sasserides, Maginus and the eastern rim of Tycho were on view.
18 Jan – 2350

(Viewed from closed window !)

Plato, Eratosthenes and Tycho had cleared the terminator, its westward movement evident in the space of three hours. The Teneriffe Mountains were on view south of Plato, and Timocharis was partly visible. The must magnificent sight, however, was Clavius. The rim of the main crater was lit, but the floor was in shadow, with the rims of the craterlets appearing like tiny rings in the void.

19 Jan – 21.55 to 22.15 Moon 9 days old.

(Viewed from closed window, windy !). Clouds scudding very quickly, with much turbulence degrading the image very badly at times. Lunar sunrise had now lit up the Straight Range, central Mare Imbrium, and the eastern Carpathian Mountains. Copernicus was a glorious sight, with its floor in deep shadow. Further south, the craters of Reinhold, Fra Mauro, Bullialdus on the western Mare Nubium, and Longomontanus were also coming into prominence.
20 Jan – 23.45 to 00.15 Moon 10 days old.

(Viewed from closed window). How quickly lunar features change ! Two days ago Tycho’s dark floor was its main feature, but now its rays were beginning to drown out nearby fine detail. Tonight’s terminator highlights were the striking Sinus Iridum (with the pair of Helicon and Leverrier still prominent to the east), the Jura Mountains, Heraclides Promontory, and the western Carpathians. Further south, there were Euler, Tobias Meyer, the Riphaeus Mountains, with Kepler and Encke on the Oceanus Procellarum. Continuing to the south, the main attractions were the eastern rim of Gassendi, Mare Humorum, the figure-8 of Hainzel, with Scheiner and Blancanus near the south pole.

SESSION 4
Date : 22-23 Jan 2005

Time (UT) : 22:40 – 05:10

Lim. Mag. (zenithal): 4.2 (near-Full Moon)

Seeing (out of 10) : 6-7, with moments up to 8

Weather : Clear, -3°C
22.40 Aligned the ETX on Procyon and Alcyone (Pleiades). Revisited favourite brighter targets in Orion, Perseus and Taurus, and was surprised at how well the Trapezium region of M42 held up despite the Moon.
HERCULES’ DOUBLE BANE - THE CRAB AND THE WATER SNAKE
23.30 The brilliance of the southern winter sky had begun to give way to some dimmer groups to the east. They included two of Hercules’ victims; the immensely long Hydra, alias the Water Snake, and Cancer, the Crab.

23.35 I began with Cancer, revisiting Praesepe (M44), but giving M67 a miss this time, due to the Moon. Despite its faintness, Cancer was surprisingly full of fine doubles. Iota was a splendid yellow and blue pair at low power, doing a very passable impersonation of Albireo. Less striking, but similar in colour, was 57 Cancri, whilst STF 1245 was yellowish and white. I then used high power to split the white pairs of STF 1177 and the well-matched Phi-2, and revisited Zeta. The seeing was poorer than on the 13th, with the A-B pair merely elongated, though the C star was easy. Continuing on high power, STF 1311 and STF 1181 were both whitish-yellow, and 11 Cnc was reddish and white. I revisited 57 Cancri to find that the brighter yellow component was again double. I concluded my tour of the Crab with high-power views of 24 Cancri (yellowish and blue) and 66 Cancri (white and bluish).


00.10 I then began to tackle that longest of all constellations, wisely deciding to restrict the doubles to those west of the 10h RA line, else I would have been up until 6 a.m. (As it happened, I stayed up almost as late anyway to observe Jupiter – see below).
The first warm-up target was a revisit of the loose open cluster of M48, before starting on the doubles in the realm of the Water Snake.
The following were wide enough for standard power:

Theta (white / blue, tough due to faintness of companion); Tau-1, (yellow and orange); STF 1210 (white); STF 1255 (yellowish pair); STF 1309 (yellowish pair) and STF 1347 (white).


High power was needed for the following:

STF 1270 (white); Epsilon (yellow / blue, attractive but tough, like Izar in Bootes); 17 Hya (white, well-matched); STF 1355 (not too easy due to mediocre seeing); not best, white); STF 1348 (one medium-power field west of above, still tougher, like a faint Zeta Aquarii); STF 1365 (yellowish) and STF 1260 (white).


My last Hydra target was one of the sky’s finest planetary nebulae, the ‘Ghost of Jupiter’ or NGC 3242. High power revealed its oblate ‘Jovian’ disk, although it was more like Uranus or Neptune in colour !
00.50 Having seen Jupiter’s ‘Ghost’, I slewed the ETX onto the position of the real Jupiter, and took a couple of hours’ nap. I figured it would be about 02.30 before it came into view from my garden vantage point. I was particularly interested in following the shadow transit of Io, predicted to start at 04.29.
JOVIAN PHENOMENA WITH THE ETX
02.50 Jupiter was just about in the ETX’s field at 73x. I saw Europa two Jupiter-diameters west of the planet, with Io, Ganymede and Callisto one, two and four Jupiter-diameters to the east of it. I could not make out either the Red Spot or the Hollow, but easily recognised the two equatorial belts and the polar regions, those being darker than the zones.
03.10 Coffee break, followed by revisits of favourite targets in Auriga and Gemini. M37 held up fairly well despite the Moon, especially when viewed at higher power to darken the sky background.
04.20 Time for some serious study of Jupiter ! When viewing in the 11mm eyepiece at 173x, the first thing I noticed was that Io had moved a lot closer to the planet in the last hour and a half. I could make out a few festoons in the cloud belts with the light blue filter, but the moments of really good seeing were quite brief, giving the planet a ‘mushy’ and out-of-focus appearance for much of the time.
04.30 - 04.45 The seeing remained good but not brilliant, but at 04.45 I noticed something different about the North Equatorial Belt. During better seeing moments, I could make out a slightly blurred dot on it, close to the eastern limb of the planet. This was the shadow of Io in transit across the Jovian disk !
05.05 Io and its shadow were almost equidistant from the Jovian limb, but in the last few minutes the view had gradually become foggier, and the awful truth hit me. The dewcap had kept the ETX’s corrector lens frost-free for over six hours (not bad for winter), but the first tendrils of frost were starting to spread on it.
05.25 Jovian disk rapidly losing definition, Io’s shadow gone from view. The corrector lens was frosting over fast !.
05.30 Parked the scope, having had to abandon seeing the actual transit of Io with some ten minutes to spare. On the bright side, I comforted myself in the knowledge that there would be more Jovian satellite events to follow later in the year !

SESSION 5


Date : 23-24 Jan 2005

Time (UT) : 22:45 – 00:35

Lim. Mag. (zenithal): 4.1 (Full Moon)

Seeing (out of 10) : 7, with moments up to 8

Weather : Clear spells, -3°C

(Murphy’s Law: Full Moon nights are always clear, except during lunar eclipses.)


22.45 Aligned the ETX to Procyon and Alcyone, having set the ETX up on the #884 tripod, to see how far south I could go. The tripod gave me sufficient extra height to reach down to extending to 30 degrees south instead of 27.
A BRIGHT DOG AND A DIM CAT
I went for another look at the Canis Major / Puppis region before surveying the much fainter group of Lynx.
22.45 I used the technique of using higher power on some of the fainter clusters in Canis Major to dilute the skyglow caused by the Moon. It worked quite well for NGC 2362 around Tau CMa, revealing a broken circlet of about a dozen stars. I could also make out about half-a-dozen stars in NGC 2354.
23.05 Reached as far south as Epsilon CMa (Adara), but could only catch a tentative glimpse of the companion, as the seeing was poor at the altitude of 7 degrees. I searched out some easier doubles in the group, namely BU 328 (all-white), h3934 (all-white), h3938 (blue and white). Higher power also split the all-white pairs of h3950 and STF 1011, the latter having a red star to its southwest in the same field.

23.20 I used higher power on M93 in Puppis. This diluted the skyglow quite well, and I was able to make out about two dozen stars forming a pattern resembling a southbound butterfly.


23.45 I slewed the ETX north to study double stars in Lynx, having looked at the tough deep-sky objects there in the last fortnight. I needed the eyesight of a lynx to see much there, especially with the Moon nearby. Still, the GOTO helped where star-hopping would have been futile. The tripod helped for the near-zenith stars – it was far easier on my neck !
Medium power gave good views of the white pairs 20 Lyn and 19 Lyn, the former being especially well-matched. Also noted were the orange and bluish pairs of STF1025 and STF1234.
High power revealed 12 Lyn to be a colourful triple not unlike Iota Cassiopeiae, with a close white / yellow pair and a more easily-resolved bluish star. Four well-matched white pairs followed, namely STF 958, STF 1009, STF 1282, and STF 1333, with the last-named needing maximum power.
More colourful, again at high power, were the white / yellow 38 Lyn , the yellow pair of STF 1369, and the light orange 5 Lyn with a faint bluish companion.

A SATURNIAN QUINTET

00.20 I concluded the night’s session with a view of Saturn and its moons, and this time I sketched the positions accurately enough to match up with Sky & Telescope’s Java applet. At high power, the Cassini division was well on view, with Titan about 2’ SE of the planet. Two fainter moons were about 1’ east of Saturn, and I subsequently identified them as Tethys (the nearer one) and Dione. Another moon, Rhea, was about 1’ north-east of the planet.



I spotted two 10th-magnitude objects in the same 173x (18’) field, one west of Rhea and the other east of Titan, but I had to check if they were simply background stars in Gemini. I found, using SkyMap, that the object east of Titan was indeed a star (TYC 1373-1617-1), and that the object west of Rhea was Iapetus, near western elongation from the planet and hence bright enough to be seen in the ETX.
00.35 Parked the scope, as I had work to go to in the morning !


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