Etx-125 observations for march 2005

Дата канвертавання24.04.2016
Памер44.35 Kb.
I had been able to piece together seven viewing sessions for this month. All sessions except one were conducted from my rear garden in Bury, Lancashire, England (11 miles from Manchester, moderate light pollution). All times are in UT, coincident with local time .
Eyepieces used throughout all sessions were:
Low power = 40mm Meade Series 4000 Super Plossl (48x)

Standard power = 26 mm Meade Series 4000 Super Plossl (73x)

High power = above plus 2x Meade barlow (146x), or 11mm TeleVue Plossl (173x)

Maximum power = 11 mmTeleVue Plossl plus 2x Meade barlow (345x).

Standard power was used throughout all sessions unless otherwise noted, generally for viewing planets or double stars.

Session 1, March 5, 2005

Conditions: clear breaks, wind E fresh, -1° C, limiting mag 4.8, seeing 5-6

Time (UT): 21:30- 00:10
This session was rather a poor affair, dominated by an obsessive attempt to nail the notorious galaxy M101 in Ursa Major.
21:30 Aligned ETX on Regulus and Aldebaran.

21:40 Revisited various galaxies in Coma, and the absence of the Moon made a noticeable difference. The trio of M98 / 99 / 100 was visible far more plainly than on February 20, and M85 and M64 were easy. I made another attempt to log M91 (NGC 4548; some older textbooks identified it as NGC 4571), and this time I was successful, as I saw it to the east of a slightly crooked line of field stars.

Another new sighting in Coma was the ghostly needle-like NGC 4565, but it took some effort to see in direct vision, forming an isosceles triangle to the north of two 10th mag stars. It seemed easier at second glance.
22:15 Home for a tea break as a band of cloud moved in.
22:45 I had another scout round Leo and its environs to locate some non-Messier galaxies, but I could only pick up two with averted vision, and the increasing clouds.
NGC 3489 in Leo appeared to be in the middle of the ‘stem’ of a faint mushroom-shaped field of faint stars.
NGC 3166 in Sextans was again barely visible, with an intriguing asterism to its south forming a flattened hexagon, not unlike a ‘Kraft’ logo.
23:55 I had another try at M101, now very high in the east and past our wall. I identified the field correctly, but could only see a dim fuzzy star in the galaxy’s position, conflicting with Messier’s description ‘pretty obscure and very large’. Was that the nucleus, and the rest of the galaxy was too dim to see ?

00:10 Getting cloudy and feeling like minus 6 in the bitter easterly wind. The most sensible thing was to end the session and go home.

Session 2, March 6, 2005

Conditions: clear break, wind NE fresh, -2°C, limiting mag 4.7, seeing 7-8

Time (UT): 19:20-22:20
The seeing was rather better than last night, but the transparency lower. This was a night for revisiting close doubles until clouds ruined the session.
19:20 Aligned ETX on Betelgeuse and Hamal.

19:35 I revisited the following variables to see how they were doing:

U Orionis was fading to 7.8

R Leporis was near its maximum of 7.3, and getting low.

R Geminorum was fading to 9.1

R Aurigae was brightening to 10.2

20:00 Revisited winter deep-sky favourites, now going down in the early evening sky. One overlooked multiple was Alcyone in the Pleades, seen as a bluish-white foursome in a pattern like a bent ‘Sagitta’, though maybe too wide to be classed as a true multiple.
21:50 After dinner, I took a look at some difficult test doubles for the ETX. STT 215 in Leo, Eta Geminorum, the A and B stars of Zeta Cancri and Iota Leonis were all visible with some effort, as was Xi Ursae Majoris (Alula Australis). Still in Ursa Major, I split the white pairs of STF 1559 and STF 1695, the former with some difficulty.
22:20 Clouds were rolling in without any sign of a trailing edge. Parked the scope.

Session 3, March 11, 2005

Conditions: mostly clear, wind N fresh, -1°C, limiting mag 5.0, seeing 6

Time (UT): 22:20–01:15


This was a night of good transparency, and provided me with a chance to seek out some non-Messier galaxies in Ursa Major and Leo, with an errant globular in the south. I used standard power tonight, as it was too windy to carry out any high-power viewing.
22:20 Aligned ETX on Regulus and Aldebaran.

22:25 I went on another tour of Ursa Major, this time aiming for a variety of non–Messier galaxies. Many were tough and barely visible in the ETX, but here is the list of my attempts:

NGC 2985: I could make out a distinct trapezium of 10th-mag stars, but no galaxy within it. FAIL

NGC 2681: I saw it south of a faint diamond-shaped asterism, but west of a slightly brighter star.

NGC 3198: just visible, forming a dim ‘sickle’ with its field stars.
NGC 3359: only one star in a very barren field, no sign of any galaxy. FAIL
NGC 3631: just visible, with a tiny triangle of 10th-mag stars to its south.
NGC 3675: I could make it out to the north of a trapezium of 10th-mag stars.
NGC 3938: just visible east of a near-right triangle of field stars, of which the furthest one was double.
NGC 3941: I was looking for the galaxy to form a rectangle with three other field stars (with the NW one a double), but got ‘no result’. FAIL
NGC 3945: I could only see a large tall triangle of dim stars filling the field, with nothing inside it. FAIL

NGC 3726: I could just make it out in averted vision, with two faint stars pointing directly to it.

NGC 3893: just visible in averted vision north of a reddish star, and with a faint star just west of it.
NGC 3953: no galaxy to be seen in a barren field. FAIL
23:00 I then continued the galaxy search in Leo and its faint neighbours for some more first-time targets. NGC 3486 in Leo Minor was again in a star-poor field with only one star to its north for company, but I just held it in averted vision. The same held true for NGC 3169 in Sextans, which looked almost stellar next to a faint field star, and shared the field with NGC 3166 to its west.
23:20 I had five more galaxies in Leo to aim for, as follows:
NGC 3227: I just held it in averted vision, due north of a fairly distinct zigzag of four stars.
NGC 3377: visible with direct vision southeast of 5th-magnitude star 52 Leo and in the same field. Slewing the scope to get the star out of the field made the galaxy easier to see.
NGC 3412: I could just make it out, forming a long triangle with two closely-separated stars to its northeast.
NGC 3607: just visible northeast of a dim triangle of field stars.
NGC 3640: could be seen forming a symmetrical wide ‘T’ with three field stars.
23:50 – 00:20 Cloud band passing over, so I took a tea break.
00:25 I finally managed to hold M101 in Ursa Major in direct vision, with the wind helping me by rocking the scope. The nucleus was fairly distinct, but the surrounding halo was very dim indeed.
00:50 I then slewed well to the south to seek out M68 in Hydra. It formed a tall isosceles triangle with two stars to its south, but it was unspectacular, as it was dimmed by haze.

01:00 I was getting tired, so I parked the scope. Besides, I had a star party in the Lakes to go to the following day, a chance for the ETX to showcase its ability in a dark sky – weather permitting. It was not a bad night, spotting 15

new galaxies close to the limit of the ETX’s capabilities in suburban skies.

Session 4, March 12, 2005

Location: Haverthwaite, English Lake District, UK rural

Conditions: mostly clear, wind NW light, 0°C, limiting mag 5.9, seeing 6

Time (UT): 19:20–23:15

This was the first time I have been able to use the ETX to its full advantage from a dark site, in one of the loveliest areas of England, with only marginal light pollution from Kendal and Lancaster, 20 miles away to the east and southeast. This trip to Haverthwaite was organised by Bolton Astronomical Society, of which I am a member.
Other telescopes on show included a Meade LX-90 and a home-made 12-inch binocular where the observer looked with their back to the object. The 5-inch ETX was not disgraced in such competition, with the darker sky revealing objects with much more clarity than was possible from suburbia. In fact, Praesepe and the Double Cluster were very easy with the naked eye, and I could also distinguish M34, M35 and M37 without optical aid.
19:20 Start of the session, with a rough align to get the setting 2-day-old Moon and Mercury in view. I could make out features on the Earthshine-lit portion clearly, and just about managed to spot the phase of Mercury despite the poor seeing at its altitude – it was slightly gibbous. Had there been no Moon, there might even have been a chance of seeing the Zodiacal Light.
19:40 The sky was now dark enough for an accurate alignment of the ETX, using Procyon and Aldebaran. It came as a bit of a shock to realise how bright Mercury appeared to the naked eye as it was ready to set.
The rest of the evening was a casual social affair, where members were invited to look through others’ scopes. My viewing session featured a fascinating mix of targets, and I left the ETX focused on each one for a few minutes at a time, allowing other club members to take a look. Targets in bold were actually observed through the ETX by colleagues as well as by myself.

20:00 to 21:30 I spent the next hour and a half revisiting winter favourites, and many of the clusters and nebulae were much more spectacular than from home.

(The actual viewing order was more random than listed here: I have arranged the objects by constellation for ease of reading.)
Orion: M42 and Trapezium, M43, M78, 2169, Sigma, Rigel

(Looked at M42 through 12” bino)

Monoceros: 2244 with parts of Rosette, 2264, M50, 2301

Taurus: Alcyone, M1

Canis Major: M41 and the Winter Albireo

Gemini: M35 and 2158, 2392, Castor, Saturn

Puppis: M47 and M46

Perseus: M76, M34, Double Cluster

Auriga: M36, M37, M38, IC405

M42 showed highly intricate structure, far better than when seen from home, even without a nebula filter. I could also positively make out parts of the Rosette, especially to the west of the cluster NGC 2244. Similarly the nebulosity of AE405 was obvious, and not just tentative as at home.

The open clusters were also much brighter; M35 and NGC 2158 were superb, with the latter appearing almost globular. M37 showed over a hundred stars down to 12th-mag, and the Double Cluster was magnificent at low power, with innumerable stars in the field.

21.30 Parked scope and took a tea break
21:45 to 23:15 I spent the next ninety minutes on a tour of spring deep sky objects, but before I continued with the show, I re-aligned the scope on Arcturus and Regulus.
The dark sky proved to help most with the galaxies. The south-eastern sky was mostly blocked by tree branches, so it was a bit ‘hide and seek’ there for targets in Leo and later in Coma, but the north was clear, with Ursa Major, Draco and Canes Venatici all well-placed.
Cancer: M44 in finder, M67, 2775

Ursa Major: M81 and 82; M97+108, M101

(Looked at M101 through 12” bino, also M97 and 108)

Canes Ven.: M51+5195; M3

(Looked at M3 through another’s LX)

Draco: 5866 (first light) (M 102 ?)

Leo: 2903, M95-96, 105, 3371(3384), M65, M66, 3628, Gamma

(Looked at 2903 through 12” bino)

Sextans: 3166, 3169

Leo Minor: 3344

Coma: M64, 4565, 24 Com

The ‘old’ cluster of M67 in Cancer was spectacular, with twice as many stars visible here as from the suburbs, but it was the galaxies which showed the most improvement. M51 clearly revealed an outer halo and a hint of the ‘link’ to its companion NGC 5195; the M95/96 and M65/66 groupings in Leo were very easy, and M101 in Ursa Major was also clearly seen as a large circular glow, far easier without the light pollution. This session included a look at NGC 5866 in Draco, sometimes controversially labelled M102. (The prevailing viewpoint today is that M102 was a duplicate recording of M101.)

23:15 I would have liked to stay on to look at more of Coma and Virgo, but I could feel my eyes tiring. Besides, I would have had to wait for several hours before they cleared all the trees, so I packed up for the drive home.

The issue of light pollution was really brought home to me this evening, as everything appeared twice as bright as on the best nights from my suburban home. In fact I felt I was looking through an ETX-175 instead of a 125 ! Galaxies actually revealed some structure outside their cores, and nebulae barely visible from the suburbs were obvious from the rural sky.
It is going to take some adjustment to view from the suburbs again. Perhaps the solution to aperture fever is to move to the Lakes !

Session 5, March 19, 2005

Conditions: variable cloud and mist, calm, 10°C, limiting mag 3, seeing 8

Time (UT): 21:00–22:25
The evening promised much, with clear skies after sunset, but rapidly misting over as the evening wore on, with only the 9-day-old Moon and the brightest stars visible. One saving grace of the mist was good seeing, so I thought of limiting my viewing to only the brightest objects. At least the bitter spell of weather had come to an end and I was able to carry out my observations under relatively mild conditions.
21:00 I did not bother with any alignments, but just pointed the scope north and let it slew to Saturn. My rough pointings have now become quite accurate from my back garden, as Saturn was still in the finderscope field. Despite the mist, the planet’s image was very clear, if rather dim at high power, with Cassini’s Division and the globe’s shadow on the rings obvious, together with a hint of the rings’ shadow on the globe. Castor and Gamma Leonis were also badly dimmed, but otherwise very cleanly split.
21:15 I then went for an in-depth study of the Moon, confident of doing some high-power observing on it. This seemed like Groundhog Day, as the observing weather appeared to favour the same phase each month ! Indeed, I was able to use maximum power (345x) at times to resolve smaller features, but 173x was better as a whole.
(Note: Lunar east and west follow IAU conventions in these notes, with Mare Crisium east, opposite to telescopic orientation).
The main craters on the terminator tonight were, running from north to south: Helicon, Lambert, Copernicus, Reinhold, Bullialdus, Longomontanus and Blancanus.
The Plato region revealed many peaks to its south (Pico, Teneriffe Mts, Straight Range on terminator, and the peaks of the Laplace Promontory just receiving sunlight. The Alps and Alpine Valley still had some shadow,and Cassini showed two sharp craterlets inside a larger low-walled one.
The Archimedes region showed what looked like a range of hills to its southwest, whilst the Apennines were superb.
Copernicus was magnificent, with its central peaks still in shadow, but the sunward wall showing its ‘collapsed terrace’ structure well. Eratosthenes was equally grand with a complex central peak. Two other features in the region stood out: the ghost crater of Stadius SSW of Eratosthenes, and a chain of small craterlets to its north.
Another ghostly grouping to the south of Copernicus, in the direction of Bullialdus, was the trio of Fra Mauro, Parry to its SE, and Bonpland to its SW. Bonpland looked the most complete, but the eastern rim of Fra Mauro and the western one of Parry appeared to have been obliterated by lava flows. Heading south again, and into the sunlit regions, the Ptolemaeus trio was still clear, with Ptolemaeus A and the central peak of Alphonsus easily seen. Again, the deeper Arzachel showed much structure in its partly-shaded wall.
The Straight Wall region was still striking, with the Wall visible as a black line. The nearby crater Birt was easily seen, together with a smaller intruder towards the Wall. Thebit was also prominent east of the Wall, together with two intruding craters.
The southern highlands were awesome as always, particularly under high power and good seeing. Longomontanus was in deep shadow, but Tycho showed extremely clear detail in its walls and central peak. It gave its youth away by its pristine regularity compared to the other craters. Blancanus was similar in size to Tycho, but more foreshortened. I could count at least ten craterlets inside Maginus, but the finest crater in the region had to be Clavius. This massive walled plain revealed an arc of five craters across its floor, plus dozens of smaller craterlets. This region was particularly stunning at maximum power when the clouds were not too thick.
22:15 Took a rest, hoping to observe sunrise on the central peaks of Copernicus, expected in a few hours.
22:25 Moon dimming before my eyes, as the mist was turning into low cloud and fog. I had to end the session.

Session 6, March 20, 2005

Conditions: variable cloud and mist, calm, 9°C, limiting mag 4.2, seeing 7

Time (UT): 20:20–00:00


This evening was slightly better than the last one for sky transparency, but still only really suitable for brighter targets, with the waxing moon becoming an increasing menace. The views of Copernicus and Sinus Iridum made up for the sky brightness, though.
20:20 Set up the ETX in the middle of the lawn for a better eastern sky.
Aligned the ETX on ReguIus and Aldebaran, and began with last looks at winter targets plus variable star measurements.
R Leporis had sunk behind nearby houses, so I was unable to measure it.

U Orionis had continued fading at magnitude of 8.8.

R Ursae Majoris had started a gentle decline, at 7.7.

R Geminorum had continued fading at 9.7 .

After all those fading stars, it was nice to know that a couple were heading the other way.
R Aurigae had brightened up a little in the last fortnight, but had not yet matched its 9.2 mag companion. I estimated it at about 9.9.
R Leonis had apparently begun its rise from minimum, as it seemed the brightest of the triangle in the field. I guessed it to be at about 8.7.
22:35 I resumed the session with Solar System views, as I had read that a Great Red Spot transit on Jupiter was due at 22:45 this evening.

Old Jove was still a little low in the sky, but had risen sufficiently to take high power. It was a shame that I had missed the end stages of a transit of Io, but all four main moons were there, with Ganymede due east and Io, Europa and Callisto due west. It took me a while to make out the Great Red Spot, as it was much subtler in hue and contrast than Voyager photos had led me to believe. If anything, I saw the Hollow in the South Equatorial Belt before recognising the Spot itself, close to the planet’s central meridian. The Spot was definitely lighter in colour than the Belt, but only slightly darker than the surrounding Zone to the south, and it was a subtle pale tan rather than red. I found that the light blue filter helped in seeing the Spot.

22:55 I took a feelgood look at Saturn, with Titan NW of the planet. The Cassini Division was fairly sharp at high power, and the shadow of the globe on rings was also becoming wider.
23:10 Time for a quick high-power look at the Moon. Copernicus had lost most of its floor shadow by now, but was still stunning, with the Carpathian Mountains to its north. Sinus Iridum (Bay of Rainbows) provided the jaw-dropper, as the illumination conditions were just ideal for the maximum dramatic effect. The western Jura Mountains, Bianchini and the Heraclides Promontory had just come into lunar sunrise, giving the celebrated ‘Jewelled Handle’ effect. The Laplace Promontory and the eastern Jura were still casting long shadows, adding to the majesty of the scene.
23:30 I slewed the ETX back on to Jupiter, and saw two differences in the planet’s appearance in the space of little under an hour. Io had moved considerably west from the planet, to about a Jupiter radius from the edge. The Great Red Spot had also been carried well to the west due to Jupiter’s quick rotation, and now appeared almost halfway between the meridian and the limb.
23:45 I took a quick look at some showcase spring doubles, including a summer favourite which was just reaching a decent altitude in the east.

After looking at Gamma Leonis, Mizar and Alula Australis (Xi Ursae Majoris), I spotted Izar (Epsilon Bootis) high in the east, and pointed the ETX to it for the first time since the end of last summer. High power showed this close gold and blue pair beautifully. I was about to pack up for the night when I saw Vega through a gap between the walls – I had to look at the Double-Double, Epsilon Lyrae. It was still a little low, but a real tonic 173x, with all four components plainly visible.

00:00 End of session – packed up the scope.

Session 7, March 25, 2005

Conditions: clear start, misting up later, calm, 6°C, limiting mag 4.0, seeing 8-9

Time (UT): 19:50–23:10
The Full Moon again put paid to much in the way of deep-sky stuff tonight, but thanks to good seeing I was still able to observe many more doubles, and have another view of the Great Red Spot on Jupiter.
19:50 Set up the ETX in the middle of the lawn for a better eastern sky.
Aligned the ETX on ReguIus and Aldebaran, and began with probably the last look at targets in Orion. The open clusters in Auriga, Gemini, Perseus and Cassiopeia still held up despite the presence of the Moon.
20:30 The Moon was now getting too bright for DSOs. The galaxies M81 and M82 were barely visible at medium power. I thus decided to concentrate on spring doubles, mainly in Ursa Major and Leo, but I also had another look at some more obscure groups.
I checked my Ursa Major list and had first-time views of the following, all at medium power except where stated:

STF 1415 (white)

STT 231 (wide, reddish)

STF 1544 (white)

65 + DN UMa (wide white, but western component also double, well seen at high power)

STF 1600 (yellow / bluish)

STF 1608 (orange / bluish)
I tried to split 78 UMa, whose separation was given as 1.3”, but failed to see the companon, three magnitudes fainter. It must have been drowned out by the primary’s diffraction ring.
STF 1770 was a tough reddish and white pair, but high power split it.
STF 1830 and STF 1831 looked like a wide yellowish-white triple at medium power, but higher power revealed closer faint companions to each fo the end stars.
I ended my Ursa Major doubles watch with a feelgood look at Mizar and Xi (Alula Australis).
21:15 I took a look at Jupiter, and detected the Great Red Spot just east of the planet’s meridian. Io, Ganymede and Callisto all lined up east of the planet.
21:25 I continued with a brief interlude in some more obscure groups. 40 Sextantis was a white pair readily seen at high power, as was the orange and white STF 1441 in the same group. Another pair with an orange primary was STF 1459 in Leo Minor. Slewing south to the middle of Hydra, I spotted two fine doubles in the same field at medium power - STF 1473 and STF 1474, both oriented similarly but the latter one wider.
21:40 I then returned to Leo to notch up some unseen doubles there, and observed the following at medium power:
7 Leo - wide all-white,

14 (Omicron) Leo - very wide white / blue pair but companion faint

S 617 - wide, orange and bluish pair

STT 239 - wide, orange primary, faint blue companion

STF 1565 – all-white.

I revisited the pair of Tau-1 and 83 Leo at low power, both to be found in the same field.

The following were well seen at high power:
STF 1389 – tough and faint reddish pair

STF 1417 - yellowish and bluish

STF 1447 - all-white

STF 1504 – another all-white pair, which needed barlowing to maximum power to split it. This star was near the ETX’s limit.

As a rest from that toughie, I removed the barlow to revisit the fine doubles of Gamma and 54 Leo.
22:25 Slewing south, I turned the ETX onto the small groups of Corvus and Crater, to the north of Hydra.
In Corvus, I revisited the yellowish and lilac Delta (Algorab), and took a first look at the well-matched yellowish pairs of STF 1669, STF 1604 and S 643 at medium power. S 634 was better at high power.

Crater had rather less to offer, but I did observe the orange and white STF 1509 at low power, and the white pairs of STF 1530 and h4481 at high.

22:50 The sky was misting up appreciably, so I took a last look at Jupiter. The Great Red Spot was by now well west of the planet’s meridian, but Europa was emerging from occultation, just east of the planet.

22:55 After this look at Jupiter, I parked the scope, as the mist was turning rapidly into low cloud.

База данных защищена авторским правом © 2016
звярнуцца да адміністрацыі

    Галоўная старонка