This month we move away from the Milky Way to the realm of the galaxies. Two bright and interesting planetaries, NGC 1360 and NGC 1535 are particularly easy to find. Both show something different regardless of the aperture in use. I have also selected some galaxies in the Fornax II cluster that are not commonly observed by amateurs.

NGC 1360 /Mink 1-3/ V V10/ PK 220-531 (03332-2552) is located in the northeast corner of Fornax, close to the Eridanus border. It is among a very few planetaries well beyond the galactic plane. This planetary is both large, bright and unusual, and is clearly visible in a 7.5cm. telescope. Visual magnitude is measured at 11.6, with a ‘B’ Magnitude of 11.5. Burnham’s Celestial Handbook Vol.2 (See Photo. pg. 904.) and AOST1 both incorrectly state that NGC 1360 planetary nature is uncertain. The description in AOST2 is shorter than AOST1, since the recent discoveries since 1968 has made most of Hartung’s original text irrelevant. An O-III filter does wonders for this object, as most of the light emitted is at this wavelength. The coloured AAO slide, also featuring in AOST2 on pg.242, is a source of wonder - especially for the greenness of the object. To quote from the slide set ‘Stars and Galaxies IV’ produced by the AAO;

"For reasons that are not understood , NGC 1360 defies all these conventions, yet its colour still clearly identifies it as a planetary nebula. The green hue is oxygen, excited by the hot central star, and to the north east of the nebula is a faint red smudge, probable traces of material ejected before the star became a true planetary nebula."

NGC 1360 lies in a particularly spartan field. At first glance it appears as a large but brightly elongated nebulosity along PA 25^O -205^O. Using an O-III filter it looks much brighter, but unfortunately reveals little structure. Nearer the centre, and slightly following, is a 9th magnitude star (Photo. Mag. 9.6) that is not the central star. In size the planetary is larger than most. Observations by to Scott Mellish (Universe 43,12 & 44,1 pg.5.) states clearly;

"NGC 1360 is a good example of what an [O-III] filter can do to bring out detail in most planetary nebulae. In sketch! (pg.22.) the oval shaped object sports two lobes either side... which are a touch brighter than the central regions of the nebula. .... This is an exquisite object deserving of close observation even without an [O-III] filter for it is brighter than you would expect it to be. .... A large and splendid object."

Most of the literature states a size about 390"sec.arc., though photographically it appears as a 'football' structure some 6.0'x4.5' (360"x270"sec.arc.). Visual diameter of the outer edge I estimated to be closer to 200"x170"sec.arc., but this is likely aperture dependant because the brightness only gradually fades when approaching the edges. Visually, the northern portion is slightly brighter away from the 9th magnitude star. Throughout the nebulosity is evidence of darker matter covering most of the brighter nebulosity - especially in a north-south direction. This can be easily seen in a 30cm. Using adverted vision, I thought I could detect a small dark knot about 90"sec.arc. to the NNW. The 'reddish' ejecta mentioned in the AAO quote is located at about 100"sec.arc. from the planetaries centre at PA345^O (NNE), and is listed as a galaxy within Mitchell’s catalogue of faint galaxies - MAC 0333-2548. This object is invisible to all amateur telescopes, though some may wish to try to see it! Another galaxy lies along the same position angle, but twice the distance from the northern edge of the planetary. Known as MAC 0333-2547, this 15.7 magnitude object should be visible in a 40cm. or 50cm. Dobsonian as a tiny inglorious smudge. (An image of the object can be seen in the photography on pg.242 of AOST2 in the top left hand corner.)

Until the early 1980's the classification of NGC 1360 was uncertain, but later it was classified as a Class III - defined using the Volrontov and Velyaminov scheme as an ‘irregular disk’. This object is similar in structure to NGC 3195 in Chameleon or even NGC 2610 in Hydra. Dennis di Cicco described the planetary in S&T June 1986 (An exposure taken by Dennis di Cicco also appears on pg.632 of the same S&T using Fujichrome 400 and a 17.5" telescope.) His description follows;

"NGC 1360 is about as large as M27, though much fainter. Its large diameter and relatively high integrated magnitude make it visible in a 12x80 finder. It appears quite elongated and the 11th magnitude central star stands out well."

Within the nebulosity are four stars - the 9th magnitude field star, two 11th and 12th magnitude stars to the south, and one white star toward the west at PA 110^O. The 11.35 magnitude ('B' Mag.=10.96) western star is the Planetary Nebulae Nucleus or PNN, and listed in the Hipparchos Catalogue as HIP 16566. Eleven reputable reference sources, state this PNN has a visual magnitude ranging between 11.0 and 11.6, so it is possible that the PNN is a suspect variable. Obviously, the star is not central to the nebulosity. This star has a spectra was sdO - indicating a spectroscopic binary from the observed duplication of the spectral lines. Later spectra determine the PNN to be a DA-type white dwarf with a mass of 0.55 Solar Masses. In 1982, the IUE (International Ultra Violet Explorer) observations showed NGC 1360 was more energetic in its UV flux than normal planetaries and in the same year, the first published temperature was given as 88 000^OK. Further observations in 1983, from both the ESO and La Silla in Chile, determined from the (very low) helium abundance a Zanstra temperature 66 000^OK± 15 000^O. By 1989, further observation of the HeII emissions, produced a hotter 77 000^OK. Oddly, the calculated absolute magnitude is given as +3.6 (twice that of the Sun), while similar references state the luminosity is about 1 000 times more luminous than the Sun.

In regards the gas shell - the planetaries’ inner gas is expanding at 27kms^-1, while the bulk of the visible nebulosity is expanding at a more pedestrian 7kms^-1. Radial velocity measures show that the object is moving towards us between +43kms^-1 and +53kms^-1. Recent estimates of distance, using the most accurate result to date by Tylenda and Stasinska (1994), places the planetary as close as 300pc. (980 light years). This value is also quoted in AOST2. If this is so, the actual size of NGC 1360 subtends a true diameter of some 0.33 parsecs or 1.1 light years.

Overall, this planetary is really worthy of a glance.

Surrounding Field of NGC 1360.

Within several degrees of NGC 1360 are a ‘fist-full’ of galaxies visible for medium to large apertures in dark skies. I have selected a few interesting ones that observers may like to have a look at. All are in the eastern portion of the Fornax II Cluster. This cluster name is really a misnomer, as most of the galaxies are in the constellation of Eridanus. NGC 1395, in Eridanus, is an interestingly bright elliptical galaxy that rarely gets a mention most amateur text. All my descriptive texts never mention them - likely just because they are not as bright nor as famous as the more southern Fornax Cluster some 10^O further south! (Note: None of these objects are contained in the Fornax Cluster.)

NGC 1398/ MCG-04-09-040 (03388-2521) is a 'face-on' Sbc spiral galaxy and the brightest in this selection. Telescopically, its size appears 4.0'x3.4'min.arc. and is visibly elongated along PA 100^O. At 10.9 photographic magnitude (B-V=0.95 U-B=0.43), it can be found some 1.4^O ESE of NGC 1398 and is placed in Sky Atlas 2000.0. Although the galaxy is bright enough to be found in a 15cm., a 20cm. will do much better. The featureless core of the galaxy is particularly obvious, and by using averted vision in a 25cm., a faint ring in the outer portions of the spiral arms can just be discerned. Scott Mellish (UNIVERSE 43,12 &44,1) in his series "Sky Sketches Post Mortem" states; "No arm structure is present and at 140X the object is reasonably large..." Like many galaxies that appear 'face on', the low surface brightness 'kills' the majesty of this object. Professional photos show an internal ring with a bar, that I couldn't see, though larger apertures may see this. Measured red-shifts are stated between 1 491kms^-1 and 1 524kms^-1, giving a distance of about seventy-five million light years.

NGC 1412/ IC 1981 (03405-2652) and ESO 482-32 (03407-2647) are two faint galaxies that are a good challenge for those with large apertures. Firstly, the story of NGC 1412 is interesting. Dryer's original description states that the object is 'Faint, Small , Extended, Gradually Brighter Centre, Star Following 2'min.arc.' (Seen in the composite image in Figure 2.) In 1933, Robert Baker investigated the region and could not find the object, now given in the RNGC as NF BAKER (Not Found). Interestingly, it is listed in the Index Catalogue as IC 1981. Both positions are identical. The mistake was made by Baker, yet this error was not corrected until about c.1975. For inexplicable reasons, though it may have been the simple confusion, it is still not in Sky Atlas 2000.0! Most advanced atlas and software use the Dreyer designation, simply bypass the RNGC.

Both galaxies are 1.8^O ESE of NGC 1360, or 0.4^O SE of NGC 1398, and are separated by 6'min.arc at PA 320^O. NGC 1412 is at photo. magnitude 14.0 at position angle 130^O and has a true inclination is c.45^O to the line of sight. The position angle is about 130^O. Compared to the other galaxies mentioned in this text, this (and ESO 482-32) is much smaller perhaps a mere 1.0'x0.6'min.arc.

North of NGC 1412, lies ESO 482-32 that is not listed in Burnham's nor in most of common references used by amateurs. Listed at photographic magnitude 15.2, it is a small 1.0'x0.4'min.arc. The observed position angle is about 60^O. A 30cm. to 40cm. should be able to see it on a clear dark night. Fortunately, it is close to the brighter galaxy, as it would likely take forever to find in an isolated field.^.

It is suggested that both galaxies are in a interactive system. Some sixty-five million years, ESO 483-23 may have passed very close to NGC 1412 at a high velocity. This ripped apart poor ESO 482-32, and material can be seen to be spewing some distance from the galaxy's centre. Unfortunately, little evidence of interaction can be seen in amateur telescopes. Measurements of the radial velocity for this system (RV=1 762kps^-1) suggest a distance of eighty million light years. Both galaxies are minor players in the Fornax II cluster.

NGC 1371 (03348-2445) is an SBa spiral galaxy, very similar in both size to NGC 1398, though the spiral arms are less distinct. The extragalactic disk is angled towards us at about 45^O at PA 210^O, while the apparent diameter is 3.6'x2.5'min.arc. Although two magnitudes fainter than NGC 1398 (Photo.Mag=12.2; B-V=0.94 U-B=-0.51), the core can easily be found in a 20cm, telescope some 1^O NNE of NGC 1360. Its shape suggests a barred spiral, that maybe just seen using averted vision using a 25cm. While the 'RNGC Notes' state that the galaxy photographically become very extended and diffuse towards the periphery - I could not determine the visually. Measured radial velocities are between 1 454 and 1 472kms^-1, a distance of 75 million light-years.

NGC 1385 (03375-2312) is a peculiar-looking spiral galaxy in a telescope. The 'S-shaped' 2.2'x1.3'min.arc. core is immediately apparent and is aligned in a north-south. Printed in Sky Atlas 2000.0, it can be found some 1.7^O NNE of NGC 1360. At a bright 11.7 magnitude ('B' Mag.=11.5, B-V=0.49 and U-B=-2.0) NGC 1385 is easily visible in a 15cm., though a 20cm. will show some detail in the chaotic centre of the galaxy. This active nucleus is known be a slight radio source at 1400 MHz (0.3 Janskys) and 2700 MHz (0.2 Janskys). Further radio observations, near the 21cm. hydrogen line, were measured by the CSIRO's 'Australia Telescope' at Narrabri. A very accurate radial velocity of 1979kms^-1±6 was recorded, that supercedes the average radial velocity measure of 1389 kms^-1 mentioned in Sky. Cat 2000.0. Given a Sc I-II type, this classification seems a bit off target, as it seems closer to an irregular Sc type. [According to the DDO classification (David Dunlap Observatory). For a highly coiled galaxy with a small nucleus. 'I-II' tells us it has highly luminosity, and is bluer than most galaxies.]

NGC 1395 (03385-2239) is the last object in our list. This giant oval EcD elliptical galaxy (Hubble Type E2 or E3) is the second brightest member of the Fornax II Galaxy Cluster. Brightest is the other giant spiral in the cluster is NGC 1232 in Eridanus (03098-2035). Gravitationally, NGC 1232 acts as the centre of the galaxy cluster.

NGC 1395 is clearly visible even in a 10cm., little detail can be seen even in the largest amateur telescopes. In (UNIVERSE 43,12&44,1 pg.6), Joe Cauchi apparently took a photo of this object, that shows four galaxies in a 1^O field. (Being NGC 1395, NGC 1413, NGC 1416 and NGC 1401. The last three I have not observed.)To quote from Joe's visual observation; "...this small bright elliptical is featureless apart from a bright centre." NGC 1395 lies in Eridanus, on the border of Eridanus and Fornax, and is best found by locating the 4th magnitude Tau Six ( ⁶) Eridani, and moving the telescope west by exactly 2.1^O. Visual magnitude is 11.2, (Photo.Mag.=11.90, 'B' Mag=10.55, B-V=0.9 and U-B=0.75.) while the spectral type is G7. In size, as given by most references, NGC 1395 covers photographically 5.9'x4.4'min.arc., but I suspected through the telescope the eye sees about third of this. Burnham's size states 1.5'x1.0', but I could not find his source. The NGC description is given as 'B,pS,E,psmbM'; Bright, pretty small, extended, pretty suddenly much brighter in middle. Yet the RNGC states a similar description; BE, R, BM; Bright Elliptical, round, brighter towards middle. Visually, this is 'right on the money'.

Three velocity measures have been made. The first in 1956 gave a larger velocity of 1820 kps^-1. Later measures in the 1980's give respective velocities of 1 699kps^-1 and 1 690kps^-1. According to the NASA/ IPAC 'Extragalactic Database', known as NED, gives the mean radial velocity as 1 699kms^-1 .

Studies into NGC 1395 have been more extensive than for other galaxies so far discussed. One of the most interesting was the discovery of a number of shells by Malin and Carter in 1983 (forming a shell galaxy)found using the technique of unsharped masking. This was later confirmed by observation made using IRAS at 60 and 100 microns. Since this time, all shell galaxies are known X-ray sources. The discovery of X-Rays from NGC 1395 were first detected by ROSAT in 1987. (An image was shown of this object at the last lecture given to us by David Malin in 1996.) Some disagreement exists between astronomers on the 'dustiness' of this galaxy due to conflicting information and interpretation of the data. It seems this mystery still remains unsolved. Two faint jets were also discovered by deep photographs by the ESO in 1985 that point in opposing directions. The interpretation is that a massive and active black hole is at the centre of the elliptical.

RZ For / SAO168619 (03325-2530) is a deep red SRa regular variable in the same field as NGC 1360. Directions to find this variable are likely obvious - but it does lie 18'min.arc. towards the north-east. SRa's are fairly stable in their light curves with regular amplitudes. An example of the class is Antares. The spectrum is given as late M5. Magnitude variations vary by 0.8 magnitudes between magnitude 8.5 and 9.4 (Photo. Mag 9.2 to 10.0), over a period of 64.6 days (Julian Date for the period is stated in the General Variable Star Catalogue (Version 4) and Sky Catalogue 2000.0 as JD 2428075, as long ago as the 30 August 1935!)

NGC 1535 / HD 26847/ VV 19/ Herschel IV 26 / PK206-40.1 (04144-1245) (Eridanus) is the most northern planetary that we will discuss in this series. Positioned in an attractive field, this slightly ovoid planetary is easily visible in a 7.5cm., and as a ‘star’ even in the telescope finder! Sir William Herschel discovered this object in 1785, and placed in his object Class IV; "Stars with burs [Nebulous disks; bur(r)s is now archaic], with milky chevelure [French for 'hair'], with short rays, remarkable shapes, etc." To find it, I used the red 2.8 magnitude Gamma ( ) Eridani (03580-1330), some 4.0^O SWW of the planetary. Simply move 18'min.arc. north and then 4.0^O west to find the field. Within the field, using a medium magnification, to the south-east is an 2'min.arc. trapezium of 11.4 to 12.3 magnitude stars. At medium magnification in a 15cm. the oval becomes apparent, estimated to be along about position angle 145^O. The image bears reasonable magnification, however, I saw little improvement to any visual features in the Celestron-8. Rev. Thomas Webb, in 'Celestial Objects for Common Telescopes' pg.127 states;

"Planetary bright with low power in 3.7" [9.4cm.] but not bearing magnification. [Lalande] has described it as the most interesting and extraordinary object he has ever seen... D'Arrest...thought [that the] nucleus excentric, edges resolvable, and colour light blue, as Earl of Rosse, who makes the nucleus granular."

I suspected a hint of mottling toward the centre, and an O-III did little to improve this. According to the "Webb Society Deep Sky Observer Handbook: Volume 2 - Planetary and Gaseous Nebulae." pg.58, a 42cm. (16.5") telescope will see;

"Blue irregularity round nebula; 351X star surrounded by dark mottling enclosed by a bright ring in slightly elongated shell."

To quote from the apt description of NGC 1535 in AOST2; "In an effective field of scattered stars this bright pale blue planetary nebula stands out conspicuously." or as Burnham's states "[A]..pale bluish disc..."

The photographic magnitude is stated as 9.6, while the visual magnitude is 10.55 and the ‘B’ magnitude is 11.6. Visually, it subtends an angle some 21.0"sec.arc. Some sources, like Sky Catalogue 2000.0 claims a size of 18"sec.arc. and 44"sec.arc., while Burnham's states 20"x17"sec.arc. Classed as ‘4+2c’, to me this is a bit confusing - Ring structure, with a smooth disk and traces of ring structure. For a 25cm. or less this doesn't describe the object adequately. I could only assumed this meant a ring with a inner ring-like disk. If the Webb Society's description is correct, a 30cm. or 40cm. should be able to see this inner ring. Figure 3 shows an overexposed image of the nearby 5'min.arc. field. while insert shows the telescopic image using a 30cm.

The white dwarf PNN (HD 26847) is an O5 star of magnitude 12.1, but it is invisible for telescopes below 25cm. I am certain the star is particularly difficult to see in poor seeing because it merges into the planetary's nebulosity. Californian Jack Marling in an article in June's 1986 S&T (pg, 633) claims in a 50cm. (17.5"); "The 12th magnitude star is easy to see." David Frew also claims to have easily seen the PNN using a direct-vision prism, that reveals a stellar ‘streak’ within the planetary. I attempted this with a C8, and admit I could not see it, though others might have some better luck. Spectrally the white dwarf is stated as ‘?npe’ - suspected nebulous lines and a peculiar spectra.

Radial Velocities were first measured in 1952, at a small 1.2kms^-1. By 1993, the latest measure is about 3.2kms^-1. The distance of 2.14 kiloparsecs was first proposed by Cahn and Kaler in 1971. More recent estimates suggest a closer 1.65 kiloparsecs.

A good 'honest to god' planetary!

Surrounding Field of NGC 1535.

NGC1538 or IC2045/ MCG-2-11-27 (04146-1311) is a 15th magnitude galaxy 22'min.arc. south and 2'min.arc. east of NGC 1535. Although its tough object to find in anything below a 30cm., this galaxy appears as a faint and featureless oval smudge some 60"sec.arc.x 40"sec.arc. at PA 125^O. Other than being an elliptical galaxy, little is known about this object.

Gamma Eridani / 34 Eri / HJ 3608 (03580-1330) is a long irregular period giant of spectral type M0 III. The spectrum also shows lines of both Calcium and Chromium. Varying in a period of 64 days, the magnitude difference is a mere 0.08 magnitudes, between 2.88-2.96V. Gamma Eri is also a double star whose primary has a magnitude 3.2, while the companion is 12.7. First measured in 1877, the separation is a wide 52.8"sec.arc,. while the position angle is 242^O. Even a 7.5cm. should have little trouble separating the red and yellow pair.

GAL 364 (04140-1222) is a dainty pair located in a starry field some 21'min.arc. north of NGC 1535. Discovered in 1871 by J.Gallo, the pair is near equal brightness at magnitudes 8.9 and 9.0. The separation between the AB components is 21.1"sec.arc. at position angle 45^O. No change has been observed since the first measures in 1901.