return to the main page

José R. Torres

 

 CCD ASTRONOMY 

Currently I am giving my first steps in CCD imaging. I am newbie in this field, and I report the difficulties and ideas I am developing as I learn. I think it is a good idea to show them to help others to resolve their problems. This link will allow you to have a look to my first imaging sessions.

 

 VISUAL DEEP SKY ASTRONOMY 

The rest of this page is dedicated to visual deep sky astronomy with my old 10" Newtonian (F/D 4.8). There is also an observation of the starburst galaxy M 82 here, taken with the same instrument and from the same place. It includes a couple of sketches and astrophysical information, plus a detailed description at the telescope. All the observation reports below are translated to English. However, the observation of M82 is not translated to English since it is too long.

 

 

 

 

Small planetary nebula which lies in the outer regions of the Perseus spiral arm. It is 7º NW of g Ori (Bellatrix) and 17' W of a pair of 8 magnitude stars 5' wide. De Jonckheere 320 is rather difficult of being distinguished from a star at less than ´100, but with UHC it stands out immediately. It looks nonstellar from ´150 and blue in color. The surface brightness is rather high (8.6 mag·arcmin^‑2). At ´400 the 13.5 magnitude central star is easily seen, and the nebula is perceived strongly oval‑shaped in NE‑SW direction, with two condensations at the ends of the major axis which are better appreciated at ´560. The edges are a little faded. The interior of the disk is darker around the central star. I think to glimpse a very oval ring, apparently condensed at the ends. I was puzzled when I saw it, but the POSS picture below agrees with my visual impressions. The nebula is 8"´5" sized and the magnitude is around 12.5, that agree well the figures in the literature. This is neither a too violent nor a massive PN (M_v = ‑0.1). The actual size is 0.7 light years and the age is ca. 10.000 years old. Its central star is 40 times more luminous than the Sun.

 

In the process of starhopping to center this nebula, you could have a look to three open clusters in Orion: Dolidze 17, 19 and 21, all of them lying in the neighbourhood of Bellatrix, poor and scarcely visited by amateurs, so they remain practically unknown. Do17 is very poor, but it includes luminous components. It gathers around half a dozen of very bright and scattered eight-magnitude stars, compressed in a diameter of 15'. It could be an asterism. Do21 is more exciting. The diameter is the same as Do17 but it gathers more stars (20 stars), although they are weaker than in the former cluster. Do19 is in the vicinities of the reflection nebula Van den Bergh 38, not too hard to glimpse. This cluster is bigger than Do17 and 21 (24'), and it includes about 40 stars, mainly white. These three clusters apparently belong to the Orion spiral arm and are fairly young.

(to top)

 

 

 

High surface brightness planetary nebula in the Perseus spiral arm, almost stellar, that we can find at the end of a trapezium of 9 and 10 magnitude stars and 92' to the W of the double star 20 Gem. This star, bright and simple to resolve (6.3‑6.9m at 31"), is accessible to small binoculars if we hold them steadily, and it is weakly perceptible at the naked eye in good nights of good quality. It is a good point to start starhopping.

 

The first time that I found de Jonckheere 900 I had no more support than Sky Atlas 2000.0 and only a 12 cm Newtonian reflector (no filters and no charts). This should encourage small instruments owners to attempt the observation of this kind of planetary nebula. Using this telescope at ´65, J 900 cannot be distinguished from a star, but ´100 are enough to perceive characteristic smooth edges. At ´200 the nebula is already excessively weakened, but it looks irregular, with an odd, almost triangular profile. It is slightly condensed, and the size does not exceed 15" in diameter. The 254 mm reflector at ´560 tells us immediately the reason of that odd aspect. The nebula is NW oval‑shaped, and a 13 magnitude star is practically in contact, 10" at the SSW. That star gives it the anomalous profile seen though smaller instruments. There are many weak stars lying in the neighbourhood. I find that this nebula measures 12"´9", and the magnitude (ca. 12.0) is larger than the figure listed in the literature. J 900 consists of an external elliptical disk, not very nebulous, and a tiny central condensation barely measuring 4" in diameter, rather bright. The central star, which I could not see, is intrinsically similar to the Sun in bright. J 900 is intrinsically smaller than J 320, but rather similar. It measures 0.4 light years and shines with 0.6M_v. It is 7000 years old.

(to top)

 

 

 

Planetary nebula lying 40" ESE from a 10.5 magnitude star, very close to an easy 9.5 mag double star. Using the 16mm König (´75), this nebula is easily perceived, even without the assistance of a nebular filter. M1‑17 looks roughly triangular. It is a 40" width faint cloud, not as elliptical as the listed data suggest. The surface brightness is rather uniform (11.0 mag·arcmin^‑2). No trace of the central star was perceived. The M1‑7 profile is elliptical and sharp. The nebula seems to present fuzzy protruding extensions weaker than the rest of the object, that point the disk to make the nebula apparently extended in a 45º PA. The close 10.5m star dazzles and prevent us to use the averted vision appropriately.

 

16' NW of the nebula there is a 9ª magnitude star. If we focus it, we will perceive immediately a curious grouping of weak stars, white and yellow (I count easily 15 in a diameter of 7'). It is not included in the Lynga Catalogue.

(to top)

 

 

 

It is 1º S of a Lyn, scattering around the elliptical galaxies NGC 2831 and NGC 2832, and the barred spiral NGC 2830. This cluster includes more than a dozen of "bright" galaxies that, except for the main, are between 14.5 to 16.5 magnitudes and present typologies rather varied. The central galaxy, NGC 2832 (11.5 m_v), is a giant elliptical, fuzzy, fairly oval‑shaped (3.3'´2.2') and lacking of any distinct feature. Its core is no excessively obvious, and the surface brightness is moderate (13.4 mag·arsec^-2). It is easily seen at ´180, and it is even slightly distinguishable in 20´80 binoculars (11 magnitude). This galaxy configures a right triangle with other two stars. At ´200 some small galaxies are spotted with a varying difficulty. One of them is notably elongated and big, although vague (NGC 2823). I count without too effort seven galaxies in a 1º field. One of the spots in the western side of the main galaxy, NGC 2830‑3, is indeed a fused image.

(to top)

 

 

 

This is a galaxy rather difficult to see in a first glance, 54' at the W of a Lyn. Using the 12 mm eyepiece (´150), NGC 2793 is seen as a very weak smudge, with an oval and quite small core (ca. 25" major axis). The core is displaced from the centre to the Eastern border and it is enclosed by an almost circular halo, somewhat weaker than the nucleus, scarcely visible and diffuse. This is a Sc galaxy view from a polar position, which is the sort of configuration usually most difficult since it gives rise to low contrasts. The galaxy is worth to find in smaller telescopes. I wonder whether it could be seen in telescopes smaller than 15 cm. The nominal surface brightness is 13.9 mag·arcmin^-2 but the gradient is low, and it is recommended to force magnification and jiggle the telescope to get more perceptibility.

(to top)

 

 

 

It is in the Leo Minor and Lynx border, within the first constellation. This object, 42' at the East and very slightly at the North from a Lyn, is the most remarkable galaxy within the area. In spite of lying just 10' from a 7ª magnitude star, this galaxy is so bright that can be easily seen using 20´80 binoculars. At the telescope it is seen as a prominent and relatively large galaxy (5' of diameter), white, and slightly oval. The bulge is very striking, quite oval, with an irregular profile and increasing internal brightness. The increment in bright to the centre is important and the galaxy even seems to present a star lying in the centre. The disk is perceived as not too uniform. It is N‑S crossed by the bar of this SBa. I think that in bigger telescopes, or under better sky conditions, the spiral structure should be perceived. The nominal surface brightness is low (14.7 mag·arcmin^-2), but gradient is rather high and the nucleus, prominent. This galaxy is absolutely superb, and strangely little known.

(to top)

 

 

 

Huge planetary nebula, with a very low surface brightness (17.4!) and an irregular light distribution. There are excellent reference stars to allow an accurate spotting. Using UHC and 16 mm König (´75), once the zone has been properly centred (Uranometria 2000 is enough), the nebula stands out as an enormous doughnut, oval in a 25º position angle. The nebula looks like a strange copy of the familiar M 57, but it is much great and weaker. The eastern arc is more luminous than the western one. The boundaries are not as diffuse as can be expected from their size and bright. The centre is weaker than the edges, and rather more luminous than the background. I could not perceive the central star, although many background stars lie on the area, some of them overlapped on the nebula. The southeast arc of the nebula is weakly visible with the help of nebular filter, and has several condensations and what seemed to me a broken fragment addressed toward the centre, that corresponds the narrowing area in the picture. The ends of the major axis are darker, as we can hope in this kind of old planetary nebula, similar to the Owl Nebula. I measured a size of 6.5'´4.5', and a visual magnitude close to 13. This nebula measures 3 light years and it was originated 22,000 years ago. As could be expected for an aged nebula, the absolute magnitude is small for both the nebula and the star: 5.5, and 7.5M_v, respectively.

(to top)

 

 

 

Galaxy notably well defined. The surface brightness is rather uniform and the profile is quite curious, pentagonal. Boosting the magnification to ´250 do not allowed me to observe any nucleus, at all, and I find a very unusual abnormally sharp border. At the North, there is a little condensation or luminous knot easily distinguished, lying on the same edge, that constitutes one of the vertexes of that pentagonal profile before mentioned. I agree with other observers that found a strange similarity to M 97. The asymmetry is also N-S present: the galaxy is weaker and fuzzier to the south. The reason of the peculiar profile relies on an enormous asymmetrical spiral arm. Also associated to this galaxy exists an immense HII region (i.e., a diffuse nebula) of 200.000 pc, besides numerous nebulae and stellar clouds. Using professional instruments, the galaxy can be partially solved in stars of the 20ª magnitude. Lying immediately at the East there is a ninth magnitude star, and in this same direction, at only 6' from NGC 2537, another galaxy: NGC 2537A, of which hardly I can see the nucleus, much weaker.

(to top)

 

 

 

Open cluster located 5º SW of z Aql. Bright, striking object, maybe the easiest to see within all the constellation It is easily perceived in 8‑17´40mm binoculars. The surface brightness is 12.0 mag·arcmin^‑2. The profile is neatly triangular. The cluster is constituted by very numerous white stars. The 20´80 binoculars for instance allowed me to count 25 stars easily. NGC 6709 includes a striking double star just at the eastern extreme, including two components distant 30" each other, that can be seen clearly as triple with these 20´80. Using the 254 mm Newtonian reflector, the cluster looks splendid, very rich in binary stars. A star hollow calls the attention at SE. And the star that with small binoculars we viewed first as double, and later as triple with 20´80, is now a spectacular quadruple star, constituted by two pairs, one balanced and the other very uneven. I could easily attribute to this cluster not less than 45 stars, all white except the three shiniest stars, being red the first one and yellow the other two. By magnitude steps, this open cluster contains 3 stars between the 9ª‑10ª magnitude, 10 between the 11‑ 11.5 and more than 25 between the 12‑14. There are much more double stars. Including the true most luminous star (at the SW border), there is another striking binary, whose components are red and blue, unbalanced but not difficult. The principal stars are lined up forming two chains, bent N‑S and crossing one to another. This configuration means that the lines are highly forced with regard to the galactic plane, which causes strong tidal effects and will end by causing their break-up. NGC 6709 is a cluster physically in an intermediate age, and of medium size. The overall absolute magnitude is ‑4, and most stars are subgiant and main sequence stars. It spans 12 light years of true diameter. The mean separation between components could range 1.4-3 light years, that is to say, exceeding the medium value separation for clusters of this class.

(to top)

 

 

 

Striking cluster without central concentration that is easily solved with binoculars or any finder. Most of it can be well solved in 20´80. However, some stars accumulations are too close and weak, so they remain as fuzzy areas through giant binos. The surface brightness is favourable: 12.7 mag·arcmin^‑1. Through the 254 Newtonian reflector, NGC 7243 looks excessively big, bright and scattered for giving us that crowded impression that we like to see in open clusters. It is mainly formed by white stars, organized in two subgroups. These two sub‑agglomerations are very definite and seem almost independent, since there is a mid central void ‑virtually lacking of any star‑, that detaches them rather well. The western group is the biggest and the most populated. It contains the spectacular double star S 2890, comfortable and perfectly balanced, classified as triple (8.5‑8.5‑9.5m at 9.4 and 73 arcsec; position angles are 11º and 178º). But it is much more that thee stars. I can see no less than eight stars in 30" radius around it. By steps, this cluster contains 6 nine magnitude stars, 14 until the 11.5, and an indefinable quantity, perhaps exceeding 70, until the 15 magnitude. It is oval‑shaped in a forced angle over the galactic plane, that suggests that the two groups are something more than a chance and could exist a true breaking plane. The cluster stands out easily with 20´80, making a good contrast with the stellar environment. Around 30 stars are seen in a superb stellar background. If we immobilize them properly, we will be able even to solve the double, which is not a negligible feat for small binoculars.

 

There are other nice clusters in the zone which deserve you have a look. Don't miss the curious NGC 2796, tiny and compact (I count 18 components in 4'), of odd morphology, with a very red star at the north end, and two chains of white stars. It is small, but easily seen with 20´80 binoculars.

(to top)

 

 

 

M 76, NGC 650‑51, Little Dumbbell, Barbell or Cork Nebula has the fame (or shame?) of being the weakest object in the Messier catalogue, but certainly it is not difficult at all. In fact it is quite easily seen using 60 mm binoculars, and very easy in 20´80, in a rich field in weak stars. Its Perek‑Kohoutek code suggests its proximity to the galactic plane. Through a 80 mm refractor it is appreciated lengthened, with two nuclei separated each other by a dark channel. My old 12 cm reflector showed the asymmetrical lobes more uneven, with some slight condensations. Finally, the 26 cm reflector at ´43 shows a very bright, defined and blue nebula, wonderfully complex. At ´180, M 76 calls the attention mightily. It looks enormous (2.5' longitude), very bright (BS 11.7) and extended in NE‑SW direction. The nebula is broken in two lobes of different brightness (this is the origin of the two NGC denominations). Both lobes, however, are closely similar in size and shape. They are isolated by a not completely dark channel, which measures about 10" width. The southern lobe (NGC 650) is the least luminous one. The northern one (NGC 651), is brighter and somewhat larger. I could not see the central star, although a 13.5 magnitude star was seen overlapped at the southern edge, on a small prominence. Magnifying more the nebula up to ´350, I could see a condensation standing out on NGC 650, which was solved in two unequal portions in size and brightness, being brighter the eastern one. At that magnification, NGC 651 also showed a triangular and irregular condensation, with an almost stellar knot in its brighter edge, and another one at the western border. Also, wrapping the nebula and making it even more similar to the true nebula Dumbbell (M 27), I perceived an elliptical halo measuring 2.7'´5.5', very weak and exhibiting a very irregular brightness distribution, until the point that the halo gave the object the surrealist appearance of a barred spiral galaxy, or a giant "S". At ´520 I think to have seen the central star, with the object very weakened. The visual magnitude of M 76 is around the 10.5. This nebula is bigger and perhaps twice more massive than M 27, but three times more distant, with an age around 20.000 years. The main body measures 2.5 light years and the central star is almost as bright as the Sun. It lies 600 light years below the galactic plane, but its axis is almost exactly perpendicular. The external halo reaches a maximal diameter 5 light years, that is to say, a very large figure for what is a typical value for this kind of object.

(to top)

 

 

 

Open cluster found by chance with 20´80 binoculars, in the starhopping process to the planetary nebula NGC 6842. This is rather bright cluster (ca. 8.0 mag defocusing stars by the Bobrovnikov method), and about 8' sized. With binoculars it is shown as a small glowing cloud, striking and easily perceptible, resolving some stars in an impressive field. With the telescope it is, however, poorly defined (Class II). Two perpendicular accumulations with regard to the cluster main axis call the attention, 4' and 3' to the NE and SW respectively. NGC 6834 includes a 9ª magnitude red star. There are other eight (10‑11m) stars following in decreasing bright, and finally, an uncertain number (perhaps 35‑40) of 12‑13m stars, all of them white and semi‑giant. On the other hand, the two subgroups include around 6‑8 stars each in 2' diameter areas. The northern group is triangular‑shaped, with three outstanding, detached stars, and more rounded, loose and balanced in bright the southern. The main star stream in NGC 6834 is organized in a 7' E‑W chain, with the weak stars projected in all directions, centred approximately at the S of chain centre. The faint stars, perhaps not true physical members, impoverish the definition of the cluster boundaries. I can count ca. 70 stars in a 10' area.

(to top)

 

 

 

Great planetary nebula in western Cassiopeia, very close (2º W) to the superb NGC 7789, which is one of the most impressive open clusters in the firmament. Abell 82 is weakly visible without help of nebular filters medium magnification (´100). Once added the UHC filter, I found it to be unexpectedly easy using 12 mm König (´100). Using this filter but boosting the power to ´225, the nebula was shown as a smooth disk, apparently uniform and without any annular trace visible. A 12 m star was almost projected by the nebula. Abell 82 border was rather well defined. A star was seen within the disk, perhaps the central star, being 13.5m visually. Disk size ca. 1.5' in diameter. I could not see traces of an external halo. The global magnitude using the filter was about 13.0. Without nebular filters, it was seen more irregular and small.

(to top)

 

 

 

Small cluster or asterism constituted by very faint stars generally arranged in a triangular shape, elongated E‑W. Cluster core was ca. 2' length. As a whole, I saw around 15 minute stars ranging from the 14.5 to 15 magnitude, sorted around a quite bright (11ª mag) yellowish star. Although its classification as a true cluster is not sure, it seems to me quite improbable such a concentration as the result of a random projection of unrelated stars. The comprised area is too small. Moreover, the background is too poor and the cluster borders, too definite. I think it is a cluster and not an asterism.

(to top)

 

 

 

Very remarkable galaxy cluster physically related to the Coma Berenices cluster (Abell 1656), but located far distant from it, in the Leo tail area. There are other some small galaxies and galaxy clusters in the in-between region, forming a vast bridge of galaxies, namely the Coma Supercluster. It was a quite mediocre night, and I was not able to see 6.0 m stars at the naked eye. In spite of this, it was not too difficult to glimpse some galaxies at the telescope. Their magnitudes was in all cases too faint, and none of them was accessible to 20´80 binocular, as expected from the literature data. Putting the attention in the cluster core, I could perceive more than 10 galaxies in a 1º field using medium power. Some of them were easy (NGC 3842‑E, 3844‑S0, 3837‑E), but this cluster clearly demands larger telescopes and/or better skies. No galaxy is actually bright and easy. At the East of the core it lies NGC 3861, a 14.0 Sb galaxy, which configures a right triangle with two bright and separate stars (30') that are not plotted on Uranometría 2000.0. It is a low contrast galaxy, only slightly elliptical and not too diffuse. The better image was got at ´150, showing then a faint halo and a moderately condensed core. There is an adjacent star or faint condensation. Near this place there is a galaxy labelled as 55 in Webb Society Galaxy Clusters Handbook. It is very close and much more faint and small, at the threshold. The magnitude is 15.7m (photographic); some 14-15m stars are near. The centre of the cluster is certainly too crowded, and the lack of resolution together with the weakness make that some central galaxies appears confounded by overlapping at the eye. One of them, however, stands out from the others: the 13.3m elliptical NGC 3842, which is immediately at the SW of a 10m star. Jiggling the telescope makes visible more galaxies, all of them having an extreme weakness. With direct vision I only can count 3 of the central galaxies. At the W two isolated spiral galaxies call the attention: NGC 3821 and 3816, the first with annular features, and the second, a distorted S0. At ´180 the contrast drops strongly, although the background still remains glowing softly, so I couldn't apply more magnification.

 

 

 

Wonderful globular cluster, bright and well resolved. It is easily located following 3-5º S the line b-d Crv. M 13 is a good reference: M 68 is approximately half in size, but with a smaller gradient. It, however, shows the same radial features that M 13, i.e. strings of stars escaping from the centre. The profile with an exponential diaphragm corresponds to class 8 globular cluster. Wonderfully solved using a 16 mm König and a Klee Barlow lens 2.8´. There are six stars outstanding on a background constituted by ca. 50 weaker stars of similar brightness and a hazy cloud of unresolved stars. The object is spherical, with a nucleus poorly defined, reaching a maximal diameter ca. 2.5'. 20´80 binoculars show the cluster greyish and weakened, since Valencia lights makes the background more apparent than at the telescope.

(to top)

 

 

 

Spiral and immense galaxy, easily visible through 20´80 binocular as a large glowing cloud. At telescope, the most relevant feature is an S‑shaped nucleus that calls mightily attention, very prominent. Also, a bar of matter arranged E‑W. The spiral structure is distinguished too weakly because of the background, but stands out if we jiggle the telescope. It is more evident in a first impression, before that the static image makes the details to vanish. This is without any doubt one of the (few) spiral galaxies that a 254 mm telescope allows distinguishing more easily spiral features. It measures 12', filling roughly speaking half field in an 8 mm König. It also looks large through 20´80 binoculars, standing out the central bar, although the nucleus seems less stellar. I think that the spiral shape should be accessible to binoculars from best places or/and darker nights.

(to top)

 

 

 

It is a weak and diffuse galaxy 30' at SE from 77 Peg, projected in a very poor stellar background, but where nevertheless, many minute stars may be distinguished. NGC 7743 was not seen with 16 mm König (´75). It began to be perceptible using 12 mm König (´100). With 8 mm König (´151), the galaxy is hazy and with a low surface brightness (BS 14.2 mag·arcmin^-2). I couldn't distinguish any neat shape. The only two features that were possible to glimpse were a very small and oval nucleus, semistellar and progressively condensed toward the centre and an elliptical halo with imprecise boundaries, more extensive and elongated E-W. The overall size was ca. 2.1', whereas the core was only 40 arcsec. The global magnitude was fainter than 13.0. Using averted vision it is appreciated more irregular than using direct vision, complex and naturally brighter, with the usual appearance of a spiral galaxy seen from a polar position.

(to top)

 

 

 

It is 1º N of NGC 7743 (or 30' NE from 70 Peg), and easier to see. This is a much more contrasted galaxy, slightly elliptical. Mean surface brightness is one magnitude brighter than that of NGC 7743. The nuclear size is only 60''´40'' and the halo, not very definite, spans 2'. The nuclear condensation is not progressive but constant, with an inner nucleus clearly non stellar. A 13 magnitude star lies 1' E from the galaxy. Global magnitude is 12.5. The appearance fits among the elliptical galaxies, although the light distribution in the core is not typical (peculiar galaxy).

(to top)

 

 

 

15' S of a right triangle of stars. Using 20´80 binoculars I measure 4.5' of diameter and 9.0 visual magnitude. The nucleus is hardly distinguished, although it is slightly irregular. Although the surface brightness is fairly low, the boundaries are distinguished relatively well. Using (T) 260 at ´100 the object is partially solved in stars, in spite of the excessive clarity of the background. It seems more round than it appears with binoculars and quite small, inscribed in a triangle of stars of the 11.5‑12.0 magnitude. The edges now are seen poorly definite and it is lost the halo. At ´180 increases even it is seen more reduced, and stands out the inner core, of 2.5'. The nucleus properly said measures 2'. Stars are distinguished easily using direct vision, and fairly more using averted, reaching now 4' of total size if you move a little the telescope in order to facilitate the detection to the eye. At ´425 the bright components stand out, especially one at the NE of the core and 6 weaker in the nucleus. The outlying stars are seen with a greater difficulty, but the granular texture of the object is evident included with direct vision.

(to top)

 

 

 

This cluster is hard to find using 20´80 in spite of knowing its accurate location. Nevertheless, it can be weakly distinguished if the binoculars are moved laterally turning the slow azimuth control. NGC 6235 stands out as a small smudge, smaller than M 107 and fairly spherical. No detail is appreciated, even seems having no nucleus. It is, however, easily found with the 26 cm Newtonian reflector at ´75, although it is not a bright object. It is appreciated as a small circular smudge immediately to the North of a 13 magnitude star and very close to a triangle of 7‑8m stars that help us to spot the object. As M 107, it also is a low gradient cluster, but in this case, more distant, intrinsically older and less obscured by galactic dust. At ´225 I see some overlapped stars, likely non‑physically related to the cluster. The object is then seen more oval, standing out more from the background. With averted vision I think to see it slightly mottled, covering the stellar dots the whole surface. A 14.0m star at the W of the nucleus is quite prominent among other weaker components and a slight general mottling. The cluster core measures 15''. The outer halo of the core, at ´425, seems triangular, elongated E‑W and measures 2.5'.

(to top)

 

 

 

Nearly stellar and bright planetary nebula in southern Ophiuchus. Found easily with UHC at ´75 easily in order to exalt its perception from field stars. At ´425 it is slightly elliptical in N‑S direction. There is a bright core than almost seems a star, and two disks. One of them, the outer, is more diffuse, whereas the inner one is the best defined. The nebula looks white, since it is at the threshold of the colour perception. Some 12-13m stars of the magnitudes close. In an immediate area of 2.5' there are some other fainter stars (14.5 magnitude and below), more complicated. I measure 10´8 arcsec.

(to top)

 

 

 

Located with 15º height waxing Moon (phase ca. 50%). M1‑64 appears as a little smudge of even surface brightness at ´150 with UHC. It is a ring nebula, bat I could not see it as such. The colour was the characteristic grey‑bluish hue of some faint planetary nebula. At ´225 the size increases up to measuring 15'' in diameter, somewhat elongated. The stellar background was impressive, what diminishes the spectacularity of the nebula. The edges were slightly pointed.

(to top)

 

 

 

Stellar planetary nebula located in central Aquila, easily spotted at ´100 centring the area and adding the UHC filter. One of the stars, in fact not the brightest, is then converted in the most outstanding "star" within the field. That night the seeing was not good. Nevertheless, at ´185, still being very small, it was perceived larger and rather smoother than the other stars in the area. NGC 6741 was one of the 12‑13m stars shaping a 4 arcmin trapeze (the second brightest within the group, that is, the eastern component). Without filter, the first component of that trapezium exceeds the nebula in over a half magnitude: With the UHC, however, the star becomes almost two magnitudes fainter than the planetary nebula; a spectacular change, indeed. Owing to its small size, the nebula is rather hard to measure with a minimal accuracy. It barely fills 2% of the field at ´425., which implies a diameter smaller than 10 arcsec, even I would say that it is smaller to me. It seems nearly spherical, of increasing brightness toward the centre, which can be partially attributed to the contribution of the central star. It doesn't seem oval, neither any trace of ring structure was perceived, just a disk of progressive internal brightness, which agrees with Brunier's description but not with Lughinbul's notes. A 14m star is 28'' at the NW.

(to top)

 

 

This planetary nebula has been observed in many occasions. This time I attempted it with 20´80 binoculars. It was trivial to centre with Uranometria. If once centred the area, the UHC filter is inserted, the nebula stands out immediately amidst all background stars. Through binoculars, once properly centred, NGC 7662 is seen blue, virtually stellar, although with smooth borders. Anyway, it is larger than the neighbouring stars, with a distinctive grey-bluish colour, which immediately calls our attention. It is 25' SW of 13 And, in the western extreme of a E‑W 8‑9m star chain.

(to top)

 

 

 

Extremely faint planetary nebula in Aquila, which in pictures seems a small copy of the Helix nebula. According to both S. Hynes' Planetary Nebulae and the Sky Catalogue 2000.0, it is fainter than 18.7m. I tried it without filters, but I was unable to find any trace using diverse eyepieces. Only at ´100 and with UHC I think to have distinguished a hazy and extremely weak cloud ca. 1 arcmin in diameter in the expected location. It is at the threshold of Algar sky, so it can be just a suggestion. The visual magnitude is at least fainter than 13.5.

(to top)

 

 

 

Large and easy‑to‑see planetary nebulae, 1.5º WSW from 12 Aql. It was found when the area was scanned in a preliminary exploration. There are abundant weak background stars. At ´75, NGC 6751 calls the strongly attention, and it is seen slightly elliptical, measuring at least 20 arcsec (not the 8 arcsec listed in some sources). The surface brightness is rather even, and the nebula is remarkably grey‑bluish. Its perceptibility is greatly enhanced with the application of UHC filter, being 2 magnitudes fainter than a 9.5 magnitude star that lies 15' W which was used to spot the nebula position. The internal region is a smooth disk. I think that I saw the central star at minor magnification; however, I couldn't confirm this at ´225. At this power a 14.5 magnitude star was seen toward the south in contact.

(to top)

 

 

 

Planetary close Delphinus head, very well located since two 8m stars fix the position with accuracy. One of these stars is nearly in contact, so make the nebula easy to find, although on the other hand perturb strongly. The trials made with UHC at ´100 without a perfect adaptation to darkness failed, except occasional transitory sights. Only when the night adaptation was enough good I could distinguish it with certainty, sweeping slowly the field. The central star was not perceived, although some other faint stars (not so blue) were seen projected on the nebula. The nebula is giant, exceeding 2 arcmin, but very faint and of low contrast.

(to top)

 

 

 

This planetary nebula was not seen at neither ´75 nor ´100, with and without UHC. The detection required more magnification. It was initially located at ´150, as a circular homogeneous smudge of 20 arcsec in diameter, very near to a 9ª magnitude star in a very rich background. The central star was not seen.

(to top)

 

 

 

This planetary nebula is almost in the field of M 34. Impressive, it was not seen at ´75 using UHC with direct vision. However, at a slightly larger magnification (´100), it was successfully found, 1º WSW of M34 and only 2' E from an 8ª magnitude star. The nebula lies at the western extreme of a small curved star chain configured similarly to Corona Borealis (all 8 to 12m stars). Abell 4 is seen with better performance at ´186, although excessively weakened, so details were too hard to see. The nebula looks circular, 30 arcsec in diameter, and little hazy. The disk seems uniform or perhaps with a little brighter core.

(to top)

 

 

 

This planetary nebula, well referenced and large, may seem easy, but it is difficult to locate in a first trial. It remained completely invisible without filters at ´75 in spite of being an acceptable night, and was finally found at ´150 with UHC. There is a compact group of three faint stars in the immediacies that could make the confusion with a nebulous smudge. The nebula stands out as a great ellipse, without nucleus neither any characteristic detail. The surface brightness was uniform and not too low. The appearance changed dramatically without UHC at ´185: a bright arc was evidenced toward the North, and the nebula left to be circular to adopt a more elliptical profile. The central star was invisible, although a 13.5 m star was nearly in contact, easy to see.

(to top)

 

 

 

It was found by chance while I was searching the planetary nebulae NGC 7139. The small open cluster NGC 7160 is 1ºS of VV Cep, and it consists of a small group of 15 stars compressed in a 7' arcmin area. Its profile is rather irregular and lacks of nucleus. Nevertheless, the cluster contrasts well from the surroundings. It is a small ‑although striking‑ cluster, with an orange star featured at the North, next to another one, yellowish (the colour of the second star could be a contrast effect). There are other 6‑7 bright components SW spread from this pair, irregularly arranged and with an approximately elliptical profile. Finally, there is a third magnitude step including weaker stars in a similar number. The overall group reminds me NGC 457, the "ET Cluster", in Cassiopeia, although evidently lacks of traversed star chain. Observed through binoculars it calls the attention even more since it is extremely small and very compressed although bright; some stars were resolved anyway.

(to top)