Observations from Lichfield (Staffs) Friday 13th Jan 2011

[TakMan]

Andrew Thornett and Damian (TakMan) from Damian’s back garden.

Equipment – A 4" Takahashi TSA102s (816mm focal length f/8) and a Takahashi EM400 GOTO mount* (controlled via a 17" Apple Powerbook running planetarium software - Equinox Pro), with Televue Ethos eyepieces; also Andy’s 20x80 binoculars on a Paragon parallelogram mount.

* The EM400 is usually kept for imaging but Ian King had said that my new SBIG STF-8300M was not going to be coming for at least another 2/3 weeks.... so I decided to offload the FSQ and get into some visual observing - far more sociable that spending a clear evening glued to watching a guide graph! This goto malarkey is faaaaaar easier though than my usual star hoping frustrations!!!!

Anyway, onto Andy's report....

At the beginning of the evening, the sky was incredibly clear – clouds of stars could easily be seen with the naked eye coursing from Orion to the Hyades in Taurus and Orion’s sword shone brightly in the sky, although later on the sky became more misty, until the sword virtually disappeared.

With the 20x80 binoculars, Orion’s great nebula M42 looked like a large Stingray fish with large fins on both sides. The dark nebula forming the fish mouth was obviously darker than the surrounding star fields and three stars could be seen in the Trapezium region of M42. With the Takahashi telescope, we could now see four clear stars in the Trapezium. The fish mouth was observed as a complex structure rather than just as the U shaped depression it had appeared as in the binoculars. The dark nebula forming the fish mouth now appeared to have a structure of its own, being seen to be a polygon bordered on one side by the fish mouth and on others by brighter star fields.

The fins on the sides of M42 extended much further – covering most of the width of the field of view of the eyepiece. In the 20 x 80 binoculars, I initially thought I could perceive parts of the dark nebula complex in which the horsehead nebula is located. Damian disagreed and a search with the Takahashi backed up his view that it was not visible. The bright star 50 Zeta Orion (left hand star in the belt of Orion) is very bright at magnitude 1.9, and it obscures faint objects in this part of the sky. This probably explains why we could not see any dark nebulae nearby – including the horsehead.

Through the Takahashi, Betelgeuse was bright orange and looked like a disc – demonstrating the difficulty observers have in determining whether small bright objects seen through a telescope are point or disc sources. M78 – nebula in Orion. Normally we would consider this to be more a photographic object rather than something to consider viewing in a 4" scope. However, tonight we could just see this above the sky glow in the Takahashi including an apparent 'brighter' region within this small smudge. Three very faint stars were located just off centre towards 10pm on a clock-face. The nebula was the size of small pea and only just visible. We could not have found this without GOTO!

Jupiter was a phenomenal sight through the Takahashi. Tonight’s view demonstrated the importance of local seeing conditions on the amount of visible detail in the planet. In the past, we have seen copious amounts of detail in the belts (albeit only occasionally). Tonight we could see five belts easily but not a great deal of detail in them and the Great Red Spot was not visible. Four moons were visible alongside Jupiter – Ganymeade, Callisto, Io and Europa. They all looked like discs and Ganymeade had a distinctive orange colour which surprised us! We could not see detail on any of the moon discs – not surprising – we have never seen such detail before.

The 20x80 binoculars gave an entirely different view of Jupiter, showing the planet and its adjacent bright moons in the context of the local star field – an incredible sight that should never be missed – wow! The binoculars were also good at ensuring that the glare from the planet did not dominate the view. Their view supplemented the expensive telescope – and we valued having the two side by side.

The Crab nebula M1 in Taurus was found just above 123 Zeta Tau. This bright star was located at the bottom right of the field of view of the 21mm Ethos in the Takahashi. I would like to say we star-hopped to it – but instead we used the GOTO. Initially looking very faint, M1 became brighter and more obvious the longer we looked at it. It was about the size of a penny piece, and continued to look like a grey oval smudge without detail. Although resembling the shape seen in short photographs of M1, the filaments seen in these photographs were not visible in the optical view.

The open cluster M38 in Auriga had four streamers of stars radiating out from the centre. Just below it was NGC1897, much smaller but still obvious. The stars in both were much dimmer than the magnitude 5.06 star 24 Phi Aurigae that was also in the same field of view. Our next target was M36 open cluster also in Auriga. Both M38 and M36 are listed as magnitude 6, and both are composed of stars of approximately the same brightness. M36 appeared to me to be slightly more compact than M38 and whereas the latter had streamers of stars with darker areas in-between, M36 appeared as a more amorphous mass with a prominent cross of slightly brighter stars overlaying it.

We viewed two more open clusters in Auriga, both found using the GOTO. NGC1931 was seen with direct vision but was very faint. NGC1893 was much bigger and surrounded on the left by three stars in a crescent. This cluster was even more faint, looked like a little Y shape, and was only just visible by direct vision. Without GOTO, we would not have known this was a cluster and instead assumed that we were looking at a denser knot of background stars.

The open cluster M37 was more condensed and more obviously globular in appearance. It was supposedly brighter at magnitude 5.6 but tonight looked darker than M36 and M38. It was composed of a great many small stars spread over quite a wide area which probably explains this discrepancy – when integrated magnitudes do not appear to reflect surface brightness.

We observed another large bright open cluster in Gemini. This was M35, easily seen with the 21mm Ethos. In the field of view of the Ethos that showed this cluster, another cluster could be seen at 8pm on the clock face. This was much smaller and much fainter. It was NGC 2158. In photographs, this faint open cluster shows a large number of golden stars – much older and further away. It was easier to see with averted vision. We also just picked up another very faint open cluster, IC2157, at 9pm on the clock-face compared to the location of NGC2158 and immediately above 1 Gemini (magnitude 4.1 star). This latter cluster looked like two crescents cupped together with open ends pointing at each other. This would have been impossible to find without GOTO!

M101 – seen with 20x80 binoculars. Noticed as a very slight brightening of the sky rather than as anything more specific and disappeared quickly when a small amount of haze appeared in sky. Located by star hopping along the line of stars from Mizar and Alcor in the handle of the saucepan in Ursa Major. Sirius in Canis Major – bright white, could not see the pup alongside.

M50 – open cluster in Monocerus – easily visible but not as bright as M36 or M38. In the centre of M50 was a small red star which caught our attention - further research later on in Stellarium would suggest this to have been 7.8 Magnitude star HIP33959. We tried to observe the Rosette nebula in Monocerus – very difficult to make out in these skies. I initially thought I could see it but Damian disagreed and I wasn’t able to confirm the observation. However the open cluster associated the Rosette nebula could easily be seen - NGC 2244. This is a group of about 15 stars in a configuration which we could easily match with that seen in the centre of comparison stock photos of the Rosette nebula.

We tried to look at the Eskimo nebula. We were not able to see it – probably because we had left the Lumicon UHC filter in place after our 'Rosette Hunt'! We only realised this after having slewed to our next target...

The Beehive open cluster M44 was a lovely sight in Cancer although impossible to get all the stars in the field of view of the Takahashi, even with the Ethos 21mm. Regulus in Leo is another bright white star – we stopped by here as we synchronised the telescope, before dropping down to Mars.

Mars was phenomenal tonight. It was located near the Moon in Leo. This evening, we could see a large bright white North Polar cap and a sensation of markings on the planetary disc although these were not distinct apart from an obvious dark area along the edge of the Northern polar cap and some subtle dark area around the southern one. We tried a variety of eyepieces including the Takahashi LE series (Five element Erfles with a fairly narrow field of view): 2.8mm, 3.6mm, 5mm, 7.5mm and then the 3.7mm Televue Ethos – the latter gave the most pleasing views…until it finally misted up!!

Mars appeared intensely red through the 20x80 binoculars – no detail on disc with the binoculars but clearly disc-like rather than point source and far more intensely coloured than Betelgeuse.

To finish the evening we took a look at the Moon. With the 7.5mm Tak LE, the Moon was larger than the field of view of the eyepiece, and we were treated to incredible close up views of crater chains. The detail through the Takahashi telescope of the centres of craters was amazing. Along the edges of the shadows on the crater floors were the obvious outlines of the peaks and dips in the crater walls from which the shadows came. In many cases these peaks and dips demonstrated detail that was not obvious through the telescope when looking directly at the crater wall itself! Some craters merged into others to form channels and varying levels could be seen in floors of yet other craters.

A truly amazing evening! Andy

....and thanks for reading!

Damian

PS After Andy had gone around 1.15am (and the sky had again started to clear), I spent another half hour viewing Mars and prepared a quick sketch of my observations - must get around to scanning that in and posting on here!