Mercury

I managed to observe Mercury this evening. Of course the main difficulty is spotting it in the evening twilight. The period is favourable as the planet approaches Eastern elongation on the 2nd June. It is facinating how the planet, invsible in the glow of the setting sun, appears so suddenly.

I estimated Mercury to be 20 degrees (actually 22 degrees according to my computer) West of Venus.

Occultation of Saturn

To observe the occultation of Saturn by the Moon, I set up the 8" dob using the 10mm eyepiece which I found gave the best magnification to see the detail on Saturn but still be able to see the approaching dark side of the Moon.

As the Moon slowly approached the planet, the dark side could be seen as a grey shape against the darker sky. I could not make out any detail except the crater Grimaldi. Although the approach appeared deceptively slow, the disappearance was quick. The time between first contact and complete occultation was only a few seconds.

Contact happened on the North West of the planet so that the Western part of the ring and the North of the planet touched the edge of the moon almost simultaneously. Contact happened between Grimaldi and the South Pole of the Moon. Somewhere near Schickard but I cannot be sure as I could not see any detail on the Moon. Titan which was trailing the planet on the Eastern side disappeared some three minutes after Saturn.

Occultation was to last between 21:55 and 22:55 local time. I used up that hour to observe the lunar surface especially the area around Theophilus which, together with the nearby Cyrillus and Catharina,was especially striking in the lighting conditions. I also observed the asteroid Vesta and the globular cluster M5. This appeared magnificent in spite of the moonlight and the light pollution. At magnifictions of x120 and x200 many stars were resolved and looked like a sprinkling of shimmering diamonds.

It was now time to wait for the reappearance of Saturn. This was slightly more tricky as I did not know the exact spot where it would emerge. I had simulated on the computer that it would appear somewhere around the area of the crater Langrenus. On cue, It suddenly appeared at the Southern end of the Mare Smythii emerging with the Western end of the ring first. Titan reappeared after it with the exact time of its reappearance difficult to determine due to the brightness of the lunar surface.

The striking contrast between the different sizes of the two objects and the rough texture of the Moon compared to the delicate detail of the ringed planet made this observation especially interesting.

More Galaxies and Other Objects

Taking a last chance before the Moon becomes too prominent I took advantage of a relatively clear night to take out the telescope.

First I took a look at the crescent Moon before it went too low. The view did wobble but the craters on the terminator showed up wonderfully. the best were the trio Petavius, Vendelinus and Langrenus, and the craters North of the Mare Crisium, Cleomedes, Burckardt and Geminus. The ashen light was strong and the features on the shadowed part could be made out. I could easily see Plato, the Sinus Iridum, Aristarchus and even Grimaldi.

Venus was only about three degrees away from the Moon and I observed that it is now approaching half phase.

Next was my main objective, finding Messier objects I had never observed. First was the Black-Eye Galaxy M64. I starhopped from Vindemiatrix and easily found it. The galaxy is quite bright and stands out. However, I could only make out its shape without any detail. I tried to split the nearby double 35 Comae Bernices (separation 1") I'm not sure if I managed or whether it was just an effect of the optics. I then starhopped to the galaxy M85 which I also had not observed before. I easily found it. On the way I observed 24 Comae Bernices, it is a fine double with different coloured stars almost like a small Albireo. An attempt to see M98, M99 and M100 failed as I always find these three galaxies exceedingly faint.

It was then time for the culmination of Omega Centauri. This globular rises to about 6 degrees above the horizon from my latitude. I tried pointing the telescope in its direction but unfortunately it is too low for the dob as it lies below the rooftops and my binoculars can't make it out in the low haze. I guess I'll have to go somewhere with a clear South horizon to see it.

I observed Jupiter through the telescope for the first time this year. It was low and the cloud bands were not very distinct. Ganymede, Europa and Io were to the West and Callisto to the East. Above Jupiter I observed Vesta now to the West of a line between BS 6235 and Zeta Ophiuchi.

I used the UHC filter to observe M57 and NGC6543 (the Cat's-Eye Nebula in Draco). M57 is fascinating and the Cat's-Eye is bright. As I searched for NGC6543, a satellite crossed the field of view. While in Lyra, I had a look at Epsilon Lyrae and I managed to resolve both pairs at a magnification of x200.

I observed my favourite galaxies; the M81, M82 pair. With my 25mm eyepiece (mag x48) they are both in the same field of view. I find they are reasonably bright and their different shapes make for an interesting view.

I finished off with Saturn. Always spectacular, the Cassini Division and cloud bands were visible. Titan was to the South, Tethys and Dione to the East and Rhea to the West.

Vesta's movement 3

I had a chance to view Vesta again early this morning at 1 a.m. local time. The asteroid has moved further East and made a roughly equilateral triangle with Zeta Ophiuchi and 20 Ophiuchi. It was a clear sky at the time with Aldebaran blazing high to the SW of the zenith, Jupiter and Arcturus low to the South and Vega high to the East. The Summer Triangle had risen and it was the first time I have seen Altair this year.

Vesta's movement 2

Last night the Vesta, BS6235 and BS6240 were almost in line. A line joining Vesta and BS6235 made an angle of around 175 degrees with a line joining BS6235 and BS6240.

Vesta's movement 1

I have been following Vesta over the last few nights. The movement of Vesta is very easy to gauge by comparing it to the straight line joining the stars BS6240 and BS6235. Two days ago a line joining Vesta to BS6235 made an angle with this line of about 45 degrees. Tonight it has closed to something like 15 degrees.

Vesta

Vesta is nearing opposition. This year it is favorable for viewing since this happens when the asteroid is close to perihelion. It has brightened to naked eye visibility from a dark site. I am not so lucky so I had to attempt to find it with binoculars. It is easy to find, just above Jupiter between the two stars forming the base of Ophiuchus EtaOph and ZetOph, near BS6235, a +6.03 star. This is only the second asteroid I have observed after having seen Iris last November. This asteroid has a special significance to me since I had my name included on a microchip, together with 360,000 others, that will be sent on Nasa's Dawn mission to Vesta and Ceres which is scheduled to launch this summer.

Galaxies and More

Finally, after almost a month of high cloud, overcast skies and strong winds, I managed to get an evening of observing. A high RH of about 80% didn’t help but the absence of the Moon encouraged me to go galaxy hunting.

I warmed up observing Venus. It is now approaching half phase as it gets closer to the Earth. Next was Saturn. The view was stunning as always. The Cassini Division was visible as well as the darker cloud band and the shadow of the planet on the rings. I observed four moons. Rhea, Dione and Tethys lay to the West and Titan to the East of the planet.

I started my galaxy observations with M65 and M66. They were both visible but faint. Next I went lower down to one of my favourites, the M104 Sombrero. I am always surprised at how bright this distant galaxy appears even though it lies low in the sky. Then it was time for the Virgo Cluster. I started starhopping from Vindemiatrix (Epsilon Virginis). At first I was somewhat lost but after a while I got going and found M60 which I observed to be quite bright, brighter than nearby M59. Next was the even fainter M58, which is easy to find as it is next to a star. Starhopping northwards was M90, again very faint. I couldn’t see M89 but I certainly found that giant among galaxies, the huge elliptical M87 (Virgo A). At one point, a satellite crossed the FOV as I was observing.

I left the Virgo Cluster and had a look at M57 which had just cleared the rooftops. It was the first time I had a chance to observe it this year and so had my first view of it through the UHC filter. Although it was low, the filter made it stand out nicely.

I resumed galaxy hunting with the M51. I found this easily and could view the two nuclei, M51 and NGC 5195. I also caught a glimpse of the faint M108 near Merak (Beta Ursae Majoris). Close by was another chance to use the UHC filter on M97. Without the filter this nebula was invisible but became very evident with the filter.

Throughout I used the 25mm eyepiece (mag x48) for the galaxies, the 10m eyepiece (mag x120) for the planets and the 15mm eyepiece (mag x80) fitted with the UHC filter for the planetary nebulae. Light pollution excluded seeing anything but the cores of the galaxies but it is always inspiring to see objects many millions of light years away.