Saturday 21st October, the forecast was for a clear and frosty night. An opportunity to try and find some really dark sky. Heading off early I arrived at my intended destination after 1 hour and 20 minutes drive. A little low cloud was gathered around a rise to the south east so I retraced my tracks and turned off onto a forest track to investigate an alternative location. After 5 minutes I chanced upon a vehicle turnaround with a 1 degree horizon to the south east, south, south west and west. The east and north were at about 10 degrees.
How dark was it? There was no, I repeat NO, light glow on any of the low horizons! There may have been some to the north and east but this was hidden by trees or swamped by the combined brightness of Jupiter and Saturn! It was clear and dark down to the ground. Capricornus was completely visible, the Milky Way brightly visible way before the end of twilight, objects were observed at less than 5 degrees elevation. The location of the North American nebula was given away as a very bright part of the Milky Way at the start of the Cygnus Rift. Observations with the 140 mm Maksutov were clearer and brighter than those made through DaveT’s 10” reflector at Gradbach!
Starting in twilight I picked off a few old acquaintances in Ophiuchus, the bright globular clusters M10, 12 and 14. A new find in this constellation was the bright open cluster NGC 6633, at mag. 4.6 it was a lovely sight.
Moving on to Sagittarius. I was hoping to find the Little Gem Nebula, a mag. 10 planetary. To my surprise it was easily located and showing a clear disc at x100. The large and bright globular M22 was very well resolved despite the 7 degree elevation.
I had rushed observations in Scutum the last time I was out. I therefore spent some time observing the beautiful Wild Duck cluster, M11. This was very bright and reminded me of views I had from Portugal. I also viewed M26, a pale and diffuse mag. 8 open cluster followed by the nearby mag. 8.2 globular, NGC 6712.
Turning to observe in Draco before it became too low in the north west, I relocated M 102 and identified a couple of relatively bright nearby galaxies, NGC 6503 and 5907. Dropping down into Ursa Major M101 was very large and appeared to exhibit detail. By far the best view I’ve had.
It was now time for some work with the filters. The previous session I’d had problems with glare using the UHC filter. This time was slightly better however, the best views were with the Deep Sky filter. The Helix Nebula, low in Aquarius was very bright, well defined and showed hints of structure. The Eastern Veil in Cygnus was equally well displayed.
I next located NGC 6781. This is a mag. 11.8 planetary nebula in Aquila. Completely missed last time from Gradbach it was now visible as a large, pale version of the more famous Owl Nebula, M97.
Working gradually eastwards my next target was in Pegasus. I had failed to observe Stephan’s Quintet on several occasions. The only success was with DaveT’s 10” reflector from Gradbach. This time, the grouping was obvious. It was visible in direct vision and brighter than seen previously. The nearest and brightest galaxy of the group is the mag. 12.6 NGC 7320. Dropping down I revisited “the best barred spiral in the northern hemisphere”. This time NGC 7479 appeared as an oblong fuzz as the central bar became more visible. Dropping lower still, a large, pale galaxy NGC 7606 was visible near some bright stars in Aquarius.
I continued eastwards collecting M76, the Little Dumbbell, and M34 a nice bright open cluster. Another failure had been NGC 891 in Andromeda. Often touted as the best edge-on galaxy, this large, low surface brightness object was easily visible and very spectacular. It fits nicely in the FOV and looks like the quintessential galaxy.
For the past hour I had been wiping dew off the Telrad and finderscope. Now the OMC 140 was showing some early signs of dewing. Taking the OTA off the mount I popped it into the car and ran the engine to heat it up a little. Coffee and chocolate was consumed whilst leaning back in my chair to take in the glorious canopy of stars. After half an hour I continued with the ‘scope.
Yet another failure from Gradbach was to be put to rest. Low down in Cetus and Sculptor were a couple of Caldwell objects. NGC 246 is a planetary nebula listed at mag. 8.5. I had expected to locate a relatively bright star or disc. Having failed a couple of days before I checked the Caldwell guide and RASC list. “More like mag. 11” and “four stars surrounded by nebulosity” gave the reasons for my earlier failure. This time a 4 by 3 arc minutes haze was visible around four stars! Moving lower down the enormous and bright, mag. 7.2 spiral galaxy NGC 253 was observed. I thought I could see detail even though it was at about 10 degrees elevation.
Winding down I looked at a few old favourites. The views of the Ring and Dumbbell nebulas were the brightest and clearest I’d ever experienced. Astounding detail was visible in both. M33, the diffuse face-on spiral in Triangulum showed detail for the first time. M81 and M82 made a beautiful pairing, I noted whilst logging my observations that a large number of relatively bright galaxies are available around Ursa Major.
Moving back towards the east I picked up a couple of galaxies in Cetus along with M77. M38 in Auriga and a very bright M1 in Taurus were my final Deep Sky Objects for the evening.
To finish Jupiter and Saturn were riding high. In occasional periods of good seeing the Cassini division was visible in Saturn’s rings, another first for me. Jupiter also showed incomparable detail!
It was well worth the drive.
by Paul Clark
コメント