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Deepsky observing with an Owl.......
Last Saturday I had a great time together with Leo. Together we observed not only some well-known deepsky objects, but also a few "new" objects. I used my 300mm Dob and got a chance to test my two new eyepieces, the 21mm Denkmeier and the 5mm Pentax XW. Leo observed with the TAL 250K. The outside temperature was between the 15 and 20 degrees Celsius. The seeing was average, but the transparency was not too good. We barely could make out all the 7 stars of Ursa Minor. But after months of rain and clouds, you are happy with every observing opportunity, so we took it with both hands. The waning last quarter Moon came up around 00.00 hours and stayed out of the way (behind some trees) until 03.00 hours. Anyway, we had a good time observing the deepsky from 22.30 until 03.00 o' clock.

In the low light of dusk we started of with a one of my favourite double stars, Polaris. What struck me was how easy it was "to see" the double in both telescopes. The white B component was very easy to see, next to the yellowish A component. The separation is a generous 18", but I always have to take a good look to see the B-component. Later that night we revisited Polaris and it was a very different story. The 2nd magnitude A component almost completely outshone its magnitude 8.2 companion. Of course it was a lot darker later in the evening, during our second visit of Polaris, so the difference in brightness was much more apparent than earlier on.

16 Cygni and the blinking planetary (Caldwell 15)
The next stop was another nice double, 16 Cygni, which had a companion in the same field of view, NGC 6826 (The Blinking Planetary). 16 Cygni consists of two yellow-golden suns of almost equal magnitude, separated about 40" from each other. About 30' to the northeast of 16 Cygni I spotted the Blinking Planetary. In the 21mm Denkmeier with a field of view of 51' it was easy to get this bright planetary nebula into the same field of view with 16 Cygni. A nice couple of objects to look at. It is a very strange experience, watching the Blinking Planetary. If you look straight at the central star (which is visible even at the lowest magnification of 76x) the nebula seems to disappear. However, if you look a bit to the left of the Blinking Planetary, using averted vision, it pops into view.

I tried several magnifications (76, 133, 229, 320) but the blinking effect disappeared at 320x This was for me the optimum magnification to look at the nebula. It was perfectly round and I could detect no real areas of uneven brightness, and there is no well-defined sharp edge to the nebula. It showed only a hint of bluish-green colour tonight. It was very difficult to really "see" the colour. The OIII filter killed all the stars in the field, so I switched to the UHC narrowband filter. This enhanced the contrast a bit but I still like the view without filter most.

T Lyrae (Carbon Star)
Again a star that surprised us. Last year we have been looking for it with the 10-inch TAL but only after increasing the magnification to 200+ we could find it. It was very dark red and almost invisible at lower magnifications. Last Saturday I pointed the 12-inch dob at the location where I should see T Lyrae, and there it was. Not dark red and invisible but very bright and intensive orange. This is the first variable star that I have ever observed near its minimum and near its maximum, and I must admit, it's a great experience. I never imagined that two magnitudes could make such a huge difference in visibility.

Image from Skytools by CapellaSoft

Phil Harrington's STAR 22, the mini-coat hanger
Next on the list were three objects from Phil Harrington's STAR list (Small Telescope Asterism Roster). The first to visit was the Mini-Coat hanger in Ursa Minor. It looks like a smaller version of Collinder 399 in Vulpecula, the (big) Coat hanger. It is made up of 11 stars and the diameter is about 30'.

Phil Harrington's STAR 23, the backward S and STAR 24, a conspicuous ring
These two asterisms can be found in Hercules. I just had a quick look, but all three STAR's from Harrington's list will be revisited for a closer examination and a sketch. At this point we went indoors for a short break and some refreshments.

Double Cluster (Caldwell 14)
After the break I turned my telescope towards the Double Cluster in Perseus, NGC 869 and NGC 884. In the Dobson I immediately noticed a difference with my 8-inch TAL. The colour in some stars was much more obvious in the 300mm Dob. At lowest magnification, 76x, I noticed three bright yellow stars among all the blue/blue-white stars of NGC 884. When checking with my observing bible, "The Night Sky Observers Guide", I got confirmation of my observation. Three red super giants can be found in NGC 884.

The screaming owl
This is not some obscure asterism, but something that scared us like hell. Around 1.30 on Sunday morning a large bird, with a wingspan of two to three feet, flew over us screaming like the devil himself was on his heels (or tail actually). After little investigation on the Internet it proved to be a Barn Owl. Wow, what a sound! Turn up the volume real loud and .........Click on this link to get an idea......but be warned, this is not for the faint-hearted!

And here is an image of this wonderful bird.

Click to enlarge

NGC 7510 and Markarian 50
After we managed to get our heartbeat down to a normal rate again, we moved to our next stop, two open clusters on Perseus-Cassiopeia Border, NGC 7510 and Markarian 50. NGC 7510 is a lovely object, even at low power. It looks like a kind of arrowhead at 76x. I liked the cluster best with the 5mm Pentax, magnification 320x, FOV 13'. The cluster is only 4' in diameter so there's plenty of room left in the field of view. I counted about 25 brighter and weaker stars that where arranged in a kind of small circle with three legs dangling from the circle. In fact it looked like an octopus! I could detect no background nebulosity and no coloured stars. Next stop was Markarian 50, but this cluster proved to be almost invisible tonight, so we will try it on a night with better transparency and sky-darkness.

M52, Czernik 43, and NGC 7635 (Bubble Nebula, Caldwell 11)
From the invisible Markarian 50, it was only a small step to a very interesting trio, just across the border to Cassiopeia. You can get two open clusters, M52 and Czernik 43, and an emission nebula, NGC 7635, into one field of view. M52 is a very irregular cluster without a real shape, while Czernik 43 looks much more organized, a kind of large triangular shape with 4 bright stars on a row on one side of the cluster. The Bubble nebula was only visible with the highest magnification and averted vision. With direct vision it stayed invisible. This is an object which we have to revisit under better conditions (no Moon, better transparency and darker skies).

At 03:00 we ended our observing session. We saw quit a few wonderful objects tonight, but for me the one thing I will remember is that impressive large bird, breaking the silence with its very harsh call. It was very special to see him soaring through the night sky, only lit by the light of the Moon. It was the first time ever I saw a barn owl and I hope I will see one again somewhere in the future.
Posted by Math on 08/08 at 01:10 PM
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