Archive for August, 2013

Stars of Cravanzana

Blog 11th-21st August 2013

 

Our summer holiday took us to north-western Italy, close to the small village of Cravanzana in the Piedmont region to stay with friends who had escaped from the UK 3 years ago and established their own organic fruit and nut farm offering comfy accommodation to paying guests, know in Italy as an Agriturismo. You can visit their website here.

Here the skies are dark and clear and their location 600m and close to the top of a hill offers great horizons. Testing the sky with my ‘Sky Quality’ meter SQM typically gives readings of 21.5-21.8 matching the best readings from Norfolk & Suffolk in the UK, so pretty good compared to my home readings of 20.5.

I have a Edmunds Scientific ‘Sky Scan’ 105mm F4 Newtonian rich-field scope over there to use when I visit, plus a Meade ETX 90, I also took my heavy but wonderful Takahashi 10×70 Astronomer binoculars with me. During our 10 day stay I enjoyed some spectacular Perseid meteors, breath taking views of the Milky Way with its sweetshop of lollipops that looked amazing in the kit I had, as you know I’m an avid big scope and faint deep sky object boys so this kind of observing was as different as the location was for me.

I of course took a challenge with me, laid down with my galactic sparring partner Andrew Robertson. Knowing the aperture at my disposal he asked if I could detect the small globular cluster NGC 6453 very close to the bright open cluster M7 in Sagittarius

With New Moon having been and gone on the 6th, the Moon’s bright shiny face increasingly made its presence known as each day passed. I got straight onto the Challenge on the night of the 12th. The Astro Scan is a good little scope however its inbuilt focuser is worse than poor, achieving and holding sharp focus is close to impossible when you push the mag up especially. With no finder scope or proper unit finder, the scope has a kind of ‘gun sight’ one has to start off with a low magnification and build up whilst trying to centre the object of interest. I knew that I would need so magnification to get the little GC to give itself up and show it was a fuzzy and not stellar. I had a Vixen 8-24mm zoom, the 8mm setting giving 53x, hardly high power but on fast small aperture optics I was hoping it would do the job. I spent more than an hour but didn’t detect the globular, drat!

The next day, I studied a more detailed finder chart on the web and really familiarised myself with the location, I had been working with my S&T pocket atlas up until then.

On the 13th I took the scope away from the buildings and up onto higher ground where I could see the region better and had more time before the ‘tea pot’ asterism crashed into the scrubby pines of the neighbouring ridge. Despite the extra effort I once again failed to pick out NGC 6453. I relayed this to Andrew by email the next day, he wasn’t surprised the smallest aperture he had read of being successful was an 8 incher.

All was not lost I had enjoyed catching sight of the brightest Nova to be seen in 14 years, naked eye in Delphinus, I did this thanks to my host printing off a simple finder chart from the web. As mentioned before I got to see some lovely Perseid meteors that appear to flare out then taper sharply to a point before disappearing, like some Neolithic spear head. I spent much time taking in the sights of Sagittarius around the Tea Pot, normally invisible from home, wondrous, beauteous and relaxing astronomy just perfect for a fine warm summer’s night when on holiday.

A little later during our stay I used the telescope to take a look at the moon and show other guests visiting the magical spectacle of the “magnificent desolation” that we astronomers take for granted.

The view from our balcony at night was quite magical, and I use that term rather reservedly as it involves manmade light (normally termed as ’Light Pollution’) be speckling the valley stretched out below and stars spangling the sky above. Now our last night was a very warm one, I crept out into the  pre-dawn morning and I was entranced by Orion rising on his side to the east from behind the dark hills and hanging with his sword obvious and his belt pointing down to the hill top village of Bergolo.

I had to capture this magical scene, which I did initially by dividing land from sky with pencil on paper then dotting in village and farm lights and stars in the sky, the next day I rendered the scene with watercolours, a new medium to me.

Orion rising over Bergolo

A wonderful holiday had come to an end and now I think of possible ways to get a large telescope under those skies 🙂

 

Dale

A couple of very good observations

Blog for 2nd & 7th August 2013

 

I don’t like to combine dates in a blog like this but I’m well behind so I need to get it done and posted!

This covers two somewhat impromptu observations both with pleasing results. The first took place early hours of Friday 2nd and followed an up-dating of the Webb Deep Sky Society web site which included Owen Brazell’s ‘Galaxy of the Month’ was NGC 6029 in Delphinus, this turned out to be the brightest member of a group, not the kind of target one anticipates for a summer night, but as luck would have it that night the skies cleared and steadied giving me a chance. I set the alarm for 00.30 local time, made a brew of tea and left the back door, I paused and looked up, recognising instantly that it was a good sky! I moved down towards the observatory and even without any feel dark adaption the double cluster and M31 were clearly visible, with the Milky Way sweeping overhead.

I located the galaxy group off of the Dolphins tail without issue and took my time to sketch, Owen had said that he would be interested to see how many members my Watec & 20” mirror would show so I was intent on rendering the scene best as I could. I was also running the uncooled Watec 120N+ through the 153mm F9 refractor giving a slightly wider field this showed 3 members readily and a 4th just, the 20” and cooled Watec pulling in 7.

Here is my sketch followed by Owen’s detailed posting from the Webb society web site.

NGC 6928 A suprise galaxy group in Delphinus

 

NGC 6928

“Summer is not thought of as galaxy season but even within classic Milky Way constellations such as Delphinius there are some galaxies. NGC 6928 could be thought of as a galaxy so good it was discovered twice. First seen by Albert Marth using William Lassell’s 48” speculum reflector from Malta it was catalogued as NGC 6928. Later it was independently rediscovered by Lewis Swift and catalogued as IC 1325. However there were still some errors and occasionally NGC 6928 is referred to as IC 1326, whereas that number in fact belongs to NGC 6930. There is a small group of galaxies associated with NGC 6928 and it would appear that 3 of them were found by Marth and given NGC numbers (^927, 6928 and 6930) and then the two brighter ones later found by Swift and given IC numbers. It appears that Swift processed his positions incorrectly and reversed the declination sign so they were not immediately associated with Marth’s discoveries. NGC 6828 itself is an edge on spiral galaxy classified as SBab. There appear to be 4-5 galaxies in the group and the group is known as WBL 663 from a paper on nearby poor clusters of galaxies. The galaxies in the group are relatively faint so a 30cm or larger telescope may be required to see the brighter ones, although 22cm can show NGC 6928 itself. It will however be faint in that aperture. The NGC galaxies are NGC 6928, NGC 6927, NGC 6927A and NGC 6930. There are a number of other fainter galaxies in the field as well with one right off the top of NGC 6930 making it appear like an exclamation mark. This galaxy was too faint to be seen by the NGC compilers but has a UGC number (11590). NGC 6927A was not a name given by the Dreyer but was a moniker given by the compilers of the RNGC who gave additional names to galaxies found on the POSS near other NGC galaxies. It would appear that probably a 45cm aperture will be needed to see NGC 6927 and that from very transparent skies. Observations with an 18” suggest that although 6928 and 6930 were visible 6927 was too difficult. The group is in the Atlas of Galaxy Trios by Miles Paul published by the Webb Society and is also to be found in the Atlas of Galaxy Trios downloadable from Alvin Huey’s website . There are a number of other faint galaxies in the field which are listed in the PGC or MAC catalogues but these are more likely targets for imagers” Owen Brazell

Very pleasingly Andrew Robertson my astronomical sparring partner was away with his big 24” telescope in darkest Suffolk and managed to view 4 members visually, here is what Andrew wrote  

“Four! and without having seen this thread. Just had 3 glorious days and nights at Haw Wood Farm, Hinton with the 24″ (23.5 really), it’s first outing since the beginning of April, got back yesterday evening, wrecked but very content, went to bed at 10pm and slept for 9 hours 🙂

 

It was good to blow the cobwebs out of the 24 but I wasn’t expecting too much; about 2.5 hours of astro dark on the Thursday/Fri night with a 20% moon rising at 0120 hrs. Friday night was forecast to be cloudy but Sat night looking good with nearer 3 hours of astro dark and no moon in the way. As it happened I had observing on all 3 nights with Thursday being the best and it getting progressively worse each night. On the Thursday I got going about 11pm with it being fully dark for that session by midnight. The moon rising didn’t really show itself until about 2am and my darkness didn’t start going overhead until about 2.30am, packed in at 3am. On the Friday it was clear contrary to the forecast but cloud kept coming over, I covered up at 2am and the Thunderstorm arrived at 2.30am. Saturday was the worst, mainly because it is a normal campsite and completely filled up at the weekend being school holidays in the summer. However the majority went to bed at a reasonable time and the site was completely dark apart from one camper whom might as well have been camping in a town centre rather than enjoying the natural country environment – unfortunately he was pitched right next to me! I gave up at 1.30am and was in bed by 2am. In addidtion my wife Amanda joined me on the Saturday morning so we had a glorious weekend, enjoying the sun and listening to the cricket. I took regular SQM readings and it was consistently only 21.3 on the Thur/Fri nights dropping to 21.25 on the Saturday.  The Milkway was prominent overhead with dark rifts but 21.3 is a poor reading for this site I frequently get in excess of 21.65, Amanda and I put this down to a slight sea haze being only 6 miles from the coast in the peak of this hot summer. Anyway, on to the observing: (But, just before shutting down my computer on Wed night I saw Tim’s update and printed of Owen’s GX of the month in Delphinus.)”

 

My observation for August 7th resulted again from someone else’s inspirational posting, this time it was Andrew Robertson’s observation of an unusual planetary nebula in Cygnus that I had heard of but had never observed

Andrew posted this “Got out again with the 18″ at home last night. Observed from 2315 hours to 0323 hours. Very misty, absolute best SQM was 21.0. Re-visited 6928 group but only got as far as 6930. Only 6269 in the Hercules group! But had some nice views of PN.s. 7027 was a lovely green bi-polar. 7026 – HAMBURGER – I’d forgotten! Quick sketch made of this one – not very good but…. :-)”

Andrew's visual sketch

 

This resulted directly in my sketch below, which resulted from the view delivered by both 20” mirror and 153mm OG and Watec camera, the former showing many more field stars and outer nebulosity around the nebula but the 6” giving a sharper but smaller image and revealing the central star. What a very exciting and unusual nebua.

When I shared it with Andrew this was my accompanying comment “On a more positive note, great observations from Cygnus by you, and once again you inspired me, I went for NGC 7026 tonight, you call it the Hamburger nebula (I note it is also called the Cheese burger by some, those more hungry I guess ;¬), I had never observed it before, very interesting planetary and something a little different.”

 

My sketches are attached, a combo effort with both 6″ & 20″ both running Watec cameras

 

What do you think? Cracking object thanks for taking me there tonight :)”

Complete observation form

As they say in the Cartoons “That’s all Folks”, got to rush, more from me soon I hope, Dale

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