Clear Skies On Demand - an astronomy blog

Saturday, July 14, 2007

Observing hidden treasures.........

Last night it was clear between 11 and 1 o clock (local time) and I had a quick look at some deep-sky objects with just to test my new eyepiece, the 21mm Denkmeier. In my dob, the 65-degree eyepiece gives a magnification of 76x and a true field of view of 51'. I pointed the eyepiece at M 27 and although it wasn't really dark (grey nights during the May-July period), it was quite an impressive sight. M 27 is really big, even at low powers, and with the UHC filter the Dumbbell shape is very obvious at first sight. The 21mm Denkmeier seems to be very "transparent", letting through much more light than the 20mm and/or 25mm Vixen Lanthanum. The stars where sharp right to the edges although I think that there is a little pincushion distortion along the edges. What I really love about this eyepiece is the generous 20mm eye-relief. Even with my glasses on, I can take in the whole field of view at once.

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The second object for the night was M 13, the big globular cluster in Hercules. The 21mm showed too much of the grayish sky, but M 13 was already resolved very well. The best view I got with the 7mm Pentax XW (230x). The cluster was completely resolved, even under these mediocre conditions. There were a lot of long streams of stars extending from the bright core. It looked more or less like a big spider. The three dark diverging lanes, which should look like a propeller, stayed invisible again. Probably I need a better seeing and a darker sky for this.

After M 13 I turned the dob toward NGC 6210 (Hidden Treasure 78 from Stephen J. O'Meara's book, Hidden Treasures). Already at the lowest magnification (76x) with the 21mm Denkmeier, this planetary Nebula looks like a deep-blue little disk. Using higher magnifications up to 230x made it look a lot bigger, still blue, but not so blue as with the lowest power. The seeing didn't allow higher magnification, so I could not go for the real details. According to Phil Harrington (The Deep Sky: An Introduction) this planetary takes high magnifications well, and is at its best 150x or more.

I ended my little tour with two objects I had never observed before, Hidden Treasure 94 (The Flying Unicorn Cluster) and Hidden Treasure 18 (The Ghost of the Moon) from the Additional list from O'Meara's latest Deep-Sky Companion. HT94 (NGC6709, Collinder 392), the Flying Unicorn Cluster, is a wonderful open cluster in Aquila. At low powers (78x) the triangular shaped cluster is very obvious, with some very nice groupings of (colored) stars. Although high magnification (230x) revealed more stars, I liked it most in the 12mm Nagler with a magnification of 133x. The cluster was nicely framed, some 40 to 60 stars with some "space" left around it. The colors came out even better than with the low power view, and I could detect quit a few "double-stars" or groupings of several stars; a very nice object, which I will definitely visit again under better conditions.

HT 18 (NGC 6781) from Appendix C (Twenty additional hidden treasures is) is a magnitude 11 planetary, about 2' in diameter. Without filters this big planetary is not so easy to see, but with the UHC filter in place it is a perfectly round, very bright and easy object. There should be some details visible at higher magnification, but because of the bad viewing conditions I did not try this last night, but again a very interesting object, which was completely unknown to me. At the moment this hidden treasure list is my favorite a perfect alternative for those who have done the Messier and Caldwell catalog. I will be back with more observing details on these interesting deep-sky objects, but I will need a darker and more stable sky. Until then, Clear Skies to all of you!

Oh, and the Denkmeier eyepiece is a perfect match for my 300mm f 5.3 dob. If you wear glasses or want a good eye-relief for any other reason, I can highly recommend this relatively small and compact eyepiece.

The Denkmeier 21mm eyepiece compared to the T4 12mm Nagler

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Posted by Math on 07/14 at 10:54 AM | (0) Comments | filed in: Deepsky observing | Print

Wednesday, July 11, 2007

Hidden Treasures

A few weeks ago I got a new book from Steven James O-Meara: “Hidden Treasures”. This is his third Deep-Sky Companion he wrote and it is definitely my favorite read at the moment. After the well known “Messier Objects” and “Caldwell Objects” this new book, Hidden Treasures, is again about 109 deep-sky objects, but this time about objects which are not included in the Messier or Caldwell catalogs. Some of them are well known, but there are a lot of objects which were more or less new to me.

Again the whole range of deep-sky objects is included, Galaxies, Planetary Nebulae, Star Clusters (open and globular), Asterisms, Bright Nebulae, Dark Nebulae and even a High-proper motion star. Steven James O’Meara is getting better and better. I like the way he writes his deep-sky companions. There’s always a lot of information about each individual object (history, observing the object, how to find it, and up to date scientific information), and for every object a finder-chart, black and white image and a sketch. The information you get in this book is also fully consistent with the two other books in this collection.

I can highly recommend all three of them. In the English language, they are by far the best observing guides around at the moment, and Hidden Treasures is with almost 600 pages packed with information on 109 deep-sky objects the crown on this wonderful series (until now).

Posted by Math on 07/11 at 10:49 AM | (0) Comments | filed in: Books and magazines | Print

Thursday, June 28, 2007

Watery Moon

During the last few weeks the weather hasn’t been very kind on the observing front, so I cannot bring you much news about deepsky, solar or lunar observing. Most of the time it has been cloudy or completely overcast. Monday night however the clouds opened up for an hour, and I got a quick glimpse of the Moon with my binoculars. This image of the Moon was taken just a mile from where I live near the water tower.

Click to enlarge

Posted by Math on 06/28 at 11:31 AM | (0) Comments | filed in: Lunar scraps | Print

Tuesday, June 26, 2007

Mount Doom....

Last week we were walking through the fields in our hometown. As you can see on the image below, about an hour before sunset we were treated on a very special sight, the Sun “touching” the top of a big cloud. The view instantly reminded us of Mount Doom, the big volcano in Mordor (from The Lord of the Rings). Hmmmm….. maybe finally something happening in Landgraaf, Netherlands

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Posted by Math on 06/26 at 11:16 AM | (1) Comments | filed in: Solar scraps | Print

Monday, June 18, 2007

Venus disappearing behind the Moon

Today has been overcast for most of the day, but around 4 o'clock it started to clear a little, and I could witness Venus disappearing behind the Moon. It was a wonderful sight to see this amazingly bright little sphere of light vanish behind something that is almost invisible, the darker part of the crescent Moon. I used my 85mm Zeiss spotting scope, equipped with the zoom eyepiece for visual observation. I also shot some images right before Venus disappeared with the Coolpix 4500. Enjoy the views, and I hope it will still be clear when Venus reappears!

Posted by Math on 06/18 at 07:28 AM | (1) Comments | filed in: Solar sytem scraps | Print

Sunday, May 06, 2007

Caldwell images on stamps

The Royal Mail (UK) celebrates 50 years of the BBC's Sky at Night television programme with the issue of 6 stamps that show 6 different Caldwell Objects. On the stamps you see 6 wonderful colour images of 4 planetary nebulae, a galaxy and an emission / reflection nebula.

Data on the different stamps / images:

1. 1st Class : Caldwell 55, the Saturn Nebula, planetary nebula in Aquarius
2. 1st Class : Caldwell 39, the Eskimo Nebula, planetary nebula in Gemini
3. 50 pence : Caldwell 6, the Cats Eye Nebula, planetary nebula in Draco
4. 50 pence : Caldwell 63, the Helix Nebula, planetary nebula in Aquarius
5. 72 pence : Caldwell 31, the Flaming Star Nebula, an emission / reflection nebula in Auriga (image by Robert Gendler)
6. 72 pence : Caldwell 53, the Spindle, a lenticular galaxy in Sextans

So if you are an amateur astronomer and stamp collector, this set of six celestial gems might be of interest to you! For more information and ordering the set of stamps, follow this link to the website of The Royal Mail.

Click on image to enlarge

Posted by Math on 05/06 at 02:03 AM | (0) Comments | filed in: General | Print

Saturday, April 28, 2007

Two sunsets and the Moon

The last few weeks the weather has been very good, and every night an hour before sunset, we took a long walk through the fields just down the road where we live. It's amazing what you sometimes can see when taking your time. Every evening we noticed not only different animals and plants, but also different celestial sights. Most of the time we carry a small digital camera with us, to record some of the things we encounter on our daily walk. Here are a few images we shot last week, two of a sunset and one of the Moon which is visible through the branches of a huge tree. Hope you enjoy the pics.

Please click on the images to enlarge!

Posted by Math on 04/28 at 08:14 AM | (0) Comments | filed in: General | Print

Monday, April 23, 2007

Venus and the Moon, a nice pairing!

On Thursday April 19th their was a pretty pairing of Venus and the Moon in the evening sky. I shot a few images with the Nikon Coolpix 4500 mounted on a tripod. On the first image you see the crescent Moon hanging to Venus's lower right, right over our neighbours house. On the second image you can see the earthshine on the part of the moon that is not illuminated by the Sun. On the third image you can see a close up of Venus and the Moon. Click on the thumbnail images to enlarge!

Photo data:

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Posted by Math on 04/23 at 02:00 AM | (0) Comments | filed in: Lunar scraps | Print

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