Category: Deepsky log

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Fecunditatis look much darker than Mare Imbrium. Between Mare Frigoris and Mare Imbrium the dark lava flooded floor of the crater Plato really stands out from its surroundings. The three very bright (young) craters Tycho, Copernicus and Aristarchus really jump out at you. The crater rays of Tycho and Copernicus are a wonderful sight, even through 7x50's.

Later that night I observed a few objects in Cygnus with the Vixen 7x50. While centring the field of view on Gamma Cygni, the star that marks the "body" of the Swan, M 29 can be seen in the same field of view very easy. It looks like a small smudge of light, about 2 degrees south of Gamma Cygni.

From there I went to Omicron 1 and 2 Cygni, my favourite group of colored stars in Cygnus. Omicron 1 and 2 are both very orange colored 4th magnitude stars, that can be found 4.5 degrees southwest of Deneb (Alpha Cygni). Omicron 1 is also a visual triple. It stands together in the night sky with a very blue star (magnitude 5) about 5.5' to the northwest of the orange Omicron 1. They form a very beautiful visual pair of stars with brilliant colors. The third star of Omicron 1 is a magnitude 6.9 star about 2' to the south of the orange star.

Next on the list was the narrow double star (for binoculars) 61 Cygni. Although the two almost equally bright components are only 29" apart, they are an easy split in 7x50 binoculars, especially when the binoculars are mounted on a mirror mount. The two stars look bright orange to me.

I also visited M 39 with the 7x50. The triangle of stars is very easy to find. Just go from Deneb about 9 degrees to the east-northeast and you will come across a bright triangle of stars. This is M 39. Because the clusters stars are scattered over an area of 30' they looked better in the 7 x 50 than in the telescope.

At 23.00 hrs UT we had a tea break.


TAL 250K (M 13, the Blinking Planetary, M 27 and M 57)
After half an hour we continued with the TAL 250K. It was still around 17 degrees Celsius outside, but the air was very dry. Nothing dewed and the books that where lying around felt dry. Later that night when I got home I checked my weather station. Humidity was only 27 percent outside.

We looked at several objects both with and without the binoviewer, and boy, this piece of equipment from Baader really makes a difference with some of the objects observed. I was shocked by the different appearance of M13. In the middle of June, when the nights are very short and it doesn't get really dark, M 13 looks just like a smudge of light with very few stars resolved when I look with my 8 inch TAL 200K. With the 10-inch TAL 250K there are significantly more stars resolved, but when you put in the binoviewer, the whole cluster just stands there, with chains of stars running from the centre outwards. I wonder how M 13 will look around the end of august, when it gets a lot darker. Anyway, on this globular the binoviewer made a real difference!

The next object to visit was NGC 6826, the Blinking Planetary. On the finder chart below (click to enlarge) you can see where to find NGC 6826. Start at Sadr (Gamma Cygni) at the centre of the Cygnus. From there go about 9 degrees northwest to δ (Delta) Cygni. From delta go north to θ (Theta) Cygni, a magnitude 4.5 star. The blinking planetary lies a little less then 1.5 degrees to the east.




Image from SkyTools 2 by CapellaSoft (Click to enlarge)



We viewed the planetary at a magnification of 200x and used no filters. We immediately saw why NGC 6826 is called the blinking planetary. When you look at it with averted vision you see a nice round and bright planetary nebula without a central star. When you look at it directly, the nebula vanishes completely and the central star becomes visible. Just by moving your eye a little it pops in and out of view. A truly wonderful object!

Later that night we observed two other planetary nebulas, M 27 in Vulpecala and M 57 in Lyra. Here the different reaction to nebula filters showed really well. While M 27 got much more contrast with the OIII filter, the same filter did nothing with M 57. M 27 looked really big and M 57 was also very different from what I am used to see in my 8-inch Klevtzov. The centre of M 57 is not open but looks a little hazy white.

At 01.00 hours UT (3.00 local time) we packed up, satisfied with the first test of the TAL 250K equipped with the binoviewer. I noticed that for some objects the binoviewer showed more detail (like M 13, the Moon), for others it didn't,. However the viewing with two eyes is much more comfortable than with only one eye. It is definitely less tiring.

At 3.30 local time I dropped into bed, while the first birds where already starting their morning concert.
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in the same field of view of the 7x50. They are separated 3 degrees from each other. In the 15x80 only both the cluster cores fit in the 3.5 degree field of view. NGC 6633 has a diameter of 27’ and a visual magnitude of 4.6. In the 15x80 I see a bright star north-northwest of the cluster. I see some 20 to 25 stars of almost the same brightness in the direction northeast-southwest. In the centre of the cluster I can see a triangle of stars.

IC 4756 is much larger. Its diameter is 52’ and its visual magnitude is 4.6.  Through the 15x80 it seems be lie within a trapezium of brighter stars. I can see about 30 to 35 stars but there is also a glow of unresolved stars.

The map below should give you an idea of what you see through a 7 x 50 binocular (North is up. East is to the left). The limiting magnitude is about 9 to 9.5 and the big red circle represent a field of view of 6.1°. IC 4756 is on the left and NGC 6633 is on the right.

Credit and © Capella Soft, “SkyTools2”

M 39
Next on the list was M 39 in Cygnus. This open cluster has a diameter of 31’ and its visual magnitude is 4.6. It is very easy to spot. From Deneb, go about 9 degrees in east-northeastern direction, and you will see the triangular shape of M 39 immediately. In the centre of the triangle I could see a yellowish star. It is a very poor cluster. I counted only 12 to 15 stars.

M 31
From M 39 I turned to Andromeda, to find M 31. Through big binoculars you see the real size of M31. This galaxy is a binocular object! When I move the mirror from the Sky Window up and down, I really see the full size of 3 degrees. M 110 is also clearly visible as a small elongated smudge of light. M 32 is invisible. I could not detect any structure or details in M 31.

Double Cluster / Stock 2
This area is wonderful for observing with binoculars. With the 15x80 Stock 2 is an impressive sight. Its stars form the figure of a man with its arms and legs spread. You will recognize this asterism immediately, using big binoculars. Stock 2 is a large open cluster with a diameter of 1 degree. It is connected to the double cluster in Perseus by a 2 degree arc of stars that runs in the north-south direction. The double cluster looks stunning through any telescope or big binocular, even through the 15x80. The “western” cluster, NGC 869 is also called h Persei, the “eastern” cluster, NGC 884, is called Chi Persei. Both clusters have a diameter of 30’, the size of the full moon.

Interesting is that each of the double cluster components have a true diameter of 65 light-years, while Stock 2 has a true diameter of 18 light-years. But why does Stock 2 look much bigger than the components of the double cluster? That’s because of the different distances they lie away from us. The double cluster lies at a distance of 7200 to 7500 light years, while Stock 2 lies relatively nearby at a distance of 1050 light years. This area is interesting enough to revisit many times, with any kind of optical aid.

Alpha Persei moving cluster (Melotte 20 or Per OB3)
This is a deepsky object for 7x50 binoculars. The 3.5 degree wide open cluster is too big to fit into the 15x80. The small binoculars leave some room around Melotte 20, so it stands out very well from it’s surroundings. In the centre of the field of view I counted 30 to 35 stars. The age of the Alpha Persei moving cluster is estimated at 50 million years. It is thought that the Alpha Persei cluster is one of oldest Gould Belt objects, together with the Pleiades. The Gould Belt is a remnant ring of bright stars, star forming regions and remains of molecular clouds that is tilted about 20 degrees to the galactic plane.

NGC 7789
This big open cluster in Cassiopeia looks like a really bright patch of light through the 15x80. NGC 7789 has a diameter of 25’ and a visual magnitude of 6.7. I could not detect any stars or granulation. The brightest star has a visual magnitude of 10.7. With the 10-inch Skywatcher and a Zeiss zoom-eyepiece, NGC 7789 looked stunning. The whole field of view was filled with maybe 80 stars of equal brightness. At moments like these you wish that you had a 400-inch telescope) Together with NGC 457 and Stock 2, NGC 7789 forms my favorite trio of star clusters in Cassiopeia.

NGC 752 (Collinder 33) and the Golf Putter
About 4 degrees south-southwest of the beautiful double star Gamma Andromedae lies another great binocular cluster, NGC 752. Together with an asterism called “the golf putter”, NGC 752 forms a great couple for observing with big binoculars. The golf putter can be is formed by a chain of bright stars that run from the northwest to the southeast. Three stars in the southeast form the end of the chain. To the east of the asterism lies NGC 752, which could be seen as the golf ball. In the 15x80 the 1.5 degree golf putter and NGC 752 look fantastic.

M 33
We ended the night with M 33 in Triangulum. With the Skywindow and the 15x80 binoculars, M33 is very easy to find. From Beta Andromedae move your binoculars to the south in the direction of the western tip of Triangulum. Keep looking very carefully if you see a really big smudge of light while moving south. Even in a light polluted sky M 33 is very easy to spot using binoculars. It is 67’x41’ in diameter. With the 15x80 I estimated its size around 30’. It is however impossible to see any structure or details in M 33 with binoculars from our light polluted backyard. This object again proves that some galaxies are great objects for binoculars.

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both components showed no hint of being doubles themselves. At 80x (25mm) they started to look like they both where doubles. At 133x they where both clearly split and at 200x they looked like two close couples of stars, aligned perpendicular to each other (see image below. North is up and west is to the left. At the top you see Eta Lyra 1 with the A (the brighter lower one of the two) and the B component. At the bottom of the image you see Eta Lyra 2 with the C (the brighter one to the left) component and the D component.

Image from Skytools2 by Capellasoft

The AB pair is separated by 2.6”, the A component has a (visual magnitude) vM 5.4, the B component is of vM 6.5. The position angle is 357 degrees. The CD pair is separated by 2.3”, the C component has a vM of 5.1, the D component 5.3. The position angle is 94 degrees. All four stars seem to have the same colour, white. They are all spectral types A.

Vega (Alpha Lyrae)
This beautiful white-bluish star is the fifth brightest star in the sky, and the third brightest to be seen in our mid-northern latitudes. The five brightest stars are:

1. Sirius -1.46
2. Canopus - 0,72
3. Rigel Kent - 0.27
4. Arcturus - 0.04
5. Vega 0.03

Vega is a multiple star system (3) but I could not detect one of the two faint companions.

Zeta Lyrae
Zeta Lyrae forms a triangle with Vega and the Double-Double. It is a beautiful double star with two bright yellow-white components (vM 4.3 and 5.9), separated by 44”. A great couple for any telescope or big binocular. According to James Kaler the A component is a hydrogen-fusing dwarf and it’s companion, the D component, is a class F “subgiant”.

Delta Lyrae
The next stop is Delta Lyrae and the open cluster Stephenson 1. Delta Lyrae is a very wide pair, which is already split in the finder scope. The magnitude 4.5 Delta Lyrae 2 is separated about 10’ from the 5.6 Delta Lyrae 1.  Delta Lyrae 2 looks orange while Delta Lyrae 1 has a white-bluish colour. Between and around these two stars I can detect a group of 10 stars that probably belong to the open cluster Stephenson 1.

Beta Lyrae
I end my short trip along some doubles in Lyrae with Beta Lyrae. This again is a stunning pair with a bright 3.4 A component and a 8.9 B component as its companion at a position angle of 149 degrees. This close couple is only separated by 46”. Lyrae has some really great doubles for telescopes and binoculars. Earlier this year I observed almost the same stars with the 15 x 80 binoculars, but these beautiful doubles are great for all instruments! The light polluted sky does not affect these beauties too much.

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