We start this harvest month with a special open cluster in constellation Cepheus: NGC 7510. This cluster is located at 10.200 light years distant in the Perseus Spiral Arm. It's a faint cluster with a triangular shape. With a magnitude of 7.9 it's a beautiful object to observe through telescopes. There are at least 16 stars visible that forms the triangle. This cluster is compact and not reconizible through regular binoculars. You can find NGC 7510 just 2 degrees WSW of Messier 52. Both objects are visible in the same field of view.
Also in Cepheus we find NGC 7380. This bright open cluster is 20' large and is also located in the Perseus Spiral Arm at a distance of 11.400 light years from earth. The cluster has a magnitude of 7.2 and is best observed with telescopes because the stars in the cluster have a maximum magnitude of 9. Within NGC 7380 there's an emission nebula. You need a wide field telescope to see this nebula.
Delta Cephei is a variable star, but also a double star. The star varies in approximately 5 days from magnitude 3.5 to 4.4. Through telescopes it's compagnion is good visible. It's located south of Delta. Both stars have a yellow colour that becomes better visible if you unsharpen the image.
In constellation Aquarius we find the Helix Nebula (NGC 7293). This planetary nebula is also called 'God's Eye', because of it's shape. The Helix Nebula is located at 650 light years from earth and that makes it the closest planetary nebula. The nebula has a magnitude of 6, but because it covers a large area in the sky (12 x 12 arc minutes), it's a hard object to observe. That makes this object a real challenge to find. You could try it best on dark, moonless nights with good conditions. It's recognizable through it's large, faint, oval shape. The central star, which lies in the centre of the nebula, has a magnitude of 12.
There's another planetary nebula in Aquarius: The Saturn Nebula (NGC 7009). It's visible as a green star through binoculars. With low magnification it's obvious why there objects are called planetary nebulae. At first sight, this nebula looks much like the two outer planets Uranus and Neptune, including the blue/greenish colour. NGC 7009 is relatively bright with a thickening in the centre. An OIII filter works positive on this object. 8 Inch, or larger, telescopes shows handles on boths sides of the nebula, that reminds of the planet Saturn. It's obvious why NGC 7009 is also called the Saturn Nebula.
We continue with the Eagle Nebula (M16 & IC 4703) in Serpens. This open cluster contains an emission nebula with the shape of an eagle. Both objects are located in the Sagittarius-Carina Spiral Arm at 6.500 light years from earth. The open cluster has a magnitude of 6 and it is easy to locate. There are about 50 stars visible through medium telescopes in the nebula with the shape of an 'S'. An OIII filter has an enormous effect on the Eagle Nebula. It's really a big difference if you observe this object with ot without the filter. On the NE side of the nebula there is a thin, dark spot visible which is called 'The Black Pillar'.
Also in Serpens we find the open cluster IC 4756. This large cluster with a magnitude of 4.6 is already visible naked eyed from dark observation sites. This bright and rich cluster is definitely a pretty object to observe! In the same field of view we see another open cluster: NGC 6633. This object is located at 3 degrees WNW of IC 4756. Although this cluster is smaller than its neighbour, it's not dimmer. A beautiful duo to observe through binoculars or large telescopes!
Finally we visit some pretty objects in Sagittarius. A real challenge is Barnards Galaxy (NGC 6822). This galaxy is an irregular member of the Local Galaxy Group and is located at approximately 2 light years from earth. Visually this object is really faint, so try to find it from a dark observing site, without any light pollution. This galaxy looks different than most galaxies: through the larger telescopes there is a glow visible with faint stars. Despite the challenge of this object, it isn't impossible to see it through smaller telescopes!
The planetary nebula Little Gem Nebula (NGC 6818) is a lot easier to observe. The object is small, but bright. It has a magnitude of 9.2. Through telescopes there is an obvious blue disk visible. An OIII filter enlarges the contrast.
Last we'll discuss an original trio: Djorgovski 2, NGC 6520 and Barnard 86. NGC 6520 is an open cluster with a magnitude of 7.6. There clearly is a circle of stars visible. 20' WNW of this object we find Djorgovski 2, a globular cluster. It has a diameter of 2'. Its centre is a bit brighter than the rest of the cluster. Between NGC 6520 and Djorgovski 2 you'll see a dark spot: B86, also called The Ink Spot. It's a dark nebula that's located in a rich star field, so it is easy to find this nebula. B86 is visible in the same star field as NGC 6520, and that gives the nebula and cluster an extra dimension.
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