With Stephen Tonkin This month’s wide-field wonders include Kemble's Kite and Cascade

1. Kemble's Cascade

10x50 Late summer evenings are among the best times to see Kemble’s Cascade: it is approximately vertical in the sky so you get the full effect of a ribbon waterfall falling into a splash-pool, the open cluster NGC 1502. To find it, extend a line from Caph (Beta (`) Cassiopeiae) to Segin (Epsilon (¡) Cassiopeiae the same distance to the 5th magnitude star in the middle of a line of 8th magnitude stars. ! SEEN IT

2. Kemble's Kite

10x50 Another asterism brought to light by Lucian Kemble is his eponymous Kite. Take a line from Segin through Iota (f) Cassiopeiae and extend it another 7Ō to V805 Cassiopeiae, which looks deep yellow in binoculars. It is the brightest of a 1.5Ō-long asterism of 10 stars of magnitude +8.5 and brighter, that has the form of a diamond kite with an easily splittable double star at its northern tip and its tail flowing south towards Perseus. ! SEEN IT

3. Perseus Double Cluster

15x70 Take a look 4.5Ō from Miram (Eta (d) Persei) in the direction of Ruchbah (Delta (b) Cassiopeiae) and you will find a close pair of open clusters. You will probably see them with your naked eye, but you really need large binoculars to appreciate the false stereopsis that makes the Double Cluster so attractive. Those stars are intrinsically extremely bright: if our Sun was there, it would be too faint to be seen in these binoculars! ! SEEN IT

4. Muscleman Cluster

10x50 From the part of the Double Cluster that is nearest Cassiopeia, you will see a curved 2Ō chain of 8th magnitude stars leading to the north. They guide you to Stock 2, the Muscleman Cluster. You will recognise it from the sparse X-shaped pattern of brighter stars which, on closer observation, have the form of a stick man who is flexing his biceps and keeping the Double Cluster on a leash. ! SEEN IT

5. M103

15x70 Go back to Ruchbah and centre it in your field of view. About 1Ō to the east, find a small (6 arcminute across) triangular glow that stands out from the background Milky Way. M103 was discovered by Pierre Méchain in 1781. What looks like the lucida (brightest star) of the cluster is a foreground double star, Struve 131AB, not part of the cluster itself. ! SEEN IT

6. NGC 129

10x50 Our last object lies between Navi (Gamma (a) Cassiopeiae) and Caph (Beta (`) Cassiopeiae). It is so much brighter and bigger than M103 that it’s puzzling how Méchain managed to miss it. The answer is likely to be magnification: if you over-magnify it, it merges into the Milky Way background, so although your 10x50s will not resolve any stars from the glow, they will more easily distinguish it. ! SEEN IT

" Tick the box when you’ve seen each one