Caldwell – Page 3 – Crayford Manor House Astronomical Society Dartford

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NGC 6946, also known as the "Fireworks Galaxy", is an intermediate spiral galaxy about 10 million light-years away, on the border between the constellations Cepheus and Cygnus. It was discovered by William Herschel on September 9, 1798.

NGC 6946 is highly obscured by interstellar matter of the Milky Way galaxy, as it is quite close to the galactic plane. Nine supernovae (SN 1917A, SN 1939C, SN 1948B, SN 1968D, SN 1969P, SN 1980K, SN 2002hh, SN 2004et, and SN 2008S) have been observed in NGC 6946.

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Imaged by: Andrew Wilson
Method: LX200 8", MX916 CCD, 30 x 60 seconds
Special Features: SN2004et marked

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Caldwell 11, C11, The Bubble Nebula

1st January 2018

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NGC 7635, also called the Bubble Nebula, is a H II region emission nebula in the constellation Cassiopeia . It lies close to the direction of the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, magnitude 8.7 young central star. The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in 1787 by Friedrich Wilhelm Herschel. The star SAO 20575 or BD+602522 is thought to have a mass of 10-40 Solar masses.

Members have successfully imaged Caldwell 11 through severe light pollution (Greater London) using 8" telescopes.

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Imaged by Simon Dawes
Skywatcher MN190
Canon 600D (Full Spectrum Mod) + CLSCCD Filter
27m Exposure from Bexleyheath, England.

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Imaged by Keith Rickard

SBIG ST7-XME CCD camera, 8" Meade LX200 Schmidt Cassegrain Classic at F6.3

30 x 30sec images in red, green, blue and luminance

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Sky Watcher Mak-Newt 190mm, Canon modified 40D, ISO 800, 73 X 3min subs total 3hrs 39min
PHD guiding with QHY5 15\11\2010, EQ6 Imaged by Julian Tworek

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Imaged by Andrew Wilson
8" LX200 and MX916 CCD

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Images by Kevin Langford

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The Caldwell Objects and How to Observe Them

5th June 2010

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Reviewed for the RAS Journal; Observatory, June 2010

1st Edition, by Martin Mobberley (Springer) 2009, Pp 288, 23.1 x 17.5 cm.

Price £24.99 (paperback; ISBN 978-1-4419-0325-9)

This book, as expected, is primarily concerned with the description and details of the Caldwell objects and this is covered to the depth suitable for an amateur astronomer. There is also a section on the compiler of the Caldwell list, Sir Patrick Moore, as well as primers on observing and imaging in general. These additional chapters are not covered in any depth. Whilst they will provide the novice with some guidance, the reader will have to go elsewhere for a comprehensive guide.

The book puzzles me slightly; I’m unsure if I should be using it as a reference book, a book to help plan an observing session or if I should take it to bed and read it from cover to cover. It sets out to be a reference book, with consistent levels of information on all the objects. It has a good index but no summary tables. Used as an observing planning aide it is likely to become tiresome because of the lack of tables, the reader will have to flick through many pages to find what objects are suitable for their equipment and location or use the inside back cover to make their own tables.

The basics for each object are covered on a single page, such as position, brightness, suggestions for finding the object and the best time of year to observe. The author also recommends the best aperture and filters for observing and provides good comprehensive descriptions. A second page for each object is used for charts and images (generally from amateur astronomers). The author’s personality and humour does come through in his writing making the book an easy and enjoyable read (I particularly like Caldwell 8 where the author describes all the great open clusters in Cassiopeia before describing C8 as ‘less than mind blowing’.).

You might be forgiven for thinking that this book is all you need (apart from a telescope!) to begin observing the Caldwell objects. However the charts provided are not suitable for finding the objects and this is pointed out by the author. Despite their low quality and small size, the charts do provide the reader with the general location in the sky and for this they are useful. The charts contain a number of objects and are only printed alongside the first object described and it quickly became irritating having to flick back to previous objects to look at the associated chart, especially when there is ample space for the chart to be repeated for most objects.
For £24.99 I would not buy this book, but if cheaper or given as a gift I would happily add it to my collection.

Reviewed by Simon Dawes

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Category: Caldwell

Caldwell12, C12, The Fireworks Galaxy

Caldwell 11, C11, The Bubble Nebula

Images by Kevin Langford

The Caldwell Objects and How to Observe Them