Acknowledgements

Firstly, I gratefully acknowledge the outstanding image processing work of PhotoShop guru Noel Carboni Noel created all the marvellous deep-sky images you can see in Chapter 10 of this book, from my raw data acquired at the New Forest Observatory. In creating these works of art Noel has spent at least as much time bringing the best out of the data as I spent in collecting it - thank you Noel I was greatly helped in my early days of imaging by two people in particular, and both still continue to...

Quick Process of a Single Frame of the Pleiades

This first example will use stacked, colour-converted data from a single Hyperstar frame of the Pleiades. Please download the unprocessed .jpeg file from jpg where you will find an unprocessed image of Merope and its associated nebulosity as the central part of the frame. This image is made up from 70 sub-exposures of 1 minute per sub taken with the Hyperstar SXV-H9C combination. Having a reasonable number of subs means the final stacked image will have a pretty good signal to noise ratio,...

Refractor or Reflector or Perhaps Both

You will need a good quality telescope for deep-sky imaging and these come in two flavours, refractors or reflectors. Refractors are the ones with the objective lens at the front, reflectors utilise a big light-collecting mirror and come in several different configurations. So here's your first big decision, refractor or reflector, and what size Also these telescopes seem to come with a variety of different mounting and control options, Altazimuth, equatorial and goto. Which do you choose...

The Images

The majority of the full-colour deep-sky images presented in this book in Chapter 11 are from the Hyperstar setup, and many have been published in either Astronomy Now or The Sky at Night magazines. Details of the imaging parameters accompany the corresponding image. There are some images from the Sky 90 with the SXV-H9C camera included for comparison with the Hyperstar work. You will see that the Sky 90 with SXV-H9C colour CCD combination gives a 40 larger F.O.V. than the Hyperstar with...

Subexposure Times with the Hyperstar

There are an upper and lower bound to consider when considering the optimum sub-exposure time to use. The lower bound is governed by the shortest sub you can take before CCD noise becomes intrusive. For the SXV-H9C camera, with the Hyperstar, and my typical imaging conditions, this would typically be around 5 seconds or so. The upper bound is where sky glow limits your integration time so that your dim deep-sky objects get lost in the sky background. You must clearly operate well below the time...

Permanent Setup

You can have the greatest imaging system on the planet, but unless it can be up and running quickly, usually between breaks in the cloud, it may end up simply being a dust-magnet. The problems associated with not having a permanent base for your imaging system are huge, but they are certainly not insurmountable. Many people do not have the luxury of an observatory in their garden, or at a local dark site. In these cases they have to limit themselves to smaller aperture telescopes so that they...

Hyperstar Imaging

Basing your deep-sky imaging on the Hyperstar lens assembly from Starizona http www. starizona.com is sufficiently differentiating that I feel the subject deserves its own Chapter. Figure 1.1 shows the Hyperstar lens assembly for an 11 Celestron Nexstar GPS scope. This is an earlier model that does not incorporate collimation screws as part of the Hyperstar lens. The Hyperstar lens replaces the secondary mirror in a Schmidt-Cassegrain type reflector and turns the SCT into a Schmidt Camera...

The CCD Camera

There are a large number of CCDs suitable for astronomical imaging on the market. There are sub-mega pixel, multi-mega pixel, black and white, single shot colour, imaging and autoguiding CCDs. It is very bewildering especially when there's all this talk about the field of view you get with different telescope CCD combinations and the even more puzzling question of how many arcseconds per pixel your system delivers. Do we need to know the numbers involved in fine detail, or can we just trust to...

Subexposure Times

I don't believe I have come across a topic that causes more contention and tension on the various forums than the subject of optimum sub-exposure time, and with it the total exposure time needed for acquiring a great image For sub-exposure times there are two boundary conditions, the lower bound and the upper bound. The lower bound is the shortest sub-exposure you can take before the CCD noise becomes the predominant source of noise. For the Hyperstar system and SXV-H9C camera with IDAS LP...

Narrowband Imaging and Light Pollution Filters

As mentioned previously, I always have an IDAS LP filter in the optical train. This filter cuts out emissions from common light-polluting sources sodium and mercury vapour lamps and as a bonus I find I do not need to radically alter the colour balance of my one-shot colour images. I have tried other nebula or light pollution filters and have found it necessary to make substantial colour balance changes to get a good colour-balanced image. Also mentioned previously was the Hydrogen Alpha...

Celestron Nexstar 11 Gps Sct

For this reflector, the mirror diameter 11 is 280 mm, and the focal length in its normal mode of operation as a Schmidt-Cassegrain telescope is 2800 mm which gives us an f 10 system in the normal mode of operation. We can put an f 6.3 reducer corrector R C on the eyepiece end of the telescope Celestron make these R C elements and this will reduce the effective focal length to 1764 mm. There is also an f 3.3 R C available made by Meade and this results in an effective focal length of 924mm....

Prdttfal

Patrick Moore's Practical Astronomy Series Navigating the Night Sky How to Identify the Stars and Constellations Guilherme de Almeida Observing and Measuring Visual Double Stars Bob Argyle Ed. Observing Meteors, Comets, Supernovae and other transient Phenomena Neil Bone Human Vision and The Night Sky How to Improve Your Observing Skills Michael P. Borgia How to Photograph the Moon and Planets with Your Digital Camera Tony Buick Practical Astrophotography Jeffrey R. Charles Pattern Asterisms A...

How did I start

Sct Collimation Guide

This Chapter may help if you are just starting out in deep-space imaging. Personally I find it very useful to see how other people entered the hobby, because in that way you can see what their major mistakes were, and hopefully you can then circumvent the major problems. I am fortunate enough to live in a semi-rural location with reasonably dark skies. I was also in the fortunate financial position of being able to buy myself a reasonable quality telescope. At this point in time, around...