Chapter Three

Our definition of an observatory is any fixed site from which observations are made. Hence we should first consider the case where there are no permanent fixtures. Even if the mounting and telescope remains portable, there are certain measures which can be taken to make observing more convenient and productive, if it is regularly carried out from a fixed spot. One of these is to have some kind of mark or marks on the ground indicating how the mount it is to be set up for correct polar...

Da

Types of equatorial mounting PA polar (or RA axis), DA declination axis, CW counterweight. have surprisingly poor performance if not well-designed. The first mounting in Fig. 1.4 is a case in point. It has too much mechanical leverage operating on the long shafts, without adequately-large thrust-absorbing surfaces. It is thus too resonant. The best GEM designs have RA and dec. assemblies which taper away from wide thrust surfaces the RA section should be larger than the dec....

Barlowed Laser Collimation

Maintaining and Getting the Best from Equipment An observatory is the principal and most practical means of organising and maintaining your valuable astronomical equipment. In this chapter I will address a few of the main issues concerning optimising and maintaining observatory equipment at its best, and mention a few products and methods I have found to be particularly useful. Collimation is the accurate adjustment of your telescope optics. No telescope will perform at its best without perfect...

Removable Telescopes with a Fixed Mounting

A halfway-house to a roofed observatory is to have a permanently-fixed telescope pier and mounting outside, and a removable telescope, stored inside or in an outbuilding. Some people leave most of the telescope outside, removing the optics indoors after every session. This does not sound very convenient to me - it would require complete re-collimation every session, for a reflector. However, there are distinct advantages to setting-up a permanent metal or concrete pier to carry the mounting, on...

Richard Miles Compact Remotecontrolled Photometric Facili

It has been generally insisted so far in this book that observatories need to be big enough to accommodate, comfortably, all the equipment that is to be used, plus at least one observer. However, this need not be the case, if the observatory structure is only to be a shelter for the equipment when it is not in use, never needing to accommodate an observer. Run-off sheds are one example of this type of shelter, but there are others. Two of these will form our final two case-studies, exemplifying...

How Large Should It Be

Apart from the design of the observatory, which we will discuss in the next chapter, this is the most fraught question for the observatory planner. There will be a natural desire to prevent costs running away, to avoid a too-heavy construction which will be difficult to use, to aim for a reasonably time-limited project, and to avoid creating a too-intrusive blot on the landscape. We will deal with the question of camouflage in the next section. These factors will often conspire, with the first...

Costs of DIY and Ready Made Observatories

The costs of large projects over-run, and the costs of small projects over-run, almost always. That is the way of the world. However, an amateur observatory generally does not have to be completed to a strict timetable. One can carry on observing productively with portable equipment in the interim, and an observatory can be used in an unfinished state. It is usually hard to say when an observatory is completely finished, and many never are. There are always...

Domed Observatories

In this category we will include all observatories that have an upper section that rotates, and walls that are fixed. The upper section, classically, is a dome, slightly more than 50 of a sphere, but it can be a cylinder, an octagonal pointed shape, or some other complicated thing. Why a dome The dome is an intrinsically very strong structure. However, observatory domes have to be much less strong than other domes, because they require an opening or slit which must pass beyond the zenith....

Adapting Commercially Made Outbuildings

It is a striking fact that the cost of mass-produced sheds and summer houses is far, far lower than the cost of buying the materials to make them - at least 50 less. These are the economics of scale. It is therefore an attractive proposition, in both financial and labour-saving terms, to create an observatory by buying, and then adapting, one of these structures. Square and rectangular pent and apex roof sheds have been adapted by amateurs into run-off roof sheds, and octagonal summer houses...

My Observatory A Combined Run Off Roof and Run Off Shed

My observatory, which has already been referred to a few times in this book, may be found at the far end of a suburban garden in Edgware, Middlesex, towards the north-western edge of Greater London. It was originally conceived to house a 20 year old 15.9 cm (6.25 in.) f8 Newtonian, and developed subsequently to house various larger telescopes and an increasing selection of imaging equipment. My speciality has always been the moon and planets, drawing, and now imaging them, although I also do...

Dave Tylers A Priori Fibreglass Dome

I have placed the words a priori in the title of this section, because this was the aspect of Dave's observatory that most impressed me on talking to him about it. It looks utterly professional, as if it was based on a detailed study of all the best dome-design precedents, amateur and professional. Yet Dave told me that when he designed it, he had not studied any other observatories, nor looked into the subject. He simply designed round the constructional techniques he knew he himself could...

Iii

Side-by-side balanced arrangement of two telescopes mounted on a tandem bar (Astro Accessories from RobinCasady.com). individual dovetail bars, are mounted on a crosswise dovetail bar so that the pair can be adjusted for their centre of gravity to lie in line with the dec. axis. They counterweight each other, and the counterbalancing required on the dec. axis is minimised. This can be extended even to using three telescopes on the same mount, with the use of a triad bar (or to...

Of Telescopes and Allied Equipment

Before proceeding to the subject of the amateur observatory itself, I propose to use some space to discuss the issue of telescopes for various purposes. It is quite likely that the reader will already have his chosen instrument and be happy with it, in which case, he can move on to the meat of the book. There will be others, however, who are thinking of upgrading their equipment, and possibly of getting a larger or more sophisticated telescope in conjunction with setting up their own small...

Foundations and Stabili

Once you have selected the site and drawn the plans, the next stage of the observatory project consists of levelling the site and creating foundations for both the observatory and telescope. These must be kept separate, so that there is minimum possibility of vibrations from the floor being transmitted to the telescope. Generally speaking, massive foundations are not required for an amateur observatory. If the lower parts of the structure are brick or block construction, then concrete...

Norm Lewiss Observatory An Experience with a Commercial

Norm's beautiful observing site in Maryland, USA, is shown in Fig. 9.43. This rather open location has the disadvantage of being windy, and, in the winter, temperatures can fall very low - to below -18 C, zero degrees Fahrenheit. For these reasons, Norm opted for a domed observatory, and purchased the 10 ft ProDome from Technical Innovations, also based in Maryland. The ProDome is constructed from four fibreglass quadrant sections, and has an up and over shutter. The ProDome design offers a...

Olly Penrices Observing Retreat

Olly Penrice and his wife Vic had long been lovers of France and all things French, and when they decided they had had enough of the weather and light pollution of England, they commenced their search for the ideal observatory site on the other side of the Channel. They had the idea of combining this, as a business, with a holiday retreat for astronomers and others. In these matters, it is a reasonable plan for amateur astronomers to look at what the professionals may have discovered before...

Visual Film or Electronic Observing

The greatest change that has come upon amateur astronomy in recent times has been the shift from visual observing and recording with pen, pencil, charcoal, etc., to the recording of observations electronically, for various purposes, including imaging, positional measurement (astrometry), and brightness measurement (photometry). The use of film photography is still common in some types of observing work, notably the recording of meteors, but it is undoubtedly on the way out. The CCD...

What is an Observatory

When people think of an astronomical observatory, if they think of it at all, they usually think of a large domed building containing a telescope. And this is one type of observatory. But an astronomical observatory (as opposed to a bird observatory, or a meteorological observatory, which are not the topic of this book) is actually any site from which observations of celestial phenomena are made. It could be an open field, a tent, a garden, or any kind of building pressed into service for the...

Balance Accessories and Extra Telescopes

Cassegrain Balance Fork

On an altazimuth mounting, the telescope must be balanced about the altitude bearings. Either it needs to be possible to slide the telescope through tube rings, which are then tightened-up, to fix the balance point, or an extra counterweight assembly must be attached to the tube, which provides a means of altering the centre of gravity, either by adding or removing weight at a fixed distance from the altitude axis, or by moving a fixed weight up and down the tube on a rail mechanism, with...

Es Reids Solar Observato

Spectrohelioscope Spherical

In solar work, there is a less-frequently used alternative to the conventional large telescope on an equatorial mounting in a dome, as exemplified by Dave Tyler's setup. Es Reid's setup, based on a heliostat and fixed spectrohelioscope, is a good example of this. This arrangement follows the example of professional astronomers, who often use such complicated and extensive equipment to analyse the light of celestial objects that it cannot be carried on a moving telescope. The solution, then, is...

Storage of Equipment

Astronomical peripheral equipment is supplied, as, a rule, very badly packaged. The cardboard boxes in which eyepieces and the like are often supplied are quite useless. The boxes will quickly disintegrate, spreading fibres onto optical surfaces, and will provide no protection against dirt and damp. A better storage solution for eyepieces is the bolt-case. These can be bought from some astronomical suppliers. They are cylinders of plastic with a top and a bottom half, which thread into one...

Bob Garners Observatory CCD Imaging from a Converted London Garage

The details of Bob Garner's observatory will be found to contradict a great deal of the advice in the earlier chapters of this book. Bob has made the best of a remarkably unpromising location for astronomical observation, using much ingenuity, and frequently shoestring means. His observatory may well be the 1 Small Astronomical Observatories and More Small Astronomical Observatories, Patrick Moore ed . The first book is on a CD ROM sold with the second book. world's worst-sited, but he has...