212, A Cheap Observatory. 



Out-door observation lias, no doubt, its advantages. 

 Telescopes are generally understood to work best when the 

 object-glass or speculum has attained the temperature of the 

 surrounding air. And certainly those who wish to familiarize 

 themselves with the constellations, and the names and 

 peculiarities of their leaders, as the more prominent stars 

 are called, will get on much better in the open air, with the 

 whole heavens before them, than when looking through the 

 narrow opening of an observatory. 



But when the higher purpose of close telescopic scrutiny 

 is the intention, then the shelter and many conveniencies of 

 the observatory are indispensable. 



So immensely remote are even the nearest of the heavenly 

 bodies that for the most part we know little ornothing of the nature 

 of their surfaces. The pencillings on their discs of lines, streaks,, 

 or spots, arising from clouds, oceans, mountain chains, or other 

 unknown peculiarities of their structure, are by the mere effect 

 of distance reduced to the utmost delicacy, and require not 

 only the best optical means to reveal them, but also that the 

 observer himself should be placed in an easy posture, and be 

 perfectly free from bodily inconvenience. 



The most interesting part of an amateur astronomer's work 

 consists in observing such details, or in picking up minute 

 objects amongst the fixed stars, measuring the interval 

 separating double stars, determining as nearly as may be 

 angles of position, and watching for variation — one of the most 

 'useful matters to which an amateur can devote his attention — 

 occasional sketches of lunar craters under different dtegrees 

 of illumination, solar spots, as the great orb rotates and brings 

 them into view ; noting the occupations of stars by the moon, 

 with a view to decide the question, yet unsettled, of a lunar 

 atmosphere; and many other niceties of observation which not 

 only invest his labours with interest, but impart to them a real 

 value. To do any of these things, however, effectively in the 

 open air, with one's telescope agitated by the passing wind, and 

 a body shivering with the cold, is clearly next to impossible. 



This remark then leads to the main object of the present 

 article, namely, to describe a "cheap observatory," which 

 the writer has recently erected for himself, and to show that at 

 a very moderate outlay an amateur, who has the convenience 

 on his premises for the erection of such a building, need not to 

 remain destitute of it. 



I le was led to th<' erection of an observatory chiefly to afford 

 greater protection to a fine silvered glass speculum, of twelve 

 inches aperture, some account of which appeared in a former 

 dumber of the [ntbllectual Observer. Since then ho has com- 

 pleted a much finer one, of a similar aperture, having a focal 



