If so, loosen the jamb-nut at the right side of the solar telescope 

 axis and turn the Capstan-head stud \\itli an adjusting pin until the 

 desired result is secured. When complete, re-set the jamb-nut and 

 test again. No. 2 and 3 adjustments ar2 inter-related and should 

 be conducted together. 



4. The Horizontal Wire must be adjusted in height so that the 

 sight line 'will be parallel with that oj the main telescope 'when both 

 telescopes bubbles are centered; or angles laid off on the vertical circle oj 

 the transit, will not communicate equivalent inclinations in the solar 

 telescope, as referred to the horizon. 



Measure the distance between the centers of the two telescopes 

 by any convenient means. Tack up a sheet of white paper, prefer- 

 ably at one to two hundred feet from the instrument. The main 

 telescope being in a horizontal position, mark a point on the paper 

 as indicated by its horizontal wire. Measure upward an amount 

 equal to the eccentricity of the solar telescope and, with its bubble 

 carefully centered, check the central horizontal wire against the 

 higher point. If it does not coincide, correct the entire error by 

 moving the solar diaphragm up or down the required amount. 



Dealing mainly with vertical angles, the horizontal wire in the 

 solar is the one requiring special attention. In the above test we 

 have taken advantage of the fact that the solar bubble, being parallel 

 with the sight-line of the main telescope, the sight line of both tele- 

 scopes can be parallel only when the above conditions are fulfilled. 



We may preferably begin this test on the assumption that the 

 sight-line of the "solar" is already perfect as collimated by the 

 maker. Inthisevent, simply bringthe solar sight-line tobearuponthe 

 upper test mark and, if the bubble requires adjustment, secure 

 this with the adjusting screws provided. 



Another method of adjusting the solar sight-line to parallelism 

 with its own bubble would be 1 the methods described for 



the dumpy level. In any event it is an independent operation and 

 has no relation to, or any effect upon, the adjustment of the polar 

 axis already accomplished. 



5. The Solar Telescope must revolve in a vertical plant that ii 

 everywhere coincident with that of the main Iclc^ope. 



The main telescope being properly collimated for all distances, 

 sight two points in the same straight line: OIK , ;>le, at 50 



ft. and a second, at 150 ft. from the instrument. Sight the solar 

 telescope on the near point and clamp the polar axis, 

 focus on the distant point. If pe is mounted e 



trically to the left of the main telescoi e, for instance, the error will 

 show to the right of the distant transit point in amount proportion 

 ate to the relati' --s of the test jwiinti from the instrument. 



