Putting it to Work

Putting it to Work

To use the routine you need to know your longitude and latitude of the observing site, the offset from GMT, and have your calculator set to the time corresponding to the time zone off set. For example, if the calculator is set to EST, then make sure the time zone of set is 5 hours. You don't need to set the calculator to the time zone of the observing site. All of the calculations are done in UT. You just need to make sure that the time zone off set corresponds to the time zone that the calculator's clock is set to.

Once you go through the alignment routine with two known stars, you can enter the Geocentric coordinates of the object and the calculator will display the azimuth and elevation values to dial in on the telescope setting circles. Just dial these in and look through the eyepiece. The object is normally in the field of view of the RFT scope.

A word about leveling and stuff.

Throughout the construction, I've used the terms elevation and azimuth. The two star alignment routine doesn't really compute elevation and azimuth. It converts positions to telescope coordinates. So you really can just plop the scope down any old way. You just don't want it to move after you've aligned it. If you plop it down so it's about level and zero on the azimuth scale is more or less north, then the telescope coordinates will approximately be elevation and azimuth. This makes it easier to detect errors in your alignment. If you know M-31 is in the north east and you calculated coordinates points the scope in some other direction, re-check your alignment.

Well, it's finally ready to go. Just waiting for darkness. The base is clamped to the table. Once you go through the alignment routine you do not want things to slip in the dark. You can see both the azimuth and elevation scales. The little table does flex some, but it comes back to it's neutral position once you quit moving the scope. The flexing is not a problem if you are using the scales to position the scope.
Reading the scales in the dark requires some illumination help. My solution is a small AA size flashlight, a red filter and a fiber optic attachment. This keeps your dark adaptation, puts the light only where you need it, and keeps you from getting stoned with real rocks at star parties.
Here is the scope pointing at M-31. I went through the two-star alignment process, dialed in the coordinates for M-31 into the calculator, computed the telescope coordinates, dialed them in and M-31 was centered in the eye-piece. WOW! It actually worked! The family cat is optional equipment.

Back One Page	Home