From: "John Murray" 
To: 
Reply-To: "John Murray" 


G'day Vibhu
        The April 1982 edition of Astronomy has an article on making
setting circles for dobs. Quoting from the article "You need three
things, Graduated circles, A calculator that handles trig functions and a
few equations". If you want I could condense the thing for you or scan
it and send. However, there is one thing I don't have. One of the equations
to find mean sidereal time at 0 o'clock on any day at Greenwich has the
variable K. Here it is. "GMST = K + 0.0657098232 x day number"
The variable K changes annually and the issue only has the value of K up to
2000. If someone could decipher what K represents and/or point to where we
can find out the rest of it is easy. The value of K for 2000 is 6.59878800.
        The good thing about these  calcs is that they enable you to
find objects in the daytime as well.


Cheers

John Murray
Whyalla
South Australia
Our ATM page is at
http://astronomy.sa86net.com

> -----Original Message-----
> From: owner-atm{at}shore.net [mailto:owner-atm{at}shore.net] On
> Behalf Of Vibhu Veerabadrappa
> Sent: Wednesday, 26 February 2003 6:38 AM
> To: atm{at}shore.net
> Subject: ATM Aiming a dob by RA/dec
>
> I am having trouble aiming and locating at the galaxies. I
> tried M81, M82 and M51 without success (tried for about a
> total of about 6hrs - will continue trying). In the meantime,
> I am thinking of putting some angle markers for the alt and
> az movements and use the RA/declination of the objects to aim
> the scope.
>
> For this to work, what are the requirements about the
> placement and alignment of the scope? For example, the base
> should be placed on a level surface. Then, when I point the
> scope at the zenith, then the declination of the scope would
> be the latitude of that spot on the earth (which is 37.5 deg
> where I stay). Then, to point to M81 (RA 09:55.6, Dec
> +69ø04'), I would rotate about 32 deg towards Polaris. Right?
> Still, when I draw the picture of the celestial sphere, the earth
>
> and the scope, I am not fully convinced this will work - even
> with azimuthal adjustments, will the scope really be pointing
> to the object?
>
> What about the azimuth? I am confused here about how I should
> align the scope, and how much I should rotate the scope to
> aim at the object.

--- BBBS/NT v4.00 MP