polar scope help!

[Julian19_71]

Hi All,

I'm pretty new to astronomy, having a bit of a dilemma with the mount I have. Currently have a gp2 but without the Polar scope option unfortunately. To buy a vixen set is way too expensive so hoping someone can confirm if any other brand would fit? I noticed most are sold without the Ra and Dec graduation rings which is also what I lack. Appreciate it if someone can point me to the right direction.

[doppler (Rick)]

Hi and welcome, The polar scope option is not really of much use in the southern hemisphere as there are no bright stars near the south celestial pole. (the northern hemisphere has polaris the pole star) As for the setting circles I have never used mine in 30 years of stargazing. The setting circles should be included in the standard mount. If you bought the mount new I would check the specifications on the paper work.

Rick

[Julian19_71]

Hi Rick,

Really appreciate your advice, unfortunately the mount was an impulsive purchase and now I'm kicking myself!

[Renato1 (Renato)]

I don't know what a gp2 mount is, but with my ancient Super Polaris mount - if I wanted to polar align (which I rarely do) - I'd be lost without setting circles with a vernier scale, without the built in bubble level and without the polar alignment scope.

I basically get it level with the bubble level, set the declination to that of a bright star (usually Alpha Centauri) and lock it, then I rotate the RA axis, and the base of the telescope, till the star is firstly in my finder, and then in the middle of my eyepiece. The telescope is now roughly polar aligned, and the pattern around Sigma Octans is usually somewhere inside the field of my polar alignment scope.

That said, unless I want to take pictures and run the motor, I don't do the previous exercise, and usually just aim the telescope roughly south, then star hop.
Regards,
Renato

[Julian19_71]

Hi Renato,

Thank for the tips! Gp2 is the vixen equivalent of eq3 I think. Ive been watching YouTube for some instructions but it seems the more vids I watch the more confusing it gets.

[Renato1 (Renato)]

Originally Posted by Julian19_71

Hi Renato,

Thank for the tips! Gp2 is the vixen equivalent of eq3 I think. Ive been watching YouTube for some instructions but it seems the more vids I watch the more confusing it gets.

Hi Julian,
I can understand your confusion, because when I got that mount, despite doing a lot of reading about star drift method and the like, I wasn't getting anywhere.

When I finally did get polar aligning down pat, on two nights I was there reading coordinates and using the setting circles to find objects - and it worked. But then I decided that it was stupid, as I was spending way too much time looking up and reading co-ordinates and setting them exactly with the Verniers on the telescope.

With the scope roughly pointed south, and the latitude set correctly on it, when I looked in the finder, rotating the RA and DEC controls, resulted in roughly going up and down, and left and right across the atlas page I was looking at. Which in turn made star hopping pretty simple, especially as I had a correct image finder, and a Telrad on the telescope.

The Telrad or any other red dot finder takes you to the closest bright star you can see on your atlas, then the 8x50 finder which is now on that star is used to hop across the image corresponding to your atlas to your object. With a little practice, it was much faster than using setting circles. When using a straight-through finder, I just turned my map upside down, and did the same.
Regards,
Renato

[SteveInNZ]

It seems the GP2 comes without setting circles of any kind and they are sold as part of a kit with the polar scope.
If you use your scope in the same place every time, you can find true south with a variety of methods (Google earth, solar transit, etc) and then place your mount so that it lines up with the north-south line. Then mark the positions of the tripod feet so you can just bring it out and plonk it down in the exact same position.
For the setting the azimuth of the polar axis, set the telescope so that it is parallel with the polar axis and use a tilt meter to set it to the same as your latitude. I use the one in my phone and that's plenty good enough for visual use.
You can also make up something to mount your smart phone on the scope and use an app like SkEye for Android (there may be something similar for an iThing) which has an indirect mode. You calibrate by pointing at a known object and it uses its gyros to tell you where you are pointing in RA/Dec and Alt-Az, plus all the trimmings of a planetarium.

Steve.