Guidance on Setting Circles

[Ed in UK]

I've attached an image of the RA Setting Circle of my EQ2 mount and I'm trying to work out what the silver pointer is for ?

It lines up with the direction of view of the telescope, the silver knob above it is the locking screw for the setting circle. 

If I unlock the screw and move the setting circle so that the co-ordinates (RA) line up with the point, then relock the screw both setting circle and pointer move in unison so any RA movement cannot measured.

When I used the circle last night I aligned the RA to the R|A mark that can be seen on the lower collar. Any movement of the scope can then be measured/set.

If the pointer is not for setting the scope in RA what is it for?

OR have I just got everything wrapped around my neck when using setting circles ????

[pipnina]

Unfortunately, setting circles are basically useless. On cheaper mounts like the EQ2 they are too small and poorly manufactured to be useful, on more expensive mounts they don't exist because you can tell them where to point after alignment.

The best way to find objects is by star-hopping and using Red-dot finder / Telrad and a spotting scope. I went through this very experience myself when I first started

[Charic]

From the image you supply, its my belief that the silver arrow points to one of the two scales on the dial, the upper scale is Northern, and the lower scale is for Southern Hemispheres.
 
Note the upside down exclamation mark between the R. & A. that is your index mark ( I think ! )

You need to point the scope to a known Star or object then physically set the scale ( unlock that  screw) and move the scale collar to match the Silver pointer to the R.A Number and fully aligned with the index mark, then lock the screw. Any other target can then be located by rotation and simple alignment using the lower index  mark  when it aligns with the R.A  number of the new target. The silver pointer you mention could well be the other side of the scope now, with only the main index and  R.A. numbers aligned.

Due to the size of the scales, it would still be a hit-or-miss affair, due to their poor accuracy, but that's how I believe your system works? 

[Ed in UK]

Thanks for your replies.

I never expected pin point accuracy from these setting circles,  just to get in the general area.

However last night I managed to use the setting circles with a degree of accuracy. Managed to return the same spot twice plus I was only a shade of Pleiades when I tested my technique.

I believe I'm doing it correctly then ?

[pipnina]

23 minutes ago, Ed in UK said:

Thanks for your replies.

I never expected pin point accuracy from these setting circles,  just to get in the general area.

However last night I managed to use the setting circles with a degree of accuracy. Managed to return the same spot twice plus I was only a shade of Pleiades when I tested my technique.

I believe I'm doing it correctly then ?

If you're having success then that's excellent, but generally I would advise to learn star hopping with the red dot and/or a finderscope as well.

Happy hunting.

[25585]

4 hours ago, Charic said:

From the image you supply, its my belief that the silver arrow points to one of the two scales on the dial, the upper scale is Northern, and the lower scale is for Southern Hemispheres.
 
Note the upside down exclamation mark between the R. & A. that is your index mark ( I think ! )

You need to point the scope to a known Star or object then physically set the scale ( unlock that  screw) and move the scale collar to match the Silver pointer to the R.A Number and fully aligned with the index mark, then lock the screw. Any other target can then be located by rotation and simple alignment using the lower index  mark  when it aligns with the R.A  number of the new target. The silver pointer you mention could well be the other side of the scope now, with only the main index and  R.A. numbers aligned.

Due to the size of the scales, it would still be a hit-or-miss affair, due to their poor accuracy, but that's how I believe your system works? 

With the equatorial I used to own, having aligned with Polaris, I would set RA & Dec to the co-ordinates for that star, thereby polar-aligning and setting the circles in one exercise.

Star/asterism/DSO recognition without co-ordinates is useful. Moving to recognised objects, check your setting circle readings against atlas or catalogue ones. As circles are not dead accurate, a gradation or 2 either side is close enough. Way out though, you might need to re-check polar alignment and Polaris co-ordinates again.

Relying on battery powered gadgets on their own, with no unpowered mechanical and optical aid, is sadly a sign of the times. Enjoy your EQ2.

[Ed in UK]

3 hours ago, pipnina said:

If you're having success then that's excellent, but generally I would advise to learn star hopping with the red dot and/or a finderscope as well.

Happy hunting.

Thanks Pipnina, believe me I'm a total newbie so probably beginners luck.

Star hopping is a skill that I need to learn and I'm sure I'll probably use that more in the long run to find objects. ?