Help Please - Really Confused and Stuck

[nheather]

I am a beginner with a Skywatcher 150PL with an EQ3-2 mount.

I have also bought a PolarScope, the new style design which requires you to unscrew the partial mount and screw the new style polarscope in its place.

This is where I get confused and may have also a bit of a mess for myself.

So my questions

1 The RA scale. This is part of the mount. I can unlock it, move it an lock it in any position I want. I can also rotate the mount around the RA axis and that has no affect on the RA scale. So how no I know what position to lock the RA scale in.

2 Is there a reference position for the mount when rotating around the RA axis. I can't see any alignment marks so where should it be when setting up.

3 Now the polarscope. When you take the old style mount off it has 5 thin plastic washers behind it. I'm guessing you should use the right number so that when screwed in, the polarscope is in the right position. But when fitting the new style polarscope how will I work out how many washers to include. I understand that midnight Nov 1, polaris should appear directly below the NCP when viewed through the polarscope. That's fine but as the polarscope rotates with RA how do I know where RA should be on Nov 1 midnight.

4 To make matters worse I slacked off the collar on the polarscope which has the indicator line so now I am unsure of the position. How can I work out where it should go. There seems to be too many variable - RA Rotation, amount polarscope is screwed in, position of the indicator on the polarscope.

Any advice would be really welcomed.

Cheers,

Nigel

[glowjet]

I should not worry too much Nigel, as most newcomers have these problems in some form or another, Astro_Baby`s tutorial on Polar aligning, even though it is for the EQ5, should give you a basic grounding on setting the scales. Apart from Midnight Nov 1st as a transit point, you could also use June 15th at 9.00 am, (10am BST) these are constants and can be used to make an initial setting of your mount indoors, as part of the procedures HTH

[nheather]

Apart from Midnight Nov 1st as a transit point, you could also use June 15th at 9.00 am, (10am BST) these are constants and can be used to make an initial setting of your mount indoors, as part of the procedures

So is a GEM mount in a specific position at the transit points. I mean can you set up a GEM mount RA and say that is how it will be on Midnight, 1st Nov. If so then I can go ahead and set the polarscope.

Cheers,

Nigel

[NGC 1502]

Hi Nigel. Sounds like you want to do an accurate polar alignment, and also use the setting circles to find objects.

None of this is needed for basic visual observations.

With an EQ mount like yours, you can set your latitude on the scale (London is 51.5 degrees) point the polar axis north. Align the finder with the main scope, and you are good to go.

The setting circles on these mounts are really too small to be of much use. Maybe you could use the declination circle (it's not adjustable) and 'sweep' the area at low power with the RA unlocked, you could be lucky.

If it were me, I'd forget the setting circles and find your object with the finder and your lowest power (largest number) eyepiece in the focuser.

You can then track your object using the RA control only. Because you are not precisely polar aligned, the object will drift up or down within the field of view as you track, so every so often you can tweak the declination control to centre it.

Accurate polar alignment is only a requirement for astrophotography.

Hope this post is relevant to your needs, if not, please say.

Regards, Ed.

[knobby]

Nice post Ed...

like Ed says , polar alignment is only really critical for imaging. If you are just observing them aim the scope so the polar scope is near polaris (compass to north and declination scale 52 degrees ish... Assuming you are near London ) then that will do fine.

Enjoy the clear skies tonight

[glowjet]

A bit advanced Nigel, Transit times for Polaris, as you probably may not have the date and time scales on the EQ3-2 as for the EQ5 series, however, having purchased a Polar scope you will want to find some way to use it, I have come across the following method, which may be worth a try, after once having installed and centred the Polar scope on the mounts central axis...

Align and level your mount N. as in the normal manor, set the Polar scope as for a transit time, with the little circle at the bottom, release your clutches and set the counterweight bar ( without the weights attached ) to hang vertically down, you can check this with a plumb line or sighting against a known vertical object, all this can, of course, be done in daylight. you should now have Polaris the NCP and your bar in a straight line, lock the clutches.

A little information is now helpful, Polaris lies on a line through and 43' to the left of the NCP, pointing almost directly to Kochab Ursa Min, but more accurately it lines out with 5 Ursa Min, but this is a mag 8 star and may not be easily seen, all this should become apparent when consulting a good quality star map.

All that is needed now is to correctly align Polaris and the NCP at the time you want to observe. If you have set your mount to the correct elevation you observe at, and now have Polaris centred in the Polar scope, it only needs to turn the scopes counter weight bar to point in the direction of Kochab or 5 Ursa Min, a pair of bins may be helpful when you do this. Then using the mounts Alt and Az adjustments, slot Polaris into the the little circle, job done, finish assembling the scope.

If you do not want to do it from direct observations, then look up Jason Dales Polar Finder program and find the diagram for the date and time you want to observe, striking an imaginary line through Polaris and the NCP, it should be fairly simple to copy the angle and make this with the counter weight bar.

All this takes longer to explain than carry out I should think, if it works for you, then you might want to think about marking your mount and using your circles, so you can return the scope to the set position HTH

[KenG]

Get yourself a copy of "The Backyard Astronomer's Guide", £19.20 on Amazon. It tells you EVERYTHING you need to know about setting up and using telescopes, with masses of illustrations. Everybody starting observing should have this book for reference.