EQ5 bubble level

[Julian Hands]

I've been using my EQ5 mount since January and always queried my polar alignment, as I always seem to have to compensate with Dec adjustment.

Tonight I studied YOU TUBE and found a good setup tip via Astro shed which prompted me to use a level across the tripod head on each of the three legs, before added the EQ5 mount. Thankfully I have a very accurate machine level which I used to setup the tripod and after 10 minutes of fractional tweetkng, had the tripod spot on. On mounting the EQ5 head, I was surprised how far out the bubble was, but left it alone and observed Orion for a while, which now tracked beautifully with just the RA.

I've now used a permanent marker to dot where the centre of the EQ5 bubble level needs to be, but will use this machine level procedure for future observing as it certainly gave a brilliant result tonight.

Lesson learnt, don't take the bubble level for granted. Surprised me and what a difference I got.

[Dave Lloyd]

That's very useful. One could spend ages looking at all sorts of alignment issues before finding that one.

[jambouk]

For the equatorial mount, it doesnmt haven't to be level, as when polar aligning one uses the azimuth and altitude adjustments to line the RA axis up with the celestial axis, irrespective of how unlevel the tripod is. Doing a star alignment then teaches the handset or computer exactly where the stars are in relation to where the mount it. So having it very level isn't important. But yes, these bubbles are often out.

[ollypenrice]

Jambok is right. All you do when you level the mount is set the polar scope reticle to the correct angle but, given its inaccuracy anyway, the effect is trivial.

It's a shame that so many manufacturers persist in this tedious way of aligning. Takahashi don't do it this way and their tripod legs are not even adjustable. The bubble level goes on the RA housing and is set to your time zone offset. The polarscope conatins a kind of planishere to give you the Polaris position. The entire alignment to within an arcminute takes no more than 3 minutes, compared with 10 minutes to level a tripod!

I very much doubt that your improved tracking has anything to do with precise levelling but it's good that it was good!

Olly

[Julian Hands]

For the equatorial mount, it doesnmt haven't to be level, as when polar aligning one uses the azimuth and altitude adjustments to line the RA axis up with the celestial axis, irrespective of how unlevel the tripod is. Doing a star alignment then teaches the handset or computer exactly where the stars are in relation to where the mount it. So having it very level isn't important. But yes, these bubbles are often out.

My EQ5 mount is manual and not Synscan setup, hence t'm unable to teach the mount to componsate for any inherent error from setup.

I appreciate that I'm not carrying out astro photography, but just wanted to make you all aware that better alignment of the EQ5 mount can be made by levelling the tripod head first. It definately made a difference and gave me more eyepiece observation time, as I never had to take my eye away from the eyepiece and feel around for the Dec handle. RA adjustment kept it tracking beautifully.

I've just looked at my Scope Nights App and I have 4 nights starting tomorrow of clear skies. Can't wait and hope you all share the clear skies ahead.

[wuthton]

I just plonk my mount down and polar align, I don't even have a bubble level. The mount is either polar aligned or it isn't regardless of whether the tripod is level. 

[Cornelius Varley]

Whether the tripod is level or not doesn't make any difference to the tracking accuracy of the eq mount, this is a function of polar alignment which isn't affected by the tripod. The only advantage of levelling the tripod is that you have a reproducible base setting, which should speed up the polar alignment.

[jambouk]

I read somewhere that having a level mount also made the Polar Alignment routine using the handset easier/more accurate.

James

[Gazabone]

I've always levelled the tripod whether it's an EQ or a GoTo altaz. However, I've always used the "bubble level" app,on my smart phone. My manual eq is the SW 3-2 with an RA motor and it's great to have my target still centered after half an hour! I guess having it level helps accuracy when using setting circles to find my fainter targets but tbh I've never tried it without levelling, after all it only takes 3-4 minutes at most.

[ollypenrice]

Imagine an invisible magic shaft passing through your mount's polar axis and holding it in perfect alignment forever, whatever else you do to it. Now you can loosen the PA adjusters and point the tripod anywhere you like, but you are polar aligned wherever you point the tripod.

No software adjusting can compensate for misalignment so far as tracking is concerned though it can compensate for PA and cone error in GoTo.

Levelling tracking Alt Az mounts is important, though.

Olly

Edit: by the way, there is no need whatever to level the mount on the N-S direction because you just alter the declination angle of the mount to centre Polaris. Levelling E-W does, as I said earlier, set your polar scope reticle to the correct angle. The nice Avalon mounts have a high quality level but running only E-W because that is all that's needed to get the polarscope right.

[Gazabone]

Forgot to add that I don't see how the built in bubble level on the mount could possibly be used to get it anything like accurate - don't know why they bother. Would prefer larger setting circles though!

[StuartJPP]

The only time being level has helped me is when doing fine adjustments in the polar scope because if everything is level and square then you can usually do 2 adjustments, once in ALT then once in DEC since they work at right angles to each other.

If the tripod is not level then you have to keep making small adjustments in both ALT and DEC to get Polaris spot on...though to be honest, the small adjustments are easier than levelling a tripod.