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To Level or Not to Level..........


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That is the question. I see so much differing advice on this subject. Surely this is a yes or no answer, but many tutorials and posts talk about levelling and others stating it's not necessary due to polar alignment routines or guiding negating this requirement. Very confusing. 

If it's not necessary why do so many people advise on doing it? Has anyone tested not bothering levelling compared with getting the spirit level out and levelling and compared the results? I'm not talking about having a mount on a 45 degree slope...that would be silly, but if levelling is not necessary what would the limits be? Is a patio slab or 2 slightly out of line going to make a difference? That's a lot of question marks.

Thanks,

Steve

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Eq Mounts don't need to be level, but if it's on a pier and stays mounted, getting it level will help with some type of software that require a level mount, if it's put up and taken down each session i wouldn't worry to much if you do use software that requires a level mount that's the time to do it...

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I used to get mine 'reasonably' level for the sole reason that it then doesn't need much adjustment in ALT to get it polar aligned. I'm talking about a portable rig here, one that has to be setup on new ground each time. I suggest you spend longer on ensuring the tripod legs cannot sink into the ground!

ChrisH

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North - South levelling is compensated for by the altitude adjustment on the mount.

East - West levelling just makes your polarscope correspond to the correct sidereal time so that the mount is correctly aligned when Polaris is centred in that little circle, assuming that your polarscope is correctly oriented in the mount in the first place.

So the answer is yes if you want to regiment the set-up and make life a bit more simple through repeatability. 

And the answer is no as a prerequisite to accurate polar alignment (PA).

Don't take it from me, sit down and really think about what PA is trying to achieve: It is simply making the RA axis of your mount parallel to the Earth's axis. No more. No less. :)

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This is unscientific... and there may be other explanations, but on my first night using my new HEQ5, I suffered from oval stars. Next day I realised it wasn't leveled at all, I tested it from the eyepiece tray, which turned out to be not at all level. Night after, I leveled properly and my stars were much better. Same guiding settings and same collimation method.

I know many esteemed members here will say it doesn't matter...  My mind is open but on the balance of MY evidence, it makes a difference!

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from my experience there is no reason for a level mount. that said, why not do it anyway? it takes seconds, it makes polar alignment easier because your altitude adjustment is up/down and your az adjustments left/right instead of degrees of angular adjustment and best of all, it looks right thus suits my ocd. :)  

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The act of polar aligning puts the mount head in the correct position (with the RA axis pointing at the NCP). Where the legs are pointed is of no concern to the rotation of the Earth. Think about it.....someone at the Equator compared to someone at the North pole will have their tripod legs at 900 to each other, yet the mounts will still track correctly.

Getting the tripod level helps if you are using a software polar alignment routine as it will decouple the Alt movements from the Az....otherwise it is of no importance whatsoever. Some Takahashi mounts do not even have the capacity to adjust the leg lengths- plonk the tripod down and use their superb polarscope and you'll be reet.

I saw one bloke proudly stating on Facebook that he had spent considerable time with an electric sander sanding his aluminium pier adapter to within a gnat's gnadger of level. I didn't have the heart to tell him....... :smiley: :smiley: :smiley:

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I level my mount before attaching the wedge (SCT rather than EQ mount)

The reason that I level the tripod is that I can do this without having the OTA or wedge attached.  When I add the wedge, and OTA only a little fine tuning will be required.  This means that between sessions, I have a system that is very repeatable.

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An equatorial mount does not have to be levelled to function perfectly. However, there is an advantage to doing so - a mount that has been accurately levelled will not show any unwanted interaction between the azimuth and latitude adjustments when actually adjusting for polar alignment.

To satisfy yourself that an equatorial mount will track accurately even with a gross amount of mis-levelling, imagine an infinitely long rod inserted through the polarscope tube of the mount such that it reaches accurately towards the north celestial pole. Now rotate the mount around the rod to an arbitrary rotation angle, lets say 16.245 degrees. Finally, assemble a mounting base with a top table inclined at the same angle and bolt the mount to it. The Polar axis is still pointing at the North Celestial Pole, will rotate accurately around the rod and yet it is 16.245 degrees off level!

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I think that if the mount Is not level then when trying to accurately polar drift align, when you tweak the azimuth it slightly changss the altitude also and vice versa... Yes you can eventually polar align the mount on a not level platform, but it does make the job more time consuming.

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All, thanks all for the responses. My HEQ5 sits in the garage and I just take it out and plonk it on the patio to start, roughly pointing the N leg where the NCP is. I used chalk once to mark the position of the legs where I was aligned - that clearly was not going to last  :tongue: ! - loving the drill some holes in the slabs idea Davey-T for repeatability.

I then check where the NCP is meant to be using polar finder and make adjustments with alt / az to get as accurate as possible polar alignment. I think the penny just dropped on what I'm actually doing when adjusting alt/az on the mount when polar aligning, which corrects any "errors" on the tripod position- correct? I've always just done this without really thinking about it.

I'm also guiding using PHD2 so if my polar alignment is not bang on then surely this would be compensated for by mount corrections (within reason)

I know it does not seem like a major task levelling the tripod section for the just do it camp but if I can avoid removing the mount from the tripod, levelling and refitting the mount it will save precious minutes (and potential dropped object accidents) during my full set up, which I need to run through each time I head out, sometimes an hour+ before I get anywhere near imaging.

Thanks again,

Steve

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They don't need to be levelled to achieve polar alignment. The example above is non-scientific as the author says and I've been very unlevel countless times and achieved good polar alignment.

If the RA axis setting circle is set up with he polar scope reticule and one uses the hour angle and the RA axis setting circle to position the small polaris circle in the polar scope to polar align, then being roughly level will help, but I suspect even then there are countless other factors wilhich will hinder "perfect" polar alignement.

So no, don't waste any time with an EQ mount getting it level.

James

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Mark the ground is the way to gain speed.

Drill holes, draw circles etc and then just reposition in the same spot each night. It will save you a good 10 minutes of faffing.

If nothing else about your mount changes between when you carry it out and when you take it back again then as long as the legs are in the same place all will be good. I would suggest drilling holes that the legs actually sit in - this way it stops that whole 'am I on top of the mark' problem.

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When I get my pier made up I've considered deliberately not having the top level and instead having it at an angle so the alt adjustment on the mount sits at a more reasonable angle (hopefully avoiding the Skywatcher "bendy bolt" problem).  At the moment the easier polar alignment is the only thing making me think I should perhaps have it level.

James

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When I get my pier made up I've considered deliberately not having the top level and instead having it at an angle so the alt adjustment on the mount sits at a more reasonable angle (hopefully avoiding the Skywatcher "bendy bolt" problem).  At the moment the easier polar alignment is the only thing making me think I should perhaps have it level.

James

I used to do this when I had my old EQ6 on a tripod. Even with upgraded bolts a certain lack of mechanical sympathy was needed when cranking the altitude bolts as you can feel it moving against the slope of the mount head. Altering the height of the north facing leg eased this a bit, though if you are using a big OTA you have to watch out for taking the centre of gravity too far 

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I used to do this when I had my old EQ6 on a tripod. Even with upgraded bolts a certain lack of mechanical sympathy was needed when cranking the altitude bolts as you can feel it moving against the slope of the mount head. Altering the height of the north facing leg eased this a bit, though if you are using a big OTA you have to watch out for taking the centre of gravity too far 

I found that unscrewing both bolts before doing any PA adjustments swing the mount back and forth to break the chinese gripp all seal glue/grease, this did allow a very easy PA with no strain on the bolts.....

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I just had some help from a friend or two to build a wooden pier to replace the "as supplied" tripod I was using for the HEQ5pro, as part of the pre-winter spruce-up. I designed a leveling head of the usual "four bolts" type, and used some old oak  (the wood not the tinned ham) for the "slabs".  The top plate is routed out to take the top puck of my old extension pillar (I found both a sweet-tin "Smith Kendon original travel sweets" and the bottom half of one of those "rotating" ashtrays to be a perfect tight push-fit when shortened). No more tripping over the tripod legs! Also new rollers on the roll-off roof, and a fresh computer with Distro-Astro - now I need to find how to connect to OPTICSTAR camera's in LINUX/EKOS/INDI (any idea's anyone?) - also need to do a new Polar Alignment.

Having tried tripods, concrete, steel and now wood piers over the years, I'm quite happy with the new build. Damping is fast, Jupiter and moons, Mars (speck) and Venus were all test objects as was the Orion Neb.

Back to the point - if you have a fixed system/obsy then leveling is something you do once (unless you have subsidence, continental drift, live in an orogenous zone, etc). It takes a few minutes, makes any polar adjustment simpler and I find vertical amd horizontal balancing takes longer than leveling.

Still I suppose "the levelers" have been around since 1648...

P

P

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