Placement of Dobsonian - in the paddock!

[mulberry (Suz)]

Hi all,
I have determined that the best spot to place my new (not yet arrived) dobsonian is in a paddock below the house (less stuff in the way). The grass is mowed but it is not level, rather a gentle slope, say 15deg. My question is: do I need to make a little level platform or can I just put it straight on the ground?
Cheers!

[peter_4059 (Peter)]

straight on the ground should work fine.

[glend (Glen)]

Well that depends. If your going to align it and use an azimuth circle on the base then yes leveling it will make your co-ordinates search more accurate. What dob is it? If it is a Goto dob then a two star alignment will be fine, but otherwise level it. I built a simple triangular leveling base for mine, with screw adjustable feet. You can put a small caravan bubble level on the base to indicate level.

[acropolite (Phil)]

I'd expect that if the OTA wasn't perfectly balanced then it would tend to swing downhill if the base wasn't level, particularly on a 15 degree slope.

[raymo]

you are absolutely right, it would.
raymo

[Allan_L (Allan)]

Hi Suz,
Congratulations on your new (not yet arrived) DOB purchase.

With a sloping ground, the short answer (IMHO)is: It doesn't matter... except that

(1) as previously stated, to some extent, gravity will tend to want to swing the tube in the direction of the slope. So depending on how "sticky" your azimuth axis is, this may cause some frustration, especially for items lower in the sky; and

(2) if you have any navigational aid(s) added (manual setting circles, digital setting circles, argo, Push to, GoTo, or tracking) then level is better.

So for the first outing, for a quick look see at easy to find stuff, you can just plonk it down and start observing, that is the joy of a DOB.
But eventually, you will be better off either excavating the site a little, or making a levelling platform, to give your mount a nice flat base to work from.

Either way, enjoy

[brian nordstrom (As avatar)]

A piece of 4x2 the same length as 2 of the 3 feet + 50mm or so under these on the down ward side to level the base and you will be fine .
Brian.

[Hzadbhat (Brandon)]

Knowing what the average rainfall there is, I'd definitely make a raised platform with crushed gravel, pack it down well then finish with pavers. Gives you a good permanent spot and will stop moisture from rising and destroying the base.

[brian nordstrom (As avatar)]

The piece of 4x2 comes home with you together with the scope and then its ready for next time , further up the slope .. cool
Brian.

Originally Posted by Hzadbhat

Knowing what the average rainfall there is, I'd definitely make a raised platform with crushed gravel, pack it down well then finish with pavers. Gives you a good permanent spot and will stop moisture from rising and destroying the base.

[mulberry (Suz)]

No goto - preferring to star hop and learn more of the sky. Rain is little at the moment - not good for the garden but great for observing. My scope arrived and I took it out for a spin. The ground presented no problem but if we were having more rain, I would definitely need a platform. So, so happy with my new toy. From a 60mm refractor to an 8"dob - wow. I got 47 TUC on my second night.

[ZeroID (Brent)]

Gotto or no goto, level works better. If you are going to use setting circles it all needs to be pretty level. 4 decent size concrete pavers will do the trick. Bed them down on some hardfilll on a bit of levelled area. Cost is minimal, bit of shovel sweat and it will make finding your targets just so much easier. You can also mark a true nth position on them so setup is consistent. And keeps your feet and gear dry.

[niko]

setting circles schmetting circles!

It doesn't need to be level but it won't hurt to prop up one side - as someone said, if for no other reason than stopping it tip over on the slope

have fun!!

[sn1987a (Barry)]

A couple of bags of Rapid Set and a level.