How to view from garden

[Tom_m7117]

Hi guys, hoping to get my first scope soon most likely a dobsonian mount. I will be viewing from the garden on the grass. I'm just wondering how I should place the scope on the ground. Should I place on a solid piece of wood etc on top of the lawn? Do I need to worry about moisture building up on the mirror? If so how do I counteract this. Also how long should it be left to call down before viewing begins?

Many thanks

[David Smith]

I place my dob directly on the grass in the garden without any issues. I have never had issues with dew on any of the mirrors. If you do it will probably be on the secondary and this can be solved by using a dew shield at the front end of the scope.

[skygazer]

Hi Tom,

I have a 200p DOB and find it takes about 30 - 45 mins to cool the scope down and a good flat surface is recommend, I usually just use a paving slab if I need to position the scope on uneven ground.

Paul

Sent from my Nexus 7 using Tapatalk 2

[Paulb3098]

Hi Tom,

As long as the ground is fairly level you shouldn't have any problems.

Good luck

Paul

[brantuk]

I have self levelling feet on my dob - which also keep it well clear of the ground moisture. I've recently heard of a couple of baseboards that have warped due to moisture after extended use in the field. One chap's even building a whole new rocker box for his ota. Where dew reaches the primary - a fan on the back is a very common solution - which also blows warm air currents out of the end of the tube and helps reduce cool down time. For the secondary a dew shield helps as mentioned - larger dobs often require a dew heater as well.

HTH

[NGC 1502]

As long as the grass is not very long and springy, then just put it straight on. Cooldown time can vary, depends on the difference between where the scope is stored and the outside temp.

You can reduce the cooling time by storing the scope in an unheated room or shed, if that is possible for you. You can use the scope at low power while waiting for it to fully cool.

A Newtonian is less prone to the optics dewing than some other designs. The first optic to dew up is usually the secondary. A dew shield to extent the tube at the upper end is a good protection for secondary dewing, camping mat foam is the popular choice for that.

Regards, Ed.

[JamesF]

I've made my own rocker box from waterproof ply and it's all painted with gloss paint so I'm not too worried about moisture, but if I had to use a standard Skywatcher dob base I think I'd lift it clear of the grass a bit. I've never had the impression that they're particularly tolerant of damp. If you're the sort of person who keeps their lawn nice and neatly trimmed I guess it might not be necessary. I'm not one of those people

James

[cotterless45]

In winter, when the feet freeze, we put out a rubber backed camping carpet, which LeeB spills his coffee on.

It's luxury glamastronomy.I've also used it in damp dewy conditions and in a tent.

Nick.

[CSM]

You may find my web site Garden Astronomy useful - or at least thought-provoking - maybe not!

[jason.p]

Please excuse ignorance, but what's a "rocker box"

[RikM]

I normally just put mine directly on the grass. If the grass is actually still wet from earlier rain then I put down a little square tarpaulin that I got from Tesco for a couple of pounds. Before I got that, I used a dustbin liner.

[brantuk]

Jason - a rocker box is the dobsonian base for a newtonian reflector (the thing it goes up and down on). This is placed on a truntable so the scope can swing left and right as well enabling you to point it anywhere in the sky