Tripod markings

[miguel87]

I consider myself very lucky to have a long dark garden with a raised patio at the back which is a lovely observing sight. I know the area of the patio which is flat test but I find that each time I set up and polar align I do have to make very minor altitude adjustments.

If I could somehow permanently mark 3 small spots on the patio to site the tripod legs, this would be avoided. However I dont know how I can mark them clearly and permanently without something so ugly that the mrs will kill me!

Any solutions?

[MarkAR]

How about 3 brass pucks with a dimple in the middle for the tripod points to sit in. Drill holes in slabs and cement them in.

[DaveL59]

so I guess a can of fluorescent spray paint would be out of the question?  

How about boring into the patio slabs and putting in a brass disc at each leg position?

[miguel87]

Thanks mark. I thought about drilling but an worried I might crack a slab 😖

[miguel87]

2 minutes ago, DaveL59 said:

so I guess a can of fluorescent spray paint would be out of the question?  

How about boring into the patio slabs and putting in a brass disc at each leg position?

Spray paint might be my first option as I could probably get it off if needed.

Any idea what type would last more than a rain shower?!

[DaveL59]

make sure you have hammer turned off and use light pressure and also keep the area wet. I'd guess too work up in bit size unless you're able to get a suitable diamond bit

[Carbon Brush]

To fit a brass puck, all you need is a dent in the slab. You aren't trying to drill all the way.
They often have hard pebbles included which makes full depth drilling a nightmare.

[PeterCPC]

+1 for drilling. I have done this and you have to look hard to see them.

Peter

 

[DaveL59]

3 minutes ago, miguel87 said:

Spray paint might be my first option as I could probably get it off if needed.

Any idea what type would last more than a rain shower?!

I'd have thought most would last a reasonable time, tho given the tripod feet will be rubbing then that'll reduce paint life. Not sure that the guys that mark up the streets use anything special in paint type and that tends to last a reasonable time on the road/pathways.

Edited April 24, 2020 by DaveL59

[miguel87]

Any idea where I might get the pucks from? I am tempted to just drill a couple of mill with an oversized drill bit and not get any brass picks, just use the slight recess in the slab?

Edited April 24, 2020 by miguel87

[MarkAR]

If you don't mind them raised then you can always use construction adhesive and glue them onto the slabs.

This might work out easier as you can set up your mount and then lift each leg a little to place them. With the mount on to it will keep them perfectly in place.

They only need to be 1/4" thick and 1" to 2" diameter. I could make some up but I would have to order some brass in, or stainless steel.

Or as you say, just drill a dimple in the slab. 

 

Edited April 24, 2020 by MarkAR

[lux eterna]

I use a cheap laser tool combined with a plywood adapter, to get a east-west alignment line on the ground. Maybe you can adapt this idea to your own requirements.

Ragnar

[jambouk]

You’d be better setting up on grass than slabs if possible.

[Stuart1971]

27 minutes ago, jambouk said:

You’d be better setting up on grass than slabs if possible.

I thought the whole point was position repeatability, which you won’t get on grass.. 🤔🤔

[jambouk]

As with everything in life, the answer isn’t binary.

After sunset, concrete emits the heat it has acquired during the daytime, much more than grass, so there will be heat currents drifting upwards and reducing the quality of the seeing around your telescope. So if you don’t care about the seeing setting up on concrete is fine. If you want the best possible seeing, don’t set up on concrete.

If you want perfect polar alignment then unless you have a permanent setup you’ll need to polar align each time you set up; so you’ll need to polar align if you set up on concrete or grass.

If you want to reduce vibrations transmitted from you walking around through the tripod and to the telescope, then I suspect grass would be better than slabs.

If you want the most stable surface to set up on I suspect slabs would be better than grass, but if you push the tripod legs into the grass firmly at the start, or use something to dissipate the load like anti vibration cups or caravan feet, then I doubt there would be any measurable differences.

James

[jambouk]

You could put three of these under the grass level on a grassy area, and then just mow over the top of them, and leave them in place all the time, either held in position with a bit of concrete or two tent pegs for each.

 

[miguel87]

1 hour ago, jambouk said:

As with everything in life, the answer isn’t binary.

After sunset, concrete emits the heat it has acquired during the daytime, much more than grass, so there will be heat currents drifting upwards and reducing the quality of the seeing around your telescope. So if you don’t care about the seeing setting up on concrete is fine. If you want the best possible seeing, don’t set up on concrete.

If you want perfect polar alignment then unless you have a permanent setup you’ll need to polar align each time you set up; so you’ll need to polar align if you set up on concrete or grass.

If you want to reduce vibrations transmitted from you walking around through the tripod and to the telescope, then I suspect grass would be better than slabs.

If you want the most stable surface to set up on I suspect slabs would be better than grass, but if you push the tripod legs into the grass firmly at the start, or use something to dissipate the load like anti vibration cups or caravan feet, then I doubt there would be any measurable differences.

James

Slabs are more stable, I dont have to realign each time at all. Grass creates way more damp, the grass can also move once you have polar aligned, vibration is non existent walking on well set slabs, worse on grass.

The ONLY downside of slabs is, like you say, the heat. Everybody I know would chose concrete over grass.

Edited April 26, 2020 by miguel87

[PeterCPC]

+1 for concrete.

Peter

[johninderby]

I prefer a solid surface rather than grass at home. The typical back garden grass isn’t a hard surface unlike the often rock hard grass surface of a public park.

Fortunately part of my sandstone patio is in the shade from mid afternoon and has good south facing views. 

 

[Space Hopper]

+1 for grass

Rob.

[miguel87]

I find dew problems alot worse observing over grass.

Also the reason more heat comes of the slabs is because they radiate it faster. So if you feel grass and slabs at midnight, the slabs will feel colder.

Under bright sun which looks brighter, slabs or grass. Slabs because they are reflecting the energy rather than absorbing it. I guess lighter coloured slabs are better than black ones!

[miguel87]

An interesting bit of info about grass and heat. Amazing stuff! 🌱