I would like, if I may, ask you to measure the spread angle of your tripod, be it Meade, Celestron, Skywatcher, Orion, AP, SB, or whatever.
I just need the angle of a leg from vertical, so if you have an inclinometer, or a smartphone with clinometer app, could you please hold it against a tripod leg and post your measurement?
I'm conflicted about the optimal spread of an astro tripod, and would like some data beyond what I have around the house.
Thanks Julian,
it seems to me that the narrow spread (around 20 degrees) is very typical of photo and other light load tripods, whereas heavy load astro tripods tend to have a larger foot print (the extreme possibly being Meade's Giant Field tripod).
I think that 30° is the most pleasing and reassuring leg spread for a tripod. That way the legs form an equilateral triangle with the ground. A wider split might put too much sideways force on the feet and too much pull on the spreader. A narrower tripod is easier to tip over, especially with a top-heavy load of an EQ mount and telescope.
Since my HEQ5 tripod collapsed I've been on the lookout for a replacement, and the manufacturer of my new tripod gave me the option to customise the angle. So I chose 30°.
Thanks all who took a minute to measure their tripods
When you do the stability calculations (I'm a structural engineer, so it's part of my "bread and butter"!), what matters is the height, orientation, and offset of the Centre of Gravity with respect to the equilateral triangle of the feet on the ground.
For "small" mounts, the mass and height of the mount and OTA above the apex of the tripod is relatively small, so the tripod can be relatively tall / steep and still have good stability with the eyepiece at comfortable height. As the mount and OTA get bigger, the Centre of Gravity gets higher above the apex of the tripod, so you need a squatter / flatter tripod to get the same stability.
Most typical equatorial mounts put a lot of counterweight mass on the polar side, so you want to place the tripod with one leg pointing due south for optimum stability.
Steffan which tripod did you get if you dont mind me asking? Im looking for a second tripod.
Quote:
Originally Posted by julianh72
Most typical equatorial mounts put a lot of counterweight mass on the polar side, so you want to place the tripod with one leg pointing due south for optimum stability.
Yes on the EQ6 tripod, the azimuth pin is in between two legs but you can move it over to the other side so it lines up with a leg.
Yes the pin is set for lower latitudes by default which allows the counterweight to swing freely past the tripod legs. I switched the pin location back in higher latitudes as it was reported to give greater stability. Maybe up there. Not so sure it makes a huge difference at Sydney's latitude...
When you do the stability calculations (I'm a structural engineer, so it's part of my "bread and butter"!)
I'm an electrical engineer but did enough mechanical engineering at uni (about 30 years ago) to realise that this calculation was beyond by abilities
I know that the absolute weight, the centre of gravity, even the grip of the tripod feet on the ground need to be taken into consideration. So chose 30° because it looks and feels nicer and more stable to me
I've been using a surveyor's tripod a few times as a make-shift, it only has just over 20° spread and doesn't look at all reassuring with the HEQ5Pro, 6" Mak and 10kg of counterweights on top
Steffen,
You mentioned the Giant Meade Tripod....
These have 4" steel tube legs. I cut one down by 250mm to better support the 12" Lx200, solid as a rock!!!
Yes, when the TSO I was built in the UK, there was limited space, so I ran the roof to the back.
Later in Belgium I had the roof running off the front....
Info sought: Leg spread of popular astro tripods
