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SmokeyJoe

Newbie question about tripod setup.

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What is the advantage of fully extending the legs of my tripod? Given that I have a nice high fence / wall around my garden that significantly cuts down the effects of wind would I not be better of leaving the legs as short as possible, protecting the scope from wind effects?

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Yes.

As long as you're comfortable at the eyepiece level, the lower the more stable, I think.

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17 minutes ago, Mikea said:

Which tripod do you have?

Standard tripod supplied with skywatcher EQ5

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EQ5 tripod is pretty stable, but I agree that shorter legs are better. Should be fine for visual - fully extended or not.

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I saw the other day at the store a C9.25 Cassegrain at the top of an equatorial mount with fully extended legs plus there was tube extension of around 10 inches between the EQ head and the legs.

I am not sure of what was exact purpose of having an instrument that high, maybe to get a specific access at the Eyepiece while standing? or to use the instrument without a diagonal?  Mystery but I would like to know.

 

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3 hours ago, N3ptune said:

I saw the other day at the store a C9.25 Cassegrain at the top of an equatorial mount with fully extended legs plus there was tube extension of around 10 inches between the EQ head and the legs.

I am not sure of what was exact purpose of having an instrument that high, maybe to get a specific access at the Eyepiece while standing? or to use the instrument without a diagonal?  Mystery but I would like to know.

 

Passing basketball professional? :icon_mrgreen:

If using a long tube, probably a long focal length refractor, a high tripod is needed to avoid the observer having to lie on the ground to observe near the zenith. If using a shorter tube this is not needed or to be desired.

Olly

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I'm a wheelchair user,so as such when observing i am only about 5ft nothing in height (i'm actually 5ft7inch). Ive only ever used any tripod with the shortest leg height possible. I did have a refractor with a 1000mm focal length on an EQ mount/tripod before and with the shortest leg height, i practically had to sit on the ground. If i extended the legs, the EP was out of reach.

Edited by LukeSkywatcher

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I have always had any of my mounts at the lowest height setting, have even considered chopping a foot off my EQ3 so its lower to the ground but I am an imager so remote viewing and a RA camera viewfinder for the polarscope are your friends.

Alan

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With my SCT and refractor, being 6'+, I tend to extend the legs - just to be able to see the DSLR view finder when setting up (I check focus and orthogonality during the day in advance of a session).

Not necessary with the Newt - then it did have a focus motor so I can check focus remotely.

Edited by iapa

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My back garden has a 6'2" fence around it on 3 sides and this seriously hampered my views when observing with my scopes set to the shortest height. To "kill 2 birds with 1 stone", last summer i had a new patio area laid (poured concrete actually) across the width of the back of the house and had it raised up from ground level by about 16", so i can wheel right from the kitchen out onto it. That extra 16" has improved my views to the east and west. I can now see almost down to the horizon in both directions. My view north over the top of the house has also greatly improved. My view south has always been a non-starter for me here because of the trees at the rear of my house. I technically own the trees they are within my property boundries on the property deeds/maps. Having them removed would be too expensive and they do offer privacy from the newly constructed 15 storey high wing of the local uni.

Edited by LukeSkywatcher
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12 minutes ago, LukeSkywatcher said:

My view south has always been a non-starter for me here because of the trees at the rear of my house

I currently live in a new build estate within houses packed in like sardines, three story house at the end of my garden (south), my house to the north, houses closely packed to the east and trees to the west! Basically if it's anywhere near the horizon no chance of seeing it!

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5 minutes ago, SmokeyJoe said:

I currently live in a new build estate within houses packed in like sardines, three story house at the end of my garden (south), my house to the north, houses closely packed to the east and trees to the west! Basically if it's anywhere near the horizon no chance of seeing it!

I wouldnt worry about not being able to see down to the horizon. Objects that low down have to fight to cut through a thicker lawyer of atmosphere/pollution to be seen. You get much better views of the same objects later on in the night when they are higher up towards the zenith because the angle is more direct and through a lesser angle of atmosphere/pollution.

Obviously SOME objects will always be low down to the horizon in this part of the world. I tend not to worry about those. Too much going on right above our heads.

Edited by LukeSkywatcher
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32 minutes ago, LukeSkywatcher said:

My back garden has a 6'2" fence around it on 3 sides and this seriously hampered my views when observing with my scopes set to the shortest height. To "kill 2 birds with 1 stone), last summer i had a new patio area laid (poured concrete actually) across the width of the back of the house and had it raised up from ground level by about 16", so i can wheel right from the kitchen out onto it. That extra 16" has improved my views to the east and west. I can now see almost down to the horizon in both directions. My view north over the top of the house has also greatly improved. My view south has always been a non-starter for me here because of the trees at the rear of my house. I technically own the trees they are within my property boundries on the property deeds/maps. Having them removed would be too expensive and they do offer privacy from the newly constructed 15 storey high wing of the local uni.

I've done some trig - interesting experiment in slide rule use :) - to work out where I need to be so see over the fence.

Worked out that the rig I have, CGEM DX, will 'see' over  7' fence when 6' away from it. 

As I indicated, interesting relearning of slide rule :)

distance from fence = (height of fence - height of mount)  / tan(angle of OTA) 

I measured mount height as being the height of the mount plate when counter weight is horizontal - lowest point. 

I assumed anything below 20 degrees will be subject to atmospheric and distinct town lights

84" - 55"/tan(20) = 80" = 6' 6"

From your other post, I am guessing that 4' 8" is a good height for your tripod?

74 - 56/tan(20) = 49" or just over 4'

These numbers do not feel right ;):)

so,I drew some pictures

 

58b9cf8045b01_Untitled2.thumb.jpg.b13bf3b63457c369d590ff349cee4cd3.jpg

Edited by iapa

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11 minutes ago, iapa said:

I've done some trig - interesting experiment in slide rule use :) - to work out where I need to be so see over the fence.

Worked out that the rig I have, CGEM DX, will 'see' over  7' fence when 6' away from it. 

As I indicated, interesting relearning of slide rule :)

distance from fence = (height of fence - height of mount)  / tan(angle of OTA) 

I measured mount height as being the height of the mount plate when counter weight is horizontal - lowest point. 

I assumed anything below 20 degrees will be subject to atmospheric and distinct town lights

84" - 55"/tan(20) = 80" = 6' 6"

From your other post, I am guessing that 4' 8" is a good height for your tripod?

74 - 56/tan(20) = 49" or just over 4'

These numbers do not feel right ;):)

so,I drew some pictures

 

58b9cf8045b01_Untitled2.thumb.jpg.b13bf3b63457c369d590ff349cee4cd3.jpg

I'll take your word on it. I can add,subtract,divide and multiply. That's where me and maths ended our relationship. Failed it in my leaving certificate exam in secondary school.

I failed it for a very good reason though.........i didnt bother taking the exam. I think the technical term was "NG" = No Grade.

Edited by LukeSkywatcher

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4 minutes ago, LukeSkywatcher said:

I'll take your word on it. I can add,subtract,divide and multiply. That's where me and maths ended our relationship. Failed it in my leaving certificate exam in secondary school.

I failed it for a very good reason though.........i didnt bother taking the exam. I think the technical term was "NG" = No Grade.

I got a free trial last week of something called sketchup on the recommendation of my tame civil engineer.

Drew the walls and the pillar, then a line at 20deg off horizontal and tagged the pillar until that line crossed theta of the 'fence', the measured the distance between fence and pillar using the 'ruler' in the app. No actual maths involved :) 

Using this to design my observatory - I will get the design validated 1st tho'

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6 minutes ago, iapa said:

I got a free trial last week of something called sketchup on the recommendation of my tame civil engineer.

Drew the walls and the pillar, then a line at 20deg off horizontal and tagged the pillar until that line crossed theta of the 'fence', the measured the distance between fence and pillar using the 'ruler' in the app. No actual maths involved :) 

Using this to design my observatory - I will get the design validated 1st tho'

My dad was a "fellow member" of the institute of civil engineers/quantity surveyors of Ireland. He worked in Saudi for yrs when i was a kid, designing and overseeing the construction of many oil pipelines there.

I'm sure he did a few turns in his grave when i failed maths.

I digress.

Edited by LukeSkywatcher

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8 minutes ago, LukeSkywatcher said:

My dad was a "fellow member" of the institute of civil engineers/quantity surveyors of Ireland. He worked in Saudi for yrs when i was a kid, designing and overseeing the construction of many oil pipelines there.

I'm sure he did a few turns in his grave when i failed maths.

I digress.

Never any good at it, but, like the challenge.

Years ago, in my 'programmer/hacker' days, I wrote something to project a line from a central point whilst that was rotating, and display (in 2d) the coverage. This was before the days of thing like freeware ray tracers etc. e.g. the internet :(

Just occurred that I should, try to, do the same again as that is what we are about with the sky watching gig, but include known local obstructions and tie to some planetarium type data so you can see when targets will actually be visible behind the multi storey next door :)

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