Pier for 8SE - planning continues...

[Brutha]

Hi All,

So, it seems that a pier is a good idea for my 8SE, so my planning is now continuing. The idea is to follow the basic plan from here: Sky at Night home made pier - see basic plan pics below.

The basic idea is filling a drainage pipe with concrete. I'd be grateful for any thoughts on the following questions:

• I'll try and get 200mm drainage pipe - I don't know if this is overkill though, would 160mm be ok if I can't get 200mm?
• I'll use the "two plate" approach I think, since it's simpler to make with just drilling some plates. Can I use e.g. 10mm aluminium plate for the two plates? (which I could potentially machine with the MPCNC machine I am currently building). Or should it be steel?
• Any other things to consider? I have seen people suggesting this approach might be prone to vibration?

Thanks!

Brutha

[michael8554]

The missing info - is the 8SE on a wedge, or in Alt/Az mode?

Or maybe you've de-mounted and it's now on an EQ mount ?

Michael

[Brutha]

Hi Michael,

Thanks - good question; no, just using the original mount (alt-az) for now I think.

BUT... ideally I leave the option open to switch to a EQ mount at some point in the future if I fancy doing it.

Cheers

Brutha

Edited January 3, 2021 by Brutha

[michael8554]

Then presumably you have plans to adapt the top plate to take the 8SE, and to provide Az adjustment ?

Michael

[Brutha]

2 hours ago, michael8554 said:

Then presumably you have plans to adapt the top plate to take the 8SE, and to provide Az adjustment ?

Michael

Yes, correct. The holes for the 8SE mount screws are actually pretty simple, seems to be 3 3/8" holes on a 3" radius (I know I have to be careful with the length of them!).

For Azimuth adjustment; you mean in future for an EQ mount? Yes, was aware of that, hence the two plate design; would need to rework the lower plate a little along the lines of this I think, which gives 20 degrees of Az adjustment: https://www.pierplates.com/products_8510.html

 

[michael8554]

I was assuming that even in Alt/Az mode, the 8SE needs an accurate "Home Position", probably level and pointing true north ?

Michael

[Brutha]

13 hours ago, michael8554 said:

I was assuming that even in Alt/Az mode, the 8SE needs an accurate "Home Position", probably level and pointing true north ?

Michael

Yes, should be more or less level (although it seems pretty tolerant and doesn’t need to be exact). The azimuth of the mount doesn’t seem to have any effect; if you are doing the usual alignment based on bright stars, it simply works out where it is pointing in the process.

With starsense you start with the scope pointed roughly east and level, and it moves around taking 3/4 images and plate solving to get the orientation. 

My first telescope was a skywatcher 127 maksutov; this was “tracking only” with no goto functionality - indeed, this needed to be aligned with true north to make it work. Although later I bought a WiFi adapter that turned it into a goto scope, and this removed the need for the alignment to north.

[malc-c]

On 02/01/2021 at 16:15, Brutha said:

Hi All,

So, it seems that a pier is a good idea for my 8SE, so my planning is now continuing. The idea is to follow the basic plan from here: Sky at Night home made pier - see basic plan pics below.

The basic idea is filling a drainage pipe with concrete. I'd be grateful for any thoughts on the following questions:

• I'll try and get 200mm drainage pipe - I don't know if this is overkill though, would 160mm be ok if I can't get 200mm?
• I'll use the "two plate" approach I think, since it's simpler to make with just drilling some plates. Can I use e.g. 10mm aluminium plate for the two plates? (which I could potentially machine with the MPCNC machine I am currently building). Or should it be steel?
• Any other things to consider? I have seen people suggesting this approach might be prone to vibration?

Thanks!

Brutha

 

A standard 160mm drain pipe when filled with concrete and rebar would be substantial enough, especially as you are only having 900mm sticking out above ground.  If you have the opportunity to use 200m pipe, then given that this would be something you wouldn't really want to "upgrade" use it now - it would futureproof the mount too.  You are also spot on with the two plate arrangement - you can then level the top plate and it makes gaining access to any mounting bolts easy.  Use aluminium, as steel rusts !  - Oh and use good quality stainless steel nuts and bolts - no rusting

You may choose to use thicker ali, plus you can anodise it to give it some protection....

Edited January 4, 2021 by malc-c

[Brutha]

Thanks Malcolm, some good reassurance there! Also, the purple aluminium mount top is very snazzy!

[malc-c]

It was either that or a nice shade of green !  

It's been 10 years this spring since I put my mount in the ground, and other than the anodizing fading a little, and a few scuff marks on the black paint the mount hasn't changed much.

Can't believe it's coming up 10 years since I started the observatory !!

 

 

 

Note that when fitted the pipe was left full length and then cut to the correct height once the southern angles had been worked out, I would advise doing the same.  I must admit it will be fun for the next owner to remove