Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Pier design - to bend or not?


jadcx

Recommended Posts

Something very odd has happened recently, and there have been fleeting references about 'your observatory'.  I'm taking this as a tacit acknowledgment and agreement to building one! 😁

However, there are some practical issues to overcome, and this will likely be the first of many, many questions.  As I have been casually drafting out my design ideas (because obviously I haven't been planning this for a few years) I've been prioritising the problem solving order.  The biggest one also happens to be the first as it turns out, which is the pier.  The observatory floor will (has to) be ~5feet (1.5m) above ground level, so the pier base will be a reasonably sizeable construction.  The position of the pier will influence the layout of the rest of the space, and so this is where I would appreciate your thoughts.

The current plan is to install a Mesu e200, but is it worth/necessary installing a bent pier to allow for no meridian flip?  I think I will have to have such a pier custom made, which adds a little complexity.  Or should I 'just' install a standard straight pier and live wit the (probably quite minor) consequences of having the flip?

Thanks for your thoughts.

Edited by jadcx
Spelling
Link to comment
Share on other sites

25 minutes ago, Davey-T said:

Mind you don't get too high and need planning permission.

Dave

Yes - I'm still waiting for clarification on this.  The Observatory will be next to an existing garage, so from the access road perspective it is at ground level.  From the house perspective, because he plot is on a slope, it's raised and will exceed the 2.5m.  Like I said above - there are some practical issues to overcome :) 

Link to comment
Share on other sites

4 minutes ago, Peter Drew said:

Difficult to make a "bent" pier stable.    🙂

I assume so, but engineering is nowhere on my list of even vague abilities.  For now I'm working on the assumption that everything is possible, but it might not be worth the money/space for the added usability.  Do you have any views on this?

Link to comment
Share on other sites

1 minute ago, RayD said:

Have you checked that the Mesu will track far enough to do what you're after?  I've not tried with mine so I don't know, but not all mounts are capable of this.

I'm not sure I follow.  Do you mean far enough to 'require' the bent pier?

Link to comment
Share on other sites

5 minutes ago, RayD said:

No, track far enough so that a meridian flip isn't necessary.

My understanding is that yes it can.  My question about whether or not to install a bent pier is really just because I'm starting from scratch and so I can.  But just because I can, doesn't mean I should, or that it is worth it - which I'm hoping some more experienced people can help me with.

Link to comment
Share on other sites

Personally feel like bent piers are a flawed design that have come about as people have started with straight piers and modified them.

Why have a straight pier with a wedge on top, when you can have a wedge at the bottom with a straight pier on top and then not need to do merridian flips :)

You can see my plan for a pier in this thread. Material has been ordered, but might be held up by covid-19. Would hope to build it in the next 2 weeks. Might be madness but I'm happy to give it a go.

 

Link to comment
Share on other sites

18 minutes ago, SamAndrew said:

Personally feel like bent piers are a flawed design that have come about as people have started with straight piers and modified them.

Why have a straight pier with a wedge on top, when you can have a wedge at the bottom with a straight pier on top and then not need to do merridian flips :)

You can see my plan for a pier in this thread. Material has been ordered, but might be held up by covid-19. Would hope to build it in the next 2 weeks. Might be madness but I'm happy to give it a go.

 

I’ve been following :)  The design looks great, so looking forwards to seeing how it goes. How are you dealing with pier isolation?  My own thoughts were that with a bent pier I can easily maintain isolation from the obs floor as the footprint is relatively small.  With the mesu pier and also with yours, the footprint is obviously much larger.  But then I know that there are some strong advocates of not worrying about an isolated pier block and ‘just’ sit the whole think on big slab. This seems simple, although less so at 1.5m high.

  • Like 1
Link to comment
Share on other sites

1 hour ago, jadcx said:

I assume so, but engineering is nowhere on my list of even vague abilities.  For now I'm working on the assumption that everything is possible, but it might not be worth the money/space for the added usability.  Do you have any views on this?

I was put off bent piers after using a 16" SCT on its huge factory supplied one, a light tap and the image wobbled for what seemed ages.  I have two 16" SCT's of my own, one is the full factory LX200 system yet despite being mounted on a "Gigawedge" the largest made for this telescope it is nowhere near as stable as it is when used in the alt- az mode, the inclined fork tynes being more sensitive than when they are vertical.      🙂

Link to comment
Share on other sites

41 minutes ago, jadcx said:

I’ve been following :)  The design looks great, so looking forwards to seeing how it goes. How are you dealing with pier isolation?  My own thoughts were that with a bent pier I can easily maintain isolation from the obs floor as the footprint is relatively small.  With the mesu pier and also with yours, the footprint is obviously much larger.  But then I know that there are some strong advocates of not worrying about an isolated pier block and ‘just’ sit the whole think on big slab. This seems simple, although less so at 1.5m high.

I've got to rebuild my observatory to house it, so I'll lay a rectangluar foundation similar to the pier base, it's only 90cm x 25cm. You can just about make out the bolt holes I've added to the base plate - in theory the bulk of the foundation can be under the centre of mass, and I could raise the concrete above the floor so rear of the pier is actually floating above the floor. Having to raise it 1.5m above the ground makes it a bit more of a challenge! 

Link to comment
Share on other sites

1 hour ago, Skipper Billy said:

It seems a lot of effort to avoid a Meridian flip. I used to avoid flips if I could but now it is setup to do it without any intervention it's a non issue.

 

I agree. I used to be terrified of meridian flips, but now I have a permanent setup, software just deals with it. I have probably done no more than about 25 so far, but every one has been flawlessly executed by both  NINA and Voyager, the two control packages I have been playing with.
 

I have had plenty of other problems, but meridian flips in the middle of a capture sequence have not been one of them.

I would be interested to know the arguments for increasing rig cost and complexity to avoid flips when the cost to do it in software is so trivial.

Link to comment
Share on other sites

5 hours ago, Skipper Billy said:

It seems a lot of effort to avoid a Meridian flip. I used to avoid flips if I could but now it is setup to do it without any intervention it's a non issue.

3 hours ago, old_eyes said:

I agree. I used to be terrified of meridian flips, but now I have a permanent setup, software just deals with it. I have probably done no more than about 25 so far, but every one has been flawlessly executed by both  NINA and Voyager, the two control packages I have been playing with.
 

I have had plenty of other problems, but meridian flips in the middle of a capture sequence have not been one of them.

I would be interested to know the arguments for increasing rig cost and complexity to avoid flips when the cost to do it in software is so trivial.

Thanks guys, I think I agree with both of you - but the opportunity to start from scratch has made me consider everything, hence the question.

  • Like 1
Link to comment
Share on other sites

Arguably the main reason is sky gradients - it's easier to process them out if they are all from the same side of the image (or at least in my experience) especially if you change filter on opposite sides ? 

I also get uneven diffraction patterns on my scope at the moment (something to sort out) but if i flip and then change filter, the star halo colours don't line up perfectly.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.