Jump to content


Photo

Aluminum Observing Chair

  • Please log in to reply
17 replies to this topic

#1 tecmage

tecmage

    Mercury-Atlas

  • *****
  • Moderators
  • Posts: 2529
  • Joined: 13 Jan 2010
  • Loc: Glenview, IL

Posted 18 May 2010 - 08:50 PM

I'm very new to astronomy, and started observing regularly a few months ago. One of the first things to hit me was when I observed M42. It was low enough that I needed to stoop down or bend over to view it.

After a few minutes, I realized that a chair was in my future. I broke out an aluminum step ladder, and found that to be okay, but not great. I looked for chairs and found that spending $150 to $300 was a little more than I wanted to spend. So I went looking for plans to build my own.

The Denver Chair is the design I kept running across. I found the original plans and a few variants that I liked. I have access to design tools, fabrication resources and people who know what they're doing. After talking with a couple of coworkers and showing them plans, the suggestion was to try an aluminum chair of my own design.

Well, the design is just about done. I'm hoping to get the design and welding done in the next couple of weeks.

#2 The bear

The bear

    Apollo

  • *****
  • Posts: 1116
  • Joined: 11 Feb 2008
  • Loc: rushville, indiana

Posted 18 May 2010 - 09:31 PM

i would be ver interested in this as i need to build one soon.
doc

#3 WaterMaster

WaterMaster

    Moat Keeper

  • *****
  • Administrators
  • Posts: 9648
  • Joined: 17 Feb 2010
  • Loc: Southeast Idaho, USA

Posted 18 May 2010 - 10:31 PM

Pics! We want pics! :shakecane:

I would love to see an aluminum design.

#4 tecmage

tecmage

    Mercury-Atlas

  • *****
  • Moderators
  • Posts: 2529
  • Joined: 13 Jan 2010
  • Loc: Glenview, IL

Posted 18 May 2010 - 10:41 PM

You and me both! :jump: I'll post when the solidworks design is done, and as we build it.

#5 bilgebay

bilgebay

    Skylab

  • *****
  • Moderators
  • Posts: 4283
  • Joined: 06 Nov 2008
  • Loc: Turkiye - Istanbul and Marmaris

Posted 09 January 2013 - 03:36 PM

What happened to this project ?

#6 David L

David L

    Ranger 4

  • -----
  • Posts: 376
  • Joined: 12 Nov 2007
  • Loc: Lee County Iowa

Posted 10 January 2013 - 12:07 AM

This is my aluminum chair design. Dave

Attached Files



#7 bilgebay

bilgebay

    Skylab

  • *****
  • Moderators
  • Posts: 4283
  • Joined: 06 Nov 2008
  • Loc: Turkiye - Istanbul and Marmaris

Posted 10 January 2013 - 12:50 AM

Looks great Dave. How are you adjusting the seat height?

#8 starman345

starman345

    Wait, I'm Thinking

  • *****
  • Posts: 9250
  • Joined: 06 Jul 2010
  • Loc: New Brunswick, Canada

Posted 10 January 2013 - 08:53 AM

Nice, love the colors. Do you have a picture of the back so we can see how it adjusts. Are the round discs on the bottom and top made of wood?

#9 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44725
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 10 January 2013 - 08:59 AM

On suggestion about chair design:

Keep the legs close together in front so they do not interfere with the mount, spread them out in the rear to provide stability.

Jon

#10 Pinbout

Pinbout

    Cosmos

  • *****
  • Posts: 8241
  • Joined: 22 Feb 2010
  • Loc: nj

Posted 10 January 2013 - 10:08 AM

This is my aluminum chair design. Dave



very nice design. :waytogo:

#11 David L

David L

    Ranger 4

  • -----
  • Posts: 376
  • Joined: 12 Nov 2007
  • Loc: Lee County Iowa

Posted 11 January 2013 - 09:32 AM

To adjust the seat height, lift up on the seat and slide it up or down. For friction material I used 1 inch washing machine drain hose. This was slid onto 1 inch aluminum stock. The seat itself is attached to a piece of slotted aluminum. 1 1/2 inch X 1/4 aluminum strips hold the seat together.
The round disks are just cutouts from scrap solid countertop such as Corian.
The bottom aluminum strip keeps the seat from spreading out.
The seat folds up rather nicely. Will have to take some more pix to show this. Dave

#12 David L

David L

    Ranger 4

  • -----
  • Posts: 376
  • Joined: 12 Nov 2007
  • Loc: Lee County Iowa

Posted 11 January 2013 - 09:47 AM

Some more pix.

Attached Files



#13 David L

David L

    Ranger 4

  • -----
  • Posts: 376
  • Joined: 12 Nov 2007
  • Loc: Lee County Iowa

Posted 11 January 2013 - 09:56 AM

pic

Attached Files



#14 David L

David L

    Ranger 4

  • -----
  • Posts: 376
  • Joined: 12 Nov 2007
  • Loc: Lee County Iowa

Posted 11 January 2013 - 09:59 AM

another pic

Attached Files



#15 rboe

rboe

    ISS

  • *****
  • Posts: 67129
  • Joined: 16 Mar 2002
  • Loc: Phx, AZ

Posted 11 January 2013 - 11:23 AM

On suggestion about chair design:

Keep the legs close together in front so they do not interfere with the mount, spread them out in the rear to provide stability.

Jon


You know, this made so much sense that that is exactly what I did with my first chair. It had a couple problems (e.g. when the seat was low it stuck out too far and tipped forward, center of mass was ahead of the foot).

So on the second chair, using what I learned from the first, I made sure at the lowest setting the center of mass was still between the feet and I put the wide feet in front because the weight was biased towards the front feet it was more stable that way.

Worked just fine and does not seem to interfere with the mount but ask desterstars, it's his chair now.

The next two chairs use an X or cross pattern for the foot with no folding bits to pinch fingers so the problem is moot with that chair design.

Using a washing machine hose is brilliant. :bow: I love it! :bow:

Being metal I suspect it's much colder to the touch and quite strong and much lighter. I prefer wood but darn it, it can get heavy. :p Nicely done sir.

#16 David L

David L

    Ranger 4

  • -----
  • Posts: 376
  • Joined: 12 Nov 2007
  • Loc: Lee County Iowa

Posted 11 January 2013 - 12:02 PM

My design uses your feet to stabilize the chair, since the chair is not so high that your feet aren't on the ground anyway. Also the seat is not real wide. I have never had this chair slip even when I wet the tubes, probably because the two main tubes are not as vertical as those on the Starbound chair. You can also straddle this chair. The tubes are spaced out so pinching is not a problem. Pinching is an important consideration. Dave

#17 rboe

rboe

    ISS

  • *****
  • Posts: 67129
  • Joined: 16 Mar 2002
  • Loc: Phx, AZ

Posted 11 January 2013 - 12:20 PM

Your chair, as it is built now, would not be the best choice for Arizona desert sites but appears ideal for your location. The other nit-pik (as you can see I really have to reach here :) ) I'd look at using the tractor seat used on some canoes as a seat or yank the seat from your school plastic stacking chairs (you know the kind, two or three slots in the back, red or blue with tapered chrome steel legs and one piece plastic seat and back). Just for more comfort on the back side.

So, you've used it a good two years now, anything YOU would do differently if you had it to do over again? Or you just wanted to build another chair.

#18 David L

David L

    Ranger 4

  • -----
  • Posts: 376
  • Joined: 12 Nov 2007
  • Loc: Lee County Iowa

Posted 11 January 2013 - 01:37 PM

I used a scrap piece of oak I had for the seat, but no reason why one couldn't make a nice and soft seat. I am not sure what I would do differently with this design, but would probably go for more height. The chair's height was determined by the length of the piece of aluminum I had. If the chair was tall enough that I could not put my feet on the ground, though, the base would have to be wider than it is now. My current design used 10-inch bolts, which I had on hand. I don't know about desert use, but it has been to okie-tex 3 times now. One thing I do like about this chair is that I can get the seat really low and rest my head on the top and look straight up. Nice when using low power binocs. Dave






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics