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An "A" frame observatory?

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#1 Ettu

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Posted 23 January 2013 - 03:26 PM

Whew..!
I've just been through the entire "post a pic of your observatory" thread, and there's not a single "A" frame version there? Except for one almost sort of one. I built one, and am thinking of some changes, so was looking for what others have done. Is anyone aware of any? I'd be interested.

Fwiw I am very happy with mine. It was simple, inexpensive, and gets the job done. My primary interest is astrophotography, so a primary consideration was wind. You just can't have even a light breeze messing with your tracking. That meant well over half the clear nights were a waste of photographic effort, and so therefore would be a roll off roof obstry. A dome was, and still is simply beyond my budget, and it really does limit one's view of the sky... one of the reasons I like getting out there. So, an "A" frame structure seemed to be a possability.

I am amazed how well it works. It does the job.

This past year, I've been laying of the astrophotography and doing observational programs. That's not what this kind of stricture was intended for, so I had some concern that my "horizon" to all but the S was 35-40 deg up. It is, but quite frankly, if the objects go above that, to get the most out of them, that's where you want to observe them anyway. And it's really nice to be out of the wind when it's freezing out and breezy, and the scope is really steady too.

If anyone's interested I'd be happy to talk more about it, but what I really came here for is to see if anyone has also built and used such an observatory. Specifically, say, a 9' square version. I'm thinking of getting a Dob, and a little more space would be nice.

I'll post a link below to my web site where there's a link to some pics. They are of my original trial structure. It's been improved since, but the concept is entirely intact.

Thanks,
Keith
http://www.willowber...et/keithnk_m42/

#2 csa/montana

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Posted 23 January 2013 - 06:57 PM

Welcome to Cloudy Nights; especially our little corner here, in Observatories!

You definitely have earned a gold star for managing to get thru the entire "Post a pic of your observatory"!! :grin: That's a lot of reading, but extremely worthwhile to see what others have done.

Wow! You indeed have a very unique observatory, and really interesting, on how it opens up! What size dob are you considering? I'm thinking you will lose a lot of viewing area with a dob; but perhaps not. We'll be interested in hearing & seeing more of your observatory here!

#3 mich_al

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Posted 23 January 2013 - 11:16 PM

An interesting idea, it has a lot going for it. Some real 'out of the box' thinking there. I may steal some of your ideas. It may help me to solve a problem that has kept me from building an observatory where my pier is now. That is how to minimize blocking the view.

#4 Ettu

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Posted 23 January 2013 - 11:28 PM

Thank you Carol for the warm welcome! I'd love to take credit for reading all those posts, but alas, just my scrolling finger got a workout. Had I spotted any "A" frame pictures though...

Actually there were a couple very interesting, unique, and beautiful examples that I couldn't just on scroll on by, and so stopped to read more about. Btw, has anyone else noticed that if you scroll through the one showing the spiral staircase, that it looks just like it moves and twists? It was fun rolling that one up & dwn a few times ;-). Really, though you can see why everyone there is justifiably proud to show off their set up.

I do have a question about domes concerning wind. Do they keep the wind out if open toward it? My "A" frame is not good if the wind is from between SE to SW. Fortunately the prevailing winds are not from that direction. On the other hand it can be rattling the walls from the W all the way around to the E and I'll be fine "inside". I don't know why it works so well even though it's so open (relatively).

Keith

#5 Ettu

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Posted 23 January 2013 - 11:56 PM

Carol, I've got a 16" f4 dob, and I'd like to set it up permanently instead of having to drag it out each time. Snow drifts are a pain in the back. That's what's making me consider rebuilding to be dual purpose. Astrophotography is going to always be my love, but my observational experieces this past year tell me I want to do more of this too. So far, my only thought is that the easiest fix or accomadation of my "A" frame that would help quite a bit, would be to hinge the shorter S wall so it can go all the way down. One problem with going bigger, is that for every foot I move the walls out, the sides go up two feet - at least when set up or squared up against the winds.

#6 csa/montana

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Posted 24 January 2013 - 12:33 AM

I have a 16" F4.5 dob. My dobservatory has 3' high walls, which gives me great views. That's why I was wondering how much sky you will have available in your setup with a dob.

#7 Ettu

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Posted 24 January 2013 - 12:36 AM

Steal away Al ;-).
When I let a wall go out beyond the bolted upright config, I can see all the way down to 12-16 deg of the horizon E & W. South is clear to the horizon. My pier is off center South, which drops the N horizon to around 35 deg. Also gives me more room on the N side of the scope for my table and chair.

There are two other significant changes from that 1st nail it up setting on the ground trial effort. The first was to raise it up off the ground about 16". Something amazing happened when I did that. Before, the snow piled up against it, & I'd have to shovel out around the hinged walls to open it easily. With it up just that little bit, a drift builds up on the windward side 3-4 mtr's away and the wind whistles it Completely snow free beside, under, and around the entire observatory. And I do mean Completely! What a delightful bit of serendipity that was! The second thing I changed was the way the top comes together. At first I just brought the tops evenly together. That left a small seam at the top. Not much but I had to always cover the scope and working table. Unfortunately the mice loved the home I provided under the covers. My newer version has one side overlapping the other. I figured I'd still have to cover everything, and I probably should, but I just haven't had to now in 2 summers and a winter and a half. It does lower the headroom a bit though, and offsets the centerline a couple inches to one side. I have to take my spotting scope off the OTA before closing up. Either that or I'd have to redo the pier an inch or so lower or move it equivalently off center.

Keith

#8 Ettu

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Posted 24 January 2013 - 01:10 AM

Carol,
With the walls open to the vertical, it's not going to be very good for a dobby. I have not gotten out the protractor and done the figuring yet, but just by rough eye guesstimate, with the sides open beyond virtical and the short S wall down, my sky access will nearly triple. That will be acceptable for me. The SCT I use for photography sits up much higher, so that has a plenty good enough view for me. Fortunately the concrete portion of my pier ends less than a foot above my floor, so with the pier post off it should be a good base for the dob. I know I'll need a foot stool when observing around the zenith. But I won't have any wind!

Keith

Keith

#9 gravitino

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Posted 24 January 2013 - 03:31 AM

Hi Keith,

I don't have an A-frame, but I have a clamshell that flips open in a fashion similar to the sides of the observatory on your site. The walls can flip far down from vertical with the counterweights, so I never have to have a lot of leverage to move them. I could imagine making it taller, like yours, to give me more headroom... :-) You can see a lot more about my observatory here: http://www.scienceje...obby/starGully/

Posted Image

Clear skies!
-- Shane

#10 Starhawk

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Posted 24 January 2013 - 07:59 AM

I didn't see any pictures of the observatory on your site, but I can identify your UFO. Notice the lines leading to it- it's an airplane. At one point in its flight it lined up with another light source and for an instant the wings showed up.

-Rich

#11 Ettu

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Posted 24 January 2013 - 09:39 AM

Hi Shane,
Thanks for bringing your picture forward. Yours (sadly, from my point of view) was the only close to an "A" frame style I found. I'm sure there are others more like mine out there, but it's probably a matter of the right person happening to look in this forum while I'm inquiring.

I don't have as good a view as your design provides. It's a compromise I have to work around, but in practice I haven't found it to be too limiting. That's probably because I've been working on a number of the Astronomy League programs where I have specific targets I'm after, and so can plan on looking at them when they're around their best, or highest.

One kind of interesting discovery I've had, is that my walls, although not particularly high, and the sky not nearly as "covered" as a dome, provide a noticable reduction in dew issues. I'd say maybe around 1/3 improvement over an open field... based on where I have to set my dew htrs, and how soon frost or dew settle on the OTA, or give me trouble at the EP's. I don't know if that's entirely due to a reduced sky and therefor reduced radiation away, or partly too because an observatory provides something over an open field?

#12 Ettu

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Posted 24 January 2013 - 09:58 AM

High Rich
Puzzling, that the "A" frame thumbnail didn't show up in your browser? I presume none of the main page showed up, with the dark "star" background and the "Greetings..." heading? Strange.... I need to get some more up to date pictures of my current observatory anyway and figure out how to post them in a post here.

Lol! The UFO... Thanks. Yup, it's a jet airplane. That was a long time ago I got that pic! Took me about a week to figure it out for sure what it was. The strobe light those planes carry is located on the underside of the body. It just happened to flash while the plane was in the picture frame, so it lit up a bit of the underside of the main wings. The red and green navigation lights on the wing tips are on all the time, so they tracked all the way across.

Keith

#13 csa/montana

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Posted 24 January 2013 - 10:04 AM

Puzzling, that the "A" frame thumbnail didn't show up in your browser?



No problem here, I just clicked on the thumbnail photo of your observatory, & the photos were there.

#14 gravitino

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Posted 24 January 2013 - 02:19 PM

Thanks for bringing your picture forward. Yours (sadly, from my point of view) was the only close to an "A" frame style I found. I'm sure there are others more like mine out there, but it's probably a matter of the right person happening to look in this forum while I'm inquiring.


I can't take complete credit for this; I had built the flip-top roof initially without the counterweights, but found I couldn't let the roof down to low angles then have enough strength to lift it again! I found the counterweight solution right here on Cloudy Nights! Peter Talmadge from the Astronomical Society of New England clued me in. Here is his thread. He also had a series of three articles in his club's newsletter in Oct-Dec 2008 (ASNNE Newsletters).

Clear skies,
-- Shane

#15 StarWrangler

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Posted 24 January 2013 - 07:10 PM

Hey keith,

Really out of the box thinkng. Very unique observatory indeed.


Alan O.

#16 Starhawk

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Posted 25 January 2013 - 09:32 AM

Ah- I found it. That's a very interesting design. How is the top seal done?

-Rich

#17 StarWrangler

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Posted 25 January 2013 - 10:02 AM

Hey Shane,

That is one of the nicest and cleanest Flip Top /Clamshell Observatories I have seen.

Enjoy,


Alan O..

#18 Ettu

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Posted 25 January 2013 - 11:33 PM

Hi Rich
I don't know if I can describe clearly how the top is closed against the rain & snow. This is a case where a picture would be worth a thousand words. Let me try.

The top end's side of the East wall rests on the West wall's top end. West wall's angle cut to mate. A piece of weatherstripping could be put at this overlapping junction. I didn't put one there yet, and so far it hasn't been needed. Perhaps because I extended the steel siding of the west wall so it extends over and covers the top end of the east wall, and a few inches beyond. That steel siding overlap protects the joint from rain etc from overhead to anything coming from a westerly direction, where 90% of our wind driven precipitation comes from.

Glab you asked, because that improvement from my original throw-it-up version, which my pictures are of, was one of the 2 most important improvements I did.

I was looking at the the top roof edges in Shane's picture, but I can't tell if he did his joint the same, or if it just butts together like mine originally did. Although that kept most of the precip out, I had to cover my equip against what did get through. Now I haven't had to.

#19 Ettu

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Posted 28 January 2013 - 01:02 PM

Maybe this comes under the heading of ... Duh, of course.

My original question at the start of this thread was if anyone else had built an "A" frame observatory like mine, and, if they'd built a bigger one, 9' or 10' square for instance? What's driving this is that I'm considering putting a Lightbridge 16" in my 8' version, which is not a good fit. The bad part of a 10' version of the same thing is for every foot of floor space gained, the walls go up two feet. Further reducing my sky access. Well, duh... hinge the top 3' so the walls not only are further away, but lower than they are now! My only concern yet, is if a 10' version will keep out the wind for astrophotography as effectively as my current eight footer does.

#20 Mike E.

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Posted 30 January 2013 - 04:04 PM

Here is a list of a multitude of Observatories to get ideas from.

http://obs.nineplane...bs/obslist.html

Also, have a look here at the plans and photos of this great design for an A-frame Home/Observatory.....

http://www.desdelpatio.org

#21 Mary B

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Posted 30 January 2013 - 05:30 PM

Sort of an A frame roof

Posted Image

Could adapt that to an A frame. I used satellite dish linear actuators for power opening.

#22 solarGain

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Posted 31 January 2013 - 05:30 AM

Weeks ago I came across an A-frame Observatory that may be what you had in mind. I have managed to find the copyrighted image only from the
book "Building a Roll-off Roof Observatory: A Complete Guide for Design and ..."
By John Hicks
ISBN-13: 978-0387766034

To search for the image key into google ( I use Safari) - Figure 1.32 Building a roll-off roof observatory- this will bring up the 2 images from the book. There maybe more information , I have no idea.

For a dob would be a problem but there is no reason not to fold/ hinge along the middle of each halve of the 2 frames to drop the height by the same. Best of both worlds then. Weathering will demand care along the hinged lengths!

I was researching for coelostats and a A-frame came up but this fully slid
away from the optics.
So if you could slide the A-frame structure completely by rotation so as to operate the scopes thru' the wide opening or such this would be a best solution. John

#23 Ettu

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Posted 01 February 2013 - 09:51 AM

Thanks Mike, Mary, John

I guess my type of "A" frame is somewhat unique...
Using linear actuators from old satellite dishes is a great idea! If I build walls higher and bigger, I'm probably going to need some mechanical assistance. I hadn't even thought much about that aspect! Eight foot walls are okay to handle, but 10 footers would be more than 50% larger. Based on my 8 footer experience, I can tell you that a breese would be a problem, and dangerous.

The idea of rolling away the "A" frame walls is an intruiging one. Because all the weight of the wall is on the hinges, that then would have to roll, it would be a tough mechanical, structrural issue. I'll probably stick with the hinged sides. Weather is not so much an issue if they hinge inward. That allows the steel siding to overlap. My choice of the hinge at 3' down is strategic. That makes the folded portion easier to handle, at a handlable height, and it's short enough that it won't hit anything inside.

Unfortunately I don't have face book accnt, so I couldn't see John Hicks plans :-( I'll have to see if I can see them some other way.

Thank you to all.
I am pretty much settling on building a 10' version. It'll incorporate everything I've learned (and am learning) so far. Unfortunately it may not be this summer. (I do have an observatory ...) My wife will be VERY unhappy if I build a new one before finishing the house and needed repairs on some outbuildings first.

Keith
http://www.willowber...thnk_m42/45N90W






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