Evening all,

Now that the dome is on the way I guess I should figure ut what to put it on. HE HE. No seriously, I have an idea of what I want to do (a 10 by 10 building). What I am trying to figure out are the height of the walls? I am using a Celestron 8 inch newtonian on the AS-GT mount. The way it sits right now the mount is about 29 inches off the ground. I have a 7.5 foot metal pole and adapter to mount the EQ head onto, so I am trying to figure out how high the walls should be. I am figuring that 3 feet of the tube will be in the ground (encased in a 3 ft by 3 ft concrete pad). I have read and seen many observatory designs on here and a few other places. I guess my big question is where did everyone get their ideas? And is anyone else using a similar scope inside their dome?

Thanks in advance,
Rodney

Rodney:
Look thru the Construction forum if you haven't already.

I'm kind of partial to the one named LLPENGUINS....., but for ease of construction, and what I think is optimal use, I like this one....

http://www.astroskies.com/forum/viewtopic.php?t=74

Whichever you choose, be sure to name it and post in the construction forum. A picture of the work site is now appropriate....possibly with the footprint spray painted on the ground??

Steve

PS: ON THE OTHERHAND, ALL OF THEM ARE GREAT, AND YOU'LL DO JUST AS WELL, I'M SURE.

One suggestion is to roughly calculate your pier height with all your setup, since you know all the dimensions on the exploradome and its transition the only unknown is the wall height.....there you can deduce the height.

A few inches plus or minus dont matter since no one images the horizon....

Abe Lincoln would have said the walls should be just tall enough to reach the ceiling from the floor.

I have a simple and possibly stupid approach that I am following for my observatory construction. How tall are you? Add a couple inches. That's how tall the walls should be. You dont want to stoop or sit all night. Whacking you head is a bad way to end a clear night of observing.

If you really want to stoop, the other consideration is while you stand, point the 8"SCT at the horizon. That's the highest your eyepiece will be and it should just peek over the shutter (comets and Mercury). I think the shutter is about one foot above the wall height in explora-dome plans. I may be wrong on that distance, but it's documented here somewhere.

That would be too tall.

I'm 6 foot tall. To build my observatory with 6 foot walls, would mean that my pier would need to be about 5 foot tall so the scope would see the horizon through the dome slot. This would mean the need for a ladder in the observatory. Not gonna happen.

Set up your scope on the tripod at a height comfortable to you. Complete with wedge for fork-mounts if you plan on using one...

From there, put the scope horizontal and measure the distance from the bottom of the OTA to the floor...

The next step would need some input from someone who has a dome setup already.. Whats the distance from the top of the wall (bottom of the roof transition) to the bottom of the slot opening?

Subtract that number from the hight of your scope, and this leaves you with how tall the walls would be at the current scope height setup. If you want taller, add to the wall height the same height you add to your tripod height.

With all due respect this bad advice....please follow NEO's advice

Just wanted to make sure of a point. I am not installing an SCT at this time. I am installing the Celestron 8" Newt. Their part # is C8-NGT, confusing isn't it. I always thought a C8 was an SCT.

If I use the calculations given, my walls are going to be SHORT. When my OTA is horizontal it is 30+/- inches from the ground. Meaning a 2.5 foot wall. Yikes.

When the dome arrives, I will place the scope in the dome on the ground and take some measurements.

Does anyone on the forum have a 8 or 10 inch EQ mounted newtonian in their ED?

I am getting jittery waiting now. And it's only been three days since ordering it.

Rodney

C8-NGT
13.1 Truss
15x70 Skycommanders
8 Coulter
4.25 Edmund

Rodney, THREE DAYS :? :!: :!:

Think how those of us that waited 300 days felt :shock:

No seriously, it is well worth the wait. You will be very happy with this dome.

The figure you come up with will be about 16-17 inches MORE then you want the height of the walls to be...

You have to remember that you have a few things sitting on top of the walls BUT below the dome itself...

1. You will have the roof transition pieces sitting on top of the walls..

2. THEN you have the ring section on which the dome sits sitting on top of these transition pieces..

3. And THEN you have the wheels between the dome itself and the top of the ring section..

Roof transition framework should be about 9 inches tall,
Ring section will sit on the above and raise you up another 6 inches
Then you will install a set of wheels on top of the ring...which will raise you up another inch or two..

I use a SCT...and I LIKE TO SIT DOWN and use my scope.. so the OTA
when on the tripod the height was about 49 inches... so in theory my walls would be 49 less 15 to 16 inches or 34 to 35 inches tall...

I actually made them 36 inches tall...so I can not point the scope
down to the horizon...but darn close...

My only mistake was that I never measured just how tall my Star Dust Chair was....It is 36 1/4 or 36 and 1/2 inches tall...just a hair to tall to
fit under the roof transisition pieces so I could store it up against the wall
without having to tilt it back a little then slide it under...

Hope this helps you a little ...

Bob G.

S.I. E. Observatory

Frederick Md.

Can you view the horizon from your location? My view is blocked to at least 15 deg in moast directions and 20 deg for the rest. I used 4' for my wall height and it works great except when viewing zenith. Then im on my knees. A short chair is in the works but for now a 5 gal bucket works fine.
At anything in between i rotate the diagonal on my sct for standing comfort. The adjustable pier is worth the price! Just hind sight as usual.
Still, Its GREAT to be domed. Geeo

If in doubt, go with higher walls and if they're too high you can raise the floor. Once the dome is on its a bitch lowering the walls. There's actually someone on the group who has an adjustable floor!

My own approach was to determine maximum and minimum comfortable eyepiece height for viewing, and using that to determine the height of the pier above the floor. I'm in a built up area and don't have a zero horizon. My minimim horizon is about 15° so the observatory was designed for my 14" to have a clear view to as low as 15°.

The ceiling height when not under the dome is 50-inches. But I went to extreems to achieve a ceiling height that guests could sit under. I've got a flat plywood roof, a homemade low profile dome mounting ring, and low profile roller wheels. Everything was layed out using AutoCad before doing the construction. See www.peterson-web.com/wish

Pete

Mooseskins has a good point, though, about comets & Mercury. You DO want to be able to get close to the horizon. I had been thinking that it wouldn't be worth seeing much down there, that whatever is low will either rise higher in an hour or so or could be seen earlier in the evening. I see that I have to think about comets and Mercury & Venus and make sure I can see low down. Then (come to think of it) there's Omega Centauri, which is very, very low in the South...

I have a 10" Newt on a GEM, so I'll be up in the air all the time, crowding the dome too! It'll be interesting to see how it all works...
Rich

So that would lead me to have 3 to 3.5 foot walls. Which leads me to the next question. How much room is left over with walls that short? And also, I am 6 foot 3 inches tall. That would be rather uncomfortable to get in and out of.

This is why I asked if anyone had a newtonian mounted inside an ED.

Hmmm, time to rethink my design.

Rodney

Rodney:
I have a SCT mounted .... so I can not comment on the space taken up etc by a Newt.

But like I said I do have 3 foot tall walls... and I am 6'1 !

I do not have a door to crawl thru...My obs is elevated so I climb a ladder and enter from under it thru a trap door... Works for me... lol

When standing up under the dome I can NOT reach the top of the dome...actually have a short dogs leash that I have to reach up for to close the shutter.... I sit my Laptop on a square 2'x2' end table that I have in one of the corners.. and use an adjustable Mechanics stool for a seat...the stool slides under the table when I am not using it...

I have no problems with 3 foot tall walls... NONE...

BTW: where in Maryland? I live between Frederick and Charlestown WV
it may be worth a trip up here to see what kind of room you would have inside... I do know if I had to get down on my hands and knees and crawl thru a 3 foot tall door I would never be able to get back up...

Bob G.
S.I.E. Observatory.

Rod:
There are a couplke observatories here that have short walls, leading to a crawl-door for an entry. I'll bet it is "interesting" getting in...
One of us even has 1' high walls and uses the shutter's slit for an entry!

Do you have Adobe PhotoShop? You could take a digital photo of you standing next to your scope, with a yardstick next to you, then take a photo of the dome with the yardstick next to it. Overlay the photos and adjust one till the yardsticks are the same size. Then you could get an idea of the size relationship.
Rich

Rich,
Now 1 foot walls I would like to see that. I was hoping someone had a newtonian mounted within an ED with 3 foot walls. 3 foot gets me right about 10 degrees above the horizon. That does not include the extra hardware (IE: dome ring, panels and dome itself.

Maybe I should simply wait til it gets here and set up the scope inside the dome on the ground. That would no doubt give me a better idea.

Thanks, Rodney

Rod:
Here in "Observatory Construction" look for these 2 threads:
---------------------------
Table Rock Observatory
by Bruce "fellrider"
---------------------------
My Humble Observatory
by Futzman
---------------------------
Bruce did what you're thinking of doing, putting the dome on mud buckets as a test to see how high to make his walls. Page 1 of this thread shows him doing this. You won't have to scroll very far down to see it.

Futzman's thread has a photo on page 3 of the dome on the short walls. It works for him, but won't work for many. He needed to keep the whole thing short in order to keep nosy neighbors from raising a stink.
Rich

I guess the real questions are what type of scope do you use and are you ever going to get something different?

I bought the adjustable height pier because of those reasons. I have 5" refractors and a 10" reflector. (I take a pic of the reflector EQ mounted)

My finished wall height is 54", after adding the roof frame, and ring with rollers, my floor to ceiling height is 119" .

Works for me and the useable horizons from my location with both types of scopes

Ken 8)

Evening gang,
OK, after talking on a few forums I think I should rephrase my question. With 3 to 4 foot walls for an observatory, how much room does that offer one for moving around inside the ob? Regardless of the scope and mount.
Also won't it be tough to get in and out of the building with such short walls?

Input from those with short walls would be awesome.

Thanks, Rodney

You cant separate your scope dimensions from the available room....

Keep in mind your available room is in function of your scope dimensions...
In any rate ....You wont find a turnkey solution here dude, you have to do the math already suggested in this same thread...

Please go back to Neo's answer, study it and you will find the logic behind it....There lies your custom made answer for your particular needs.

If you want a wild guess answer just go for 4ft walls...You will like it
Specially if you have a 10X10 building, It is just HUGE

Rodney:
Bottom line is that the finished product must meet your needs. The higher you make your walls, the more likelyhood you'll have to use a step stool to reach the eyepiece. The shorter wall height, the more difficult it will be to get in and out and the less storage space you will have. You will be able to reach the eyepiece without a step stool.

Draw a 7'6" circle on the floor and put your scope in the middle of it. This will tell you about how much room you'll have around the scope, IF you're standing up and trying to walk around it. You WILL have to refigure your walk around to not bump the scope. There is actually plenty of room in most cases, it's just hard to get used to the idea of having a "wall" around you while observing.

For the wall height....My advise....build the 4 foot wall. Finish the transition frame and tack it on top of the wall in a temporary fashion. Put the dome on top, and check it out. If the 4 foot is too tall, cut some off and add some if it is too short.

Pour your pier last, after you decide how tall you want your walls. Dig the hole for the footer, form it for concrete and leave an access hole in the floor of the observatory.

Steve

I really appreciate everyones valued input toward my inquiry.

Clear skies and have a good one,
Rodney

You have to also remember that the 7 foot 6 inch diameter is SHOULDER ROOM ... you have another 14-15 inches of FOOT room under the dome..
but away from the walls of the building ...

This foot room also allows for you to build shelving, and storage space out of the way and not be under foot so to speak...

The dome itself is 8 foot in diameter but it has to sit on something, (the ring)
and the rings diameter is 7'6 inches...

Do as Steve suggested...I think we all did !

I drew my 7'6 inch circle on the floor of my garage with the circle touching the garage door...I then opened the garage door 4 foot and placed a 2x4 14 inches outside the open door where my buildings wall would be.. I then pointed the scope directly at the garage door then danced around it...

Not going to lie about it I did not have a lot of room between the open door and the front of the scope with a dew shield on but it was not a tight fit...

As for the door....LOL I built my OBS off the ground so I could walk under it and enter thru a trap door via a 7 foot ladder...

So far I have plenty of unused room inside.. after adding sheling, storing two other OTA's a chair, a roll about eyepiece case, a laptop and a small desk, a Microwave to reheat my coffee, a clock radio, and a couple of folded up tripods that came with the two spare OTA's, and a coiat rack to hold my warm winter observing jacket and sweat shirt and stocking cap...

Bob G.

Rodney,
Bring your scope down to the Bad Moon Observatory, we'll mount it on my Atlas, and you will be able to see what would be a comfortable height.

Ken 8)