Dob observatory

[Raybot (Ray) (Ray)]

Hi guys,

***Daft question alert***

We are thinking ahead to possibly building a house in the future, and I'm thinking about how/if I could build an observatory. I was considering a dome rather than the sky shed variety, however as a visual- only observer, would want to house a large go-to, tracking, Dob (eg. 16" GSO or Skywatcher).
I know you'd construct a pier to house an astrophotography setup, but what mounting considerations should be made for such a Dob ?

Just a concept at this stage, but would appreciate your thoughts

[glend (Glen)]

Not daff at all Ray. When I moved into my retirement property I considered the same thing, but for me a dedicated building was not justifible because I have a large detachd garage/shed at the back of the property and inside locked gates. I have a pad in my backyard for my 16" GSO and it is usually rolled out there to observe. However, I built a custom base out of marine ply which includes attachment points for th classc dob wheel barrow style handles, so moving it around is easy. I find that keeping the dob in my garage/shed is best for me and its a straight paved rollout to the pad. The be can be poured, or large format pavers (which I use). This way I don't have to worry about the cost of, or security of, a separate structure. My garage/shed is protected by good locks, and is separately alarmed as well - not that its required in my area. One great benefit of the big structure is plenty of room to fiddle around with collimation, mods, etc and storage for scope stuff. Good luck and be aware there are some new production big dobs being released later this year - 20" GSO and 18" Lightbridge.

[Raybot (Ray) (Ray)]

Thanks for the response Glen.
I guess I would be getting a goto & tracking dob, and never having used one, I was wondering if there is an advantage in fixing the base location.
I could at least do something like imprint the base feet on the wet concrete to ensure the dob is always identically oriented in case I need to move it, but don't know if this is actually going to help setup the scope at the start of each session.
Is there any point to this approach, or would I have to align the scope before each session anyway ?

Thanks

[barx1963 (Malcolm)]

Not really any point in fixing the base unless you were planning in installing it on a tracking platform that needs to be polar aligned. For normal visual use it is unnecessary IMHO.

Malcolm

[Raybot (Ray) (Ray)]

Thanks Malcolm, Sounds like I should just keep things simple

[barx1963 (Malcolm)]

That is not to say that a permanent home for a larger dob is a bad idea. It would save setup time, reduce risk in moving it and could reduce effect of wind. Another benefit would be storage of charts tables etc.
The biggest issue would be the size. A structure large enough for a decent sized dob would be large. For my 20" for example it would probably need to be say 6 metres on each side, maybe 2 or 3 metres high and I am fairly certain the SWMBO would not want that in the yard!
An alternate would be some sort of smaller roll off structure that proects the scope when not in use and simply rolls away when the scope is to used.

Malcolm

[astroron (Ron)]

Originally Posted by barx1963

That is not to say that a permanent home for a larger dob is a bad idea. It would save setup time, reduce risk in moving it and could reduce effect of wind. Another benefit would be storage of charts tables etc.
The biggest issue would be the size. A structure large enough for a decent sized dob would be large. For my 20" for example it would probably need to be say 6 metres on each side, maybe 2 or 3 metres high and I am fairly certain the SWMBO would not want that in the yard!
An alternate would be some sort of smaller roll off structure that proects the scope when not in use and simply rolls away when the scope is to used.

Malcolm

Malcolm I was going to go down that route for my 16" Dob but reallised I would need at least a 6mt structure and some sort of way to lower the walls, as you loos quite a lot of sky the smaller the observatory.
A 4mt enclosure with 1.5 meter high walls cost me 30° or more of the sky .
I have plans to do your last solution and build a Roll Off Box which will give me greater freedom to viewing the sky.
I first saw a 25" scope at Ilford belonging to Mike Kerr housed this way.
With the box rolled off he was able to put a table and chair in it and use it as a observing hutch.
Cheers

[astroron (Ron)]

Originally Posted by barx1963

That is not to say that a permanent home for a larger dob is a bad idea. It would save setup time, reduce risk in moving it and could reduce effect of wind. Another benefit would be storage of charts tables etc.
The biggest issue would be the size. A structure large enough for a decent sized dob would be large. For my 20" for example it would probably need to be say 6 metres on each side, maybe 2 or 3 metres high and I am fairly certain the SWMBO would not want that in the yard!
An alternate would be some sort of smaller roll off structure that proects the scope when not in use and simply rolls away when the scope is to used.

Malcolm

Malcolm I was going to go down that route for my 16" Dob but reallised I would need at least a 6mt structure and some sort of way to lower the walls, as you loose quite a lot of sky the smaller the observatory.
A 4mt enclosure with 1.5 meter high walls cost me 30° or more of the sky .
I have plans to do your last solution and build a Roll Off Box which will give me greater freedom to viewing the sky.
I first saw a 25" scope at Ilford belonging to Mike Kerr housed this way.
With the box rolled off he was able to put a table and chair in it and use it as a observing hutch.
Cheers

[Tinderboxsky (Steve)]

In your earlier post you mentioned "I guess I would be getting a goto & tracking dob, and never having used one, I was wondering if there is an advantage in fixing the base location".
If the goto you get has a park position and it remembers the setting from your last session when starting up then there are considerable savings in set up time for each session. In this situation, set up simply involves placing the Dob in exactly the same fixed position form the previous observing session, turning on and one is then ready to go to your first target for the night. Fixed ground marks make this easy.
I have an Ioptron Minitower Pro (that remembers its alignment setting when placed in the Park position before tuning off) that I attach to a fixed outside pier with a quick release dovetail clamp for. The dovetail allows me to easily attach the mount in exactly the same position each time on the pier. When the mount is turned on, it remembers the settings from the previous session and is instantly ready for use without the need for a fresh alignment routine. This makes set up very quick and easy.
Cheers

Steve.

[Raybot (Ray) (Ray)]

Thanks Malcolm, Ron, I hadn't considered the sheer size required and perhaps a roll-off roof would make more sense.
Steve, yes this is really what I was getting at, if a 'park' position is available in the tracking system then a consistent base location would be useful to reduce setup times.
Thanks all for your comments

[barx1963 (Malcolm)]

The logic of my earlier post regarding a permanent setup for a large dob being unnecessary is that doing an alignment with a dobs is a really simple process. I am not sure if the go to dobs have a home or park position anyway.

Malcolm