I Have an idea ...

[Sir-Henry]

Shortly (God willing) I will have a large garage erected on my back garden - 3 metres X 8 metres. The back third or so will be a replacement for my current 8' square shed, but having recently rescued a shower door and a load of clean wood (I'm going back for more later today) from a skip I will be able to install an opening glass panel in the roof. With an extending post directly under it I think I could make myself an observatory of sorts. Any ideas for sources of such a seriously rigid  extending post? Either as a purchase or as a DIY project since I have the tools and skills if I can obtain the correct components.

When the funding becomes available I may (?may?) be tempted to upgrade from my current Tasco Luminova for fixed cosmological exploration and keep the Tasco as a grab-&-go.

Ps. I obtained permission from the owner of the skip's contents, so no laws have been even slightly infringed.

[Qualia]

Sounds great. I'm sorry I can't help with the enquiry but I'll give this a boot up and hopefully someone who has more experience will be able to give a pointer or two. However, just thinking out loud, if it were me and I had a garden before putting effort and expenses in an observatory, I'd use the garden as my observatory per se and start out by up grading on the Tasco telescope. Just a thought

[brantuk]

Have a look in the DIY section for Obsy Builds and Obsy Piers - I believe that's what you're looking for. You can purchase ready made piers or fashion them yourself using building materials and a pier adaptor plate for your scope. Either way they need to be cemented in place for rigidity.

[Sir-Henry]

Thanks to both of the above for the moral support and tips. Unfortunately there's only a tiny part of my garden that isn't illuminated by street lights which is all too close to the back gates where the scope is a visible and tempting target to ... certain classes of people. It also happens to be occluded by the shed, the house and a large tree making a very limited arc for viewing most celestial objects. Add to this the LP from Rotherham town center and several nearby suburbs and the lower latitudes of the sky are difficult to observe. At times this can extend all the way to the level of Polaris! Just a few feet of extra altitude could make all the difference for home observations and - as I said before - the Tasco could take a back burner for forays further afield.

A good solid extending column with a decent DOB on top and a better scope: Say 10-12". As an all-rounder it should be as much as I expect I would ever need or be able to afford.

[Lee M]

I'm guessing (no experience of an obsy) you need to think carefully about what you will and won't be able to swing the scope onto with your proposed design. You wouldn't want to get all carried away with the project and then find you can't see as much of the sky as you'd want.

[Lee M]

I see. Understood. Both typing at the same time.

[Sir-Henry]

I should point out that there's an old slag heap (? from WWII?) less than 100 metres from my back gate which limits horizontal observing due South to about 6⁰ from the horizontal for about a quarter mile, but the town centre is in that direction so it's 6 of one, half a dozen of the other. Due to its age there are also trees of significant height growing up its flanks and bushes on top adding another degree in places. Handy for walking the dogs, but of little use otherwise. With an obsy poking through the roof of the garage the scope would be mostly out of sight while simultaneously being in the shadow of the house. Installing it would be the simplest part other than assuring that it is truly perpendicular, but 'been there, done that'. If I can 'see' it in my mind I can design, construct, weld, concrete, etc, etc it. Big headed? Moi?? I just have a little problem with the old ticker which means that a day's work can take 7-10 days. Still; no pain, no gain.

Yah gotta laugh, aint't'cha?

[Sir-Henry]

Oh, and while I'm picking your brains: What is the consensus of opinion on zoom lenses? I'm pretty sure that the extra elements might absorb some of the light and that some colour aberrations could be incurred, but how bad will this be? and are there any other drawbacks to them? eg. fringing, edge drop off, slow cooling, etc.

Here's a thought: Can I safely cool the tube & mirror with a shot from a CO₂ fire extinguisher? Externally only, naturally.