Gina's Mini Widefield Imaging Observatory

[Gina]

Following on from my "where to put a second pier" thread here the topic has moved on so time for a new thread 

Having decided where to put the pier and what to use for the pier, the next stage is to provide a cover for the pier, the mount and the widefield imaging rig.  The design started off with a hinged roof box but has moved on to a mini observatory with a roll off roof for unattended or remote controlled imaging - via plastic storage boxes of various sorts.

The location is close to the southern boundary fence around 5-6 metres from my main observatory as shown in the attached photos.  View to the north and north-west is very restricted by the bungalow and trees behind on rising ground.  The view extends almost to the horizon from NE all the way round to the west

And this gives an idea of how the triple imaging rig will fit on the NEQ6 and SW pillar mount.

[Davey-T]

Another project to keep you busy, what do you do in the morning, toss a coin to see which one to work on today ? 

Dave

[Gina]

I already have idea for supporting the roll off roof - either 1" of 1.25" aluminium tubes.  I have 5m lengths of these I was going to use for other projects but no longer bookmarked for anything.  The pier etc. will be contained in a box structure to keep out the weather and provide a pretty dry environment probably helped by a mains dehumidifier as the atmosphere here, up in the hills, can get very humid in winter. 

The roll off roof will probably roll off towards the WNW where the view is more limited in elevation.  Unlike my main obsy, I think this roof will roll right off clear of the main box by a foot or more to enable a good view westwards and be well out of the way.  There will not be a warm room, of course as this will be provided by the house.  The mini obsy will be just big enough to contain the kit with a door in the north wall to provide access.

[Gina]

Another project to keep you busy, what do you do in the morning, toss a coin to see which one to work on today ? 

Dave

I think I suffer from a grasshopper mind and can get tired of one thing and work on another   This project has been on the books for some time now

Today I am having a little rest from construction work and concentrating on thinking, planning and posting

[Gina]

I've been looking through my supply of timber etc.  I have quite a lot left over from making my main obsy so no problem with supplies for the framework.  70mm x 47mm for the corners and lots of other stuff.  I may make the roof panels from exterior grade plywood covered with rubber roofing.  Unfortunately, I have only short offcuts of shiplap cladding - I made a good job of estimating that for the obsy   But I do have plain sawn boards about 100mm x 10mm which I could overlap, herringbone fashion, to use as cladding but only one of 5m long and another 100mm x 15mm x 5m - probably not enough.  Alternatively, I have 4 3m lengths of 300mm wide interior grade plastic cladding.  Wonder how long this would last outdoors   When I bought it a few years back I didn't know it was interior grade - I didn't find out until I got it

I think I'll probably use the 1" ali tube for the roof runners and pieces of the 1.25" for the uprights away from the main box.  The latter can be driven into the ground to provide solid supports.  These tubes are of a grade of aluminium designed for exterior use in harsh environments and have been lying on the ground for several years without showing any sign of corrosion   I shall print fittings to connect the roof runners to the uprights and the wheels for the roof.  Plain bearings will be quite sufficient for this much lighter roof and ABS has quite a low coefficient of friction and good wearing properties.  Plain shanked SS bolts will provide the axles.

I have plenty of 95mm x 20mm sawn timber to use for the carriage framework though I think single pieces each side will suffice compared with the double I used for the main obsy.  35mm x 18mm sawn timber will make the roof framework I think.

[Davey-T]

I think I suffer from a grasshopper mind and can get tired of one thing and work on another   This project has been on the books for some time now

Today I am having a little rest from construction work and concentrating on thinking, planning and posting

I do a lot of that, but as soon as I start actually making something it becomes blindingly obvious what I should have done, and all my plans go in the bin 

Dave

[Gina]

Ah yes   My designs seem to change all the time too   Gotta start somewhere though

[Gina]

Of course, actual work on this project depends on the weather.

[Gina]

Here are two photos of the NEQ6 mount on the pier looking roughly westwards showing the field of view.  First is in a possible imaging position and second with the mount parked.

Here is a SketchUp model showing the "bones" of the construction.  Base slabs with the pillar mount less feet for clarity and wooden corner posts supporting the roof rails.  The roof is shown in darkish grey representing rubber roofing which I think I shall bring down the sides and fasten up underneath.  The aluminium support rails extend to the WNW and are supported on larger aluminium tubes driven into the ground. 

The corner posts will have a framework added plus cladding and a door to contain the imaging support equipment, dehumidifier etc.  I plan to drive a couple of galvanised iron pipes into the ground to hold down the structure and stop it blowing away.  The corner wooden posts will have DPC between them and the blocks/slab they will rest on.

[Gina]

I now have my widefield triple imaging rig mounted onto the base plate and that in turn on the NEQ6 mount on the SW pillar mount.  These photos show the rig in the parked position and I can now work out the dimensions of the roll off roof

[laser_jock99]

Looking good.

[Gina]

Thank you

I have modelled more details of the frame designn showing the framework around the top of the base and the carriages and cross member of the roll off roof.  I haven't shown the wheels that support the roof and which run on the round rails.  The left hand side as it appears in the first view, will have a flap that folds down outwards to clear the view to the east (assuming this proves necessary - otherwise this end could be fixed to the base). 

There will be more roof framework supporting 6mm plywood that forms the roof, which I plan to make out of 35mm x 18mm timber.  I have yet to work out how to make this rigid yet still clear the imaging rig as the roof is rolled off.  Maybe aluminium or galvanised gussets.  The plywood will extend downwards and overlap the base framework to keep the weather out.  I may add a batten around the inside of the plywood at the lower edge onto which the rubber roofing can be to turned under and up and then fastened with clout nails.  A secondary advantage of this would be that it would prevent the roof lifting off in storm force winds.

To show the difference between the base and roof frames I have used different coluring for the timber in the model.

[mhard26339]

"Necessity is the mother of invention" keep the little grey cells busy Gina

Regards

Mike

[Gina]

Oh yes, I like to keep the little grey cells busy

I might "hang fire" on building this until I get the C11 I'm buying for planetary imaging.  I'm thinking that it would be less effort to put the C11 on the second pier with NEQ6 rather than haul off the massive kit from the EQ8 and putting it there.  The C11 has a CF tube so a bit lighter than the ali version and I hope I'm right in thinking that the mounting/guiding requirements are less for planetary (with the much shorter exposures) than for DSO imaging.  If I do decide to use this place for the C11 it will want a bigger roll off roof.

[Gina]

I have been reminded that the C11 weighs 12KG and is big and awkward to lug around.  The pillar mount legs and concrete blocks make the second pier awkward to access for humping a heavy scope onto the NEQ6 mount and once it has a wooden box round it, it may be even worse.  OTOH the obsy has an electric winch with pulleys up to the roof that allow heavy gear to be raised and lowered with little effort and - more importantly - less risk of injury or damage.

In view of all the above I have decided I will not be putting the C11 on the NEQ6 after all and this will be a dedicated widefield setup.  This means that I can carry on and build the wooden supports and roll off roof as I already know the dimensions of the WF triple rig.

[szymon]

I think that's probably a good decision :-)

[Gina]

Here is a diagram showing the interior dimensions of ithe roof.  The bottom is level with the top of the base framework and posts with a piece of wood on the top level with the bottom of the NEQ6.

[Gina]

I have plenty of 6mm exterior plywood and other timber but not sufficient EDPM rubber roofing or any adhesive.  Buying just the amount needed the cost from Rubber4Roofs comes to £49.33 inc VAT but using a standard shed kit costs £40.92 Incl. VAT for a bigger piece of rubber Thats for a 6' x 3' pent roof shed - the smallest they do.

[Gina]

Here's a model of the bones of the obsy to scale.  Only one roof frame is shown.  The wheels the roof rolls of on are omitted and so is the wooden piece across the front that takes the ends of the roof rails/tubes.  The front end will have a flap the keep the weather out and the far end of the roof will be closed in.  I'm hoping to do some construction work on this tomorrow.

[keithatrochdale]

Here is a diagram showing the interior dimensions of ithe roof.  The bottom is level with the top of the base framework and posts with a piece of wood on the top level with the bottom of the NEQ6.

Mini Obsy Roof 01.JPG

That is a very small construction.

[Gina]

Yes, it's small   Only has to contain my widefield triple imaging rig consisting of three camera lenses and CCD cameras in a turret as shown on post #10 above.

[Gina]

I have a new design for the roof, simplifying the consrtuction.

[Gina]

3D view.

[tekkydave]

Ah yes   My designs seem to change all the time too   Gotta start somewhere though

I find the best outcome is when you can 'converge' on a solution rather than have everything planned to the nth degree. It helps to have a rough idea of where you want to end up, though.

[Gina]

I think I shall have to do some construction before I can get anywhere near the final design.  There are so many things at all sorts of odd angles to be accommodated that measuring up and planning from that is very difficult.