I think I made my observatory too small

[tooth_dr]

Here is my build thread.

http://stargazerslounge.com/diy-observatories/89201-my-budget-roll-off-roof-obs-build.html

I've mounted the 10" on the EQ6, and I've just been outside trying to get the thing polar aligned. Two websites promised clear skies, guess what, cloud wall to wall

Anyway back to my problem.

I figured 3' around the pier (circumferentially) in my 8' x 6' shed would be ample room for my 10" scope. Now after slewing it around a bit it looks like I've drastically underestimated the size of the 10", or rather I didn't realise it would be so far down towards the mirror end to get it balanced.

Seems like the shed is too small, feeling a bit gutted. Weather has been really rubbish lately, now the shed is too small, I feel like locking it up in the parked position for good and leaving it at that.

Any suggestions?

I've got two options i mind (well three if you count giving up on it):

1) Swop it for an 8"

2) Add weight to the open end to shift the COG further up the tube, but it's already pretty loaded for an EQ6.

Cheers

Adam

[barkis]

I sympathise with you, you must be so disappointed.

However, it just demonstrates the need for careful planning when taking on a project like this.

I wouldn't fiddle about with counterbalancing the scope. If the weight is almost at capacity for the EQ6, then you must prepare yourself for an Obs. modification. I know it's a pain to even consider this, but in the end, I think it's the sensible solution. You have room to do it, so condition your mind to that solution, and full steam ahead. You won't be sorry. Calculate how much more room you need, then add another foot at least.

Ron.

[adamsp123]

Judging by the amount of CWs you have to balance it I would go for the smaller scope option, you don't need a large aperture for imaging and I would be tempted to get something with a smaller F ratio ie faster photographically.

The lighter load on the mount will be highly beneficial as well for imaging, certainly you want to be well under the load capacity of the mount.

My 2ps worth.

[NickH]

Have an 8x6 with a C11 and it's fine...just had to add one more CW, and the EQ6 is happy with that... have to piggyback the guide scope (ST80 keep it light), but aside from that... all's well, in fact had more problems with the TMB and the drawtube focuser being out quite a way in terms of space (had to move a shelf) than the C11

[tooth_dr]

Cheers chaps.

I spent a bit of time looking at this early this morning, I let it go last night as I was too annoyed to do any more with it.

In the light of day the space issue is to do with the way the mount rotates as I point the scope south. If I had an Alt=Az mount I'd have had no problems, but with an EQ mount space is too tight south, with too much space north wards.

I've been able to rotate the tube so that the view finder and focuser are at a different angle, and adjusted the position of the dual mounting plate accordingly. I've also allowed the roof to slide open an additional 6". The issue was around with the scope fouling the roof.

I am pleased to say that the 10" scope now clears the south wall by a few cm, and no matter what orientation I choose, the scope cannot touch the south wall.

The east wall is a different matter, and it could still potentially foul the shed wall at one part, but only by a mere 3cm. I reckon with careful balancing I should be able to avoid this wall too, and 'just' get away with it.

My Dad has a 200p explorer, and this would definitely fit into my obs, with sufficient clearance on all sectors. This is def an option as he would be happy to swop for the time being.

Tonight it is supposed to be clear so I'll get it running and see how it fairs out. It's easy to plan these things out, but I feel for me sometimes I have to be using it to see where it needs changes, etc, there is only so much planning I can do on paper (as already demostrated lol)

Fingers crossed for later.

Thanks again

Adam

[adamsp123]

Good luck! I hope it all works out OK.

Pete

[tooth_dr]

thanks Pete

Been out all evening just looking at Mars. Its my first time using the 10" since I bought it 4 months ago, and it was certainly worth it! So great being able to get set up quickly. Things aren't perfect but a HELL of a lot better than lumbering gear in and out!

Regards

Adam

[David Pavlich]

I wish I were here earlier and had a chance to talk to you about dimensions. I built an 8X8 rolloff. I have a C14 on an MI250. Had it been 7X7, I would have been in trouble. As it is, I take off the dewshield before I park the scope, it's that close. My backyard is small and the CFO said no bigger than 8X8 and quite frankly, I'm just thrilled that she let me build the thing at all.

Be that as it may, I knew it would be a squeeze, but it's closer than I thought. However, it works when observing and imaging.

David

[tooth_dr]

Hi David

The shed is tight in the 6 foot dimension but I knew it was gonna be close. The 10" reflector is 4' 2" long and fits in with an inch or so to spare at some angles. In fact it looks like it is gonna hit but it just misses it. I put it down to careful planning rather that blind luck (ps ignore my first post above lol)

Regards

Adam

[David Pavlich]

Hi Adam,

I recently did a shuffle of the shelves to make some extra room. The way I first had it, when the RA axis was horizontal, I had to crawl underneath it to get to the other side. Now I can suck in my belly and squeeze past the counterweight shaft. Heck, that's incentive to keep from eating too much King Cake and gumbo!

David

[michaelmorris]

Hi Adam.

A further few options to consider:

- Off set the mount on the pier a little and move the scope in the rings to make up the rest of the necessary adjustment

- Move the whole pier.

- Cut the old pier off at the base and add a steel pier bolted into the old pier foundations, but off set by a few centimetres

- Move the shed (not the pier) a few centimetres to one side.

[tooth_dr]

Hi Guys,

First of all thanks, this is a great site where there are so many people willing to offer help and advice. I'd never have made it this far without using the resources available.

I had a Eureka moment yesterday lol, when I decided to ditch the SBS setup and go with a PB setup. I offset the ED80 on top of the 250px such that it shifted the weight slightly more towards the open end of the 250px. The downside to this was that I had to ditch the ST80 (but tbh it was only there on a whim, and I'll now have it for my grab and go setup on an EQ1).

I set it all up earlier and I'm am really pleased that it clears everything (albeit by literally a centimeter in one place but this is with the cover on so it's slightly more once it is off). It means I can relax now knowing that when the mount slews to a new target I don't have to stand with the controller to abort the slewing if it gets too close!)

The other thing about the SBS setup was that the guidescope was actually blocked by the shed walls at times even when the imaging scope was well clear of any obstructions. This was probably the last straw in my mind.

I was able to use my homemade dovetail to support the setup, and not the standard 250px dovetail. I also had a length of aluminium which secures the guide scope on top of the 250px.

The other benefits were that the counterweights had to be moved up 10mm towards the mount, and there is a lot more free space in the shed to move around when it is parked down, to get in to open the roof.

All in all an hour and a half well spent drilling, tapping, and bolting the new configuration.

Thanks again

Adam