Home Observatory UK

[gnomus]

I thought I should provide an update from a previous post - http://stargazerslounge.com/topic/236956-ian-king/   I decided not to go for the Ian King observatory and have, instead, gone with Home Observatory UK.  It seemed inappropriate to continue under the 'Ian King' thread - hence this new post.

The plan is for a 9' x 9' observing area with a (roughly) 9' x 4' warm room tacked on to the northern end.  The roof will roll off, over the warm room, to the north.  The pier will be bolted on to a block of concrete sunk some 3' into the ground. This block will be isolated from the rest of the concrete foundation.

The foundations will be 4" concrete over a 4" layer of hardcore.  I've now got the foundation dug out:

(The wheelbarrow is covering the place where the 3' pier block will be - it's not yet sunk to full depth).  

Clearly, there is still quite a bit of work to be done, but I hope to have the observatory in place within the next 5-6 weeks.  I'll post updates, and will have endless questions (which I think are likely to focus on electrics and related matters).

[kirkster501]

Good luck Steve.   As per our PM's I am also going to use these guys.  I do not have the time to build it myself and I am not convinced I can do it much that much cheaper with not having their economies of scale.  Julie at HomeObservatory UK is extremely helpful and has given me lots of advice.

Good to see you have dug out.  Make sure you run some conduit for your cables.  Run one for the mains and another for the data cables if you can (I couldn't and have run one only).  I used Wickes 40mm pipe and fittings, very cheap and does the job perfectly.

I also suggest a few pieces of rebar hammered in for the peer as well before pouring the concrete.  It is very cheap from a builders merchants.

Steve

[gnomus]

Thanks Steve. I have also found Julie to be helpful. It's maybe not obvious from the photo, but at bottom right you can see a blue piece of pipe. This is conduit for 2 network cables that are buried underground and run back to the house. I also have my 10mm armoured cable run and buried (it's in the black bin bag). These will be run under the concrete, when that time comes. We are going to put some sort of rebar cage into the pier pit.

[fondofchips]

Nice one Steve, should be ready for the winter observing season.

[gnomus]

OK - here's the first of many stupid questions:  Does anyone know what thread pitch/diameter is used on the base of my CGEM mount to attach it to the pier?  The bolt that comes with the tripod is (obviously) way too long, and I am going to have to find a replacement.  I don't want to knacker the mount by using the wrong sized bolt.  I had a look at the CGEM manual, but I could not find any info on this.  Can anyone assist?  

Thanks in anticipation.

[kirkster501]

According to this thread it is M12:

http://www.cloudynights.com/topic/466037-mounting-a-cgem-dx-to-a-steel-pier/

It is the same on the NEQ6 as well.

I can bring you a piece of M12 threaded rod Steve and a couple of nuts and a washer when I come up to see your setup in June - assuming the offer is still on???  Otherwise you can order it of the fleabay for a couple of quid.

[gnomus]

Steve

Thanks - I will get a piece of M12 and try it out.  I will want to have it all set up for your visit!  BTW - it's looking like it might be just into July now.......... 

[fondofchips]

I underestimated the amount of concrete around the bottom of the pier and had to dig down again to put more concrete around it. - 

I did get away with it though, there is roughly 1.6 tonnes of concrete around the pier base.

The frame to attach to the bottom of the pier is made from 4 x 16mm threaded rod 1.2 metres long.  The bottom end of the rods is bent to stop the rods spinning in the concrete.  I just used oddments of brackets and bolts to hold the frame together until the concrete set.

I didn't isolate the pier as I'm only observing, the whole base is one piece of concrete and slabs.  I did put some thick rubber between the bottom of the pier & the concrete, mainly to avoid condensation caused by the cold coming up from the concrete.

More base pictures here: -  http://stargazerslounge.com/gallery/album/2477-my-obsy-build/

Clear skies,

Fondofchips.

[gnomus]

My next question relates to pier height.

The observatory is going to be used for imaging, but I do want to be able to use it for some visual sessions too.  To date, we have observed from the garden with the tripod at full height.  Standing around for a couple of hours can get a bit wearing.  I am hoping to be able to do visual observing from an office chair in the shed.  Testing out at home, it seemed that a pier height of around 35" (that is 35" to the start/bottom of the CGEM mount) would give me a wide range of seated viewing possibilities (sometimes - when the telescope is nearly horizontal - I am looking almost straight up into the eyepiece).  I have tested out a 35" height in the garden with bits of string and plywood acting as makeshift observatory walls.  It looks like I will be able to get good unobstructed views to the East and South - the observatory is having a rolling (foreshortened) side to the East, and a fold down panel to the South.  To the North are neighbours' houses, and to the West is my house, so I cannot see to the horizon in those directions.  

Does my suggested pier height (of 35") seem OK, or is there something I've forgotten about?  

[Thanks in anticipation of your assistance - COMING SOON: Electric Focusers - aaaaaarrrggghhhhh] 

[gnomus]

OK - no thoughts on pier height, as yet. Never mind.

Here's my latest question. I have three OTAs - a Celestron Edge HD 8"; a Skywatcher ED 80; and a Skywatcher ST 80 (which I mount on the ED 80 for guiding). At the moment, I'm contemplating a set up whereby I 'swap' between the Celestron 8" and the Skywatcher ED 80/ST 80 - that would mean physically swapping the tubes depending on what I want to do that night.

I wonder, however, if there is a way of having all three tubes mounted simultaneously. This would mean the set up would be more 'permanent', and it would be quicker to get going of an evening. I don't know, however, if my CGEM (not DX) mount is up to the task of carrying all three tubes. Nor do I know what would be the best way of connecting all three if the mount was capable.

It would be helpful to hear what others are able to do with a same or similar set up to myself.

Thanks

[DaveS]

Hi Gnomus

I've just taken delivery of a Pulsar Rigel pier, rated to be 1125mm high. Standing it on my patio it comes to about the same height as my HEQ5 tripod which will be about right for my imaging box.

For a triple rig, have a look at this:

http://www.firstlightoptics.com/adm-losmandy-type-d-series/adm-losmandy-style-triple-mounting-bar.html

A bit pricey perhaps but designed for the job.

From browsing the boards here, I'm getting the impression that multi 'scope rigs use something more rugged than the CGEM, into Mesu territory.

[gnomus]

Hi Gnomus

I've just taken delivery of a Pulsar Rigel pier, rated to be 1125mm high. Standing it on my patio it comes to about the same height as my HEQ5 tripod which will be about right for my imaging box.

....

From browsing the boards here, I'm getting the impression that multi 'scope rigs use something more rugged than the CGEM, into Mesu territory.

Thanks for the pier info.

Yes, I wondered if I might need something a bit more heavy duty for a multi-scope set up. Trouble is, you can very quickly get into nosebleed territory....

[Earl]

Pier height depends-on mount height, wall height, fov, and OTA considerations.

First of all work out your unobstructed FOV.

Then how this relates to your wall height.

Then How Hight the OTA sits on the moiunt to view this calculated minimum heiight

How hight the Mount sits from the pier afdapter.

this will give you the minimum height you need.

If you have head room to park in a weights down looking at polaris, add a bit of pier height.

I think thats about it.

EDIT

Parking in a weights down posistion is not essential on the whole and you could park with your ota and counterweight bat horizontal and save head room if needed and allow greater pier height. (probably worth serious consideration)

Oh and dont forget walls can assist in block LP and wind, so its a bit of give and take.

[fondofchips]

Pier height is the most difficult thing to get right on your obsy.

Depends on: -

Obsy wall height

Your height

Type of scope you are using, generally a frac can be mounted higher & a reflector lower due to the eyepiece position.

Height of nearby obstacles, houses, trees etc.

I kept my pier a little lower as I cannot really observe low on the horizon and I have houses, trees etc fairly close.

So that I could still observe lower on the horizon I had extensions made for the pier, this also covered any future changes of telescope.

Extensions in the background in this photo: -

I will always say this - the pier height can be sorted easier when the obsy is built, it does delay things slightly but so does having the pier altered.

Cheers,

Fondofchips.

[Earl]

Another thought if your walls are too high you can make them to fold down a foot or so, that might provide better options.

[gnomus]

According to this thread it is M12:

http://www.cloudynights.com/topic/466037-mounting-a-cgem-dx-to-a-steel-pier/

It is the same on the NEQ6 as well.

I can bring you a piece of M12 threaded rod Steve and a couple of nuts and a washer when I come up to see your setup in June - assuming the offer is still on???  Otherwise you can order it of the fleabay for a couple of quid.

I can confirm (to anyone who may be interested) that a M12 bolt fits the base of the CGEM. Thanks again Steve.

[gnomus]

Thanks Fondof and Earl. Complicated business! I am having a folding panel to the south and a 'rolling side' to the east. I will try a bit more messing about as best I can.

The chaps are coming some way to build the observatory. They are also fitting the pier so doing it in 2 stages is not a viable option.

I suppose my main question relates to whether or not seated observing is a viable option in a roll-off roof observatory. I would like to observe from a comfortable office-type chair (on wheels preferably). These tend to come as a standard height. I know that you can get 'observing chairs'. These look to me to be more like 'perches' than chairs' however. I don't mean to offend any observatory chair owners - I just don't think that these things will work for me - I am more Jupiter than Mars, if you get my meaning.

[gnomus]

Electric Focuser

I have upgraded the focusers on my C8 Edge and ED 80.  I have put Moonlite focusers on each.  As I will be having a warm room, it seems to me that it would be better to have some way of adjusting focus from the warm room.  I am having some conduit fitted under the observatory floor through which I can run cables.

A short time ago I saw an electric DC focuser option on the RVO website - but that appears to have disappeared.  It was a little expensive at just under £200, if I recall.  Then there is the even more expensive stepper motor type as found here: http://www.firstlightoptics.com/moonlite-focusers/moonlite-high-res-stepper-motor-with-miniv2-controller.html

I assume that I could put a motor on each of my focusers, and as I chop and change telescope I just plug the control cable into the focussing unit.  

Are these (or indeed if only one option is left, is this...) the only option open to me in terms of electric focussing?  Going the Moonlite stepper route seems a shade on the expensive side.

It would be interesting to hear how others deal with focussing especially when two telescopes (which, given that I don't have a heavy duty mount - see above) will need to be swapped around depending on the task in hand.

Thanks again for your patience.

[fondofchips]

I would think that having invested in the Moonlite focusers then using the stepper motor system would be a good idea.

I would contact FLO though and find out how long the standard cables are that come with the stepper motor system.  There is no specification for cable length on the FLO site yet.  If you need longer cables then it will cost extra.

Cheers,

Fondofchips.

[gnomus]

......   If you need longer cables then it will cost extra.

Cheers,

Fondofchips.

Cheers to you too!!!!  

[gnomus]

Oh I found the DC motor option:

http://www.rothervalleyoptics.co.uk/moonlite-dc-motor-with-slip-clutch-controller.html

I do like the idea that these units come with a slip clutch which I think will be much easier when doing visual work at the scope.  Does anyone know if the stepper motor units have a slip clutch feature?  

Does anyone have any experience of either of these units?

[fondofchips]

I have the one in the Rother Valley Optics listing, works very well as long as you keep the controller in your pocket during very cold weather to keep the batteries warm. 

Cuts down any shake as you don't have to touch the scope at all to view.

I would buy another adaptor for the focuser & move it to my new scope when I changed it.

Aren't obsys fun?  well they are when they are finished, but they are never quite finished, there is always another tweak.....just saying.

Cheers,

Fondofchips.

[gnomus]

Thanks for the feedback. I must say that I prefer the price of the DC motor option. I'm tempted to go ahead and purchase. Is there a compelling reason to pay the extra for the stepper motor version? Are there any reasons why the DC version would be unsuitable?

[Earl]

Steppers give a more repeatable and finer performance iirc due to design

[gnomus]

Steppers give a more repeatable and finer performance iirc due to design

Thanks Earl.  How big a deal is this extra precision?  Do most folks go for the stepper variety, or is this just for the high-end guys?