Chris's Obsy build

[Chris]

Glad you're making good progress Chris How about some more photos?

Thanks Gina:) Well I do like to post the odd photo on this thread:D hopefully more this weekend, I'm only working half day Saturday:) I really hope the weather improves!

[Chris]

A bit of relief now its better sealed from the elements, I've felted the fixed roof, sealed any open bits with flaps of DMP folded in two, and sealed the wood with 2 coats of wood preserver pretreatment, and two coats of Cuprinol- seagrass colours range so far, although it looks more sky blue on the pictures for some reason? I've also started building the large angle brackets for the front of the obsy to extend the rails a bit further. Not much more work until I can start kitting out the inside!!

I've not painted the door yet as I'm doing the door and trim either cream or a darker blue, It does look a bit bright on these pics, its not quite so in your face in the flesh luckily:D

[Gina]

Coming on very nicely Chris

[Chris]

A few more bits and pieces done here and there:) I've installed the locking system to hold the roof down although I'm working on refinements to this.

I've made up a couple L-shaped 30" x30" wooden brackets which I've treated, painted, then screwed and silicone sealed in place, I didn't want to use no more nails because they might need replacing in a few years and silicon will stop water being drawn into the gap between the obsy and brackets. To strengthen the brackets I'm adding steel inner brackets although I'm not sure which way round to have these (see pics).l

I've had a bit of a problem with black mould on a few upright timbers, I don't think it helped that I hadn't finished the damp proof overhang at the back of the obsy so some water got in and sat behind some materials that I was storing. I have sorted the damp proofing, and I've used a bleach based mould cleaning product to kill the mould. Once fully dried I'm going to treat the timbers and paint the inside to seal it, also once I've got the electric hooked up I'll buy a small dehumidifier but for now I've got some passive Calcium chloride ones just to help a bit.

[Gina]

Coming on nicely

[Andyfx]

Looks a right neat job Chris! Mind you don't make it too cosy or you'll end up living in there lol :-D

[Chris]

Thanks Andy:) I've slept in worse places, I was once too tired and drunk to walk home after a night out so I fell sleep in a bush! This was back in my youth off course:D

I've beefed up my wooden pier adaptor by adding an extra 18mm ply disc so Its all ready to be concreted in now. Obviously allignment is rather crucial because its going into concrete, so is it best to stick the mount and adaptor on the pier on a clear night so as to line it up with the polar scope and mark the position, or will a compass in the day time suffice as there will be azimuth adjustment any way? I kind know the first option is the safest option, I'm just wondering how other people have done this?

Heres a pic of my beefier plywood adaptor, the new disc could benefit from a couple more coats of paint but hey oh:)

[Gina]

I used the reverse of a sundial. Set up a piece of cardboard on the pier head with a nail stuck up in the middle. Then on a sunny day put a mark where the shadow fell at noon (making allowance for longitude). In fact I put several marks and averaged the result allowing for the time. You only need to be within about 10 degrees anyway as there is a goodly amount of adjustmet on the mount.

[yesyes]

Then on a sunny day ...

This is going the be the tricky bit....

[r3i]

Obviously allignment is rather crucial because its going into concrete, so is it best to stick the mount and adaptor on the pier on a clear night so as to line it up with the polar scope and mark the position, or will a compass in the day time suffice as there will be azimuth adjustment any way?

Gina's sundial method is a good way to do it, but I just used a compass. The amount of azimuth adjustment on the SkyWatcher mounts (or least on the NEQ6) is very generous.

[Chris]

I used the reverse of a sundial. Set up a piece of cardboard on the pier head with a nail stuck up in the middle. Then on a sunny day put a mark where the shadow fell at noon (making allowance for longitude). In fact I put several marks and averaged the result allowing for the time. You only need to be within about 10 degrees anyway as there is a goodly amount of adjustmet on the mount.

Cool, I never would have thought of doing that, Ipswich is fairly close to GMT so I'm guessing it wouldn't be worth making adjustments for hour angle?

Thanks:)

[Chris]

Gina's sundial method is a good way to do it, but I just used a compass. The amount of azimuth adjustment on the SkyWatcher mounts (or least on the NEQ6) is very generous.

Doh! I just realised that around noon the blooming trees in my neighbours garden will be in the way (I have a terrible southern sky both for LP and obstructions) so its unlikely that this method will work for me:(

I think I'll go the compass way, once I've got a compass. Like your guys say theres quite a lot of ajustment on the mount plus more adjustment on my pier plate as the tripod head sits on the pier plate so this can be twisted left or right until they hit the bolts. There should be plenty of room for error, it would probably be fine if I just used maganetic north.

Thanks:)

[Gina]

Just beware that any iron around will upset your compass. That includes iron in rebar in a concrete pier. I couldn't use a compass on top of the pier for this reason.

You can use the sundial method at a time other than noon and just correct for the time angle (like a sun dial works for most of the time the sun is out) - 15 degrees per hour.

[Chris]

Thanks Gina, again I wouldn't have thought of that:D

[Chris]

I have now orientated my pier plate to north, I did it the safe way in the end using Polaris:) While I was at it I thought I might as well temporarily secure the pier plate with tape so I could setup my recently aquired cosmetically challenged Celestron ED80. I wanted to check both the clearance between the scope and the rolling roof and also see how well I'd estimated my pier height for comfortable imaging and viewing.

I'm quite pleased with the clearence, with the scope parked horizontally I have about 5-6" clearence. The pier height felt a bit on the high side though, I would need a small step ladder for a Newt I recken. With this in mind today I sawed about 1.5" of the pier adaptor bolts just to make the height a little more comfortable and as a side effect give slightly more clearance for future upgrades such as bigger aperture or a side by side setup with a dual mouting bar.

I got up nice and early today so I could get the pier adaptor concreted in before the list of family duties:D This didn't take that long so I also had time to give the inside of the obsy a coat of 5 star wood treatment after I'd previously had a bit of a black mould issue on the upright timbers.

I'll give the conrete a good 5-6 days to cure then the Obsy is offically usable!! huraaah!! Still far from finsihed but usable.

[r3i]

Looking really good. Probably a good idea to reduce the length of the pier bolts and keep them as short as possible. I wonder if over-long bolts might introduce some flexing?

[Chris]

Thanks Mike:) I initially kept the bolts long just to be on the safe side, I was thinking that I can always cut them shorter but you can't make them longer again:D Once I'd measuered up and seen that the pier was more than high enough I cut 1.5" off the top of the bolts and also moved the bottom plate up so there is more threaded bar going into the cocrete, the plates should be a good 2.5" closer together and hopefully this shows on the daytime pictures. I've now got about an inch worth of adjustment up and down, but anymore than another inch down then I can't get the central bolt in to hold the mount in place. I also doubled up on the large washers so I could tighten eveything up really well. This is the first completely wood pier adapter I've seen so I've got my fingers and toes crossed that it works ok:)

[Gina]

Coming on very nicely Chris Bet you're dying to get in it and give it a good testing out

[Chris]

You bet Gina:) I must admit I got a bit of a tingle down my spine when I mounted the scope on the pier last night:D Not long now for my first imaging run in the obsy! I just need to sit on my hands for while to make sure the concrete sets fully first.

Looking at the pier height and how it looks like it suits fracs and RC's better than Newts, I'm revisiting my earlier idea of a dual imaging rig, I have 2x 350D's and 1 ED80, so if I can get hold of another ED80 then that might make for an interesting imaging rig! if not that then sell everything and buy an 8" RC and a reducer, than I can either run it at long focal length @ f/8 or do wider field work with the reducer at about f/5.4. I had settled on getting a quattro but I think the exit pupil might be about 8 foot of the ground! I think everything will become clearer when I try out my 150p in the obsy as the length dimensions won't be that different to a 200mm Quattro (FL 750mm verses 800mm).

[Gina]

I did mine the opposite way round - I put the pier in first then built the woodwork around it.

[Chris]

I did mine the opposite way round - I put the pier in first then built the woodwork around it.

Me too, obsy foundations and pier in first then I built the obsy around the pier.

[shellfish]

Looks great have you had a chance to get out over christmas? You got to post your first lmages her lol

[Daniel-K]

looking good chris, i still need to fit some heavier duty castors on mine, got a few bits left but they can wait till spring time plus got the decking to build around the outside

[Chris]

Looks great have you had a chance to get out over christmas? You got to post your first lmages her lol

Cheers shellfish:) yeah first light was bitter sweet really as it was the same day sir PM passed away, it was an apt tibute though. I imaged the rosette neb with my 150p f/5, see below I'll post it here:)

[Chris]

looking good chris, i still need to fit some heavier duty castors on mine, got a few bits left but they can wait till spring time plus got the decking to build around the outside

Thanks Dan, your not alone mate, theres plenty I still need to do, some of the things I've done so far need improving on also, I'm still getting a little bit of water ingress unfortunately not loads but enough for some of the lower timbers to remain damp, also a patch in the corner of the roof of the warm room? I've gone round the obsy about five times with the all weather silicone sealant but I still have issues, if it ceases raining long enough for it to dry out properly I'll seal the inside with shed paint (I've already treated the internal timbers)

oh yeah bad news:( I've sold my HEQ5, 150p, ED80, WO66, ST80, and my 20x80 binos. The good news is I've used the money to buy a nearly new NEQ6 pro and 200p:) It all on the pier now looking the biz, I'll post some pics in daylight.

How you geting on with the Cats eye kit Dan?

also I can recommend the 75mm castors form Screwfix:)