nightvision

Just returning to Astro and this deep galaxy hunting is inspirational!

Really impressive, what camera are you using?  .... Just found it in another post SX Ultra.

This explains them very well: https://www.designingbuildings.co.uk/wiki/Breather_membranes_for_buildings

That's the thing; when the designer and builder is the same person the whole project becomes organic/dynamic, it happens so often... my wife just calls it 'over-engineering again'.  I call it 'optimisation that delivers results and motivational energy' (how noble). ?  oh yes and more work and more expenditure...?   Good luck with your obsy trials and tribulations..

! Yikes sorry I mentioned it, seems you have enough on your plate with this impressive build.  If you go ahead you could just float the osb edges and put some supporting wood behind the seams, the structure looks solid enough.

This loglap seems good value and is unlikely to come apart like shiplap.  

Loglap at £1.30 a metre: https://www.ebay.co.uk/itm/100mm-x-22mm-TREATED-SHED-TIMBER-CLADDING-LOG-LAP-GRADE-A-SEE-POSTCODES-/272755487107?_trksid=p2385738.m4383.l4275.c10&var=571890564978

It can be quite alarming seeing seasonal daylight appear between cladding boards or via knot holes! 

You could take the cladding purchase off the critical path; separate aesthetics from structure and get your obsy operational by sealing the whole structure in 9mm exterior shutter-ply (only £14.40 for 2440x1220 sheets).  More stable than ship-lap or feather-edge cladding and more resilient than OSB.  Leave a few mm expansion gap between boards and seal with silicone.

For about £150 it would give you a weather and bug proof structure in one day,   

At a later date you could install any cladding on top of the ply (make sure to mark the stud locations).   It won't matter what warps or shrinkage you get in the cladding you choose as the box will already be sealed.

Outdoor and obsy cabling considerations: Pipes can really attract slugs, had a motor control unit burnt out by a slug that thought a buried electrical conduit a good route to somewhere nice and warm.  It started a fire on the pcb where the mains transformer was mounted.  Now all conduit/cabling pipes are sealed with silicone. 

The NLC's do look amazing tonight!

1 minute ago, Davey-T said:

Yes it's pretty solid (over engineered )

Dave

A picture or 2 would be great, I'll start a thread on adjustable piers.

Sounds impressive, does it keep PA from night to night?  Sorry to James for the thread hijack!

1 hour ago, Davey-T said:

My plastic shed is 6 foot X 6 foot with 6 foot wall height housing an SCT on a wedge on a meter high pier, this is generally OK but I made the pier motorised with an electric ram that raises it another 300mm to clear the side at lower dec' and I need this ATM to view / image the planets at present.

Dave

I've been looking at actuators, is there a thread on how you did this?  Interested in what you used mechanically to get a precision lift, was it a telescopic pier?

Good luck with your build Alex, I've done loads of projects lately and found some local suppliers that really help keep costs down.

Check out some of the cheapest pressure treated framing timber in the country and not too far away so cheap delivery.

http://www.diyclick2buy.com/

Another local supplier (good for ply, treated framing and decking) with a great reputation:

https://www.savoytimber.com/

For shiplap/loglap these seem the best value:

http://www.ebaystores.co.uk/qualitytimberproducts  

Curious about the roof tech you intend to use, any more info?

Be careful when adding or laminating more lateral thickness to your end supported beams, this will add more weight and not a lot more resistance to long term flex.  Thinner taller beams if they can't move laterally will be stronger and lighter, laminating thinner beams with carbon will save weight and increase rigidity.

 If you are height restricted (2.5m) you may not be able to increase your yellow beam size to 150x22.  You might see some distortion of the yellow beams over time.  You could consider using some carbon tape and resin between the yellow beams and also do a little pre-stressing while the resin sets.  It would be even better to use 4 x  100x22  with carbon laminated between each beam.  This would probably do the job: Carbon tape.  You would also need some laminating resin .

This could work; a small raised frame would get you above the mud/water and be safe:  

https://www.edecks.co.uk/products/2394/219/107/0/Charcoal-Red-WalkSure-Anti-Slip-Decking-(32mm-x-125mm)

https://www.edecks.co.uk/subdept/107/0/Anti-Slip-Decking

Erm Moderators - isn't it time that VA had some sub folders marked for Guides,Tips etc UNDER VA. I know some exist else where but it would be nice to get to it quickly in the area of interest VA'a are most interested in. It would be a shame to loose this user manual amongst all the other waffling(albeit very good waffling). 

Agree, I think this should happen especially as this is a developing area with many of us learning the ropes and others pioneering techniques.

Looks smooth.... but maybe a bit too flimsy!! 

I think that may be the largest/heaviest pier construction ever posted on here... 

Awesome!!!

Falls off seat! 

To add a footnote to this, with my 450D and 127 Mak I have now been able to reduce the exposure time and ISO setting to 1/200th @ ISO200. When I have tried this in the past I've had severe problems with ghosting in the images which appear to be solved by configuring APT to delay activating the shutter for two seconds after the mirror is locked up. I think this has made a noticeable improvement to the quality of my images.

I assume that if you aren't able to use APT or a similar application for image capture you may need to stick to higher ISO settings and faster exposures.

James

Brilliant thread James, BTW I currently use a Canon remote shutter release and the mirror-lockup option works on first press and shutter works on second so no more ghosts. With this arrangement I can use ISO100 and exposures of around .01 seconds when using an IR filter. I will be using APT once my obsy is built.

I see your point. However this could be a real breakthrough for the astro amateur community; if only we could find a safe procedure to do it! This thread shows that we are nearly there. Maybe the way to go is to try first with cheap second hand webcams? Then come up with a workflow plan for expensive DSLR sensors. Imagine the possibilities: H-alpha filters in light polluted areas or when the moon is in the way, then using a camera which hasn't been de-bayered to add colour. This has the potential to transform amateur astrophotography.

I believe investigations to date have shown that webcams appear to have a different set of layers that come away easier so they may not be appropriate for developing an approach for DSLR sensors. I sometimes wonder if Canon might be prepared to give out some information.

Thanks Bill for the detailed info I thought it might be to sort out focus but had not heard of quartz types.

Can you provide the details for the supplier of the quartz replacement glass?

I obtained a 1000d with a full spectrum mod (no replacement glass) and plan to use it with a CLS-CCD filter for astro and IR filters for some creative daytime fun. I did some tests when I got the camera and some of my lenses focus OK to infinity and strangely the auto-focus seems to work (it might be that the modification included moving the sensor forward as you describe). One manual M42 50mm will not focus to infinity in visible light but I think it might be close enough for infinity at IR. The images unfiltered appear to by slightly smudged by flair (I assume it's the IR/UV/Visible focus spread). I did a test with a red filter on the flash, this made the images very sharp. I have ordered 3 IR filters (680/720/850), my un-modified 300d will do for normal photography. Looking forward to reading more about your pioneering sensor modifications.

....

anyway, off to do full spectrum conversion on my other camera, my quartz filter arrived this morning

Interesting; what is the Quartz filter for?

Makes me wonder what it does to your teeth!

It seems many approaches sort of work and there are also structural differences between webcam sensors and DSLR sensors so I guess it remains an inexact (and potentially expensive) science for now, it's great that we have so many pioneers.