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Bizibilder

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Posts posted by Bizibilder

  1. You could make up some clips from thin steel that the chain would "clip" into? You may even get away with "U" staples round the chain pins - if there is also enough room for the sprocket - maybe use a wide motorbike chain on a thin push bike sprocket to give yourself enough room?

    A thought - Do you need to be able to rotate the dome a full 360? maybe just a segment - enough for a couple of hours rotation - would be enough. You could then just have several bits of chain (or one moveable chain segment) and move your motor to suit?

    One thing about slow systems - like the one to drive a dome - is that they can be very crude and still be entirely successful, its only when things start moving "quickly" (whatever that means!) that the system has to be set up to run precisely.

    PS I've just read your other threads - looks like an interesting project!

  2. Just a thought about the above from Barkis. If you mounted a motor on the wall (ie fixed) with its drive pointing up into the dome, then a sprocket wheel would mesh with a chain that was secured around the dome (the chain being flexible in one direction only - assuming bicycle chain type). If you have the motor well geared down then you would not need a particularly powerful motor. I wonder if a car window motor or windscreen wiper motor would be OK - for a 12v power supply, of course.

    Hope this helps.

  3. Really, No!

    If you think about it - on the EQ5 they are either side of 60mm in diameter (one a bit more, one a bit less!!!!! I just measured them!) so a circumference of about 3x60=180mm (taking Pi as three as done in schools these days!!!) gives you about 1mm=2deg. This you are supposed to read in the dark with your body contorted to even see the darn things! I think not. They even have a "vernier" scale CAST onto the body of the mount - laugh - I nearly fell off my chair!!

    On the EQ1 (which came with my SW80mm guide scope) the circles are 60mm and 35mm - even worse.

    In the "good old days" of the 60's and before it was always suggested that the minimum diameter for circles was 6" (150mm) and 10" or 12" was even better! but you were warned that these were only suitable for "rough finding " objects.

    As to star atlases - save your pennies!! - there are several exellent ones on the web:

    http://www.uv.es/jrtorres/index.html This has three called A, B & C - A is basic 21 sheets of A4 for the whole sky, B has 103 sheets and is really useful for finding stuff and C which is 566 sheets and has far more on it than any amateur could ever need!

    http://www.asahi-net.or.jp/~zs3t-tk/index.htm Taki's atlas to mag 8.5 again on A4.

    Plus the downloadable "Stellarium" and "Cartes du Ciel" which is linked to the "Virtual Moon Atlas".

    Hope this helps.

  4. Honest answer - setting circles as supplied are "below par" (can't use naughty language on the forum!!)

    They tend to be weak and flimsy - on my EQ1 & 5 they certainly are! AND are "stuck" to just about everything with "Chinese grease" - the stickiest stuff known to man!! The result is they do their own thing!!

    I started out in the 70's using circles to find things - so I was quite concerned to find just how useless modern ones are!! I assume the reason is so that when you finally get fed up you will go out and buy a nice expensive goto!!

    I'm not sure what the solution is - there are threads that show how to "service" your mount - they may help.

    Rant over!!

  5. Hi David B

    The synscan 127 is about £350 as far as I can see (First Light Optics - they sponsor this site - I have no connection with them apart from being a satisfied customer). For deep sky objects - galaxies and nebulae APARTURE is king! ie you need to collect the most light possible - these objects are faint!! So have you considered either a 200mm or 250mm Dobsonian? - these fall either side of your price (go for the 250 -you won't regret it!).

    They dont have the goto but this is no real disadvantage - as a beginner most of the fun is learning your way around and gaining from the excitement of finding some of these elusive "faint fuzzies". Dobs are portable - which may be important - even if only to bring it indoors after use!

    You can (if you get the bug you will!) always upgrade to an equatorial/goto type mount at a later date.

    Hope this helps.

    PS There are lots of posts like yours from beginners - and very welcome they are!! - have a look in the beginners section of the forum - there is so much advice that you will soon be really confused!!!!!!!!!!!!!!!!!!!!!!!!!!

    Keep asking - thats what we are all here for.

  6. Sorry if I've put you off, it wasn't my intention to do so!! I must admit I have given the prices that I have for a "brand new everything" build. On reflection I reckon that you could build a basic roll off shed, most likely from wood, for considerably less outlay. Without a solid base - just use paving slabs - I reckon that you could build something basic for around a couple of hundred - especially if you can get a good shed for "free" to start with? if you are prepared to do quite a bit of the work yourself.

  7. I'm just building a roll-off so these prices are current: (in round numbers)

    Metal shed: £200

    Professional laid base inc materials: £150

    Concrete pier base/shuttering for shed etc: £50

    Timber frame for shed & roof: £100

    Nuts bolts & screws & locks & wheels etc: £150

    Sealant & paint: £50

    Total: roughly £700 - notice that is all the bits and pieces that soon add up!!! It is still considerably cheaper than any "professional observatory". Whats more you can make a "bespoke" design to suit your own situation.

    Could I have made it cheaper? - maybe - I used stainless screws for everything - and bought more than I needed!, Bought a cut-off saw (included in the above prices!) and did not skimp at any stage. I have about £20 of wood unused. So I suppose I could have saved £50-£100.

    Getting the roof to work was easy!! The difficult bit was the doors (due to the shed design - not my handiwork!!)

    Have a look at m'Blog (In the signature) to see how it all went together.

    Also: http://linnhe.co.uk/index.html

    And at: http://cmhas.wikispaces.com/PutlandsObservatory

    Hope this helps.

  8. Clean it as you go and don't use car oil to lubricate it!! (Its the wrong stuff and will go all "gooey" in no time!) You need machine oil. Try your local Machine Mart or PM me and I can give you details of what you need and where to get it. The belts could be replacesd with the segmented type - to avoid having to dismantle the headstock bearings - IF these are in good nick - leave well alone!

    You now have a new hobby and Astronomy will soon be on the back burner for a while (quite possibly years!!!!)

    Good luck with the new toy.

    The lathe tools supplied are good for the bin! The blue ones are inserted carbide bits - you can see the carbide welded to the end - these are impossible to sharpen without special grinding equipment. The others are High speed steel and it may be possible to rescue them - you will need a bench grinder anyway.

  9. Clean it as you go and don't use car oil to lubricate it!! (Its the wrong stuff and will go all "gooey" in no time!) You need machine oil. Try your local Machine Mart or PM me and I can give you details of what you need and where to get it. The belts could be replacesd with the segmented type - to avoid having to dismantle the headstock bearings - IF these are in good nick - leave well alone!

    You now have a new hobby and Astronomy will soon be on the back burner for a while (quite possibly years!!!!)

    Good luck with the new toy.

    The lathe tools supplied are good for the bin! The blue ones are inserted carbide bits - you can see the carbide welded to the end - these are impossible to sharpen without special grinding equipment. The others are High speed steel and it may be possible to rescue them - you will need a bench grinder anyway.

  10. Yup - rotate the tube. You will find that there are some good "compromise positions" that you will use more than others. The trick with loosening the rings is not to let the tube slip out of balance. One way is a piece of tape with a mark or marks on it (useful if you are inclined to add eg cameras etc to unbalance the tube) or some sort of fixed ring to stop the whole thing sliding. I believe that "embroidery rings" are the favoured option for the girls, the boys use jubilee clips!!!!!!!!!.

    Hope this helps.

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