Astro-angel

astro-angel · #1 03-08-2005, 08:53 PM

Hi all,
I have a 12" Dob which is awesome, but i seem to be having a problem with it. I am only a tiny lady and i have had to take off the stabelising springs to move it out side, but now i can't get them back on as i dont have the strengh, is there an easier way to stabelise it with out the springs? as i need it to be stable so that i can get into astralphotography, also to, is it safe to wrape my scope in a tarp so that i dont have to keep moving it in and out? as i'm a relative newby i dont want to damage my scope.

Thanks in advance for any help
Astro-angel

ballaratdragons (Ken) · #2 03-08-2005, 09:02 PM

Hi Astro-Angel,

I have the 12" dobbie as well and I haven't come up with another method than the springs. Mind you, I haven't needed too.

If no-one else has an answer I will try to come up with a simpler method.

It is probably not a good idea to just wrap the dobbie in tarp and leave it outside. I would be worried about the base absorbing too much moisture from the air (depends on where you live) and the Tube rusting. It would be better to put the whole thing on wheels, roll it in and out of a shed or garage when you use it and keep it covered in the shed.

asimov (John) · #3 03-08-2005, 09:06 PM

Not owning a dob, I can't help with the spring question. I often drape a tarp over my set-up scope at night, If I take a break from viewing just to keep the dew off it. But I wouldn't just drape the tarp over it & leave it out for day's on end. I'd rather see my OTA inside under cover! My EQ mount is a permanent fixture, so I built a sheet metal cover with wheels on it for it. I guess you could do something similar with yours? leave the dob mount out under a tarp or something & just bring the OTA in?

But a dob base being made of wood, you may have a problem with moisture/warpage etc in this weather. So probably not a good idea..

elusiver · #4 03-08-2005, 09:07 PM

check our Rajah's system.

http://www.iceinspace.com.au/forum/s...ht=balance+ota

el

seeker372011 (Narayan) · #5 03-08-2005, 09:09 PM

Quote:

Originally Posted by elusiver

check our Rajah's system.

http://www.iceinspace.com.au/forum/s...ht=balance+ota

el

is that the right link???

asimov (John) · #6 03-08-2005, 09:39 PM

Yep. Laurie's brake band setup on his dob, seeker.

Starkler (Geoff) · #7 03-08-2005, 10:36 PM

My scope, a 10 inch dob lives in my garage covered with an old bed sheet to keep dust off it. I move it around fully assembled on a cheap trolley/hand truck with inflatable tyres, $35 I think it cost me.

I think the issue with the springs is finding a way of pulling on them that wont hurt or strain your fingers. Consider attaching a piece of wooden dowel or similar to the end of the spring that you can grab with your entire hand to exert the necessary force.

rmcpb (Rob) · #8 04-08-2005, 09:05 AM

Possibly a combination of some of the ideas in this and the other thread would be useful here:

Use a trolley for moving the scope - if that works for you then problem solved, otherwise:
Maybe forget the springs.
Use some old speaker magnets with a felt covering for balance.
Use the fine adjuster for the small irritating movements we all have trouble with.

Worth a thought.

ving (David) · #9 04-08-2005, 09:42 AM

g'day. one of our forum member found it easier to put the spring on upside-down, ie: attach them to the base rather than the OTA and lift to put them on. if your scope doesnt over-balance with eyepieces in theres no real reason to use the springs tho. so if you can get away with out them do so.

as for moving the scope around, try purchasing a trolley like mikes (iceman). theres a link on the website to his trolley.

elusiver · #10 04-08-2005, 09:52 AM

also.. put keyrings on the ends of the springs instead of the little canvas type thingies.. that way you'll be able to put u'r full weight behind it when you stretch the string down without fear of the canvas thing snapping.

el

veloran · #11 06-08-2005, 12:01 PM

I have played with an 17" dob alot and from experience I have to say "put the springs back in!".
telescopes work on exact alignment (columation) and without the stabiliser springs the tube will be taking more vibration and shock then is good for the secondary mirror. In a dob or basic newtonian the secondary mirror out of columation to the primary is just death.
If you're a small lady then having to columate a 12".. it's not going to be fun at all as you have to be extremely precise..

A simple wheeled trolley will do the trick for movement... put him on one of those and 'slowly' push it where you want to go.
OR build a trundle system..
it's simply two long poles with wheels at the end.. put a bracket on each side of the mount that they can slot into from underneath and you now have a dob-Wheelbarrow which makes everything MUCH easier due to mechanical advantage (the weight is decreased by the fulcrum so it is lighter to move).

a 12" dob is not really a newbie level scope and needs special teatment.

1) If you really want to leave him outside a small shed and not just a tarp is a good start.. treat dobbie good and he'll treat you good (plus with a few golf-balls set in the roofs runners you can turn a shed into a moving roofed observing hut
2) telescopes don't like heat but need cold.. always keep it in mind when thinking location
3) always park him at zenith and always put on his tube cap.. moisture and dust will strip your mirrors coating (bigger the mirror bigger the cost to fix)
4) As a newbie you'll find tracking an object a lesson in humility with such a large dob. learn to track an exact section of the moon for 5 mins then bright star or planet for 5 mins.. if you can do that then start toying with the idea of photography with a dob.

slice of heaven · #12 06-08-2005, 12:15 PM

veloran, 17" dob sounds nice

You lost me on how the tension springs on the alt bearing affect the collimation

ving (David) · #13 06-08-2005, 12:50 PM

hi veloran!!!
welcome to the pleasure zone

thanks for your input

ballaratdragons (Ken) · #14 06-08-2005, 01:53 PM

Quote:

Originally Posted by ving

one of our forum member found it easier to put the spring on upside-down, ie: attach them to the base rather than the OTA and lift to put them on.

Yep! That was me David.

Astro-Angel, here is the link for the diagram of how to do it. It is a lot easier to get the springs on and off. And no busted knuckles if anything breaks.

http://www.iceinspace.com.au/forum/a...achmentid=1187