12" Eq

[Adrian-H]

ive been thinking alot latey on ways i can improve and to start astrophotography, what do you guys think about geting a big chunky EQ GTO mount, and then going to the hardware store to buy some wood, and stick that big chunk of a 12" scope ontop of it? i find myself using my 6" just because it has a EQ mount. by all means im sure i could do it, i dont have many problems when it comes to crafts, then when im up to that part ill have to think about what i want to do next, most likey start with geting a camera and assential wares.

[[1ponders]]

It'll want to be a damn big and chunky EQ to start with. EQ6 would probably stuggle a bit for astrophotography with a 12" OTA sitting in it. For stability alone I would consider getting proper tube rings and dovetail to suit, rather than cobble one together out of wood.

What's the 6" scope your using? If it's a reflector and you are looking at getting into DSO imaging then you could certainly do a lot worse than starting there. 6" is plenty of aperture to start with. The bigger your scope the more robust your mount needs to be. An eq6 would handle a 6" relfector np at all. A 12" though would be a real struggle astrophotographically speaking. Not even sure a Losmandy G11 would be suitable. It might carry the weight for astrophotography, probably, but the lever arm movement would be too much for it I would think.

If it's a good 6" start with that.

[asimov]

This is a pic of my 12.5" newt, on my home built EQ. the mount alone weighs in close to 150kg. And even this mount finds it hard to keep her steady enough to do astrophotography. It's ok for visual use.

I must admit, the OTA alone weighs 40 kg. More heavier than a 12" GSO OTA I would imagine.

As 1ponders suggests, it's the lever arm action that kills it. It it we're in an observatory rather than outside it would work...the slightest breeze is enough to bring an imaging session to a complete stand still.

[Adrian-H]

now that looks nice, anyone have any suggestions for some very heavy strong computerized motor mount rings+dovetail for a 12" or parts that be used for a 12" that are very strong and stable, im sure with a long enouth rings and enouth counterweights it should hold up with a very sturdy mount, im sure some scmit rings are probly as large as 12" just gotta find some long thick ones, a slow motor would do alot better on friction then a faster one, personally only thing i want the motor for really would be photography, would be cool to let it dirft too

yeah by far the gso is alot lighter, the dob mount is the heavyest peice of the gso, physics is used in astronomy, you can use it to stabilise your scope too

[janoskiss]

Ken (ballaratdragons) was working on a custom built EQ mount for a 12" f5. I wonder how he is going.

Ken! Come back! You're needed over 'ere.

[Adrian-H]

maybe we should add a hydrollic arm!

[asimov]

Yes, Come back Ken!

[asimov]

Think stepper motors & big gearing reductions to drive it Adrian.

[[1ponders]]

You could certainly find a mount that would carry your 12" Adrian. It would depend on how much you were willing to spend, or how much time you were willing to put to building one.

[JohnG]

Hi

Might I suggest that you ascertain the weight of your proposed OTA, you then need to double it, to account for cameras etc. Then check out the carrying capacities of whatever mount you are looking at, for astrophotograhy you really need a mount with atleast 1/3 more carrying capacity than the combined weight of your equipment, suggestions...maybe a G-11, capacity - 30Kgs, probably not, EG-6, 25Kgs - probably not, Losmandy Titan, yes, 160lbs from memory, cost, well, this is the killer, $10,000 - $11,000, Assen Technolgies, more. As you can see, it starts to get expensive real quick. If you can hold of an old AO GEM, can't remember the name now, you might be able to upgrade the motors. Rings and dovetails, check this site
http://www.parallaxinstruments.com/
Lever arm movement has been mentioned, you need to carry the weight as close to the head as possible, put most of your weight up there and place a lighter one down further for balance, the reason, simply to stop the motors from ocillating when making a correction, the further you have the weight down the shaft, the more it takes to stop a motor and reverse it's direction.

Food for thought.

JohnG

[Adrian-H]

they look really nice

[asimov]

Your cheapest alternative is to have a crack at building one thats for sure.

Look around on the net...or in here for that matter, theres plans out there on how to build almost anything.

[Adrian-H]

the EQ6 mount can carry up to 40lbs, anyone know how much kg's a lb is? and how many lbs or kgs a 12" gso newt tube is?
i would allways end up buying a tracking platform tho

[janoskiss]

I just tried to PM Ken, but he won't accept PMs no more. :(

[Kieken]

One kilogram is 2.2 pounds I believe. And I think a GSO 12" F/5 newt has a weight of 15kg => somewhere around 33 pounds. Keep in mind that you are dealing with a pretty large tube so the slightest breeze can make the tube move.

Back here in Europe we have the OTE150, a nice German EQ mount with a PE of +-5" (not sure though). It costs as much as a G11 but can handle 70 pounds visual and 55 photographical. A dealer puts 14" F/4 newts on it and sells them as "perfect" imaging platform. To bad it's as ugly as hell ;).

[lost_in_space]

Hi Kieken, I am heading down this path myself in the future, and I don't give a flying fat rats attitude as to how ugly it is, it is the view in the EP that counts. Do you have a link?

[Adrian-H]

What are you talking about the GSO is a Wonderfull looking Trash ca... errr i mean telescope, some people make there shower caps ,dewcaps for there gso

[Kieken]

Here (http://www.teleskop-service.de/OTE/ote150.htm) you have the German page of the OTE150. I'm still looking for a decent English page but I think it's pretty obvious what you can find there. If there are problems with language or so just pm me.

EDIT: This (http://members.aon.at/astrofotografie/fr_ueber_mich.htm) guy uses the OTE150 in combination with a 10" F/4.8 for shooting pictures. Again, this site is in German.

EDIT 2: This (http://www.astrofotografie-laupheim.de/index.php) guy uses a 12" newt on the OTE150. But I guess it's an F/4 and lightweight.

[Adrian-H]

i like the eq mount

[Starkler]

Google translator to the rescue

http://translate.google.com/translate?u=http%3A%2F%2Fwww.telesk op-service.de%2FOTE%2Fote150.htm&langpair=de%7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools

[JohnG]

The name of the mount I was trying to remember was the Astro Optical Supplies, Samson, if you can find a second hand one of these you would be more than able to carry that OTA, have a look at Paul Mayo's (PhotonCollector) site and you will see his setup.

JohnG

[[1ponders]]

I think Scott (Tornado33) uses a samson as well

[JohnG]

I seem to remember an Anssen mount for sale on the Buy, Sell Forum last month, Stella2 or similar was the seller, don't know if it was sold or not.

JohnG

[netwolf]

I have previously found this site (Same one as the one posted for OTE150 mount) has the weight and other specs for GSO and Orion dobs.

http://www.telescope-service.com/dobsonians/dobsonians/dobsoniansstart.html#gso

The 10" GSO Tube is 15kg, the 12" GSO tube is 19.5Kg

I too have been looking at EQ mounts to suit my 10" dob for a while.


Regards

[Adrian-H]

thanks you guys are really helpfull, keep shooting ideas in if you get them , the more, the more options, i wanna find something that is gonna love that 12" for the rest of its life i hope. but not overspend on it. hopefully it will turn into something of a good DIY review.

[Kieken]

Though EQ mounts are cool I think we are forgetting something (if someone else did mention it in this thread then I just blame my sleepy head for not noticing it ;) ).

What about a good equatorial platform? I've seen a couple of images made with them and they look pretty good. And it would be more stable then a "cheap" EQ mount + it would be cheaper.

[Adrian-H]

id probly spend about 2-3k tops

[Kieken]

Well 2~3000$ is not much for a EQ-mount for imaging. And I guess you would like to use it for visual to, right?

Here you have two links to platform makers. One is from Osypowski (http://www.equatorialplatforms.com/). Some say they are the best. Don't forget to check the astrophotography section. The other company is Johnsonian Designs (http://www.johnsonian.com/). Their models are cheaper then those of Osypowsky.

Another option is buildinf one :).

[Adrian-H]

i change my mind im geting an equatorial plat thanks for all the idea's they where all great makes me think now hey the fact that a dob can hold up so much weight you can do some really awsome things with it, that you cannot with a EQ, so i think i want to go with the low limitations on scope weight, probly gonna pop my dob heavy with afew mods after i get a EQ Platform, added a mmmm telrad today!