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ever seen a dobsonian mount for a cassegrain?

Started by toml, 01/19/2009 03:06PM
Posted 01/19/2009 03:06PM Opening Post
i'm thinking of taking my 6" mak traveling (morocco!) which is airline portable but the mount/tripod etc is not. very not.

so i'm thinking of making a collapsible dob mount for it. not super tall so i'm counting on finding some outdoor tables to use when i'm there.

not perfect but usable is my goal.
first i need inspiration. i need some pictures or links you may have in your bookmarks.

please share. thanks!
tom

Posted 01/19/2009 05:41PM #1
I've seen an SCT on a homemade Dob mount atop a tripod at a star party but I don't have a photo of it handy.

Dave Mitsky

Chance favors the prepared mind.

De gustibus non est disputandum.
Posted 01/19/2009 05:48PM | Edited 01/19/2009 05:49PM #2
Tom Lacovik said:

i'm thinking of taking my 6" mak traveling (morocco!) which is airline portable but the mount/tripod etc is not. very not.

so i'm thinking of making a collapsible dob mount for it. not super tall so i'm counting on finding some outdoor tables to use when i'm there.

not perfect but usable is my goal.
first i need inspiration. i need some pictures or links you may have in your bookmarks.

please share. thanks!
tom


Hi:

I suggest considering some sort of ALT-AZ head on a solid photo tripod as an alternative. MAKs are short and work reasonably well with a mount that puts the scope alongside the head. There quite a variety of such mounts, the Vixen Portamount, the Unistar, etc. My C-5 works reasonably well this way just using a Bogen 3040 with a 3047 head and the scope mounted sidesaddle.



Jon

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jonisaacs's attachment for post 127490
Posted 01/19/2009 06:23PM #3
You would likely wand to build an offset Dob. mount like that used for a refractor. In this example a local rock would serve as the counterweight. Also you would likely need to build a box to hold the tube and attach the side bearings to.


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AstroJack's attachment for post 127491
Posted 01/19/2009 07:18PM #4
Hi All,

This is not my scope but I do admire the design and may copy it someday. Hope this helps.

Keith

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klawson's attachment for post 127495

Scopejunkie


40 year old restored C14 with recirculating cooling w/Skywatcher DOB GOTO Conversion (CPC14)

Synscan DOB mounted Sky-Watcher Evostar 150mm/1200mm ED Refractor

"Rescued" Craig's List Orion 120mm/1000mm Refractor


USAF Vet




 
Posted 01/19/2009 07:28PM #5
Tom,

WHile the idea of adapting a dob mount for this purpose has an appeal to the ATM junkie in me, --I cannot imagine anything you build being any more packable than a small photo tripod with the proper scope attachment. And it sure would be a lot more flexible and easier to use.

Alex
Posted 01/19/2009 09:49PM #6
Another option would be to build something similar to Orion's 6" starblast design that folds.
Posted 01/19/2009 10:59PM | Edited 01/20/2009 12:09AM #7
Thanks all for the discussion so far. I've made a numbered picture of my junky basement to facilitate discussion!

So: here's my basement, and all manner of my stuff, Have a good look and a good think, then tell me: what would you do? build a collapsible dob mount thing, or try to make something out of the parts shown here?

I also agree that a tripod and alt az head may work, but my concern with that is 2 fold:
a) the Intes (1 in the picture) weighs 10 pounds, not that i'll be doing imaging, i just want it to stay upright... not sure if the N60 i have will do that. if i get a vixen portamount i probably can't use the N60 tripod as well.
note: i can handle a bit of vibration (i'm roughing it after all).

b) the legs of the lightweight N60 tripod (3) are going to take up precious luggage room.

Referencing the photo below.
(1) MK67 10 pounds fits in the pelican case just barely.
(2) a Nexstar 60 mount used for my solar scope (good find on craigslist $65! including a 60mm refractor in the corner (5) i never used.) -- that plastic ring adapter on it appears to come off. i'd have to buy/make a ring if we think the N60 can even hold 10 pounds? note that the shape/size of the n60 mount is such that it fits in right alongside the mk67 in the pelican. no prob.
(3) the legs from the N60, the spreader could come off and the legs could lay flat in my luggage diagonally, too bad they don't get any shorter than that.
(4) the bottom bit of the N60 head...screws on under tripod.
(5) the 60mm refractor... not in use
(6) a smaller lighter phototripod, but has a video head on it integrated, don't think i can use that for anything but a digi cam... just including it to show desired size or if you get any ideas.
(7) spreader tray / stablizer... may just leave this at home.
(8) coronado scope that normally resides in the N60 mount (that's why i picked up this mount from craigslist)
(9) a nexstar 8 with a Ray's Bracket, on a beefy tripod. This is NORMALLY used to hold the intes mk67.
(10) the N8 beefy tripod. not travel friendly!
(11) peekaboo-my hand build 13.1" string dob...you can just barely see a pole mount block here. the message here is i CAN build stuff if needed. but don't need to for it's own sake... only if we think it's a good idea.

so, what do we think ... make a collapsible dob mount?
example minus the tripod:
http://celestialwonders.com/dob4sct/index.html


use the parts here after making a ring?
or buy a vixen portamount or ministar instead (can i then use this tripod (3)? or if i do have to buy legs are there some that collapse smaller?)
example:
http://www.universalastronomics.com/


Thanks for putting all your heads together folks!
Tom


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