Equatorial Platform for Dobs in Oz?

[mswhin63 (Malcolm)]

I saw the TL systems design, one of the problems with that is it compromises on the radius to achieve variable latitude. The radius they use is not interchangeable. The front and back radius are fixed and only have the angle at which you place it. That goes against the principle of the EQ platform's number one aspect. To vary the latitude the radius and the angle need to change.

Motors are subjective, I am look at high accuracy in an attempt to get really long exposure imaging.
The servo control I am using is better suited for visual and planetary imaging.

[GraemeT (Graeme)]

Well, last Friday saw the trial of MkII, still having a few problems with vibration wobbles but I think I've tracked down the problem to the levelling feet ont the grass, so a redesign with pointed tips rather than flat is underway. Pictures should be attached - fingers crossed.

[GraemeT (Graeme)]

Rewind is achieved by loosening the knurled screw and manually winding back with the crank handle on the right. The right bearing housing has a microswitch to stop the lead screw self-destructing if I forget to watch it as it reaches the end of its travel. I got about an hour out of a 2200mAH Lipo battery.

[skies2clear]

Good work Graeme! Hope the new feet sort it out as that's often the problem on soft surfaces like grass.

Malcolm's point on the TL Systems platform is taken. Didn't research it thoroughly enough.

[Visionoz (Bill)]

The TL systems seemed to have had a bad rap; read a review previously - found another one cheapie which is quite impressive for the dough they're asking for - see here: http://atomicplatforms.com/pics.html

Shame that probably shipping to Oz is quite high for it

HTH
Cheers
Bill

[skies2clear]

Bill, thanks for the info on Atomic Platforms. Looked promising, but sadly would like to inform you, they are not interested in sending their product to Australia, or anywhere outside the US of A. Pity. They quoted a pretty pathetic excuse in my view, which sounded more to me like they don't know how to pack anything properly. So better left alone in that case, but thanks anyway,

Clear skies

[GraemeT (Graeme)]

Basic diagram:

[glend (Glen)]

Just bumping this old thread back up for a re-fresh. Having looked at the Eq Platforms available for Dobs (as mentioned here originally) I am leaning towards going with the Servocat Jr and hoping it will be able to handle my 16" GSO - anyone running that configuration?

[5ash (Philip)]

Originally Posted by jenchris

Pardon me being a bit thick, I thought the idea of an equatorial platform was to cant the base to make it point to the pole - which would be something like 34 degrees off horizontal in Adelaide.

More like 56 degrees off horizontal to get 34 degrees pointing at the pole , quite a steep incline for a heavy 16" dob .
Philip

[Satchmo]

Originally Posted by glend

Just bumping this old thread back up for a re-fresh. Having looked at the Eq Platforms available for Dobs (as mentioned here originally) I am leaning towards going with the Servocat Jr and hoping it will be able to handle my 16" GSO - anyone running that configuration?

I know of someone pushing a 16" binocular with one - if in doubt talk to the manufacturer. It doesn't cost much more for the beefier gear box that will push a 40" - it may be wise to buy one that will drive future 'scopes as resale of accessories is always at a big loss.

[glend (Glen)]

Thanks Mark, I have parked that idea for awhile. I did speak to Astro Devces and there will be no probem driving it from Sky Safari Plus. I realised my Pushto system was lighter weight, made no noise, and is much faster to target than any Goto system. The only advantage might be in tracking but not a real concern for visual use.

[Satchmo]

Hi Glen - I wouldn't understimate the power of having tracking - some say it is like adding a few inches of aperture. Having a truly still image allows your brain to really integrate the finest details properly and sort out the noise from the real photons. I had a Dob Driver on my 14" for a while and could see the benefit although it was not a system that was easy to use.

[BowenW (Bowen)]

Originally Posted by 5ash

More like 56 degrees off horizontal to get 34 degrees pointing at the pole , quite a steep incline for a heavy 16" dob .
Philip

I am in Adelaide, and have a DOB/EQ platform, and it has no chance in hell of falling off, I use it for 3 dobs ranging from 6" to 14" ( all use the same platform ) for some reason people seem to think that this type of platform is unstable, if you look at this image showing the range of movement you will see that the dob has no chance of falling off

http://www.equatorialplatforms.com/E...1-animiert.gif

image courtesy of http://www.equatorialplatforms.com

when I constructed mine I made 3 different sets of end plates ( for my 3 regular viewing spots ) it takes all of 2 minutes to change the platform from site to site, The one I use for home is set to my exact lat of 34.7. I will take some photos when i next set it up to show it with the dob at all extremes of movement. I have in the past knocked over my EQ5 with only and 6" Newtonian on perfectly level ground, when I tripped on a power cable for the drive, I cant even make the dob unstable on the platform, as the COG is way to low. The tracking is also just as good as the EQ5, and in some cases I would have to say even better. I chuckle to myself each time people make posts about how this type of platform is unstable, when there are 30" dobs sitting on them http://www.equatorialplatforms.com/osp.corwin.jpg

as long as you plan it correctly you wont have any issues. they are not hard to make and there are plenty of resources available on the net to show you how to go about it.

for those interested in building there own check out these to sites they have all the info you need to make your own.

http://www.reinervogel.net/index_e.h...Planung_e.html

http://homepage.ntlworld.com/molyned...l_platform.htm

choice is yours as to what style you build

clear skies...

B