#261  
Old 05-05-2007, 10:00 PM
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RB (Andrew)
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Congrats Jerry, great setup.
May I ask what baseplate you're using between the TOA and the EM400?
I've got the same setup, TOA 150/EM400, but love how you've set yours up with all the extra bits.

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  #262  
Old 05-05-2007, 10:37 PM
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Omaroo (Chris Malikoff)
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Hey Paul - where's the rest of the counterwight? How much do you have on?
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  #263  
Old 06-05-2007, 08:36 AM
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Offset Plate and Counter-weight

Offset Plate.

The offset plate is a plate of 6061 Aluminium (would prefer 6081) which has small ammounts of Titanium and Cobalt etc. The plate is 12.7mm thick and weight 3.79 Kg. I calculated the offset dimensions (by hand). All bearing surfaces (EM400 drive boss etc.) are machined. The holes on the RHS are M8 drilled and tapped for accessories. The holes for the TGM-2 mount are countersunk(also tapped). And finally the plate was anodised.

Counter Weight

The total counter weight as seen is 19.5Kg and as shown is "bottom heavy". The little green weight on the end (replaces the safety screw) was made from lead out of battery terminals (all my fishing weights melted!!). This weight has a bolt molded into the lead so it screws in as a replacement "screw". The counter weight was calculated(by hand!) before I made it. Please note that the bottom weight (3.5 Kg) in right on the end of the weight shaft so its effect is maximum. Also the total load, by design is closer to the RA drive axis than in the original Tak design because of the use of the high strength of the structural alloy used in the plate.


Hope this explains things,

Jerry
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  #264  
Old 06-05-2007, 10:15 AM
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Hi all,
Here's a shocking photo of me and my new toy.
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  #265  
Old 06-05-2007, 10:22 AM
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Hi Duncan, is that your radio telescope in the background.

Nice scope
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  #266  
Old 06-05-2007, 10:27 AM
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I don't think the missus would let me convert it LOL. I was going to take some photos today but my little darling took the camera up to Mt.Garnet Rodeo. LOL
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  #267  
Old 07-05-2007, 10:40 PM
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Dragging out the old friend.

The yard imaging cannon is nearing readiness...

After a six-month hiatus, I;ve dragged out the 12" LX and have now fitted one of the William Optics 66mm Petzvals as guide scope. The new larger dew shield I made is felt-lined and seals around the OTA beautifully. The slight extra weight of the shield is good as it offsets the weight of the cameras and G/S. I'm still to fit the lower 2-D counterweight and also need to rotationally balance it around RA. The Dec motor on one fork, along with the GPS affect the balance so I need to occupy the battery recess on the other fork with around 1.25kg.

Should be out and about as soon as I can get GuideDog to run properly on the older (read: semi dew-dispensible) lappy.

There goes the back again........

Cheers
Chris
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Last edited by Omaroo; 07-05-2007 at 11:03 PM.
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  #268  
Old 07-05-2007, 10:47 PM
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She looks beautiful Chris

But I'm a little bit biased

Cheers
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  #269  
Old 07-05-2007, 11:00 PM
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hehe.. of course you are Ric Large SCT's with piggy-backed scopes all mounted on a wedge really are a thing of beauty though, aren't they? I can't wait to see if I can get a good polar alignment now......
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  #270  
Old 07-05-2007, 11:12 PM
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I have also been toying with the idea of a piggy back scope as well, maybe an ED80. but the wedge must come first and I only have enough brownie points for that at the moment.

Cheers
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  #271  
Old 08-05-2007, 03:25 AM
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Quote:
Originally Posted by 74tuc View Post
Offset Plate.

The offset plate is a plate of 6061 Aluminium (would prefer 6081) which has small ammounts of Titanium and Cobalt etc.
Thank you for the info Jerry, I've admired your setup since I first saw it in an featured in an ad in one of the local magazines.

I'm looking forward to setting up my TOA150/EM400 up soon too.

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  #272  
Old 08-05-2007, 07:17 AM
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marc4darkskies (Marcus)
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Quote:
Originally Posted by 74tuc View Post
Here are pics of my imaging and visual setup showing:

1. A TOA 150 refractor for general viewing and photography.
2. An 80mm guidescope on the guiding mount,
3. A Canon EOS 350 with a 20 - 200mm lens(USM) for widefield shots.

Jerry.
Nice to see other 150 owners - very nice setup there Jerry! See my signature below for a link to my stuff! Have you noticed any differential flexure with your TGM?

Cheers, Marcus
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  #273  
Old 08-05-2007, 06:58 PM
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Hi Chaps,

Thanks for the good words and Marcus I've looked at your first pic on pbase and I think it is very impressive. I like the detail provided with your 'scope/camera. When the financial dust settles here I might consider getting a camera like yours. I told the financial controller here about the wonderful camera you had (she was cooking at the time), she sought of went stiff then started hurling vegies into the wok with more force than I thought was necessary. I walked away without saying a thing and surfed the web .

Re: Differential flexure.

I am sure the TGM gives negligible the plate flexing will cause more DF. DF can be managed in my case as I do not use focal lengths longer than 3000mm.

The problem I have is that I cannot prove to myself the minute blemishes are caused DF alone. Off axis the star image distortion is caused by spherical aberration (no field flatner), polar alignment inaccuracies, and DF.

I have made a counter weight for the guidescope/mount combination but not installed this weight as the system is still under test.

The main thing is to choose a guide scope matched to your system and choose one that is as light as possible. The optimum guidescope is smaller than one chosen by common rules of thumb. I use an achromatic refractor with a green filter and a B&W guide CCD. Chromatic aberration (and other distortions) has the effect of reducing the guiding accuracy. I am writing a note (partially complete) for the ASSA on the relation between the main 'scope/imaging CCD and the guidescope/guide CCD. I'll pass this on to you when it is completed.

Regards,

Jerry.
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  #274  
Old 08-05-2007, 08:56 PM
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marc4darkskies (Marcus)
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...I told the financial controller here about the wonderful camera you had (she was cooking at the time), she sought of went stiff then started hurling vegies into the wok with more force than I thought was necessary. I walked away without saying a thing and surfed the web .
Try bribery - worked for me!

Quote:
Originally Posted by 74tuc View Post
...I am writing a note (partially complete) for the ASSA on the relation between the main 'scope/imaging CCD and the guidescope/guide CCD. I'll pass this on to you when it is completed.
I'd be very interested to see that - thanks Jerry! Email me.

And thanks too for the kind words on my first image ... now if only the moonless nights would coincide with some clear skies for a change!!

Cheers, Marcus
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  #275  
Old 08-05-2007, 09:04 PM
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Here are my humble scopes. The ED115S is not pictured as it's up for sale!

It's incredible to think that I bought the semi-apo Megrez for 679 UK pounds when they first came out, and now you can get an ED80 for less than that in dollars.


Morton
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  #276  
Old 08-05-2007, 10:35 PM
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Hi Morton,

I'm interested to know how much you want for the ED115 - I have a friend who might be interested. Please send me a private email - thanks.

The wide field views through the Megrez would look excellent (?). Next time there is a clear night look at the Stargate asterism at about x50 - tell us what you see. I am most interested.

Marcus,

I'll try the bribary thing later - I'll not lay it on too thick, though - she's got a bit savvy on the cost of things astronomical!!

Re Guide Scopes: I'll send you the first installment on Thursday - I'm off work tomorrow(Wednesday).


Clear Skies,

Jerry.
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  #277  
Old 08-05-2007, 10:45 PM
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The ED115 has just sold. Sorry.

Morton

P.S. Excuse my ignorance of southern skies - what's the stargate asterism???
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  #278  
Old 08-05-2007, 10:54 PM
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Hello Morton,

Sorry about the 'scope - Such is life.

Stargate? see:

http://platformx.sourceforge.net/Name/index.html

Jerry.
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  #279  
Old 08-05-2007, 11:04 PM
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Nice - definitely worth looking for.

Morton
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  #280  
Old 25-05-2007, 06:21 PM
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Starkler (Geoff)
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The ED115 has just sold. Sorry.
Sold to me in fact

Heres a couple of pics of my new toy
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