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Dr Benway
professor emeritus
   
Reged: 03/27/08
Loc: Abilene, TX
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: Luigi]
#3172953 - 06/20/09 10:00 AM
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It is very stable. The picture shows it in the park position. It does look like the CG is very exaggerated. Things look very different once you actually slew to an object. Meridian flip is not an issue with this set-up. Advantages over something else? None that I can think of. I also use a GM-8 with autoguider for longer exposures. I set this up as a quick grab and go for 2 minute unguided exposures, which suits the Hyperstar3 (F/2) just fine. As to the sow's ear, many people swear you can't run a mini tower in EQ mode.I built this rig to prove them wrong. I had been shooting in alt/az for several months with good results, but was limited to field rotation. My longest exposures were limited to 40-56 seconds, depending on what part of the sky I was targeting. This set-up solved that problem.
John
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Dr Benway
professor emeritus
   
Reged: 03/27/08
Loc: Abilene, TX
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: Dr Benway]
#3172996 - 06/20/09 10:24 AM Attachment (131 downloads)
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Here is Steve Forbes' Mini Tower wedge setup with a C8...
John
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EdTheEdge
Pooh-Bah
Reged: 04/10/09
Loc: Lomita, CA
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: Dr Benway]
#3173062 - 06/20/09 11:30 AM
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The more I see these mounts the more I want one!
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Eric Gage
scholastic sledgehammer
   
Reged: 12/13/05
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: EdTheEdge]
#3173905 - 06/20/09 10:54 PM
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Pardon my ignorance, but what is the point of the wedge? I tend to doubt that the wedge will provide the alignment accuracy necessary for astrophotography, and visually, it throws off the eyepiece ergonomics.
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Luigi
Postmaster
   
Reged: 07/03/07
Loc: MA
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: Eric Gage]
#3174606 - 06/21/09 01:07 PM
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Does it have autoguiding inputs?
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StarStruckCarter
member
Reged: 08/31/08
Loc: Manchester, NH
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: Luigi]
#3191931 - 06/30/09 10:22 PM
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If you talk to Steve he will inform you that he designed the wedge to be fully adjustable from 0 - 90 degrees.
He will also tell you that the wedge should be pointed north and that one tripod leg should be placed under it on the north.
Steve sent me an email where John Bozeman says that the MT is apparently able to autoguide with Meade Maxim DL. He's waiting for clear weather to confirm this.
According to Steve, he originally noticed that the MT was being supplied with the same controller that was included with the gotonova. He realized the potential of the combination and when he was told it wouldn't work, took it as a challenge. I'd say that he has proven his theory that it can work in both modes.
I have noticed that Steve uses his with a CG5 or Orion Atlas tripod instead of the factory one. They are taller and stronger.
As for polar alignment, after a 3 star alignment the controller provides an error report which allows one to dial in the alignment in only a few tries.
jhc
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GaryML
sage
   
Reged: 02/16/09
Loc: San Diego, California
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: StarStruckCarter]
#3192050 - 06/30/09 11:32 PM
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I don't mean to be rude, but I simply don't understand why anyone would want this Mini-Tower wedge system.
The Mini-Tower costs $800. The bearing upgrade costs $300. The wedge costs $380. So now we're at $1480 (and even more if you need to add a bigger counter-weight shaft and/or other parts). And what you have something without a polar alignment scope or any other polar alignment method, looks rather unbalanced on the tripod, has just a skinny tripod, supports 25 lbs at best, and has no manufacturer's warranty (just the store warranty).
You can buy an Orion Sirius for $1200, a Celestron CGEM for $1400, or a Losmandy GM-8 (no Gemini but with motors) for $1500. These mounts will clearly work better for imaging (e.g., auto-guider port, polar scope and/or polar alignment software), are much more stable, supports 30-40 lbs, and have a manufacturer's warranty. Why would anyone want the Mini-Tower with the wedge when you can get a real GEM mount with much better performance for the same money or less?
This Mini-Tower wedge may be interesting as a DIY hobby project, but I can't understand why anyone would buy one.
Edited by GaryML (07/01/09 12:32 AM)
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Dr Benway
professor emeritus
   
Reged: 03/27/08
Loc: Abilene, TX
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: GaryML]
#3192836 - 07/01/09 11:42 AM Attachment (128 downloads)
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I spent this last dark cycle field testing the Mini Tower on the wedge in EQ with a C8, Hyperstar3 and QHY8 OSC. It is pretty easy to get a good alignment, as mentioned above.
The autoguiding software Steve mentioned is Orion's Maxim DL Essentials for the StarShoot DSCI II. The only reason I recommended this is because PHD Guiding doesn't support the camera. I found that the GotoNova ASCOM driver will communicate with the mount via the USB cable, so I feel pretty certain it will autoguide. I will test this feature next time out.
I got good pictures at 90 seconds exposure unguided. Each night I had a breeze to contend with, resulting in a few tossed frames.
Here is a widefield shot of M8 & M20. This was 7X90 seconds stacked in DSS, processed in PixInsight and Photoshop 7.
John Bozeman
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Luigi
Postmaster
   
Reged: 07/03/07
Loc: MA
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: Dr Benway]
#3192971 - 07/01/09 01:05 PM
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>>>but I simply don't understand why anyone would want this Mini-Tower wedge system<<<
Stand out in a crowd, go against the grain, follow a different drummer, turn a silk purse into a sow's ear, to prompt individuals to ask why would you do this?
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Wes James
Postmaster
   
Reged: 04/12/06
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: Luigi]
#3193015 - 07/01/09 01:24 PM
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Looking at this setup- it just looks like it's going to put a lot of strain on the Mini Tower mount. With the mount's normal position- vertical- all weight is supported in a vertical direction- down- perpendicular to the shaft. The weight is being supported in the bearings, equal on each side (assuming a reasonably well balanced load). There is no side thrust/load on the bearings. When you tilt it up 20-30- or 40 degrees on its side, now you're placing a lot of side thrust on the bearings and drive train that its not normally encountering or designed for. Comments? I've never seen inside one, so I may be way off base. Have been following the MT with great interest, though.
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Dr Benway
professor emeritus
   
Reged: 03/27/08
Loc: Abilene, TX
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Re: iOptron Mini Tower with Trapezium Wedge
[Re: Wes James]
#3193051 - 07/01/09 01:50 PM
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It has aftermarket Timken precision bearings installed by Steve Forbes at Trapezium Telescopes. Trust me, it is built like a tank. I imagine the load limit is probably much higher, as well. I know Steve ran a C11 on the upgraded mount at the Winter Star Party without any problems.
John
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