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where to find focuser flange for binoed refractor

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#1 gonzosc1

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Posted 18 August 2013 - 01:39 PM

I have an ES 152 refractor and in focus is limited of coarse for BV. I'm trying to work out the in focus problem without cutting the ota! so I would like to find a flange to puts the focuser closer into the ota.

The ES flange sticks out 3-4 inches from the ota. the plan is to get shorter flange, another focuser with shorter draw tube as to not cut into light cone. this way the ota can be used binoed or mono with just a quick swap out of the flange/focuser.. 3 screws and its done.....

ideas?? thoughts???

#2 Eddgie

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Posted 19 August 2013 - 09:07 AM

Not at all clear on this. You said "3-4 inches." I am trying to envision a flange that sticks out this far.

Did you mean 3/4ths of an inch?

If not, perhaps a picture would help so I can see what you are talking about.

In the mean time, I recommend that you find a PDF of the Maxbright Binoviwer User's Guide.

If your scope will focus with a 2" diagonal, there is a good chance that it will reach focus with a Maxbright binoviwer and a 1.25x GPC.

The Owner's guide tells you how the in-travel for different Maxbright configurations.

To measure your in travel, rack your focuser all the way out and tape a piece of white paper over the end where the eyepeiece goes.

Now, point the scope at the moon and rack the focuser in while watching the projection of the moon. When you see the moon come to focus, measure the distance from the joint where the focuser tube mates to the visual back to the rear of the focsuer tube housing (where the visual back bottoms out). This will tell you your in-travel (and how short you will be from raching focus) and you can use the user's guide to determind how much GPC you would need.

Buying a new focuser is not an inexpensive proposition, but without knowing what you are tying to do (no picture) it is hard to provide much additional info.

#3 gonzosc1

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Posted 23 August 2013 - 07:50 PM

by flange I mean the part between the focuser and the ota. it cones out about 3". I would like to find something that does not cone out like that to bring the focuser closer in.

yeah cost of focuser can get out of hand but not looking for the top of the line one either.. figure I could get a like focuser with a shorter draw tube.

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#4 Tamiji Homma

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Posted 23 August 2013 - 08:40 PM

You might want to contact Precise Parts.

www.preciseparts.com

I did something similar a few years ago since I was going to use Starlight Instruments FT3445 focuser, I asked Starlight Instruments to build custom flange to mate my OTA (William Optics FLT 152) with FT3545 focuser.

I unscrewed stock focuser and sent to them and they did measurement and figured out what was required and made custom flange for me. They sell the same flange as standard product now. It took several months and many email exchanges. They are really good but it costs and takes time.

If you know the spec of the OTA thread and focuser, you could specify what you need using online tool,

http://www.precisepa...in/adapter.html

I have made several custom adapters by Precise Parts. I am a happy customer. They are fast and reasonable (relatively speaking :)

I mean anything custom built costs and takes time.

Tammy

#5 Eddgie

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Posted 23 August 2013 - 09:58 PM

Well, before you do that, make sure that there is sufficient clearance for the focuser tube when it is in its new forward position.

If there are baffles close to the end of the current focuser tube, moving the focuser in might not buy you anything because it could be that the front of the focuser will now hit the baffle.

I have this situation in my 6" APO. The baffle prevents me from cutting the tube to much because I am already almost hitting it.

I could go to a shorter focuser tube, but then I might not have enough travel to reach focus with my 31mm Nagler, and that would make me sad. :(

#6 gonzosc1

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Posted 24 August 2013 - 03:47 AM

Well, before you do that, make sure that there is sufficient clearance for the focuser tube when it is in its new forward position.

If there are baffles close to the end of the current focuser tube, moving the focuser in might not buy you anything because it could be that the front of the focuser will now hit the baffle.

I have this situation in my 6" APO. The baffle prevents me from cutting the tube to much because I am already almost hitting it.

I could go to a shorter focuser tube, but then I might not have enough travel to reach focus with my 31mm Nagler, and that would make me sad. :(


ok so we are in sort of the same boat here with the 6'ers. when I can I will pull the flange to see what the baffling looks like. I will also do as you said earlier and determind the in travel measurement.

#7 Eddgie

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Posted 24 August 2013 - 07:49 AM

Oh, and I guess you need an answer to your question.

Many of the focuser companies sell adapters to match the focuser to different size OTAs.

I know that in my own case I bought a Feathertouch focuser for my 6" APO and Starlight Instruments made an adapter for me. It was not nearly as much as I thought it would cost to have a custom made adapter, though the total cost was something like $180. The did the CAD design for $85 I think, and then the balance was to produce the part.

Sounds though like you would be better off looking for someone that sells an off the shelf adapter.

#8 gonzosc1

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Posted 24 August 2013 - 08:55 AM

yes an adapter would be best for me to keep cost down. I have been looking arould and found that GSO and Antares sells focusers at a decent price.
they list adapters for the meade AR6. so need to do some home work on the measurements between the two to see if the meade adapter would fit the ES ota....

#9 tim57064

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Posted 24 August 2013 - 12:43 PM

I have the same problem with my CR-6, not enough in travel to use bino viewer.It is very disconcerting to have spent so much on duplicate eyepieces and not being able to use it in my Refractor. Works really well in my SCT's.I will be watching this thread for more info.

#10 Messyone

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Posted 24 August 2013 - 06:24 PM

Tim I did a thread on my refractor just recently. Can't do a link to it, somewhere a couple of pages down. Changing the focuser to a GSO Linear Bearing was the first step and using a 1.25" prism diagonal works great. The latest mod got me to use the WO's without an OCS.
Matt






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