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Old 29-01-2009, 02:37 PM
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turbo_pascale (Rob)
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2" focuser for 65ED

I have a Burgess 65ED Backpacker, which is a nice little "part built" OTA (a very nice little gift from Greg Bradley!)
They were $20 scopes which for whatever reason didn't get in to full production and then were sold in a kind of fire-sale to the ATM market. They came without a focuser. The glass if FPL53, so is high quality. The problem with them was they required some mods to collimate them properly (See link: http://www.astronomyreviews.com/ed65/ed65fix.htm)
Subsequently, they made a focuser (rack & pinion) which is 1 5/8".

What I would like is a proper 2" focuser (preferably crayford), so I can use it with my DSLR. The problem is the OTA diameter to mount the focuser. The inner diameter is approx 71.5mm, the outer diameter is approx 74mm.

I can't seem to find one of these anywhere. Clearly, I'm a bit anxious about spending a fortune on a focuser when the scope was $20, but a 65mm with ED glass is kind of nice for some widefield imaging, and also, as the name suggests, portability.

Anyone got any ideas on if there is something appropriate I can use? I'm not necessarily keen on getting someone to machine an adapter unless absolutely necessary. Several people have used an Antares focuser, but at approx US$150 seems over the top, especially as it still requires an adapter and modifcations.

Turbo
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Old 30-01-2009, 07:13 AM
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mick pinner
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hi Rob, l could machine you up an adapter for free if you end up needing one. PM me if necessary. Mick.
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Old 30-01-2009, 10:53 AM
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turbo_pascale (Rob)
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Thanks Mick.
I found out that Burgess still had some of the R&P focusers, so I got one to test it out (was cheap). Apparently they aren't horrible and do the job. If they can't quite hold the weight of the 350D, I'll be in touch. Thank you so much for the offer.

Turbo
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Old 05-10-2020, 08:29 PM
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turbo_pascale (Rob)
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Just for fun, I'm reviving an 11 year old thread.

After the recent talk of the new Radian Raptor 61, I remembered that I had in a box an old Burgess Backpacker 65ED, that I never got around to finishing the project for.

To be honest, not sure I even understand the need for a super-wide field scope, especially since I have access to a Canon 70-200L f2.8 which I can use which is going to be a similar focal length on my crop sensor DSLR/ASI1600MM.

In any case, I pulled out the scope, and went to check the collimation, which I never got around to modifying the scope to fix the known problems.
It was horrible - as expected.
Attached is a crop from my ASI290MM of an artificial star (the very bottom two stars are reflections off the torch bezel) from both my 80ED and the 65ED

The link for the fix is here:
http://www.astronomyreviews.com/ed65/ed65fix.htm

Now, after waiting for over 11 years to get to it, finding the setscrews and o-ring and tapping kit threatens to cost me more than the entire scope did (given I have to buy the set screws in boxes of 100 I'm looking for M4x5 as a close equivalent)

Does anyone know where I can purchase the parts listed in the link above relatively easily. So far, without buying in bulk, eBay shipping from China sometime around Christmas seems to be my only option. I'm sure it's just not knowing where to look.

Hey
Quote:
Originally Posted by gregbradley
gregbradley
, did you ever do yours?

I'm also interested if this works, to attempt to fix my Orion ST80, as it exhibits similar traits (I only use it as a guide scope, so it's not all that bad for that purpose)
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Click for full-size image (Artificial Star - Saxon 80ED.png)
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