Has anyone seen or used a Boren-Simon Astrograph?
Posted 06 July 2010 - 01:59 PM
I'm a bit intrigued to say the least, but I can't see much in the way of information/user generated images from these things. Searching various places yields images taken by one of the "creators" of this scope.
Faced with this or a Tak Epsilon 180, I'd obviously prefer the Tak but my wallet would much prefer this scope. Imaging is my main/only use for this scope so I'm not worried about visual performance.
I can live with a few corners cut quality wise to save $2500.
Posted 06 July 2010 - 07:19 PM
Note that one of the correctors even has the 65mm backfocus specified in the scopes web site.
Buying one of the higher spec'd correctors and putting it on a cheap newt would still be way cheaper than buying this package....
There's plenty of stuff around on Keller correctors. Just google. They are very highly thought of. I will one day buy one for my GSO newt.....especially since they can be swapped from scope to scope...imagine a 16" cheap Meade dob put on an eq mount and converted from f4.5 to f3.3 !!!!
hope this helps...
Posted 07 July 2010 - 10:51 AM
In my mind, a key factor in the success of this will be keeping the tube flex out of the equation. With a heavy camera, the tube will flex, getting the corrector (and camera) out of collimation. If that's in check, then just having a focuser up to the task of f/2.8 or so. I'm not seeing anything in there to stiffen up what looks to be a normal rolled-steel tube. The end-cap there so close to the focuser helps a good bit and the tube ring placement can help a lot here too. But, this is a battle I've fought several times and it's something to be aware of.
- PascalN likes this
Posted 07 July 2010 - 07:06 PM
The Boren-Simon has a stainless steel tube, and given what you've just stated Craig I suspect it's a battle I don't feel like fighting myself. Just to clarify though, are you suggesting adding this corrector into the AT8IN to make it an F/2.8? That would be an interesting endeavour. If that's essentially what the powernewts are it could be a worthwhile one too.
Posted 07 July 2010 - 07:33 PM
Posted 08 July 2010 - 09:40 PM
I do not mean to speak poorly of the AT scope, but I'm not all that certain that one can take the AT scope, insert a Keller corrector, and wind up with the same quality instrument that the Boren-Simon claims to be. It has that "too good to be true" ring to it... and I can't tell you how many times I've eventually paid twice as much by trying to save money on the initial purchase.
Posted 08 July 2010 - 11:20 PM
Shady indeed. But I've e-mailed the question.
Edit: The GSO 8" Newt claims to have a "1/12th wave" mirror, so lets not be fooled, unless Zambuto has moved overseas.
GSO Page: http://www.gs-telesc...ntent.asp?id=79
Posted 09 July 2010 - 05:48 AM
A corrector can only flatten the field and lower the focal ratio. It cannot improve upon the optical quality of a so-so mirror. I'm not saying that the Boren-Simon mirror is superior to that used by AT. In fact, they may be one in the same. I have no way of knowing and no means of comparison.
But the entire cost of the AT scope (OTA, mirrors, dual focus Crayford, spotting scope and rings) is $450. So is anyone really suggesting the addition of a $900 - $1,800 Keller corrector on a $450 telescope? Perhaps the wisest thing for the OP to do is to bide his time... and save his pennies... and wait for others to review the B-S (no pun intended) astrograph, rather than consider buying a really inexpensive scope and a lot of expensive lipstick to make it look pretty. - Just my $.02
Posted 23 August 2014 - 06:43 AM
any more experiences with these rare birds?
or is tak epsilon the only game in town?
Posted 23 August 2014 - 04:21 PM
I don't see the website for the Boren Simon Powernewts anymore (are they still in business?), but I did find this:
People trying to modify the AT8IN to make their own "powernewt" have lots of collimation problems requiring them to beef up the OTA and focuser.
The Tak Epsilon is more expensive but I understand it is flat across a full frame 35mm sensor or bit larger, but the PowerNewt is designed for the half frame crop sensor.
Here is another fast and expensive 8 inch astrograph:
Edited by gdd, 23 August 2014 - 04:34 PM.
Posted 24 August 2014 - 12:51 AM
I bought an AT8IN and an ASA Keller reducer.
I replaced the focuser with a Feathertouch (with motor) and reinforced the tube. I also had to get a CatsEye XLKP because the thing is incredibly sensitive to collimation.
Short story: after eight months of futzing around I sold the Keller and got a Paracorr.. I never got round stars out of the Keller, even with OCD collimation. The tube isn't strong enough, even with reinforcing. It flexes and throws off the collimation. I got round stars out of the box with the Paracorr. Of course f/2.8 is not f/4.6
Also, any tilt in the CCD will cause defocus. At f/2.8 the zone of critical focus is about 8 microns I think. The tiniest tilt will cause bloomed stars in one corner of the CCD. I verified this, if (one) corner was sharp, the center was not. If the center was sharp, about 20% in one corner was not.
At f/2.8 orthogonality and rigidity is everything.
On the other hand I know someone who has never collimated his Epsilon, and it still produces round stars even after bumping along back country roads.
I can't see how the Boren-Simon can be better - they are using the same tube, the same linear bearing focuser. In theory my setup was superior (stronger tube, Feathertouch focuser) but I still couldn't tame it.
The only good news was I was able to sell the Keller reducer for a minimum loss. But the time wasted was priceless.
Posted 24 August 2014 - 12:53 AM
Incidentally I got my Keller reducer from Harel Boren. So, the specs on the net imply that the Boren-Simon uses the ASA Keller reducer, my anecdote seems to confirm that.