Brian, my reply was a bit tongue in cheek! My f8 is a beautiful instrument but a bit average on jupiter and the moon an baader semi-apo filter helps there though. I've become a refractorholic too so any thread that mentions refractors ...I'm there.
Cheers, Matt
I hear you Matt , I have 3 in NZ and only 5 here in OZ , yep ,, a refractorholic all right . As Troy , yourself and all on this thread can confess to...
Brian.
Quote:
Originally Posted by MattT
Brian, my reply was a bit tongue in cheek! My f8 is a beautiful instrument but a bit average on jupiter and the moon an baader semi-apo filter helps there though. I've become a refractorholic too so any thread that mentions refractors ...I'm there.
Cheers, Matt
I am dreaming of a TMB 203 f/9 Apochromatic Refractor! So, am investing in a couple of lotto tickets every satursday....hope my investment will hit the jackpot soon.....hahaha.
Ok, some photos. Had it out on Friday night for some testing. Some very good points I noticed, and some disappointing things.
Good points. The focuser is beautiful, but you'd expect that from a 3" FeatherTouch. Came in a nice case, and the scope itself is just solid and feels like quality. Quite weighty for it's size. First thing I noticed was the focusing between filter changes. With the ED80 there was quite a bit of shift and had to refocus noticeably. With the TMB92SS, I checked focus between filter changes but the shift was nominal. I understand this is because it's obviously a much better apo, so better colour control.
Disappointments. First thing I noticed was the way the focuser is connected to the OTA. It seems to slip/creep rotationally. It's connected via 3 nylon tipped screws that go into a groove the runs around the focuser piece. No matter how tight I did them up, with finder guider in the bracket the whole focuser crept around with the offset load. I ended up having to put the finder guider on the top dovetail so the focuser wasn't eccentrically loaded. I need to get to the bottom of this, whether it's a FeatherTouch or scope issue. See photos below.
Second was the field flatness. I was using the Orion Flattener I'd been using with my ED80 with some success (although minor eggy stars still in one corner). The TMB92SS fits exactly within the specs of the Orion Flatteners advertised range of effectiveness. But the field was not flattened. I need to do more testing to see if it's the scope, flattener, spacing of camera, or maybe sensor tilt? Due to operator idiocy I did not get test images with just camera and no flattener. Duh.
Troy I can send you my Hutech 7887 FR/FF which is fully adjustable for focal length by spacers between the two sets of two! elements. It comes with a Canon T-ring and 2 inch thingo (nosepiece) that goes into your focuser. It does not vignette a full frame as the clear aperture is close to 46mm.
Bert, thanks heaps for the offer. I might even take you up on it. Looking up the specs of that flattener now. I need a M42 T thread at the camera end and the focuser is set up to take a 2" at the moment. Quick look at the Hutech site seems to say it's got different connectors. Will have to look and see how I can connect. Other thing is that it's a reducer as well, not just a flattener. I'm already pretty wide with the 506mm FL.
Troy what is the distance from the T-mount thread on your camera to the sensor? It will give me some idea of what bits to use so your camera fits the FR/FF.
With an 80ED and the 7887 FR/FF the field was pin sharp across the full field of the Canon 5DH from corner to corner.
Disappointments. First thing I noticed was the way the focuser is connected to the OTA. It seems to slip/creep rotationally.
The retailer may be able to supply you with slotted brass screws to replace the thumbscrews so you can put more pressure on the focuser to stop it rotating too easily. Alternatively use pliers to tighten the thumbscrews more.
If you want the brass replacement screws but the retailer can't supply them Barry Gooley from KK may be able to help you. These are only ok if they're bearing on a teflon surface, not metal, unless they also have the teflon insert. (your scope is constructed a little differently to the sharpstar I had on closer inspection)
Thanks mate. Will look into it. Kind of weird on who to approach about it. It doesn't appear to be the focuser itself causing the problem, but the OTA's connection. But that's TMB. I checked their Yahoo Group, and the traffic in there is virtually dead. I think I saw a tumbleweed roll past while searching. I ended up emailing the store I bought it from and will go from there.
so any thread that mentions refractors ...I'm there. 
Woaw already ?? great service there Troy ,, review comming up ?? 
