Lunt Mod
Posted: Sat Jun 03, 2017 2:45 am
For Merlin 66
I could not download the webmaster address for some reason unknown, but am answering your request on Solarchat. The Lunt MOD finally turned out to be a success (I had my doubts at first because of high altitude jet stream perturbations since March 1 2017. Finally got some good seeing just recently.
The LUNT etalon is a cantankerous piece of hardware - the collimator has to be very close to its favoured position or you get a blurred image and I understand from Brian at Lunt that it is f/2. (Doesn't leave a lot of room to play with- a few millimetres of tolerance is all you get). You have to work out the dimensions PHYSICALLY with an ad hoc cardboard tube - positionned on the snout of the Collimator tube butted up against the black hub of the
etalon assembly behind it. I glued a mm scale to the top of the tube for ease of measurement. This is the hard part: take off your focuser assembly and with a video camera in the LUNT focuser slide the dummy cardboard tube in and out of the donor telescope tube, note the focus position on the tube looking at your monitor and allow a mm on either side for error - it's a sweat to do this because keeping the cardboard tube-Lunt assembly plus it's focuser steady and within the optical cone of light requires real dexterity - it took me about an hour to guarantee I had the right focus. When you finish this draw up a scale diagram (preferably in mm) so you can build the tube plus flange assembly. To save machine costs get Moonlight focusers to send you their extender kit -
probably you will need a 1-3/4" extender and a 1-1/4" extender plus an upper tube to complete your extension series. The tube between (same diameter as your donor tube) you have to buy from Global Engineering who supply a full range of 14 & 16 gauge anodizing grade tubing. - It costs very little to buy and ship. Don't anodize it like I did because white automotive paint reflects light better. I sent you the working diagram for the Meade 102ED - it will be
different for every brand of scope (the connecting tube being the difference, all the rest the same.I was amazed at what this MOD can do. Attached is a 2X barlow (nosepiece barlow on the DMK41AUO) in BAD seeing - just blew me away! If you need the diagram again just ask and I'll send it again. Attached is my image on a bad seeing day.
John
I could not download the webmaster address for some reason unknown, but am answering your request on Solarchat. The Lunt MOD finally turned out to be a success (I had my doubts at first because of high altitude jet stream perturbations since March 1 2017. Finally got some good seeing just recently.
The LUNT etalon is a cantankerous piece of hardware - the collimator has to be very close to its favoured position or you get a blurred image and I understand from Brian at Lunt that it is f/2. (Doesn't leave a lot of room to play with- a few millimetres of tolerance is all you get). You have to work out the dimensions PHYSICALLY with an ad hoc cardboard tube - positionned on the snout of the Collimator tube butted up against the black hub of the
etalon assembly behind it. I glued a mm scale to the top of the tube for ease of measurement. This is the hard part: take off your focuser assembly and with a video camera in the LUNT focuser slide the dummy cardboard tube in and out of the donor telescope tube, note the focus position on the tube looking at your monitor and allow a mm on either side for error - it's a sweat to do this because keeping the cardboard tube-Lunt assembly plus it's focuser steady and within the optical cone of light requires real dexterity - it took me about an hour to guarantee I had the right focus. When you finish this draw up a scale diagram (preferably in mm) so you can build the tube plus flange assembly. To save machine costs get Moonlight focusers to send you their extender kit -
probably you will need a 1-3/4" extender and a 1-1/4" extender plus an upper tube to complete your extension series. The tube between (same diameter as your donor tube) you have to buy from Global Engineering who supply a full range of 14 & 16 gauge anodizing grade tubing. - It costs very little to buy and ship. Don't anodize it like I did because white automotive paint reflects light better. I sent you the working diagram for the Meade 102ED - it will be
different for every brand of scope (the connecting tube being the difference, all the rest the same.I was amazed at what this MOD can do. Attached is a 2X barlow (nosepiece barlow on the DMK41AUO) in BAD seeing - just blew me away! If you need the diagram again just ask and I'll send it again. Attached is my image on a bad seeing day.
John