My Reducer need 55mm BF.STT-8300+FW8G gives 52.8+3.7+1.5=58mm.One custom adapter(in place of 2) can gain space. Can I have the dimensions of the thread needed?
The thread of the FW8G-8300 is dependent on the end plate used. It can be 2.156, 2 inch, or in some rare cases or T-thread. https://www.sbig.com/products/accessories/stl-cover-for-oag-8300/ I am not fully clear on what you need. The Back focus numbers are here: https://www.sbig.com/support/product-documentation/backfocus-table/ Page 7 has more here: https://www.sbig.com/site/assets/files/1414/stt_filterwheel_manual_080812.pdf Call or email if you need specific info.
Thanks for all these information. It is more clear now. I wish to do astrophotography with an APS-DSLR and with the package Pro STT-8300+FW8G (autoguiding) in 2 conditions: 1)normal focal with ES127mm-952mm focal (f=7.5) refractor + FeatherTouch 3" 3035 (2"nosepiece back aperture) From your information, I suppose I use the 2 adapters included in the STT Pro Package (STL Thread adapter plate and STL Thread to 2" Nosepiece). From your table I have a backfocus of 52.8+3.7+1.5=58.0mm(no problem). 2)reduced focal (952x0.7=666) (f=5.25) with ES127mm refractor +FeatherTouch 3" 3035 (2"nosepiece back aperture)+ES 3" 0.7x reducer/field flattener.I need to ask to PreciseParts (Florida) adequate adapters. For the link with the 2" nosepiece of the FT focuser, I need first an adapter (2" nosepiece/3" Reducer/FF). For the APS-DSLR I have the back adapters+T-ring/bayonet. For the SBIG package, I suppose I must use the STL Thread adapter plate only and ask to PreciseParts an adequate adapter to the back of the 3" ES reducer/FF. I only need to have the dimensions of the STL Thread adapter plate(? what are they?).Unfortunately the backfocus needed for the ES reducer is 55mm. I have 52.8+3.7=56.5mm + the minimum length( 9.2mm) for the adapter STL thread adapter plate /ES 3" Reducer. The Total backfocus is therefore 56.5+9.2=65.7mm. The backfocus seems to be too high with this reducer and the SBIG Pro STT+FW8G package.
Explore Scientific technician said that the tolerance around the 55mm needed by the ES reducer is minimum. The only possibility is therefore to minimize the length with building only one direct adapter between the rear of the reducer (M75 0.75 thread) and the filter wheel cover. What are the characteristics (dimensions, bolts or thread ) needed for the direct fixation to the filter wheel.Thanks in advance.
Hi Georges, I have uploaded the Filter wheel plate drawing below in case you need to make something that attaches to the filter wheel housing. Please look at the drawing below and tell me if this helps. Using this drawing you could have something made that would bolt to the face of the filter wheel using the four female bolt holes.
