Hi, I have been looking at the above STXL 6303E combination and can not work out the total back focus. I have a maximum of 71 mm with my Orion Optics (UK) AG 12. Can anyone help confirm the exact distance as I will need an adaptor made up? Thanks, Chris
Hi Chris, The STXL and FW8G has the following back focal distance. The short answer is 59.61mm. Below is the breakdown of the combo. Mechanical BFD = 61.84mm or "2.435 Optically corrected BFD = 60.60mm or "2.386 **Optically corrected BFD using 3mm filters in the filter wheel = 59.61mm or "2.347 ** Orion states the AG12 BFD to image plane is 79mm. http://www.orionoptics.co.uk/AG/ag12.html I hope this helps.
Hi Tim, That's very useful and thanks for the detail. Will I need the 3 inch adaptor and if so what will be the total back focus distance please? Thanks for your assistance. Chris
I went to precise parts and made up a part to see what it would look like. A simple threaded adapter ring to 3" barrel would add 0.25" Are you using the ACU-3 focuser ?
Hi, I have the FLI Atlas Focuser which uses a mod made by Orion to mate with the wyne field flatner. Orion will make up an adaptor but they need to know the exact back focus requirements. Thank you for pointing out the correct total of 79 mm. Chris
79mm from the metal back of the scope to the CCD is the critical number. You can always call night or day. I try to be available for customers most times. I turn off my phone when I sleep so feel free to call anytime. My Skype is puckettccd if you're international. Regards Tim
