Image train ES102 with reducer
Posted 06 April 2021 - 12:09 PM
Few questions: the reducer has threads on the extension tube side. The extension tube doesn’t have threads. Is it ok that the reducer is just inserted into the extension and snugged with screws? Lots of camera weight hanging off the end...
I’m not sure about the Hotech adapter either. It doesn’t seem to mate to the reducer.
Curious if I need some sort of adaptor or spacers.
On another site, I was told someone had a custom adapter made. Are there retail options?
Posted 06 April 2021 - 12:18 PM
Seems kinda odd that the extension tube isn't threaded on both ends. I have many for my ES 102CF, and every one of them is.
Posted 06 April 2021 - 12:33 PM
Posted 06 April 2021 - 01:29 PM
It appears that some of the ES102's extension tubes are threaded and some are not. Mine is not, and I have the same imaging train as you. The Hotech has a self-centering mechanism that keeps it centered. The SV ff/fr does not, and my images are slightly vignetted on one side, and are probably slightly out of focus on one side. Doesn't really bother me, but YMMV.
Posted 06 April 2021 - 01:41 PM
If so, is there a problem using the screws vs threads? (Just makes me a little nervous.)
Have you used a 2” filter with your setup and how did that affect back focus?
Posted 06 April 2021 - 03:19 PM
I use a cooled astro camera, My full train is:
scope > extension tube > Hotech FF -OR- SV ff/fr > OAG > filter wheel > ASI183mm . Backfocus is 55mm.
I would prefer to thread the FF into the extension tube, to reduce any droop, but I haven't found a part for that. I found that the SV needs to be pushed into the focuser to overcome a small step, at least in the version I have.
I get good round stars in the corners regardless of filter with the small sensor in my ASI183. Not sure how it would work with your larger sensor.
Posted 06 April 2021 - 07:26 PM