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RASA8 camera adapter

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In earlier posts I expressed an opinion on the soft backing material Celestron use on their camera adapter plates, stating I was not a fan due to any flexing or uncertainty it introduces into the imaging train.

Well, it looks like it is there for a reason. My bespoke all aluminium adapter plate has picked up on the secondary lens collar causing it to come loose. This has necessitated removing the primary cell from the tube so I could get my hand up inside to hold it to enable a retighten. Then came the task of collimating the scope, an Ocal camera was used to align the optics followed by a star test using a ASI120 mini so the adjustment screws were accessible. I’ve still got some work to do on this but I think I am going to take the opportunity to make an adapter plate that will hold a 2” filter and my RisingCam 571c. I’ve never been fully satisfied with the 3 screw wedge arrangement that’s used with the QHY268c so I’ll give an all screwed assembly a try.

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Yes, I don't like those plates with the retaining ring. I would have bought the full Octopi image train for my RASA 11 had been available, but I bought the earlier shorter one to go with the Baader UFC.  After that I ended up replacing the plate and retaining ring with a Precise Parts adapter, which is much better. All costs hundreds of course, so if you can do it yourself, brilliant!

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Here is the new adapter, designed to attach the RC571c to the RASA8 and accommodate a 2” filter.

It started life as a M72/M48 reducer that came with my Esprit 150. The large thread was machined off and sufficient internal thread left to hold the filter. On the other side a slight recess was machined to centre the RASA collar (a good call by @Tomatobro), the M48/M42 reducer had to be machined within a millimetre of its life to obtain the required back focus, so much so that the reducer comes off the thread when fully screwed on, hence the 3 grub screws to hold it securely in place. The NBZ filter holder is quite deep so it will be awfully close to the RASA secondary lens when in place, I will have to watch that.



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