HOW TO ATTACH SONY NEX-F3 FOR PRIME FOCUS ON THE 2" PORT OF NEXSTAR 130 SLT
After some frustrating attempts to attach a digital camera to the Nexstar 130 SLT, I finnaly found a solution.
Unfortunately it was not trivial.
Good point for this telescope is that he comes with 2" inlet ring, making usable for 2" eyepieces and adapters.
Then I found this adapter for the E-Mount on eBay (standard for Sony Nex-F3 camera).
Seller is cncsupplyinc.
Photo from the advertisement.
Photo of the adapter I received.
Original 2" ring, that comes with NexStar 130 SLT as standard accessory.
Everything was OK, it fits perfectly on the E-Mount of the Nex-F3, but when I tried to get some focus on the
NexStar 130 SLT, I found that the focus point was something around 5 to 6 mm inwards the 2" port.
The focuser was all moved down and still no focused....
That was really disappointing for me, because I have bought a half dozen adapters and was unsuccessful already.
View of the camera, tied to the adapter at the 2" port, without modifications. No focus is possible at ant condition.
Well, before quit and start looking again what to purchase next, then came to mind how to modify the adapters to
make them adjust to the proper position.
The idea is to do a small milling with a lathe, keeping the important diameters and reducing the flange portion of
both adapter and 2" ring. This would give me more 10~12mm of excursion, and should solve the problem
of prime focus. A good metalworking lathe is necessary to do this. Some engine recovery office shops do have this kind of
machine and they do not ask too much money to do small jobs, since it is soft metal (aluminium).
Machined E-mount adapter for Sony Nex-F3 digital Camera.
Comparison before/after machining the adapter.
Machined 2" adapter (from Celestron NexStar 130 SLT standard accessories package).
Sony Nex-F3 finally with proper assembling.
Comparison between before (left) and after (right) modifications.
Even after focusing at buildings nerby, this modification gave me around 7mm of additional inward excursion,
for closer pointing it might be needed.
IMPORTANT: Take care of how you will do the machining of the parts because these mods are definitive.
Once done, cannot be reversed, and also you might lose warranty for these parts.
Keep the diameter of the parts which match to each other as close as possible of the original one.
Just reduce the flanges to get more axial movement of the focuser.
Hope this helps someone.
Next steps: Learn how to use the camera and buy a 2x 2" Barlow lens for increasing gain.
How it is working?
Red arrow shows my sister's building, as seen from my office window.
Picture taken with the adapter, and 1/32 exposure time.
PLS check my other astro pictures at CelestronImages website
How to solve Nexstar 130 SLT Azimuth tilt problem