Electronic finder -Zuiko 50mmlens+QHY5

[Merlin66]

Call me old fashioned but even if I trust the GOTO I still like to see where I'm looking.....

Just rigged up an old Zuiko 50mm f1.8 lens via a 25mm spacer ( pulled from a x2 convertor!) to the QHY5. Running under PHD and 0.5sec exposures I can easily get down below 8.5 mag with a field close to 5 x 5 degrees.

I can now mount this on the piggyback adaptor and see where I'm pointing....very nice!!

[Peter Drew]

Good plan Merlin66. I've tried the same Zuiko lens attached to a Watec 120N on my 16" SCT (on which I don't trust the GOTO!). One monitor shows the "finder" field and the other the image from the main scope fitted with a Stellacam 3.

[Merlin66]

I agree Peter, every family should have one!

Easy to use and compliments the EQMOD control very well!

[beamish]

You have my interest ! Perhaps an improvement over the home-made 50mm finder, any pics ?? ...and more details of how you put it together?

Ta, Karlo

[Merlin66]

I'll get some photos uploaded ASAP.

There's only two "tricks" I found:

The standard 1.25"> T thread nosepiece is about 30mm long and hits the rear element of the lens and doesn't allow the 45mm back focus you need. Cut it to around 20-21mm long.

The 1.25" adaptor "body" - I used a parafocal ring expoxied into the camera spacer body - drilled a couple of additional holes and tapped them 4mm - nylon screws hold the camera....

[beamish]

XLNT, I'll look fwd to seeing them

Karlo

[Merlin66]

The attached images show the set-up of the 50mm Zuiko lens and the adaptor with the QHY5 camera.

You'll see the nosepiece has been cut back to 20mm

The small aluminium channel was drilled and tapped 1/4" whit and tied with a cable clamp. This allows the unit to be mounted on the piggyback adaptor on the scope (or on a tripod for a bit of fun!!)

The 1.25" insert is visible in the 25mm wide camera adaptor tube and the nylon clamp screws go through it to the insert which was epoxied in place.

The backfocus of the lens is 45mm and the ccd chip in the QHY is 12.5mm behind the front flange, so this gives a distance of 32.5mm for the overall adaptor (including the 1.25" to T nosepiece)

The inner element of the lens protrudes into the adaptor so the distance from the flange on the nosepiece to the end MUST be around the 20-21mm. Any longer and it will touch the lens and not come to focus. Hope this helps!!

[beamish]

Very interesting indeed, I also happen to have all the bits !!! Could be a winter project.

Cheers Merlin.

Karlo