Do you have a Baader 2"-1.25" low profile adapter?

[michaelmorris]

I currently have a Meade Zero-shift electric focuser mounted on the back of my 8" LX200 Classic. My only real criticism of it (apart from sounding like a lawn mower!) is that 1.25" adaptor only has a single retaining screw. This means that heavy 1.25" eyepieces/barlows/eyepieces have a tendency to tilt or rock slightly. What I am after is a similar low profile 2" to 1.25" adaptor but with either two retaining screws or a compression ring fitting to eliminate this problem. The Baader 2"-1.25" low profile adapter for Steeltrack (First Light Optics - Baader 2"-1.25" low profile adapter for Steeltrack) looks as though it may fit the bill nicely. Just like the Steeltrack, the Meade zero-shift focuser has a small cut out slot at the side to accept the retaining screw for the 1.25" adaptor. It would be great if the Baader adaptor would fit in the slot on the Meade zero-shift focuser.

1 - Do you know the distance from the front of the adaptor to the back surface of the retaining screw?

2 - What diameter is the retaining screw?

Thanks

[Peter Drew]

Why not drill and tap some more retaining screw holes in the existing adaptor?

[michaelmorris]

Why not drill and tap some more retaining screw holes in the existing adaptor?

Because the extra screw(s) wouldn't have any slots in the outer casing to accept them unless I also took a file to the focuser casing. I'd rather not do that.

[Peter Drew]

Ah yes Michael, point taken, I have a similar focuser on a 16" SCT, I use an alternative standard adaptor with three retaining screws when necessary.

[johninderby]

I use one of these with my BF-15 blocking filter on my solar Ha scope. I needed a few mm extra in-focus.

You can remove the retaining screw completely and not use the brass compression ring as there are also 3 nylon grubscrews set around the barrel and which really hold anything extremely securely as well as properly centered. The grubsrews are 18mm down from the top lip and 11 up from the end of the barrel. Don't know why Baader doesn't publicise this feature.

Here's a photo showing one of the grubscrews.

John

[michaelmorris]

Thanks John, that's really useful. What is the distance between the two red lines I have marked?

[johninderby]

Thanks John, that's really useful. What is the distance between the two red lines I have marked?

It's 7mm between the bottom of the hole and the lip.

John

[michaelmorris]

It's 7mm between the bottom of the hole and the lip.

John

Thanks John, you're a star.

[michaelmorris]

Well, the Baader adaptor arrived today from First Light Optics (as usual - great service).

The verdict on the adaptor? NICE, very nice indeed. What an improvement!

It's very well engineered and the three nylon grub screw fittings are a superb touch that mean it really grips the diagonal.

As anticipated, the retaining screw was a fraction too short for the Meade Zero image shift focuser. However, the Meade retaining screw uses the same thread as the Baader so it's simply a matter of swapping the Meade threaded thumbscrew on the Baader adaptor.