SCT Crayford focuser on Skymax 127?

[Bobcat]

Hi,

Has anyone managed to use these SCT focusers on their Skymax 127 scope?

SCT Crayford focuser

Modern astronomy also have a couple in their accessories section.

Not even sure whether this is possible to use with the Skymax scopes but any info would be useful.

[Merlin66]

In theory yes they can be used.... but I'm not sure of any real benefit.

You need the MAK to SCT thread adaptor, then the focuser just screw on.

http://firstlightoptics.com/products.php?cat=55&pg=3

1/2 way down the page

[Bigwings]

Not sure but I think its a different thread than an SCT.

May I ask why you want to change the focuser. Generally on an SCT it is done by those into imaging. The visual boys /girls often add an extension to the small focus knob which enables you to do fine focusing good enough for visual work and at a fraction of the price. It makes the diameter of the focus knob about the diameter of a small jar lid.

I made mine by getting a small deep plastic lid from a medicine jar about 3" across.

Coating the focus knob with butter, filling the lid with car body filler then pushing it centrally onto the focus knob.

It slides off quite easily and you just slide it on when you want fine focus. Cost coppers or you can buy them from accessory shops for about £25

[Bobcat]

I don't want to change the focuser but was just going through the site and saw those focusers. And wasn't too sure what they were all about.

Just curious.

[Pappy Nick]

In theory yes they can be used.... but I'm not sure of any real benefit.

You need the MAK to SCT thread adaptor, then the focuser just screw on.

http://firstlightopt...php?cat=55&pg=3

1/2 way down the page

Just thought I'd update link to http://www.firstlightoptics.com/adaptors/skywatcher-maksutov-to-sct-adapter.html

[JamesF]

In some circumstances they'd be as useful to imagers using Maks as they would to imagers using SCTs and for exactly the same reason. The mirror shifts when the focuser changes direction.

I have a converter for an SCT connector for my 127 Mak and have been tempted to do just this, but it causes another issue. For lunar or solar imaging I get an image that perfectly fills the frame on my 450D when it's connected directly to the visual back using the T-thread. Putting the camera on an external focuser would move it further away from the back of the OTA and to move the focal plane to the new position of the camera sensor the primary mirror must be moved with the focuser. Doing so increases the effective focal length of the OTA slightly and the image becomes too large to fit in the frame.

James