Is hacking off a bit of my focuser a good idea?

[Alaness]

I've noticed to my dismay that I have once again picked up a scope that won't reach focus with my 550D. I'm thinking of taking a hacksaw to the end and removing a cm or so so I can get enough inward travel. Any reasions why this may or may not be a good idea?

I figure if I mess up I'll just need to buy a few one anyway.

Cheers.

[Andymac79]

Hack. Not a great action on astro stuff. What scope is it?

[JamesF]

Depending on how much you think you'd need to take off, you may then find that eyepieces won't focus because you've limited how far out they can get.

James

[Ant]

That's exactly what I did.

I cannot remember which scope it was, but I think it was an 8" f5 SW newt, it wouldn't focus with the 300D.

So I took the two inch adapter (part of the focuser) out and removed all but about 8mm of it, I had enough to drill and tap thumb screws back in.

I did then have to get an extension tube for EP's to focuser but being mainly an imager, that wasn't much of a hardship.

The other alternative is to acquire a second 2" adapter for the focuser and only cut ne of them down, so you have one for imaging and one for observing.

Cheers

Ant

[Ant]

I've just found a picture of the part that I shortened, I cut it through the centre of the sticker that says 2" adapter, then drilled new thumb screw holes.

[AstroAdam]

I've just found a picture of the part that I shortened, I cut it through the centre of the sticker that says 2" adapter, then drilled new thumb screw holes.

You shouldn't have needed to do that Ant.

The 1.25" adapter that comes with the scope (i.e. the one that your standard eyepieces push into, and you have to remove to put the 2" adapter you posted the photo of), should split into two pieces. The 'neck' unscrews and leaves a T-thread to attach a t-ring for a DSLR. The fact that your unscrewing the neck of the 1.25" adapter means that your camera sits flush with the top of the focuser.

I have a Skywatcher Skyliner with that self same focuser, and I think the adapters that come with them are the same?

Cheers,

Adam.

[Moonshane]

here's another option. no hacking required

[Ant]

Yes, I know about the hidden thread it is a great option if you live under dark skies, but then you cannot use 2" LP filters - and I needed them really badly lol.

On an earlier scope, where I only needed a few mm, I moved the primary mirror up the tube... But all in all I found the hacking option better.

Cheers

Ant

[AstroAdam]

Yes, I know about the hidden thread it is a great option if you live under dark skies, but then you cannot use 2" LP filters - and I needed them really badly lol.

On an earlier scope, where I only needed a few mm, I moved the primary mirror up the tube... But all in all I found the hacking option better.

Cheers

Ant

Ah! And suddenly it all makes sense

You;d be surprised how many people miss them!

[Gina]

Use clip-in filter in the camera if you can't fit a 2" screw in one. Bit more expensive but a much better solution than hacking your scope about.

[Ant]

Again I disagree, the part that I cut short was about £15 (from memory), buying a second light pollution filter is much more expensive.

The clip filter, while very good is a one trick pony, the 2" LP filter I've used as part of the imaging train with a scope. I've used it screwed the filter thread on the ends of zoom lenses, I've also used it when connecting the H9 to a camera lens.

I do agree that the clip filter is a very neat way around the issue, but lets also remember that the direct connection is only on the 1.25" version of the adapter that I took a picture of above, and for a dSLR you'll get severe vignetting using a 1.25" anything in the image train.

Cheers

Ant

[pixelsaurus]

For those that do need to mod their eyepiece focusers to mount a camera at prime focus, the following link should be of use. The register is the distance from the front of the camera mount to the image plane.

http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html

[Alaness]

Well I did it. I've hacked off about a cm from the focuser as planed. I also had to remove the gear track and glue it back on further up.

All seems to be working fine, I'll test it out when I get clear skies.

[Alaness]

Well I did it. I've hacked off about a cm from the focuser as planed. I also had to remove the gear track and glue it back on further up.

All seems to be working fine, I'll test it out when I get clear skies.

[Alaness]

Well I did it. I've hacked off about a cm from the focuser as planed. I also had to remove the gear track and glue it back on further up.

All seems to be working fine, I'll test it out when I get clear skies.