Quote:
Originally Posted by monoxide
yup, id like to try one just to lighten the load on the mount and make it easier to setup/balance, might be able to go deeper since im maxing out the mount at the moment.
next question is, the lumicon easy guider or the orion one?
the orion one sounds pretty good with the helical focuser for the guide camera, not sure if the lumicon has this?
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There are a couple of things about the Lumicon a I like and several I don't.
Like:
1. The fact that the internal prism is quite wide compared, for example with the celestron Radial Guider.
2. The fact that you can move the focuser assembly around PARALLEL to the optical plane of the scope. It helps to find those guide stars.
The don't likes:
1. The coupling to the telescope 2" compression ring adapter is rubbish. It is too shortr and is prone to slump. If you had a w" adapter with say 2 or 3 screws at 120 degrees then you can hold the OAG firmly. But as it is, only a slight bump will dislodge it. And because I have a couple of grand worth of camera hanging off it, this makes me jumpy;
2. The guide camera assembly cannot be indepoendently moved without also moving the imaging camera. By comparison, the Celestron Radial guider has the ability to swing the focuser around the main tune by about 140-150 degrees and lock it in. Thismakes for a lot of flexibility finding a guide star and means you don't ave to redo flats every time you move to another object.
3. The fitting at the back of the Lumicon makes it very hard to attach a Canon EOW style camera directly - because the flash assembly fouyls the focuser assembly.
I only have a Celestron OAG suited to a SCT so have't experimented wioth others but I find it is much better at dealing with guide stars than the Lumicon. I prefer the Lumicon overall becase it uses much less back focus.
I find that the OAG works really well on my 127 mm refractor. Stars are quite sharp and clear whereas stars in the 8" Newtonian tend to be somewhat distorted by coma and other optical effects that flow from the fact that the image is being snagged from the very edge of a mirror that has built-in coma because of being quite fast.
SO on a refractor, I say GO and for choice, I say borrow a couple of different types and see what works best with your imaging equipment. Depending whether you're using a DSLW or a CCD, you may go for different brands/designs.
Peter