CN FORUMS ARCHIVE Telescope Reviews: Binoviewer and 10 Inch Dobsonian !!!!!!

I use a Z10" and a Denk Standard (I have also tried a WO BV in this scope), and here are the specific issues I have run into:

1) You'll need an OCA. Your BVs will not come to focus otherwise, and the 1.6x OCA that comes with the WO BVs will not work. I got a PowerMag Wheel from Siebert optics, and it works fantastic. I have purchased both a 1x and 1.3x element for this setup, which means, with the 1x element screwed in place, I can switch between 1x-2x-3x; and with 1.3x element in place, I can switch between 1.3x-2.5x-3.5x.

While this may not be the setup you want to use, my experience with the PowerMagWheel gives me the impression that you may not be able to bring the BVs to focus with a 1x OCA (aka zero-mag) without upgrading your focuser to something with more drawtube travel. I have a low profile Moonlight CR2 with a 2.75" long drawtube and I can just reach focus at 1x with the focuser racked all the way in, and the OCA sticking into the light path. If you don't use the MagWheel, perhaps you'll have a different experience. A single mag OCA may not require the same focuser travel that the multi-mag wheel requires. But, alas, I've only used the MagWheel. Maybe others have experience they can shed on this subject. The focuser travel of the stock Z10 focuser was sufficient for me to use the 1.3x element.

Your best bet is to call Harry Siebert (he's a nice guy), if you want a decent OCA. Tell him what you have (a stock Z10, presumably), what you want, and he'll hook you up with an OCA solution.

If you don't use an OCA, you can barlow your BVs, but the magnification that this will produce will be too high to be usable on anything but planetary work.

2) Your BVs might be too heavy for the stock crayford focuser. This was a pet-peeve of mine and what led me to upgrading my focuser. I found that I always had to crank the focuser lock real tight to keep the drawtube from occasionally slipping inward. This, of course, made fine-tune focusing difficult. Then again, the added weight of the MagWheel might have contributed to this. You're mileage will vary depending on how much your BVs weigh, how much your EPs weigh, how much the OCA weighs, etc. I did not experience this issue using WO BVs with the included 20mm EPs, and a TV barlow. It was only after I upgraded to the Denks with the MagWheel that things started getting heavy.

3) You may need counterweights. Your scope will get very nose heavy. I purchased magnetic weights from scope-stuff and they work great. How many you'll need depends on how much stuff you have on the nose of your scope and how heavy your eye pieces are.

Once you get your BVs working, you'll love them. I use nothing but my BVs now and don't see myself ever giving them up. In fact, I almost exclusively use nothing but a pair of Siebert 24mm Ultras with the MagWheel. I've sold off almost all of my other EPs. I do have a pair of 24 Pans (fantastic BV EPs!), but the eye relief is too tight for me to use with my eyeglasses.

Anyway, that's what I went through in search of a nice BV/Z10 setup.

Hope this helps.

Edited by ndelo (08/07/07 10:06 PM)