Meade LXD75 SN-10

I purchased my LXD-75 SN-10 as a large aperture "portable" telescope. Since most of my observing is of DSO's , I didn't want an SCT. The scope IS reasonably portable.

So far, this telescope has met or exceeded my very modest expectations, but it has a few warts that need attention,
(1) The focuser is a piece of junk; I replaced the stock focuser with one from JMI , the NGF-55 , which is made specifically for the LXD-55 and LXD-75 Schmidt Newtonian telescopes. This is an entirely satisfactory focuser.
(2) The finder scope doesn't really "focus"; (edited 7/18/2005 --there is a way of focusing the finder, but it requires loosening a locking ring near the objective to do so; even then the finder is very astigmatic):however the eyepiece unscrews, so some folks might be able to get their dioipter correction before the ocular falls on the ground.
(3) The telescope is right at the limit of the mount's capacity for visual use; I would not recommend it for any but the lowest magnifications in any kind of windy conditions.(edited 7/18/2005: the mount has a lot less "wiggles" if set up on a soft surface; i.e. a lawn vs. concrete or deck)
(4) The eyepiece furnished by Meade requires immediate replacement. Lots of coma, and hard to focus sharp stellar pinpoints. I know they cost a lot, but the SMC Pentax XW series eyepieces virtually eliminate coma due to their design which contains a Barlow-type field element. Naglers work O.K., but not as well.

Meade could sell lots of these if they made it into a finished product. The optics are quite good. This could be the best Rich Field telescope that is not an APO that is reasonably priced. If they fixed it with a better (heavier duty) mount, focuser,finder,and eyepiece, I would have no trouble buying a larger aperture scope of this basic design.(edited 7/18/2005: another gripe is the lack of rotating tube rings; the finder scope never seems accessible without loosening the tube, and then the scope slides out of balance!)

Update 7/18/2005: I wound up selling the scope to a fellow club member. I just tired of continually rebalancing the scope during use. Not very user friendly, but O.K optics!

My comments are for the optical tube only. The supplied LXD75 mount is inadequate for the scope and shouldn't be bought for mounting the scope unless you intend on reselling it to save a few hundred dollars on a package deal. I use my LXD75 mount on smaller scopes and it works fine up to about a 20# optical tube. The SN10 needs an Atlas mount at the very least for any kind of serious work. I bought an Atlas mount and like it.

It's best to locate a used OTA on the used market, as the SN10 is a project scope. The focuser must be changed out for something like a JMI, Moonlite or Feathertouch. You may want to replace the stock rings and dovetail and get some good rotating rings and a better dovetail than the Vixen variety. The collimation of an f/4 scope is critical, and you should include the cost of collimation aids. You will need a lens hood at the least and a dew heater if living in humid climate. Flocking the tube increases the contrast a bit. The finder scope is junk, so figure on replacing that as well. What you get are very good large aperture optics at a bargain price. A step up from this scope would be the Vixen 10" modified Cassegrain scope based on Klevtsov design for about $3600 for the OTA alone. That gives you a lot of leeway in outfitting the SN10 to bring it up to par.

Visually and photographically, the SN10 produces better images than a Celestron C11 and does it at considerably less cost. The SN10 just requires a bit more mounting consideration. Once collimated, you don't have to worry about mirror flop and image shift as in a C11, and collimation will be more stable. For visual use, you will need rotating rings to obtain comfortable viewing positions. The extra contrast of the Newtonioan design over the SCT makes this worth the cost.

The down side is that you may need to buy some expensive f/4 qualified EP's, but since Baader came out with the inexpensive Hyperion EP's that are excellent for both visual and photographic use, that's not much of an issue anymore.

My final vote is that if you buy it just as a bare bones OTA at a bargain price and fix it up just the way you like it, as you should be doing anyway, then it is a bargain that seems to have no equal if you need serious aperture for deep sky work and a very fast focal ratio for astrophotography.

When the seeing permits, the SNT design gives better planetary views than a comparable aperture SCT. The perfect coma corrector for the SN10 is the Baader MPCC, and it works visually as well as photographically. It's only needed when doing wideangle, low power work. It will correct the coma and field flatness to where it rivals the Vixen 10" modified Cassegrain scopes. You should be able to outfit the SN10 with everything you need for half the cost of the Vixen OTA, which is the closest rival in cost that I know of. The Vixen isn't nearly as fast photographically. No Cassegrain variant that I know about can rival this fast Newtonian for photographic speed while maintaining good image quality.

Those who image using slower speed 35mm transparency film should really check out this scope. Just remember this is a project scope, and it will not even come collimated from the factory, or probably from its previous owner as well.

Junky mount doesn't point, and isn't nearly stable enough for this size of a telescope.

Optics are average. Overall fit and finish is cheap looking.

Very dissapointing purchase.