E621Keith

FYI, the objective on the ZS80II APO and the ZS80 FD APO anniversary model looks like this

ZS80II

http://www.widescreen-centre.co.uk/ProductPhotos/zs80ed-21.jpg

ZS80 FD

http://www.gsrhodes.com/WO_ZS80FD_10thAnn_Lens_Shot_small.jpg

I am not that concern about the focuser, it can be easily upgraded. I'm more worried about the writings on the objective lens. The writing on the objective of the ebay scope appears to match those on the achromats in the reviews.

You should be careful. This may be the WO Zenithstar Achromat, not an APO. If he described an achromat as an APO, then that's false advertising.

http://www.williamoptics.com/support/reviews/AU_S&T_WilliamOpticsZenithStar80.pdf

http://www.williamoptics.com/support/reviews/TomTrusockZenithstar80Review.pdf

£250 for an achromat is over priced in these day, especially you can get a new Starwave 80ED for £50 more and price of a used ED80 is around £250 or less.

The motor I have has a gear ratio of 1/120, so it must be a modified MT1. May be Vixen converted some for the SP.

Raphael, Thanks for the detailed information.

I have a DMD2 controller driving MT1 in RA and Dec. Although my dec motor has a V shape cut similar to the SP motor. Not sure if the previous owner machined the grove himself. It attaches to the pluck using four set screws.

As for other Polaris motors and controllers.

Vixen DD1 was succeeded by DD2. DD2 was recently replaced by DD3 which has a built in ST4 guide port. They still drives the MT1 motors, although the MT1 now comes in white.

I think Skysensor 2000's MT4 is a servo motor so it is not compatible with stepper drives. SS2K was replaced by Starbook S for no good reason, and SBS uses a newer white servo motor that is not compatible with SS2K.

I think it would be a case of buying a plain dovetail and a bit of DIY or take it to a local machine shop and have them drill the holes.

Astroparts do a bit of custom machining. I've never used them, but I've seen them recommended on SGL before.

If your system is 7kg, it's best if you go for a custom dovetail. I'd guess your lens attaches to your quick release plate with something more rigid than a single 1/4" bolt. While I have no problem hanging a 70-200/2.8 or a 300/4 on the Modern Astronomy dovetail, I certainly would not want to put any big super telephoto on one.

What mount are you going to use. You'll probably need an EQ6 or larger.

One of this

Deluxe Vixen Style Photo Dovetail (about half way down the page)

Accessories @ Modern Astronomy

By all of 20 cm. Exit pupil might be an issue

Time for eye surgery.

Source: Wikipedia Attribute: Kok Leng Yeo

How about rigging up the two Kecks for binocular view

You mean like the LBT. Ok, their mirrors are 8.4m, not 10, but they are still bigger than the VLT's.

Cured by 32" and want to relapse? Take a look at Orion USA 50" Monster Dobsonian - Telescopes UK: Telescopes & Telescope Accessories in your only London shop

Yours for only $123,000!

plus £200 for a tall ladder. Better not have vertigo

Someone on this forum once said

"The best way to deal with a temptation is to yield to it"

The cure for aperture fever, is to buy a even bigger telescope.

There is a 20inch dob on ebay atm

http://www.ebay.co.uk/itm/Huge-20-Inch-F4-Dobsonian-Telescope-Deep-Sky-Watchers-Delight-/190610470462?pt=UK_Photography_Telescopes&hash=item2c6144f63e#ht_500wt_946

Pentax Japan listed the XP in their Japanese site but not the English site. Since it's a 0.965 eyepiece, it may be made for their domestic market only.

XP PENTAX

I ran a search on Google Japan and it returned a lot of results. Unfortunately I cannot understand Japanese nor the Google translation of those web pages, but I gather there were 5 eyepieces in the XP series 3.8, 8, 14, 24 and one other. Of these only 3.8, 8, and 24 remained in production. They seem to used the eyepiece for planets only, even the 24mm (from looking at pictures accompanying the text).

I am sure someone who understanding of Japanese will be able to make better use of that information.

so17

Nikon once made this contraption with a built in 10mm eyepiece. However, I don't think the eye piece is removable, so you'll need to swap the lens instead.

Nikon Lens Scope Converter

I'd imagine attaching it to something like a 50mm f1.4 should make a very interesting wide field instrument.