Removing OTA From Lx90 fork arms

[netwolf]

Hi All.

Need some help, now that I have the G-11 I want to know if it is possible to easily remove the OTA from my LX90 and then put it back.

I want to be able to take it out use it on the G-11 and then when done pop it back into the LX90. Has anyone been able to do this.

I have read there are issues of alignment of the scope with the fork arms. Also confirmed this with Bintel who advised that a "special" instrument was required to realign the OTA.


I like the Lx90 as a quick setup but really want to start using the G-11 to learn polar alignment and do some DSO work.


Regards
Fahim

[acropolite (Phil)]

Fahim, from what I understand it's not hard to remove, it's getting it back on correctly that's the problem. Apparenty it's necessary to loosen one of the arms, as well as removing the screws, given the FOV of the LX is fairly narrow, it might be easier (and in the long run cheaper) to buy an ED80 to bolt on to the G11..

[Omaroo (Chris Malikoff)]

Fahim - I've also heard that replacing the OTA on the LX90 and LX200 models is fraught with difficulty because of the Level North hardware. It's not only Bintel that have told me this. I went to enquire about the same thing you have - putting my 12" OTA on a GEM mount and then popping it back onto the forks when I was done and lots of people all agreed on the one thing - don't!.

Why not use the LX90 on your wedge, which you already have, and use it for DSO photography?

[netwolf]

Phill, ED80 or a small retractor is on my list. And I am on the lookout for a used one.

Chris, the wedge i have is a standard one and i am bit concerned about its sturdiness on a tripod. I am hopping at some point to have a permanent pier onto which i can place the G-11 or the wedge and pop on the Lx90. The tripod with a wedge for some reason does not "feel" like a good idea to me.

I just thought perhaps someone has solved this little puzzle but it seems even on the LX90 groups its not recommended. Better most suggest to get a 2nd C8 ota.

Regards

[jase (Jason)]

As others have mentioned, getting the OTA out of the fork arms is easy, but getting it back is the difficult part. You need to ensure the DEC axis is orthogonal (perpendicular with the RA axis) otherwise you point accuracy will be "out of wack".

There are some procedures to follow to get things back in line - http://www.mapug-astronomy.net/Astro...ent/OTA-1.html

I've done this with a Nexstar 11. I removed the OTA and put in on a Losmandy Titan with no problems. Getting it back was easy as the OTA has two pins on each side that must align for it to be re-mounted in the fork arms. This makes the whole process much easier. Don't think Meade has such pins to assist the user so you'll need to follow the directions above to get things re-aligned. Alternatively "ditch" the LX90 OTA/Fork combination and buy yourself a dedicated OTA. You'll find that the capabilities of using the G11 instead of the fork arms a real benefit especially if you're planning on imaging. The low PE of the G11 will beat the LX90 fork with ease. All comes back to what your intentions are and whether you're comfortable in taking the risk (which IMHO I'd consider low).

[[1ponders] (Paul)]

I'll second Phil here and suggest a shorter FL OTA to start with. Trying to get a DSO imaging career (even with a G11) off to a flying start using a 2000mm FL is fraught with headaches and frustration.

[acropolite (Phil)]

is fraught with difficulty because of the Level North hardware

I doubt it, the LNT hardware is one of the poorest pieces of engineering on the planet, wobbly and gets disturbed when you change the battery, re-calibration of the LNT (if you bother) is simple. (let it work out where it thinks it is, then show it where Sigma Octans is)

Fahim, you'll also need to buy the necesssary mounting hardware to adapt to the G11. I notice there's an 8 inch celstron OTA in the buy trade for sale, if the dovetail fits the losmandy that may be a good option.

[netwolf]

Phill, that OTA would be ideal but its outside my current budget.

I have the mounting hardware for the Meade 8", well I got it for piggybacking a guidescope but its the same plate that slides onto the saddle of the G-11. so no problem there.

BTW I don't have LNT on my scope.

I have been generously offered the use of Apoman's Borg 77Ed, so i will start with this while i save up for another OTA. He has it installed in guide rings ontop of his AP Refractor. I think i am going to need some 80mm rings plus a losmandy universal plate to mount it on my G-11. I can always reuse this for the ED80 when i get it. Perhaps i should place a wanted ad for the ED.

Regards
Fahim