Jump to content


Photo

Recommend Omni 102XLT Mods

  • Please log in to reply
19 replies to this topic

#1 csrlice12

csrlice12

    Voyager 1

  • *****
  • Posts: 10409
  • Joined: 22 May 2012
  • Loc: Denver, CO

Posted 03 December 2012 - 02:03 PM

I'm picking up a Celestron Omni 102 XLT Acromat tomorrow. Any mods/ideas I need to be aware of (besides removing the glue they call lubricant from the focuser?)?. Any recommendations for a 2" diagonal. It comes with a 1.25" diagonal (not sure how good it is). I have the polar scope to install; no motors for now, maybe down the road (more glue like lubricant to clean??). Really looking forward to this as a companion scope (and semi-GrabnGo) to my 10" Dob (LugnGo).

#2 beatlejuice

beatlejuice

    Surveyor 1

  • *****
  • Posts: 1553
  • Joined: 05 Apr 2011
  • Loc: Hamilton, ON,Canada

Posted 04 December 2012 - 02:03 AM

OK, mine is a 120 but same idea, I am assuming a CG4 mount, if not then disregard some of this:

-Orion 2" dielectric diagonal
-Orion RA drive (best addition)(dont need DEC drive)(dont need polar scope, just eyeball N leg at polaris and it tracks remarkably well.)
-Orion accufocus,3rd best addition(I didn't play with the focuser but it is another option)(thinking Moonlite in near future)
-Orion 16" mount extension (2nd best addition)
-9x50 RACI finder I already had on my XT10
-Baader solar filter (very nice)
-Dovetail shoe mounted on rings for telrad (scopestuff)
-telrad base with dovetail foot (scopestuff)
-2" baader semi-apo filter(screwed into diagonal if used)(the jury is still out on this one. Good for moon and Venus but prefer nothing on Jupiter and Saturn)

Eric

#3 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 43398
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 04 December 2012 - 06:40 AM

Any mods/ideas I need to be aware of (besides removing the glue they call lubricant from the focuser?)?.



Congratulations on your new scope, you ought to have a lot of fun with it. :jump:

I do recommend reworking the focuser, the Rack and Pinion Synta focusers are all essentially identical but cleaning, regreasing and careful attention to assembly can make for a surprisingly effective focuser. For the ambitious, replacing the plastic strips with bondable teflon takes it to the next step.

A 2 inch diagonal is a nice addition to provide some wider fields of view.. I would skip the declination motor and go with an RA only, the drives are slow so the slow motion control offers better response.

Jon

#4 Zamboni

Zamboni

    Viking 1

  • *****
  • Posts: 871
  • Joined: 03 Jan 2005
  • Loc: Colorado Springs

Posted 04 December 2012 - 11:47 AM

I'm getting a 120 next year and the first task will be to redo the focuser. Can you recommend a good source for the adhesive teflon strips? I'm already familiar with the relube process as I did it with a 2" Synta newtonian R&P, but I think I'll do it with Pete's Red Grease since I'm not happy with the results from white lithium. Just not viscous enough.

#5 Locoman

Locoman

    Viking 1

  • *****
  • Posts: 760
  • Joined: 09 Mar 2009
  • Loc: Abilene, Kansas

Posted 04 December 2012 - 09:23 PM

Teflon with one Etched side for gluing (8711K91) This is what I used. Doesn't have an adhesive side. I just cut four strips and glued them inside the draw tube.

#6 Sky Muse

Sky Muse

    Mariner 2

  • -----
  • Posts: 239
  • Joined: 26 Oct 2012
  • Loc: De Soto County, MS

Posted 04 December 2012 - 11:41 PM

Before installing the Celestron #94223 polar scope, the three-set-screw "What's this for?" will have to be unscrewed and removed. After figuring it out, I had to use pliers to remove the one on my CG-4 mount, but it unscrewed with no trouble, and then in went the scope. I also replaced the scope's blank right ascension flange with the marked one from the original "whatever". A jeweler's flat-blade will be needed. Note the plastic spacers and their positions and be careful with the tiny set screws. Mine now looks like the picture in the scope's clueless instruction manual, but with the original marked flange instead. Now for the aligning...:help:

What's this for?

Attached Files



#7 csrlice12

csrlice12

    Voyager 1

  • *****
  • Posts: 10409
  • Joined: 22 May 2012
  • Loc: Denver, CO

Posted 05 December 2012 - 08:39 AM

You know, I was asking myself that question. You'd think the "hole" for the polar scope would just be a capped hole (and the front is). This piece is located under a white cap at the back of the mount where the polar scope goes. I'm thinking it's gonna have to come out for the polar scope to fit. I'll be working on that this weekend.

#8 Sky Muse

Sky Muse

    Mariner 2

  • -----
  • Posts: 239
  • Joined: 26 Oct 2012
  • Loc: De Soto County, MS

Posted 05 December 2012 - 11:15 AM

It has three spring clips on the inside that must've held an older, slightly-smaller polar scope when the mount was first offered in black some years ago, and with the thumbscrews for aligning afterwards. I'd rather that they had left it off entirely, but I guess it was included just in case someone had the older scope design laying around, or...

...for a laser pointer? :thinking:

Yes, it will have to come out. Remove the three thumbscrews, then loosen the single set screw on the two retaining rings just behind the marked aluminum flange and unscrew, then remove the thicker setting circle assembly so as not to damage it, then the adaptor itself from the mount. Transfer the marked flange in place of the blank one that came with the scope. It might come in handy. Then all that's left is to screw in the scope assembly and align per its instruction manual, though expect a bit of trial and error.

Cheers,

Alan

#9 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 43398
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 05 December 2012 - 01:33 PM

Teflon with one Etched side for gluing (8711K91) This is what I used. Doesn't have an adhesive side. I just cut four strips and glued them inside the draw tube.


I used that same 0.015" thick Teflon but I removed the two lower plastic strips on the focuser itself and replaced them with the Teflon. When assembling, before I install the pinion I adjust the "nibs" near the focuser lock so that the drawtube has no slop and moves smoothly.

Jon

#10 beatlejuice

beatlejuice

    Surveyor 1

  • *****
  • Posts: 1553
  • Joined: 05 Apr 2011
  • Loc: Hamilton, ON,Canada

Posted 05 December 2012 - 04:07 PM

Are there any detailed step by step instructions for this whole process in some past thread or otherwise? For instance, I'm not sure I even know the difference between a pinion and a gib

Eric

#11 csrlice12

csrlice12

    Voyager 1

  • *****
  • Posts: 10409
  • Joined: 22 May 2012
  • Loc: Denver, CO

Posted 05 December 2012 - 04:43 PM

While for now, I'll use the stock rack & pinion focuser; any recommendations for an upgraded focuser (less than $200).

#12 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 43398
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 05 December 2012 - 04:55 PM

Are there any detailed step by step instructions for this whole process in some past thread or otherwise? For instance, I'm not sure I even know the difference between a pinion and a gib

Eric


Eric:

Maybe this will help:

Reworking a Synta Rack and Pinion Focuser

#13 beatlejuice

beatlejuice

    Surveyor 1

  • *****
  • Posts: 1553
  • Joined: 05 Apr 2011
  • Loc: Hamilton, ON,Canada

Posted 05 December 2012 - 05:51 PM

Maybe this will help:

Reworking a Synta Rack and Pinion Focuser



Thanks Jon, I will keep this as a reference for when I decide to give it a go.

Eric

#14 Mike4242

Mike4242

    Apollo

  • -----
  • Posts: 1079
  • Joined: 02 Nov 2011
  • Loc: Memphis, TN

Posted 06 December 2012 - 03:35 PM

While for now, I'll use the stock rack & pinion focuser; any recommendations for an upgraded focuser (less than $200).


I've been thinking about replacing the focuser on my Omni 102 with this dual speed GSO for $150.

http://agenaastro.co...al-speed-96m...

#15 Gary Riley

Gary Riley

    Mariner 2

  • -----
  • Posts: 295
  • Joined: 01 Dec 2011
  • Loc: White Bluff, TN

Posted 06 December 2012 - 08:45 PM

I have the Orion 2 inch 2 speed focuser on my 102mm XLT and it does a good job with my Baader Hyperions.

Gary

#16 csrlice12

csrlice12

    Voyager 1

  • *****
  • Posts: 10409
  • Joined: 22 May 2012
  • Loc: Denver, CO

Posted 07 December 2012 - 08:19 AM

Gary, did the screw holes line up to mount the Orion focuser to the Celestron Scope, or did you have to drill? I want to be sure to order something that will "line up" so the swap out will be simple....then there's that dreaded "C" word (it's a refractor, the "C" word here is NOT easy like a dob). At least once it's collimated it'll be done. The scope shop just collimated it...almost hate to ruin that.....

#17 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 43398
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 07 December 2012 - 08:28 AM

Gary, did the screw holes line up to mount the Orion focuser to the Celestron Scope, or did you have to drill? I want to be sure to order something that will "line up" so the swap out will be simple....then there's that dreaded "C" word (it's a refractor, the "C" word here is NOT easy like a dob). At least once it's collimated it'll be done. The scope shop just collimated it...almost hate to ruin that.....


I don't think collimation should be a concern... One option: You don't really need a two speed at F/10. A used Orion ED-80/ED-100 Crayford should fit.

Jon

#18 csrlice12

csrlice12

    Voyager 1

  • *****
  • Posts: 10409
  • Joined: 22 May 2012
  • Loc: Denver, CO

Posted 07 December 2012 - 08:39 AM

Thanks Jon. I value your opionion highly (and your's too Mike, I had been looking at that GSO focuser). Guess I'll try the focuser it came with for awhile and see how it goes, maybe a few month's down the road. I am going to need to swap out the one in my Dob though with a 2-speed. That one shouldn't be as hard though...

#19 Mike4242

Mike4242

    Apollo

  • -----
  • Posts: 1079
  • Joined: 02 Nov 2011
  • Loc: Memphis, TN

Posted 07 December 2012 - 04:32 PM

The stock Omni focuser isn't really all that bad. I've just been spoiled by the 2 speed on my other scope. :)

#20 Gary Riley

Gary Riley

    Mariner 2

  • -----
  • Posts: 295
  • Joined: 01 Dec 2011
  • Loc: White Bluff, TN

Posted 07 December 2012 - 04:46 PM

@cslrice12: the Orion 2 speed focuser matched up fine. No re-drilling. Works fine too. Did have to adjust focuser tension on setscrews with the Baader Hyperion eyepieces when viewing near zenith. After that, no problems.

Gary






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics