Jump to content


Photo

MI 250 Referbished and installed WOW!

  • Please log in to reply
21 replies to this topic

#1 f29pc

f29pc

    Viking 1

  • *****
  • Posts: 732
  • Joined: 23 May 2005
  • Loc: Maine

Posted 05 August 2009 - 09:29 PM

I sent my MI 250 to Larry in June for the upgrade program he is offering to older mounts. He tore down the mount found a bad DEC bearing, and my RA gear was toast, and the RA worm had a chip in it, (although the uncorrected PE was under 7 arc sec peak to peak!). I had him replace the RA worm and gear with his new brass worm, and install new DEC bearings. The upgrade also included the new clutch levers (no allen wrench), the DEC worm and gear also got re-lapped. The rocker is also a new design, one piece with a lot less backlash in the alt. and azm. adjustments. I opted for the solid counterweight shaft, but modified and powder coated the weights myself. He also stripped and repainted the mount.
The result... WOW .. The new RA has a very smooth peak to peak of 6.8 arc sec that PemPro reduced to 1.5 peak to peak. The DEC guides much better, and after a 3 star alignment, the pointing is spot on. I slewed from M27 on the east to M13 on the west, three times and they were centered on my ST2000 chip every time. And the best for last, I got a FREE MI 250 sticker for my pier! Was it worth it, with out question, I bought my mount 3rd hand, and now have a brand new MI 250 with all the latest upgrades, and one smoooooth machine. If you go to my site under mounts, you can see the old and the new. The mount is now ready for the Plane Wave 12.5 (probably ordering in a few months) Now if Larry can just do something about the WX in the northeast!
Clear Skies, Paul

Attached Files



#2 LLEEGE

LLEEGE

    True Blue

  • *****
  • Posts: 12889
  • Joined: 03 Mar 2005
  • Loc: Cloud-chester,NY

Posted 05 August 2009 - 09:44 PM

:bow: :bow: :bow:

#3 f29pc

f29pc

    Viking 1

  • *****
  • Posts: 732
  • Joined: 23 May 2005
  • Loc: Maine

Posted 05 August 2009 - 09:59 PM

Oh Yea, I forgot, I upgraded to the Maxon motors also.

#4 CounterWeight

CounterWeight

    Cosmos

  • *****
  • Posts: 8103
  • Joined: 05 Oct 2008
  • Loc: Palo alto, CA.

Posted 06 August 2009 - 12:03 AM

Beauty of a mount - even better the great service upgrade and attention to detail, I can only dream of such things...

is that you shot of M51 in the background?

#5 Yedgy

Yedgy

    Viking 1

  • *****
  • Posts: 700
  • Joined: 22 Jul 2008
  • Loc: Phoenix, AZ, USA

Posted 06 August 2009 - 12:55 AM

Larry is spectacularly easy to work with.

#6 nik hodges

nik hodges

    Viking 1

  • -----
  • Posts: 975
  • Joined: 20 Apr 2007
  • Loc: UK

Posted 06 August 2009 - 03:05 AM

looking uber cool

#7 Psyire

Psyire

    Apollo

  • *****
  • Posts: 1339
  • Joined: 24 Jun 2007
  • Loc: 55* North

Posted 06 August 2009 - 04:54 AM

Very nice, congrats!

#8 Joel

Joel

    Gemini

  • *****
  • Posts: 3123
  • Joined: 08 Jul 2004
  • Loc: Merrimack, NH

Posted 06 August 2009 - 06:20 AM

Looks great Paul! I'm sold on the MI-250.

#9 David Pavlich

David Pavlich

    Transmographied

  • *****
  • Administrators
  • Posts: 27224
  • Joined: 18 May 2005
  • Loc: Mandeville, LA USA

Posted 06 August 2009 - 08:28 AM

The thing looks terrific, Paul! The only thing that would have made it look better was for it to be black. :grin:

Since the 250 that I have is the model just before the new, higher capacity 250 was unveiled, I'm not going to send it. The only difference would be the new rocker that would change the capacity although, I do like your report of a better adjustment on the new rocker. The internals that Larry does for the upgrade are already in mine. As a matter of fact, I waited an extra 2 weeks for delivery so that he could include the new stuff. I also bought a used SS CW shaft for it. I had the CWs bored and drilled and counterbored for set screws.. Big improvement. And I painted the CWs black.

1.5 peek to peek, eh? I don't know if it can get any better than that. I'm looking forward to your first image...kinda' like waiting for Hubble's new stuff after the refit. And a 12.5" CDK? I am officially envious. I've seen some images produced by said scope. We'll be seeing your name on APOD. :ubetcha:

David

#10 David Pavlich

David Pavlich

    Transmographied

  • *****
  • Administrators
  • Posts: 27224
  • Joined: 18 May 2005
  • Loc: Mandeville, LA USA

Posted 06 August 2009 - 08:30 AM

Oh Yea, I forgot, I upgraded to the Maxon motors also.


I wonder...is that something that can be done in the field...or the backyard, as it were?

David

#11 f29pc

f29pc

    Viking 1

  • *****
  • Posts: 732
  • Joined: 23 May 2005
  • Loc: Maine

Posted 06 August 2009 - 10:31 AM

Post deleted by f29pc

#12 Bowmoreman

Bowmoreman

    Clear enough skies

  • *****
  • Posts: 9162
  • Joined: 11 Sep 2006
  • Loc: Bolton, MA

Posted 06 August 2009 - 10:46 AM

Wow Paul, that is beautiful; every bit the visual equal of AP900 or AP1200's!

The upgrade is something I may do at some point in the future, but mine is working so spectacularly well right now that I see no need to mess with it. I'm going to be nowhere near maximum load (probably maxing out around 45# for the foreseeable future).

But that is GORGEOUS!!! Truly beautiful!

BTW: I agree with the WX here in New England! Blech. Had ONE clear night a few nights ago - yep: almost full moon!

Clear enough skies

#13 f29pc

f29pc

    Viking 1

  • *****
  • Posts: 732
  • Joined: 23 May 2005
  • Loc: Maine

Posted 06 August 2009 - 11:12 AM

David, the Maxon motors can be installed very easy in the field, BUT.. They are 300.00 a piece. I upgraded to them because I challenge Larry's new rocker by loading the mount to the limit (up to 95lbs at times!) and the higher torque motors would make sense. The Maxons are about a half inch longer so they stick out from the mount more, that means less clearance when you are going through the meridian. I tightened up my safety limits a bit.
Paul

Attached Files



#14 f29pc

f29pc

    Viking 1

  • *****
  • Posts: 732
  • Joined: 23 May 2005
  • Loc: Maine

Posted 06 August 2009 - 11:14 AM

And the RA

Attached Files



#15 David Pavlich

David Pavlich

    Transmographied

  • *****
  • Administrators
  • Posts: 27224
  • Joined: 18 May 2005
  • Loc: Mandeville, LA USA

Posted 06 August 2009 - 09:31 PM

Thanks, Paul. Man...Larry does some nice work. The mount just looks great. Right now, I'll have about 65lbs on mine. I wouldn't think it'll be much of a strain as is. However, at some point, it may see more weight.

Question: What's the red wires I see in conjunction with the RA and Dec motors?

Have you ordered the CDK? I understand that it's about 4 months after the order is placed. Can't wait to see it!

David

#16 hersey0308

hersey0308

    Vostok 1

  • -----
  • Posts: 102
  • Joined: 04 Dec 2008
  • Loc: Ontario Canada

Posted 06 August 2009 - 10:23 PM

i agree with nik. this is a "tasty" set up.
david

#17 f29pc

f29pc

    Viking 1

  • *****
  • Posts: 732
  • Joined: 23 May 2005
  • Loc: Maine

Posted 07 August 2009 - 08:31 AM

David, I haven't ordered the CDK yet, still waiting to get our contract finalized, probably next month. The red wires are leads to 2 magnetic proximity switched (one on the DEC axis and one on the RA). There are 2 small magnets, one on the DEC shaft and one on the bottom of the saddle plate, that when the scope is in the park position, the circuit is closed and tells the observatory control software that it's OK to closed (or move) the roof. If either switch is open, the roof cannot be moved unless a manual override is pressed. If my scope is pointing high in DEC, the roof can rip it off the mount! You can see the DEC switch mounted on the L bracket on the right side of the Gemini, and on the bottom of the saddle.
Paul

Attached Files



#18 David Pavlich

David Pavlich

    Transmographied

  • *****
  • Administrators
  • Posts: 27224
  • Joined: 18 May 2005
  • Loc: Mandeville, LA USA

Posted 07 August 2009 - 09:49 AM

I imagine that winch you installed to move the roof wouldn't notice that it was peeling off a scope or two while moving the roof. Now that would be depressing.

David

#19 DeanS

DeanS

    Gemini

  • *****
  • Posts: 3242
  • Joined: 12 Jul 2005
  • Loc: Central Kentucky

Posted 07 August 2009 - 01:22 PM

Looks great to me.

Sounds like a very worthwhile upgrade, made a good mount even better. I do like all the recent things Larry has done to the mount.

#20 Paul Romero

Paul Romero

    Viking 1

  • *****
  • Posts: 969
  • Joined: 05 Apr 2005
  • Loc: Reno, NV

Posted 07 August 2009 - 05:54 PM

Hi all,

My mount had serious damage inside, and this is the perfect upgrade for it! Without this retrofit offering, the cost for Mountain Instruments to repair mine would have been as much without all the new great parts!

David, I should of bought yours. It was a poor decision to purchase a 'bargain basement' mount.

Hey everybody, what kind of cases are you using to transport your MI-250 in? Larry uses Kmart storage tubs filled with foam for his, but I already have one Pelican 6120 for the DEC, and I am thinking another one would be good for the RA + counterweights+shaft+Gemini...

cya,

Paul

#21 David Pavlich

David Pavlich

    Transmographied

  • *****
  • Administrators
  • Posts: 27224
  • Joined: 18 May 2005
  • Loc: Mandeville, LA USA

Posted 07 August 2009 - 05:59 PM

Hi all,

My mount had serious damage inside, and this is the perfect upgrade for it! Without this retrofit offering, the cost for Mountain Instruments to repair mine would have been as much without all the new great parts!

David, I should of bought yours. It was a poor decision to purchase a 'bargain basement' mount.

cya,

Paul


It is now the one you see in this post.

David

#22 HunterofPhotons

HunterofPhotons

    Apollo

  • -----
  • Posts: 1062
  • Joined: 26 Apr 2008
  • Loc: Rhode Island, USA

Posted 08 August 2009 - 09:58 AM

.... what kind of cases are you using to transport your MI-250 in?......
Paul

A larger Pelican will hold the whole mount:

Posted Image

dan






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics