Jaimo!
Pooh-Bah
Reged: 10/11/07
Loc: Exit 135 / 40° North
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Coulter Odyssey 8 Brown Tube
#5414205 - 09/10/12 09:50 PM
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I have a friend who is just getting into astronomy and his uncle had given him a brown tubed Coulter Odyssey 8. After a few conversations with him, we decided that I would try and "tune it up" a bit. Neither he nor I want to sink much cash into this scope as it has the potential to be average at best, so I'd like to keep the spend under $50. After getting the scope back to my place and attempting to colluminate, which was not easy with the original cell, I could not get a good image over 50x in this scope in star tests. I figured that maybe the original cell was acting like a heat trap and it was difficult to colluminate... bottom line it was built a cheaply as possible. After reading some older posts and reading a few things on line, I had built a new mirror cell. It didn't cost anything as all of the parts were scrap in my shop, it turned out well, easy to colluminate and allows good ventilation to the mirror.
Here lies my first problem, the new cell weights considerably less that the original, probably by a pound or so... (see photos), and the tube keeps falling forward. I considered ballasting the rear end of the scope, but I have also considered moving the fulcrum...?? Any help would be appreciated.
Also about the $50 budget, I leaning towards getting the mirror re-coated as there are a few worn spots and with OWL's half price offer going on right now...
Brown Tube Coulter Odyssey 8
The Focuser, I believe this is stock.
Down the Tube:
New Mirror Cell:
What's left of the old cell:
Thanks,
Jaimo!
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bob midiri
Carpal Tunnel
Reged: 06/17/04
Loc: pa 19320
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Re: Coulter Odyssey 8 Brown Tube
[Re: Jaimo!]
#5414582 - 09/11/12 04:28 AM
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Velcro on the bottom of tube and bean bags with lead weight that you can velco to the tube. easy and cheap. bob
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apfever
Carpal Tunnel
Reged: 05/13/08
Loc: Colorado
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Re: Coulter Odyssey 8 Brown Tube
[Re: bob midiri]
#5415148 - 09/11/12 12:43 PM
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I suggest you get a good testing on the mirror before coating. PM SENT. These Coulter scopes are well known to have optics that go from OK to not good. Was the mirror tapered? Thickher on one edge than the other? Was the back ground? If the mirror cell is good and the optics clean, you can still get a star test to check the optics even if the coatings are marginal. If you are not happy with the figure, why recoat?
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actionhac
Post Laureate
Reged: 08/09/08
Loc: WA
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Re: Coulter Odyssey 8 Brown Tube
[Re: apfever]
#5415714 - 09/11/12 04:54 PM Attachment (35 downloads)
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That focuser sure does look original, it is the same as the earlier blue tube Odyssey with the gigantic 1/4" bolts holding it on.
You must have a early red tube, and I agree a "brown" tube!
Here is the "sink drain" focuser found on most of the red tubes:
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actionhac
Post Laureate
Reged: 08/09/08
Loc: WA
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Re: Coulter Odyssey 8 Brown Tube
[Re: actionhac]
#5415732 - 09/11/12 05:03 PM Attachment (33 downloads)
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The previous owner of my Odyssey 8 replaced the sink drain focuser with a cast iron Criterion focuser and added a optical finder. In other words added a bunch of weight to the front, same problem you have now after you made that very nice lightweight cell.
The previous owner decided to move the side bearings on the tube rather than add weight. I noticed you had thought of doing the same, moving the balance point. It works great and you won't add any weight to the optical tube but you will be drilling some new holes in the tube. The new holes might end up under the bearing and unnoticed.
That paint job on your tube is really cool looking.
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Jaimo!
Pooh-Bah
Reged: 10/11/07
Loc: Exit 135 / 40° North
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Re: Coulter Odyssey 8 Brown Tube
[Re: actionhac]
#5420226 - 09/13/12 11:35 PM
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After replacing the mirror cell and bungee cording a 2.5 pound weight to the back I went out and star tested with a 16mm, 20mm, & 24mm Meade 5000 SWA. I first started on the double cluster, I could not get sharp stars or an even focused field of view in the 16mm or at 56x… At 37x and 45x were a little better but the outer 50% FOV stars became seagulls and outer 20% stars looked like fireworks. Only the center of the field was reasonable sharp, and not that sharp. I then switched over to the Andromeda Galaxy, it seemed OK... However, it is less bright than the stars in the Double Cluster and it is fuzzy anyway. Am I missing something, could it be the secondary?
Quote:
That paint job on your tube is really cool looking.
It's not paint, it is more like contact paper covering the sonotube OTA.
Thanks,
Jaimo!
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actionhac
Post Laureate
Reged: 08/09/08
Loc: WA
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Re: Coulter Odyssey 8 Brown Tube
[Re: Jaimo!]
#5420317 - 09/14/12 01:28 AM
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Collimation is critical at the Odyssey's 4.5 focal ratio. Here is some good information:
http://web.telia.com/~u41105032/kolli/kolli.html
Buy one of these if you don't have one all ready:
http://www.scopestuff.com/ss_coll2.htm
Make sure the telescope has had plenty of time to temperature equalize.
Using a eyepiece the same size as the scopes focal ratio, 5mm is fine for your 4.5 Odyssey. Defocus a bright star and look for a steady disc of light. if unsteady and boiling the tube may need more time. When steady you can touch up collimation and star test, and use more power.
Robert
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Jaimo!
Pooh-Bah
Reged: 10/11/07
Loc: Exit 135 / 40° North
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Re: Coulter Odyssey 8 Brown Tube
[Re: actionhac]
#5420870 - 09/14/12 12:40 PM
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Thanks Robert,
I have a Cheshire and a Gladder Laser with the built in barlow. I may need to put a center spot on the main mirror to help me out a bit... I like the link, it get to the meat of things without being too basic.
Jaimo!
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GeneT
Ely Kid
Reged: 11/07/08
Loc: South Texas
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Re: Coulter Odyssey 8 Brown Tube
[Re: Jaimo!]
#5421165 - 09/14/12 03:56 PM
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I balanced my 12.5 inch Portaball with a 3 lb ankle weight, the kind that flex and strap around the ankle. They would easily fit at the bottom of your tube. I used Velcro tape. These weights are easy to cut, so you could cut the into two or one pound sections.
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Jaimo!
Pooh-Bah
Reged: 10/11/07
Loc: Exit 135 / 40° North
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Re: Coulter Odyssey 8 Brown Tube
[Re: actionhac]
#5429947 - 09/19/12 09:18 PM
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Quote:
Collimation is critical at the Odyssey's 4.5 focal ratio. Here is some good information:
http://web.telia.com/~u41105032/kolli/kolli.html
So, I wored on the collimination last night during a rain storm and noticed the laser bouncing off the secondary was not even coming close to hitting the center of the mirror. I straightned things up and was able to get near 100x at some of the clusters in Cassiopeia. My next step is to find the center of the mirror and mark it with a page protector and proceed to colliminate with a little more precision. Thanks for the help.
Jaimo!
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actionhac
Post Laureate
Reged: 08/09/08
Loc: WA
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Re: Coulter Odyssey 8 Brown Tube
[Re: Jaimo!]
#5430007 - 09/19/12 10:00 PM
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Try this out. A barlow on your laser:
http://www.cameraconcepts.com/barlowed%20laser%20collimation.pdf
This is a very good article.
Robert
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Jaimo!
Pooh-Bah
Reged: 10/11/07
Loc: Exit 135 / 40° North
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Re: Coulter Odyssey 8 Brown Tube
[Re: actionhac]
#5430060 - 09/19/12 10:46 PM
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Here's what I am using...
http://www.collimator.com/tublug.htm
Jaimo!
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actionhac
Post Laureate
Reged: 08/09/08
Loc: WA
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Re: Coulter Odyssey 8 Brown Tube
[Re: Jaimo!]
#5430102 - 09/19/12 11:25 PM Attachment (19 downloads)
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That's a nice unit. Your right you need a center mark on the primary.
I measure the mirror and draw a circle that size, cut it out and carefully place it on the mirror. The compass leaves a small hole in the paper at the center you can slip a felt pen through to mark the center of the mirror.
Then place a hole-reinforcer ring on the mirror centered on the felt pen mark.
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simpleisbetter
Carpal Tunnel
Reged: 04/18/11
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Re: Coulter Odyssey 8 Brown Tube
[Re: actionhac]
#5430165 - 09/20/12 12:24 AM
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Stay patient and keep working. I was able to easily get 225x on my old Odyssey 8, no thanks to that darned drainpipe drawtube focuser. And I was only limited to that because my 4mm ortho was my shortest f/l eyepiece at the time. I'm certain once you get all the bugs worked out you'll have fun with it.
Another idea for bottom end weight. The Coulter is one of those scopes that responds well to attaching a piece of chain to the mirror cell, so that the weight progressively changes depending on altitude - more weight at Horizon and less to almost none at Zenith.
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Jaimo!
Pooh-Bah
Reged: 10/11/07
Loc: Exit 135 / 40° North
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Re: Coulter Odyssey 8 Brown Tube
[Re: actionhac]
#5430693 - 09/20/12 11:01 AM
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Robert,
Thanks for all of the help. I like your method for locating the center, it seems easy and straight forward. I guess I'll be off the the office supply store this evening.
Steve,
I am intrigued with the chain idea, I have never heard of that one, very creative.
Thanks,
Jaimo!
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simpleisbetter
Carpal Tunnel
Reged: 04/18/11
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Re: Coulter Odyssey 8 Brown Tube
[Re: Jaimo!]
#5430738 - 09/20/12 11:23 AM
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That idea was one someone else had shown years ago. The only trick I ran into was finding just the right length and weight chain so that balance was properly distributed as you changed scope altitude. Too heavy or short and weight won't be relieved toward Zenith, but too light or too long, and you won't have enough weight from 45* to Horizon especially with heavier eyepieces.
But with a little trial and error it's a good inexpensive solution that can easily be bolted to the Coulter wood backplate.
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Jaimo!
Pooh-Bah
Reged: 10/11/07
Loc: Exit 135 / 40° North
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Re: Coulter Odyssey 8 Brown Tube
[Re: Jaimo!]
#5431608 - 09/20/12 08:12 PM
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I went to the office supply store and picked up some hole reinforcements, they only had the peel off type... I think I'd rather use the type you wet, but this was the best I could do. I snapped a few photos along the way, kind of a "Finding the Center of a Newtonian Mirror for Dummies". You can also see the deterioration of the mirror coatings, however if we want to keep this under $50, I'm going to suggest to my friend to buy a good colliminator...
Supplies:
Measuring the Mirror - yes it is 8", but you can never be too sure.
Setting up the Protractor:
Making the Template:
Fitting the Template to the Mirror: - At this point there is a TINY hole where the protractor was, I tried to photograph it without success. Then place a dot through the hole with the Sharpie.
Placing the Hole Reinforcement:
Finished Product:
Thanks for everyone's help, and according to my local weather reports I may have a clear sky sometime next week... 
Jaimo!
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orion61
Vendor(Clear Edge Optical)
Reged: 10/20/07
Loc: NW Iowa BURRRR
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Re: Coulter Odyssey 8 Brown Tube
[Re: Jaimo!]
#5432757 - 09/21/12 01:54 PM
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get some wheel weight lead from a tire shop, Melt it in a tin can with a screw stuck down the middle where it is sticking out 1/2 inch, (you can use a Coleman stove, when done cut it out of the can and screw it on the back of the scope.
You can paint the weight if your afraid of lead .
I did this when I put a 2" Heavy focuser on my 10"
worked like a charm. cost was about 50 cents.
It really didn't affect cooldown since it was on the outside.
the larger the can the thinner the weight wi be.
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*skyguy*
Pooh-Bah
Reged: 12/31/08
Loc: Western New York
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Re: Coulter Odyssey 8 Brown Tube
[Re: orion61]
#5433380 - 09/21/12 08:08 PM
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Quote:
get some wheel weight lead from a tire shop, Melt it in a tin can with a screw stuck down the middle where it is sticking out 1/2 inch, (you can use a Coleman stove, when done cut it out of the can and screw it on the back of the scope.
You can paint the weight if your afraid of lead .
I did this when I put a 2" Heavy focuser on my 10"
worked like a charm. cost was about 50 cents.
It really didn't affect cooldown since it was on the outside.
the larger the can the thinner the weight wi be.
I've been using this method to make counterweights for over 30 years. AAAAnd wwwwworking wwwwith llllead hhhhasn't mmmade mmmme cccrazy, yyyyet! 
Fortunately, it has a low melting point and high vaporization temperature. Just make sure the work area is well ventilated.
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greju
Carpal Tunnel
Reged: 10/13/05
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Re: Coulter Odyssey 8 Brown Tube
[Re: *skyguy*]
#5434575 - 09/22/12 02:38 PM
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Quote:
Quote:
get some wheel weight lead from a tire shop, Melt it in a tin can with a screw stuck down the middle where it is sticking out 1/2 inch, (you can use a Coleman stove, when done cut it out of the can and screw it on the back of the scope.
You can paint the weight if your afraid of lead .
I did this when I put a 2" Heavy focuser on my 10"
worked like a charm. cost was about 50 cents.
It really didn't affect cooldown since it was on the outside.
the larger the can the thinner the weight wi be.
I've been using this method to make counterweights for over 30 years. AAAAnd wwwwworking wwwwith llllead hhhhasn't mmmade mmmme cccrazy, yyyyet!
Fortunately, it has a low melting point and high vaporization temperature. Just make sure the work area is well ventilated.
With all the alternatives available to "modern" man this idea IMHO is one of the most dangerous postings I have seen on Cloudy Nights. In other words, do not try this at home!
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