Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

The vintage Coulters

  • Please log in to reply
44 replies to this topic

#1 grif 678

grif 678

    Vanguard

  • *****
  • topic starter
  • Posts: 2,413
  • Joined: 22 Dec 2010
  • Loc: NC

Posted 13 September 2021 - 01:18 PM

I use to read the Coulter ads a lot back in the 80's, and the 13 inch appealed to me, but I never got one. They had a monster 29 inch one. Do any of you have one of these, and what was it like looking through one of these. They claimed it had an illusion of being in space more than any other scope available at that time. They had an 8", 10", 13",17" and the 29".



#2 Don W

Don W

    Founding Member

  • *****
  • Posts: 24,785
  • Joined: 19 May 2003
  • Loc: Wisconsin, USA

Posted 13 September 2021 - 01:26 PM

From all I've read about the 29", it just didn't perform well at all. The mirror was too thin and would not keep a figure when mounted. For the most part the under 13" mirrors were pretty good. The 13" were mostly good, but hit and miss. The 17.5" were just not very good. Many people had them refigured in the 80s. Even after remounting mine in a well built dob and mirror mount, I could hardly get 100X out of it before the image degenerated.

 

On the other hand, in the 70s and early 80s, Coulter produced some very good unmounted mirrors that you would put in a homebuilt scope. These were thicker and had good figures.


  • tim53, markb, mdowns and 2 others like this

#3 scngc7317

scngc7317

    Messenger

  • *****
  • Posts: 436
  • Joined: 09 Feb 2009
  • Loc: Menifee California

Posted 13 September 2021 - 02:01 PM

 
RTMC # 16         waytogo.gif     I was there when they unloaded it, had to get a ton of volunteers to help
later that night they had it on the ring nebula - very bright but at a low power view. - I guess so they didn't have to move it so much bigshock.gif
 
 
82RTMC16
 
cartoon in next S&T
82RTMC05

Edited by scngc7317, 13 September 2021 - 02:09 PM.

  • tim53, brian dewelles, mdowns and 4 others like this

#4 GEC

GEC

    Vostok 1

  • *****
  • Posts: 100
  • Joined: 13 Sep 2017

Posted 13 September 2021 - 02:20 PM

Agreed on the earlier Coulter Mirrors. I bought an 8" f/7 that I still have and occasionally use. I also got a 17.5 mirror from to build a dobson around. Figure was only fair and I had it resigned after Shoemaker Levy 9. I wonder how the 29 mirror was mounted in its cell. That might account for some of issues.

#5 clamchip

clamchip

    Voyager 1

  • *****
  • Posts: 11,492
  • Joined: 09 Aug 2008
  • Loc: Seattle

Posted 13 September 2021 - 03:18 PM

I don't think they had bubble wrap back then, the 29 probably would have

benefited from the mirror floating on 1 inch bubble wrap. 

The Odyssey's really need to acclimate because of the closed tube before 

they work best.

The blue tubes you can open the tailgate and let the mirror adjust, taking your 

chances with the bats.

Don't expect a superplanetary at f/4.5 and the sink drain pipe focuser.

I've had great fun with my Odyssey's over the years and no complaints of

any kind.  2 red tube 8's, a brown tube 8, blue tube 10, red tube 13.1 inch,

blue tube 17.5, plus a Coulter Optical  6 inch f/8 mirror, 2 10 inch f5/6's.

 

Robert


  • Piggyback, Augustus and Defenderslideguitar like this

#6 ShaulaB

ShaulaB

    Gemini

  • *****
  • Posts: 3,280
  • Joined: 11 Oct 2012
  • Loc: Missouri

Posted 13 September 2021 - 04:00 PM

Wow, a 29 incher must have really brightened up galaxies. A pity it would not perform well enough on planets.

My avatar shows a 1989 homebuilt 10 inch Dob with a Coulter mirror. It has been a blast using it for decades.

Edited by ShaulaB, 13 September 2021 - 04:00 PM.

  • mikerepp and Defenderslideguitar like this

#7 Piggyback

Piggyback

    Apollo

  • *****
  • Posts: 1,285
  • Joined: 14 Sep 2013
  • Loc: Germany

Posted 13 September 2021 - 04:43 PM

I was the german distributor for Coulter in the 1980's. Their offerings included 17" Dobson mirrors that had a strong following with the german ATM crowd. Unfortunately, Coulter was a mom and dad enterprise and delivery took a year and more. Here I show off my Hendrix devotion and the Coulter CT-100 travel scope 4.25" f/4 Newtonian. It was a well thought out design but the optics were flawed.

 

IMG_0996.JPG


  • Gil V, dgreyson, PawPaw and 8 others like this

#8 tim53

tim53

    Hubble

  • *****
  • Posts: 15,582
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 13 September 2021 - 05:14 PM

 

 
RTMC # 16         waytogo.gif     I was there when they unloaded it, had to get a ton of volunteers to help
later that night they had it on the ring nebula - very bright but at a low power view. - I guess so they didn't have to move it so much bigshock.gif
 
 
 
 
cartoon in next S&T

 

I was there too.  They lifted the OTA using a pair of 2x4's as "handles, with one or two guys at each end to lift.  One split and they almost dropped the scope.  I also remember looking at the Ring (aka "the blue bagel nebula"), and finding the view really disappointing.  They may have made more than one mirror (I really don't know, though), but they can't have made many of those complete scopes - they didn't scale up well at all.


  • Gil V likes this

#9 Michael Covington

Michael Covington

    Author

  • *****
  • Posts: 6,946
  • Joined: 13 May 2014
  • Loc: Athens, Georgia, USA

Posted 13 September 2021 - 05:28 PM

I was the german distributor for Coulter in the 1980's. Their offerings included 17" Dobson mirrors that had a strong following with the german ATM crowd. Unfortunately, Coulter was a mom and dad enterprise and delivery took a year and more. Here I show off my Hendrix devotion and the Coulter CT-100 travel scope 4.25" f/4 Newtonian. It was a well thought out design but the optics were flawed.

 

attachicon.gifIMG_0996.JPG

I got a Coulter CT-100 for Christmas 1979.  (I was getting back into astronomy after a period away from it, so I knew what to expect from this telescope -- but it seemed to have an optical problem that I never completely figured out.)  I should get it out and investigate further.  I managed to observe about half the Messier Objects with it; at lower power it was more or less OK.


  • Piggyback likes this

#10 Augustus

Augustus

    Vendor

  • *****
  • Vendors
  • Posts: 11,143
  • Joined: 26 Dec 2015
  • Loc: Stamford, Connecticut

Posted 13 September 2021 - 05:58 PM

AFAIK Coulter made something like six of the 29-inchers. Someone on here made a truss Dob with one a while back and it worked well. They were 1.25" or 1.5" thick so support is crucial. AFAIK Tom Dey had one and made a warping harness for the mirror to adjust the figure?

 

I have had good experiences with the Pyrex 13.1-inch mirrors. My 13.1" Odyssey gave great views of Mars. I got a 13.1" with a big chip in it in a trade today and it has a nice figure, no astigmatism or other issues that I can see (albeit it has 2 square inches missing from one side). Most of the complaints seem to be about the 5/8" thick Murnaghan Coulters from the '90s - the one of those I had had a fair bit of stig and obviously the duct tape based cell of the Odyssey wouldn't work with one.

 

I've never had the 10.1" Odyssey mirrors but I've used a 10" f/4.8 and 10" f/5.6 Coulter and both were very good - the 10" f/5.6 gave me some of the best views of Mars I've ever had besides with the 13.1 and with a 5" apo. 

 

My friend Jordanne has a 17.5 and I bench tested it and it was pretty nice, though I theorize it may have been refigured before she got it as the back is obviously ground flat and not simply straight from the sheet Pyrex.


  • Piggyback likes this

#11 CHASLX200

CHASLX200

    ISS

  • *****
  • Posts: 24,003
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 13 September 2021 - 06:29 PM

I use to read the Coulter ads a lot back in the 80's, and the 13 inch appealed to me, but I never got one. They had a monster 29 inch one. Do any of you have one of these, and what was it like looking through one of these. They claimed it had an illusion of being in space more than any other scope available at that time. They had an 8", 10", 13",17" and the 29".

I only had a 10.1". But all the 1's i took a peek thru were rude and crude.  I am a remember the FOV in a 17.5" that was a sea of mush and Coma at a star party. This was back in 1983 i think way before most had a Nagler and way before the Paracorr days and real collimation tools.

 

I mean sure the image was bright but just pure slop to my then 20 year old eyes and now my eyes hate coma 10 times worse so i would hate to see what i would think today.  I guess a Paracorr would clean up the image some. But just think of them thin mirrors in crude cells and these mirror's were no Zambuto's by a long shot.

 But back then no one and their monkey's uncle ever dreamed of a 17" or bigger scope pre 1981.  Unitron and fracts were sinking fast around 1980 and the SCT and cheap DOB's were the new stars of the show.


  • Bonco2 and Piggyback like this

#12 CHASLX200

CHASLX200

    ISS

  • *****
  • Posts: 24,003
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 13 September 2021 - 06:31 PM

From all I've read about the 29", it just didn't perform well at all. The mirror was too thin and would not keep a figure when mounted. For the most part the under 13" mirrors were pretty good. The 13" were mostly good, but hit and miss. The 17.5" were just not very good. Many people had them refigured in the 80s. Even after remounting mine in a well built dob and mirror mount, I could hardly get 100X out of it before the image degenerated.

 

On the other hand, in the 70s and early 80s, Coulter produced some very good unmounted mirrors that you would put in a homebuilt scope. These were thicker and had good figures.

Had a few of their older mirrors that did very good. Like all my Meade scopes used them. But the thin Dob mirrors were hit and miss like SCT's.
 


  • Don W and mdowns like this

#13 DAVIDG

DAVIDG

    Voyager 1

  • *****
  • Posts: 10,415
  • Joined: 02 Dec 2004
  • Loc: Hockessin, De

Posted 13 September 2021 - 06:57 PM

 I have had a 13.1" since about 1988  that I paid $499  and on the back is 4.25" f/4 that Coulter sold as a kit.  The mirror in my 13.1" is 1/4 wave  and I have enjoyed the deepsky images it gives for many years. I have remounted the mirror on bubble wrap and use it with 28mm Pretoria coma correcting eyepiece.   The 4.25" f/4 was a sphere when I got the kit for  $29.95 so I refigured it to a parabola. I suspect that the CT-100 had the same issue.  

 

                  - Dave

coulter 13.1 DMG.jpg


  • highfnum, Piggyback and Augustus like this

#14 Don W

Don W

    Founding Member

  • *****
  • Posts: 24,785
  • Joined: 19 May 2003
  • Loc: Wisconsin, USA

Posted 13 September 2021 - 07:00 PM

I helped a club member build a 10" f/5.6 dob with a Coulter mirror around 1982. It was thicker than the thinner fast mirrors. He's still using it. Still gives very nice images.


  • mdowns and Augustus like this

#15 highfnum

highfnum

    Fly Me to the Moon

  • *****
  • Posts: 5,358
  • Joined: 06 Sep 2006
  • Loc: NE USA

Posted 13 September 2021 - 07:02 PM

i got the 10 inch version 

ok for deep sky

1/3-1/2 wave as is 

 

my meade ds-10 has a much better mirror 



#16 Chuckfishes

Chuckfishes

    Lift Off

  • -----
  • Posts: 11
  • Joined: 29 Dec 2018
  • Loc: Sudbury, Ma

Posted 13 September 2021 - 07:16 PM

I've had a 13.1 since 1984. It was purchased used with a 1982 build date.
The wow factor was viewing a neon green M42. M27 was green too!
The scope was my window to deep sky as a youngster.
My observing site was an abandoned railroad bed between two ponds behind my parent's house.
I was not deterred by carrying that scope in two trips to my spot.
200 ft through a trail in the woods, then 10 feet up the embankment of the rail bed.
Those were the days!
  • Piggyback, mikerepp and Augustus like this

#17 mdowns

mdowns

    Gemini

  • *****
  • Moderators
  • Posts: 3,395
  • Joined: 12 Jun 2010
  • Loc: SW,FL

Posted 13 September 2021 - 07:25 PM

I bought the 10 new in 80/81 and the 13  in 83.Both of those had optics a grade or two better than shaving mirrors.However,they were great for folks like me at that time,who lived in a large city and had to pack up and drive out to the country.I did that countless times with each scope.BTW,the coutler 10"f5/6 mirror I bought and built into a scope in 75 was a very solid performer and never left me less than pleased.

Attached Thumbnails

  • 93784812_10217004117315466_3973829142419341312_o.jpg
  • 46491871_10213163342018484_8206250466070233088_n.jpg

  • Piggyback, mikerepp, Augustus and 1 other like this

#18 CHASLX200

CHASLX200

    ISS

  • *****
  • Posts: 24,003
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 13 September 2021 - 07:31 PM

I helped a club member build a 10" f/5.6 dob with a Coulter mirror around 1982. It was thicker than the thinner fast mirrors. He's still using it. Still gives very nice images.

I have yet to ever have a old school slower Newt ever give a bad image.  They were all great.  I have had them all from all the makers. But every fast Newt i had pre 1990's was just bad. But eyepiece tech and no Paracorr was the main reason back in them days in the 70''s and 80's.


  • Bonco2 likes this

#19 davidmcgo

davidmcgo

    Soyuz

  • *****
  • Posts: 3,683
  • Joined: 09 Oct 2004
  • Loc: San Diego, CA

Posted 13 September 2021 - 07:42 PM

The CT100 I got had a spherical primary.  No coma with a low power eyepiece but started to mush out above 30x or so.  Admittedly 3 of the 5 Astroscans I have owned have been about the same or the. Or collimation so bad they didn’t do worse at any rate.

 

A number of years back, Sheldon Faworski was selling some Carton Optical 4.25” f4.5 mirrors, so my CT100 now has one of those in it, along with an Antares secondary, just because .  Now it is really sharp.  On axis.  A 1.25” Paracorr would be a nice accessory.

 

Dave


Edited by davidmcgo, 13 September 2021 - 08:52 PM.

  • Piggyback, Michael Covington and Augustus like this

#20 davidmcgo

davidmcgo

    Soyuz

  • *****
  • Posts: 3,683
  • Joined: 09 Oct 2004
  • Loc: San Diego, CA

Posted 13 September 2021 - 07:46 PM

I did see some really nice planet views with a friends blue tube Odyssey Compact and my early Odyssey 8 was easily better than a similar Halley era Powerstar 8 and Meade equivalent in our club.

 

One of the nicest Jupiter views I had was a Coulter 1970s 12.5” f6 in an open tube (2 angle irons basically with plywood plates) on a pipe alt az mount at the WSP in 1991.

 

Dave


Edited by davidmcgo, 13 September 2021 - 08:52 PM.

  • Augustus likes this

#21 CHASLX200

CHASLX200

    ISS

  • *****
  • Posts: 24,003
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 13 September 2021 - 07:55 PM

The CT100 I got has a spherical primary.  No coma with a low power eyepiece but started to mush out above 30x or so.  Admittedly 3 of the 5 Astroscans I have owned have been about the same or the. Loki at ion so bad they didn’t do worse at any rate.

 

A number of years back, Sheldon Faworski was selling some Carton Optical 4.25” f4.5 mirrors, so my CT100 now has one of those in it, along with an Antares secondary, just because .  Now it is really sharp.  On axis.  A 1.25” Paracorr would be a nice accessory.

 

Dave

I had a Astroscan back in 1980 that was a sea of mush and a Comet catcher in 1986.


  • Don W likes this

#22 brian dewelles

brian dewelles

    Vostok 1

  • *****
  • Posts: 112
  • Joined: 09 Nov 2009
  • Loc: Wickenburg AZ.

Posted 13 September 2021 - 10:31 PM

I had a 17.5" coulter thin mirror that was refigured by enterprise optics i sent the mirror to discovery telescopes and they put it in a split sonotube on a nice dob mount. I loved using that scope the views were spectacular. Of course with all the modification it wasn't exclusively a coulter by any stretch but it ended up as a great scope that i miss.


  • mdowns likes this

#23 Kasmos

Kasmos

    Skylab

  • *****
  • Posts: 4,110
  • Joined: 19 Aug 2015
  • Loc: So Cal

Posted 14 September 2021 - 03:25 AM

I was the german distributor for Coulter in the 1980's. Their offerings included 17" Dobson mirrors that had a strong following with the german ATM crowd. Unfortunately, Coulter was a mom and dad enterprise and delivery took a year and more. Here I show off my Hendrix devotion and the Coulter CT-100 travel scope 4.25" f/4 Newtonian. It was a well thought out design but the optics were flawed.

 

attachicon.gifIMG_0996.JPG

Are those Quantum posters in the background?


  • Piggyback and Michael Covington like this

#24 tim53

tim53

    Hubble

  • *****
  • Posts: 15,582
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 14 September 2021 - 10:30 AM

I just remembered that, shortly after I started working at Meade in 1978, I bought one of those coulter 4.25" f/12 optics sets.  I mounted it in a fiberlite tube I got at cost at Meade, and put a R&P focuser left over from my Optical Craftsmen Discoverer that I took the optics from and put into my Springfield.  For a mirror cell, I made the backplate from a defective 826 clock drive backplate casting that was destined for the recycler anyway.  I cut it round, which made it about the right size for the OTA.  it's been a long time, but I might have used a second one for the mirror to sit in, and adapted mirror clips and other parts from a 6" cell to complete the job.  I do remember that I took a 6" secondary spider and ground down the central hub casting so it didn't obstruct more than the small 3/4" secondary mirror.  I cut the vanes short and remounted the mounting screws on them.  For end rings, I took a pair of the 6" rings, cut them and bent them around the tube to determine where to cut them to the circumference of the tube, and then drilled holes near the end and mounted them to the tube using oval headed machine screws with nuts on the inside.  The completed OTA was really attractive.  I don't have any pictures of it anywhere, but I believe one of the issues of either S&T or, more likely Telescope Making from the 1979 RTMC shows it mounted piggyback on the 826 I was loaned for a few months for astrophotography tests (my copies of TM were lost in a house fire 20 years ago).  I was going to use the 4.25" as a guide scope, but there was so much flexure in the system that I never got any that weren't badly trailed.  The 4.25" had very good optics, though.  Planetary and double star views were exquisite.  And that, with probably a spherical mirror.

 

I sold that OTA to a friend in the early 80s.  But I really wish I'd kept it.

 

-Tim


  • mdowns likes this

#25 Piggyback

Piggyback

    Apollo

  • *****
  • Posts: 1,285
  • Joined: 14 Sep 2013
  • Loc: Germany

Posted 14 September 2021 - 12:31 PM

Are those Quantum posters in the background?

 

Eagle eyes, Kasmos.

I was selling the Quantum line for a while in Germany. People liked it but preferred the pumpkin C8. More bang for the buck or so they thought.


  • Kasmos likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics