Jump to content


Photo

Edmund Newtonian 3", short fast and red

  • Please log in to reply
13 replies to this topic

#1 Littlegreenman

Littlegreenman

    Gemini

  • *****
  • Posts: 3187
  • Joined: 08 May 2005
  • Loc: Southern California

Posted 13 September 2013 - 03:06 AM

My latest fun find. A fast Edmunds reflector. I haven't had a chance to look through it yet. The front opening is 4", but looking down the tube it looks like mirror is around 3", or masked off. The tube is mounted on the fork, with a part that slips into the mount head; spread the legs, tighten down the knob on the head and you are ready to go. Someone should upscale this for 10" scope.

I have not been able to find any info on this scope, despite wasting hours on Google. Tube is about 14" long.
Distance to eyepiece is about 12-13". I plan to remove the mirror and clean it; it has a fair amount of dust and dust devils on it.

Anyone ever seen one like this?

LGM

Attached Files



#2 Littlegreenman

Littlegreenman

    Gemini

  • *****
  • Posts: 3187
  • Joined: 08 May 2005
  • Loc: Southern California

Posted 13 September 2013 - 03:10 AM

Close up of the tube. Focuser body is plastic.

Attached Files



#3 Littlegreenman

Littlegreenman

    Gemini

  • *****
  • Posts: 3187
  • Joined: 08 May 2005
  • Loc: Southern California

Posted 13 September 2013 - 03:12 AM

Another view. The fork rotates around the mount, 'head'. It's all light enough that it just works. A knob on the unseen side of the fork tights that down.

Attached Files



#4 Littlegreenman

Littlegreenman

    Gemini

  • *****
  • Posts: 3187
  • Joined: 08 May 2005
  • Loc: Southern California

Posted 13 September 2013 - 03:14 AM

An incredible innovation: a square or rectangular seconday!

Attached Files



#5 Littlegreenman

Littlegreenman

    Gemini

  • *****
  • Posts: 3187
  • Joined: 08 May 2005
  • Loc: Southern California

Posted 13 September 2013 - 03:15 AM

We'll see if it's worth putting in an oval secondary.

LGM

#6 Darren Drake

Darren Drake

    Mercury-Atlas

  • *****
  • Posts: 2806
  • Joined: 09 Oct 2002
  • Loc: Chicagoland

Posted 13 September 2013 - 06:19 AM

I have an ota somewhere. Maybe I'll post a pic over the weekend.

#7 ArizonaScott

ArizonaScott

    Fly Me to the Moon

  • *****
  • Posts: 5969
  • Joined: 29 Apr 2004
  • Loc: Scottsdale, AZ

Posted 13 September 2013 - 07:51 AM

I'd love to find one of those for sale. I remember them fondly from the Edmund catalogs in the 70's.

#8 Chuck Hards

Chuck Hards

    Fly Me to the Moon

  • *****
  • Moderators
  • Posts: 5798
  • Joined: 03 May 2010
  • Loc: The Great Basin

Posted 13 September 2013 - 08:24 AM

I bought several of those Edmund 3" mirrors many years ago, surplus. Only ever looked at one with the Ronchi, but it wasn't too bad IIRC. Is your scope f/6? Looks about right from the photo. I started 3 OTAs and still have them boxed in the garage. Your post makes me want to dig them out and finish them. I opted for aluminum tubes, but isn't the Edmund scope a PVC tube?

#9 terraclarke

terraclarke

    Fly Me to the Moon

  • *****
  • Posts: 5204
  • Joined: 29 May 2012
  • Loc: The Bluegrass State

Posted 13 September 2013 - 08:37 AM

The first telescope I ever built was a 3 inch F6 Edmund. I bought the mirror and diagonal, cell and focuser and had a rolled and seemed galvanized sheetmetal tube made for it at our local HVAC place back in 1966. I had a 1&1/8 inch f.l. Edmund eyepiece for it and it was a fun little hand holdible RFT. I wish I still had it. It's been long gone for years.

#10 amicus sidera

amicus sidera

    Skylab

  • *****
  • Posts: 4133
  • Joined: 14 Oct 2011
  • Loc: East of the Sun, West of the Moon...

Posted 13 September 2013 - 09:04 AM

Nice find! I'm sure that you're going to enjoy using it. :cool:

These 3" f/6 scopes were introduced by Edmund around 1982, and were available for pretty much the rest of decade. Nice little package with usually very good optics; like their predecessor the 3" f/10's, relatively few seem to turn up on the used market despite the not-inconsiderable quantities which were produced.

Fred

#11 Littlegreenman

Littlegreenman

    Gemini

  • *****
  • Posts: 3187
  • Joined: 08 May 2005
  • Loc: Southern California

Posted 13 September 2013 - 10:18 AM

The tube is probably PVC. At least it isn't metal. F/6" ? Sounds about right.

LGM

#12 actionhac

actionhac

    Skylab

  • *****
  • Posts: 4344
  • Joined: 09 Aug 2008
  • Loc: Seattle

Posted 13 September 2013 - 10:37 AM

I'm surprised the focuser body is plastic, I have a feeling its a good plastic since its Edmund Scientific.
I'm sure it has a excellent mirror.
I wonder if the rectangular diagonal mirror's square corners will produce diffraction spikes.
I love Edmund. I'm glad I was born when I was because I grew up with Edmund.

Robert

#13 Matt Lindsey

Matt Lindsey

    Messenger

  • *****
  • Posts: 404
  • Joined: 06 Jun 2008
  • Loc: Baltimore, MD, U.S.A.

Posted 13 September 2013 - 01:18 PM

My first scope, got mine new in 1983. There was a thread on this scope in the reflectors forum last November.

It's a great wide-field instrument with decent optics. However, you absolutely must unglue the secondary mirror from the stalk, or suffer bad astigmatism as soon as the scope adjusts to outside temp. Just remount with some silicone.

#14 TOM KIEHL

TOM KIEHL

    Apollo

  • *****
  • Posts: 1473
  • Joined: 17 Nov 2012
  • Loc: N.E. Ohio

Posted 13 September 2013 - 10:01 PM

http://www.cloudynig...ct=87430&sor...






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics