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

A Classic Telescope has been sawed off................

  • Please log in to reply
46 replies to this topic

#26 Chuck Hards

Chuck Hards

    You don't know Swift from Astrola

  • *****
  • Administrators
  • Posts: 21498
  • Joined: 03 May 2010

Posted 16 June 2018 - 01:10 PM

And you've stuck it on the perfect mount, Chris!  Nice.  waytogo.gif


  • Kasmos likes this

#27 Kasmos

Kasmos

    Apollo

  • *****
  • Posts: 1296
  • Joined: 19 Aug 2015
  • Loc: So Cal

Posted 16 June 2018 - 01:34 PM

Thanks Chuck.

My 814 is always out and ready so all of my small refractors end up being tested/used on that mount. 


  • Chuck Hards, terraclarke, Bomber Bob and 1 other like this

#28 Bigern

Bigern

    Vostok 1

  • *****
  • Posts: 157
  • Joined: 18 Aug 2016
  • Loc: Miami Fl.

Posted 17 June 2018 - 11:26 AM

Love these small cut down refractors! I have a Kmart Focal zoom scope I would like to turn into an astronomical scope and cut down too. How do you know where to cut it?



#29 Russell Smith

Russell Smith

    Mariner 2

  • *****
  • Posts: 210
  • Joined: 27 Aug 2017
  • Loc: 76707

Posted 17 June 2018 - 02:11 PM

What a fun project. I read some earlier threads on this subject and just had to try my hand at it.

Started with a mayflower 806 click zoom. made a scope on a stick and cut the tube. focus assy. from a 9te5 and here you are.

Not as well executed as many others but functions well. Here it is just last night on lunar duty.  

Attached Thumbnails

  • 20180616_200656.jpg

  • Deven Matlick, Chuck Hards, terraclarke and 4 others like this

#30 Russell Smith

Russell Smith

    Mariner 2

  • *****
  • Posts: 210
  • Joined: 27 Aug 2017
  • Loc: 76707

Posted 17 June 2018 - 02:19 PM

I haven't chopped too many Classics, but I'm very pleased with this one -- I converted a Tinsley Saturn 40mm terrestrial spotter into a 50mm right angle finder for my Tinsley 6" Cassegrain.  The spotter's lens was shattered, and the large replacement may be older than the scope it rides on...

 

attachicon.gif Tinsley - RA Finder S71.jpg attachicon.gif Tinsley - RA Finder S72.jpg attachicon.gif Tinsley - RA Finder S73.jpg

Now that has real personality. way cool waytogo.gif bow.gif


Edited by Russell Smith, 17 June 2018 - 02:24 PM.

  • Bomber Bob likes this

#31 Chuck Hards

Chuck Hards

    You don't know Swift from Astrola

  • *****
  • Administrators
  • Posts: 21498
  • Joined: 03 May 2010

Posted 17 June 2018 - 03:25 PM

Love these small cut down refractors! I have a Kmart Focal zoom scope I would like to turn into an astronomical scope and cut down too. How do you know where to cut it?

You will need to remove the objective cell and measure it's focal length.  That's the starting point.  Then it's just a matter of following my thread or other's instructions already posted, but if you want to start your own thread on it, we'll coach you through the process.


  • Bomber Bob, Bigern and Russell Smith like this

#32 Bigern

Bigern

    Vostok 1

  • *****
  • Posts: 157
  • Joined: 18 Aug 2016
  • Loc: Miami Fl.

Posted 17 June 2018 - 04:52 PM

I'll check out the other threads so I can learn how to measure the focal length thanks! 



#33 gallileo60

gallileo60

    Explorer 1

  • -----
  • Posts: 80
  • Joined: 03 Feb 2016

Posted 19 June 2018 - 06:29 PM

Hey guys humor me, but whats the advantage of cutting down a long tube frac?? Isnt it at the correct focal length from the factory?? Am I just missing something...Ive been playing around with scopes for years, but this one has me...If there is a good reason, ive got a 70mm that I might consider hacking...Anyway All of your efforts look good, and I admit you guys know something I dont for sure....Thanks......



#34 Bomber Bob

Bomber Bob

    Voyager 1

  • *****
  • Posts: 13657
  • Joined: 09 Jul 2013
  • Loc: The Deep South, USA

Posted 19 June 2018 - 07:14 PM

When the correcting & zoom lens assemblies are removed, the actual focal ratio of the objective is often around F7 -- it doesn't need an F10 / F12 tube length.



#35 Kasmos

Kasmos

    Apollo

  • *****
  • Posts: 1296
  • Joined: 19 Aug 2015
  • Loc: So Cal

Posted 20 June 2018 - 02:04 AM

Hey guys humor me, but whats the advantage of cutting down a long tube frac?? Isnt it at the correct focal length from the factory?? Am I just missing something...Ive been playing around with scopes for years, but this one has me...If there is a good reason, ive got a 70mm that I might consider hacking...Anyway All of your efforts look good, and I admit you guys know something I dont for sure....Thanks......

Gallieo60,

 

Do not hack your 70mm scope!

 

To be clear, the 60mm scopes that are being cutdown are only the variable power types that don't and can't use multiple eyepieces. They have a fixed eyepiece on the end of the draw tube with no star diagonal, and as Bob mentions above, they have built in zoom assemblies that slide far in side the OTA. 

 

To change the magnification you slide the two piece telescoping draw tube to 4 different lengths with click stops for each each power. Typically they are magnifications of 15x, 30x, 45x, 60x.

 

Go back to the first post and look at the first photo carefully. Check the lower scope. You can just see the click stops on it's draw tube.

 

The objective lens in these scopes actually have about a 400mm focal length, but with the built in zoom they look like typical 60mm x 700mm refractors.

 

In stock form they were really made for terrestrial use since they can only be used for straight thru viewing. The advantage of cutting them is to use much better eyepieces and a star diagonal. This also means using a replacement focuser since the stock one won't accept different eyepieces.

 

When done they can make a nice little low power grab and go, plus some like to use them as finders on larger scopes.


Edited by Kasmos, 20 June 2018 - 02:15 AM.

  • roscoe, Chuck Hards, Garyth64 and 1 other like this

#36 Chuck Hards

Chuck Hards

    You don't know Swift from Astrola

  • *****
  • Administrators
  • Posts: 21498
  • Joined: 03 May 2010

Posted 20 June 2018 - 08:48 AM

Amen to what Chris posted.

 

DO NOT cut down a scope that didn't start life as a terrestrial zoom scope from the factory.   Actually it doesn't have to be a zoom, it's the erector lenses that actually add all the extra length.  Fixed-magnification terrestrial scopes can be cut-down as well.


  • Kasmos likes this

#37 roscoe

roscoe

    curmudgeon

  • *****
  • Posts: 8823
  • Joined: 04 Feb 2009
  • Loc: NW Mass, inches from VT

Posted 20 June 2018 - 08:51 AM

You will need to remove the objective cell and measure it's focal length.  That's the starting point.  Then it's just a matter of following my thread or other's instructions already posted, but if you want to start your own thread on it, we'll coach you through the process.

quick info - assemble everything, your focuser, diagonal, EP, and the objective, on a stick or other temporary assemblage, and mess with it till you get focus.  If you're thinking of using more than one EP, check all  to make sure they are in the focus range.....  then mark and cut the tube to fit.



#38 gallileo60

gallileo60

    Explorer 1

  • -----
  • Posts: 80
  • Joined: 03 Feb 2016

Posted 20 June 2018 - 11:25 AM

Amen to what Chris posted

Ok got ya...Thats funny cuz back in the 70's My first scope was like that, and being a kid I cut the slot with a file to "INCREASE" the mag on it..It was either a Focal, or A Tasco.........Thanks for the answers..Sorry to hijack the thread...



#39 deSitter

deSitter

    Still in Old School

  • *****
  • Posts: 12129
  • Joined: 09 Dec 2004

Posted 20 June 2018 - 01:44 PM

Here's one of my Tom Sawyers. This one has a very early Tasco focuser with a heavy, single piece drawtube and split spring nosepiece. My favorite classic focuser! It's so heavy it makes for the balance point you see here. This one started life as a Milben Towa clickzoomer. Tripod legs are also from that scope.

 

-drl

 

Attached Thumbnails

  • Sawyer.jpg

  • tim53, Deven Matlick, memento and 3 others like this

#40 PETER DREW

PETER DREW

    Viking 1

  • -----
  • Posts: 902
  • Joined: 31 May 2017

Posted 20 June 2018 - 04:33 PM

I've cut many a refractor, it's part of my reputation in the UK smile.gif . Prime examples were a 7" AP, a 6" AP Superplanetary and a Vixen 102FL. No pictures you will be relieved to hear.



#41 Tenacious

Tenacious

    Viking 1

  • *****
  • Posts: 552
  • Joined: 19 Oct 2015
  • Loc: Northern KY

Posted 01 September 2018 - 03:33 PM

Once again, you guys have inspired me.  Thank you Memento, Roscoe, Kasmos, Chuck, Barry, Bomber Bob and others.  I picked up a 55VTE for parts last winter while traveling on the east coast and then I started seeing your posts.

 

DSC02172.JPG

 

Since I didn't have a classic focuser adaptable to 1.25" EPs, I ordered this from ebay.  It took 2 weeks to arrive from China and I thought of doing a review of the focuser.   I can't recommend one unless the buyer wants to repair it before use  (my focuser axle pivoted like a teeter-totter).  Also, the advertised 52mm thread does not natively fit a standard 60mm OTA.  On the plus side, it was easy to repair and make an adapter ring for the OTA.  The real attraction was the draw tube, about 2" in diameter and internally threaded (baffled) its entire length.  I'm not too worried about cutting into the light cone!  There is a 1.25" VB included.

 

DSC02170.JPG

 

For now, I intend this to ride as a supplement on my rescued Tasco 10TE-5.  Probably, a RFT is more suited to its own alt-az mount.  If I really like it, I can always make a travel version.  OTOH, a f/7 seems like a good companion to a f/16.     For aesthetic reasons, I made a longer dew shield to match the 10TE-5.   I'm also going to paint the tube white.

 

DSC02171.JPG


Edited by Tenacious, 01 September 2018 - 06:21 PM.

  • Deven Matlick, Chuck Hards, Geo31 and 3 others like this

#42 Kasmos

Kasmos

    Apollo

  • *****
  • Posts: 1296
  • Joined: 19 Aug 2015
  • Loc: So Cal

Posted 01 September 2018 - 04:09 PM

Nice job, I hope it works well for you.

 

I wasn't very thrilled with my cutdown Mayflower (distracting CA and hard to focus as power went up), so I've been hesitant to waste a good focuser on it and refine it. 

 

I've asked before but nobody answered.

What kind of 'useable' magnification should I expect from a 60/400mm achromat? 


  • Tenacious likes this

#43 Chuck Hards

Chuck Hards

    You don't know Swift from Astrola

  • *****
  • Administrators
  • Posts: 21498
  • Joined: 03 May 2010

Posted 01 September 2018 - 05:10 PM

They are essentially binocular objectives.  I never use them for high-power views, I leave that to the long scopes.  I probably use my cut-down 55VTE at 30X or less, most of the time.  Probably 20X as I'm awfully fond of that 20mm Erfle.


  • Kasmos and Tenacious like this

#44 Tenacious

Tenacious

    Viking 1

  • *****
  • Posts: 552
  • Joined: 19 Oct 2015
  • Loc: Northern KY

Posted 01 September 2018 - 11:14 PM

Tonight wasn't much of a choice for first light, seeing was less than average and there were variable breezes.  I did get the 60mm f/7 RFT mounted on the 10TE-5.  I have to agree with you Kasmos, if this RFT were my only access to the sky, I might not bother looking at planets.  OTOH, I still need to get the tube baffles installed and I haven't checked collimation yet.  I ran through all of my RKEs just to see how they would perform on Jupiter.  As expected, the 28mm (15x) and 21.5mm (~20x) gave the most pleasing views.  As I increased power to 8mm (52.5x), the image had no new details and focusing was more about choosing the lesser of aberrations.  It was tough to make out any cloud bands on Jupiter's face and the image scale was small.  Saturn was a bit more impressive due to the contrast of the rings to the planet.  To be fair, even the 10TE-5 wasn't showing much detail either.  The seeing was that bad.

 

As Chuck pointed out, this scope does a wonderful job at low power and wide fields.  Cruising around the star fields of Sagittarius was enjoyable.   With the RKE28 in the 10TE-5 for 43x and a 20mm Erfle in the RFT for 21x, I could continually switch between the wide, over-all view and the close-up detail view.  I think I'm going to like this combination!

 

I soon tried all the long FL EPs in the RFT.  Interestingly, the 32mm and 40mm Plossls didn't seem to have all of the dim stars that should be there.  The sweet spot seemed to be EPs in the 20mm to 25mm range. 


Edited by Tenacious, 02 September 2018 - 08:31 AM.

  • steve t and Kasmos like this

#45 Kasmos

Kasmos

    Apollo

  • *****
  • Posts: 1296
  • Joined: 19 Aug 2015
  • Loc: So Cal

Posted 02 September 2018 - 12:38 AM

Since it's been awhile, I'm trying to remember how high of power I used before everything fell apart, but think it was about 30x. Like Chuck said it was much better around 16-20x. I know I used a 40mm, 25mm, 20mm, 18mm and a 12.5mm but was limited to .965" eyepieces because it's has a .965" Tasco focuser. I have another focuser that will accept a Vixen 1.25" visual back but wasn't sure this scope's objective merited using it. 

 

The problem is I'd have to cut the tube another inch shorter for the better focuser, but if I don't like it, I can't go back to the .965" focuser without re-extending or buying another tube.

 

I need to retest the scope and then make a decision.

 

What I would like to have is one of those somewhat rare 60/400mm scopes made by SYW and see how good they are.

 

I know that Bomber Bob has or had a Lafayette branded one and Chuck had a Simmons 1294.

What do you guys think of them?


  • steve t likes this

#46 Jeff B

Jeff B

    Aurora

  • *****
  • Posts: 4946
  • Joined: 30 Dec 2006

Posted 02 September 2018 - 09:52 AM

I sawed off many a classic, older AP to make them bino-friendly, much to the shock and horror of a couple of "collectors". 

 

My most recent butchering, I mean, useful modification,  was a cute little Unitron 60mm F8 guidescope I'm now using as a finder for the TEC 200ED.  I cut it back so I could use 1.25" diagonal with it.  And boy, it's an excellent, wide field scope in its own right using an old 30 Orion Ultrascopic, giving a 3+ degree TFOV that's sharp to the edge.  

 

Jeff

Attached Thumbnails

  • Unitron Restored.jpg
  • Close Up 2.jpg

  • tim53, Deven Matlick, steve t and 3 others like this

#47 terrapin

terrapin

    Messenger

  • *****
  • Posts: 435
  • Joined: 15 Mar 2009
  • Loc: Oakland, California

Posted 02 September 2018 - 05:57 PM

My version was an old Sears vari-power 60mm that I converted about a decade ago after seeing a thread here. The Towa objective seems pretty decent. I used it in February to capture this moon-Saturn conjunction with my smartphone.

Attached Thumbnails

  • 27503739_10155315138251593_6416571444815998193_o.jpg
  • 27913187_10155352577821593_4402771901434222299_o.jpg

  • Deven Matlick, steve t, Bomber Bob and 3 others like 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