National Geographic 70mm Refractor (2017 model)

Tell us about those other projects you are working on.
Post Reply
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

National Geographic 70mm Refractor (2017 model)

#1

Post by GCoyote »


Picked this up as an (almost) complete kit for $20 last week.
20200123_103250 (800x600).jpg
I'm already reusing the mount, tripod, and other components in other projects but the OTA is missing the threaded plastic clamp that retains the eyepiece. :flame:
20200123_103313 (800x600).jpg
I tried to swap with the eyepiece holder from a 70mm Meade but the threads on this scope are a tiny bit undersized and the Meade part just falls off.

The carbon fibre tube seems really sturdy and I'd hate to just toss it. Online search is not getting me exactly what I need which isn't surprising as that's not something you'd normally remove I don't think. There is no actual manufacturer info on the data plate. That and the fact that a Meade part doesn't fit makes me hesitant to make a blind purchase.

Any ideas on a substitute part or a simple fabrication? I wondering If I can make it out of PVC.
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
User avatar
gregl
Milky Way Ambassador
Articles: 0
Offline
Posts: 1091
Joined: Fri Sep 06, 2019 2:30 am
4
Location: California
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#2

Post by gregl »


I think PVC would work fine. Canvass your neighborhood for someone with a lathe. It would be about a ten minute job to make up an adaptor from a PVC pipe coupling. There are more folks out there with home lathes than you might imagine. Check the local model railroad club and the local hotrod club. The Chesapeake & Allegheny Live Steamers certainly has members with lathes: http://www.calslivesteam.org
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#3

Post by GCoyote »


Possible. There is a hobby store in town that has a model railroad club. I'll check them out.
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
User avatar
Lady Fraktor Slovakia
Co-Administrator
Co-Administrator
Articles: 0
Offline
Posts: 9860
Joined: Mon Apr 29, 2019 9:14 pm
4
Location: Slovakia
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#4

Post by Lady Fraktor »


Check with Explore Scientific, they sell this telescope and may have some parts around. https://explorescientificusa.com/collec ... -telescope
You could also check Astro-Parts Mall, Telescope Warehouse or even Scopestuff.
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
The only culture I have is from yogurt
My day was going well until... people
Image
User avatar
pakarinen United States of America
Inter-Galactic Ambassador
Articles: 0
Offline
Posts: 4013
Joined: Fri Jun 14, 2019 3:33 pm
4
Location: NE Illinois
Status:
Offline

TSS Awards Badges

Re: National Geographic 70mm Refractor (2017 model)

#5

Post by pakarinen »


Heh. I just saw one of those 70mm at Hobby Lobby yesterday. Didn't check the price.
=============================================================================
I drink tea, I read books, I look at stars when I'm not cursing clouds. It's what I do.
=============================================================================
AT50, AT72EDII, ST80, ST102; Scopetech Zero, AZ-GTi, AZ Pronto; Innorel RT90C, Oberwerk 5000; Orion Giantview 15x70s, Vortex 8x42s, Navy surplus 7x50s, Nikon 10x50s
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#6

Post by GCoyote »


pakarinen wrote: Sun Jan 26, 2020 1:07 pm Heh. I just saw one of those 70mm at Hobby Lobby yesterday. Didn't check the price.
The one I rescued was the 2017 model which came with a terribly over bright LED finder scope. The newer ones seem to have reverted to more conventional/useful finders. Having already dropped the OTA once, I can attest to the sturdiness of the carbon fiber construction! :oops:

I found a bit of PVC scrap that seems about the right size for the eyepiece holder so that's option 1.
I also picked up a an old Meade 60mm OTA for a whopping $6 that I might be able to extract the entire focuser from to repair the NatGeo so that's option 2.

What I neglected to mention is that this is ongoing project #4 and I just had a brainstorm for project number #2 so I need to run out and get more parts for that one!

Thanks for the help everyone and stay tuned. :popcorn:
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#7

Post by GCoyote »


Update: Well the Meade focuser was a bit to small. The gear teeth and the focuser knob couldn't mesh when moved to the larger plastic focuser body. So much for option 2.

Back to the hardware aisle! :D

Edit: Oh and while I had it disassembled, I reversed the focuser tube so instead of the undersized threads, I now have a clean square plastic tube end to work with.
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
User avatar
gregl
Milky Way Ambassador
Articles: 0
Offline
Posts: 1091
Joined: Fri Sep 06, 2019 2:30 am
4
Location: California
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#8

Post by gregl »


Too much fun!
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#9

Post by GCoyote »


Brain storm; instead of trying to manufacture a custom part, can't I get a cheap 1.25" extension tube and either glue or screw it in place to hold the eyepieces?

https://www.ebay.com/i/192591340777?chn ... 8sQAvD_BwE
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
User avatar
Lady Fraktor Slovakia
Co-Administrator
Co-Administrator
Articles: 0
Offline
Posts: 9860
Joined: Mon Apr 29, 2019 9:14 pm
4
Location: Slovakia
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#10

Post by Lady Fraktor »


No reason not to try it out :)
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
The only culture I have is from yogurt
My day was going well until... people
Image
User avatar
gregl
Milky Way Ambassador
Articles: 0
Offline
Posts: 1091
Joined: Fri Sep 06, 2019 2:30 am
4
Location: California
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#11

Post by gregl »


Well for eight bucks you can't go far wrong.
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#12

Post by GCoyote »


Ordered!
Expected delivery on or about Mar 9.
(to be continued ... )

And while I wait, on to the next project!

:D
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#13

Post by GCoyote »


NG70 and extension 20200227.jpg
Perfect fit!
NG70 extension installed 20200227.jpg
Final decision: Screw or Glue?

If I use a screw I'd want to drill and tap the aluminum extension tube but the draw tube itself is pretty thin plastic and I'm afraid it would crack if (when) I bump it in the dark.

If I glue it in, it's permanent. For the price that's no big deal. Plus that would remove any play in this particular joint. I'd just have to lightly sand the inner surface of the draw tube and the outer surface of the extension tube. I don't think thermal expansion would be a problem on a part this small.

Am I missing anything?
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
User avatar
gregl
Milky Way Ambassador
Articles: 0
Offline
Posts: 1091
Joined: Fri Sep 06, 2019 2:30 am
4
Location: California
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#14

Post by gregl »


I vote for glue. Threads in thin plastic won't be reliable.
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#15

Post by GCoyote »


I figured to drill a full dia hole in the plastic and only thread the aluminum but that's still pretty soft and therefore risky.
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
User avatar
gregl
Milky Way Ambassador
Articles: 0
Offline
Posts: 1091
Joined: Fri Sep 06, 2019 2:30 am
4
Location: California
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#16

Post by gregl »


Yeah. I'd predict that the al. is not one of the more machinable ones. Much of that extruded stuff is "sticky" when machined and soft. If the rack is removable, you could replace the tube with a bit of 6061 tube which would take threads nicely. Then put the rack on the 6061.

Of course, if you really want to jump off the deep end, you could go to Stock Drive Products and get a new rack and pinion (https://sdp-si.com). Then you'd have to find the tube off Ebay as the o.d. is more than likely metric. McMaster has lots of al. tube but I don't see any metric o.d.s. (mcmaster.com) Some time with Google will turn up metric tube suppliers.

Perhaps it's time to buy a lathe! :smile:
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#17

Post by GCoyote »


So ... glue!
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
User avatar
Lady Fraktor Slovakia
Co-Administrator
Co-Administrator
Articles: 0
Offline
Posts: 9860
Joined: Mon Apr 29, 2019 9:14 pm
4
Location: Slovakia
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#18

Post by Lady Fraktor »


Just remember to give the tube and adapter a good scuff before gluing.
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
The only culture I have is from yogurt
My day was going well until... people
Image
User avatar
GCoyote United States of America
Local Group Ambassador
Articles: 0
Offline
Posts: 2707
Joined: Mon May 13, 2019 2:53 am
4
Location: Laurel, MD, USA
Status:
Offline

Re: National Geographic 70mm Refractor (2017 model)

#19

Post by GCoyote »


Just had to let the glue cure overnight, clean off a tiny amount of excess at the seam and, it's done!
NatGeo70mm Done 20200229.jpg
The squirrel population is starting to lodge invasion of privacy complaints but the weather forecast may be better tomorrow.

I'm declaring this project DONE. Thanks to everyone for the help and ideas.

https://media.giphy.com/media/vN3fMMSAmVwoo/giphy.gif
Any metaphor will tear if stretched over too much reality.
Gary C

Celestron Astro Master 130mm f5 Newtonian GEM
Meade 114-EQ-DH f7.9 Newtonian w/ manual GEM
Bushnell 90mm f13.9 Catadioptric
Gskyer 80mm f5 Alt/Az refractor
Jason 10x50 Binoculars
Celestron 7x50 Binoculars
Svbony 2.1x42 Binoculars
(And a bunch of stuff I'm still trying to fix or find parts for.)
Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

Return to “Other "Do It Yourself" projects”