New Project: Mini-Dob for the kids

[michael.h.f.wilkinson]

I have an old 4.5" F/4.4 Newtonian, with reasonable mirrors, and sub-standard mount floating around. I am now turning it into a octagonal-tube mini-dobsonian for the kids. For the tube, my eldest and I have made some sketches (I will post them later), and for the mount, I am thinking of getting a 4" lazy Susan bearing from Simply Bearings, and some Teflon and Ebony-Star foil from TS. I have started cutting the plywood for the tube. I will post progress as I go along.

[asteria]

Looking forward to hearing about the scope. Thanks. Ed

[michael.h.f.wilkinson]

Here is the sketch I promised (in pdf). The main tube is made from 5mm plywood for the outside, attached to four octagonal sections of 18mm plywood (leftovers) 15cm across. Three of the sections have a 140mm circular hole cut through them, the last (which holds the mirror) an 80mm hole cut in it. Both the primary and secondary mirror supports are scavenged off the old Konus 4.5" F=500mm scope.

miniDob4_5.pdf

[fwm891]

Michael, Great project - really takes me back to when my daughter wanted a telescope.... (she tells me what to do now!)

Attached an image of the telescope I built with her: 6-inch f4 Dob with small cabinet to keep eyepieces etc in...

OTA sits inside the mount for storage.

Francis

[michael.h.f.wilkinson]

Michael, Great project - really takes me back to when my daughter wanted a telescope.... (she tells me what to do now!)

Attached an image of the telescope I built with her: 6-inch f4 Dob with small cabinet to keep eyepieces etc in...

OTA sits inside the mount for storage.

Francis

That looks really nice Francis! I like the all-in-one design (the missus will too: no bits lying around ). I was thinking along similar lines for the base. It is good to see an example like that. I was wondering about the orientation of the focuser. Is pointing upwards when the scope is pointing at the horizon the best in you opinion? I was considering mounting the focuser horizontally.

[fwm891]

Michael, It was done like that as it meant she could turn the OTA over (eyepiece down) and it has a little clip-on screen to project the sun onto as it was instilled from an early age that she should not look at the sun through a telescope without the correct filters... We later made a solar filter with Baader foils. Solar filter and projection screen are in the photo, on left hand side.

It also meant that as she grew she would still be able to look into the scope without having to get on the floor to access the eyepiece (easier for you as well!)

We built it when she was 7 or 8 and made the height so the eyepiece at its highest point was at her eye level then... This little scope has travelled well although its not been used for a few years now.

[michael.h.f.wilkinson]

Michael, It was done like that as it meant she could turn the OTA over (eyepiece down) and it has a little clip-on screen to project the sun onto as it was instilled from an early age that she should not look at the sun through a telescope without the correct filters... We later made a solar filter with Baader foils. Solar filter and projection screen are in the photo, on left hand side.

It also meant that as she grew she would still be able to look into the scope without having to get on the floor to access the eyepiece (easier for you as well!)

We built it when she was 7 or 8 and made the height so the eyepiece at its highest point was at her eye level then... This little scope has travelled well although its not been used for a few years now.

Thanks for that. In my 4.5" a table-top design might be best. The smaller tube size would also reduce the height range the EP travels through. I will go for a Baader film directly.

[fwm891]

Michael, The table-top sounds great. Make sure you can flip the OTA over so that the eyepiece is available for left or right viewing when sat at the table...

Good luck and clear skies

[Moonshane]

these are great designs and along the lines of something I will be making soon as a travel scope. I have just bought my donor, a 6" f6 and this should hopefully be OK for chair based use.

I hope to have the base in a format the easily disassembles so it can fit into a 'plane friendly size and in the car with all the camping gear.

I'll start my own thread eventually and will post a link here in due course. Will be a summer project though possibly (unless this bad weather never ends and then it might be a winter project!).

[michael.h.f.wilkinson]

Michael, The table-top sounds great. Make sure you can flip the OTA over so that the eyepiece is available for left or right viewing when sat at the table...

Good luck and clear skies

Good point. Flipping the scope over should be fairly easy, provided I make a double mounting for finder scope or rdf.