144 replies to this topic

[Jon Isaacs]

I live about an hour north of Yosemite NP. In summer, an easy 1-hour drive east on a 2-lane road puts me at the crest of the Sierra Nevada Mountains (above timberline) where it's extremely dark. First good snow closes the road for winter. Many other good places to go within 30 minutes that have wide open vistas. My 8"f6 newt is well suited to these sites, and it fits comfortably in the back of a small SUV.

I like to go out every clear night year round though, watch the sun go down while the scope cools, and look at whatever's up that night for about an hour, less if it's cold, a little longer if something special is happening. Smaller newt or small refractor works better for this relaxed style of observing from home.

 

 

To me, it seems like you have the right scopes for your needs.  The AT-72 for quick looks, for terrestrial viewing and just having fun.  The 6 inch Dob for viewing in the difficult terrain around your residence and an 8 inch Dob for putting in the car and driving a ways.. One scope can't do it all.  

 

Jon

 

(I own a Twilight 1, it's not really competent to handle a 4 inch refractor, an 8 inch SCT is beyond it's capabilities.  There are others that would work but might be awkward to carry very far.)

[gwlee]

 

I live about an hour north of Yosemite NP. In summer, an easy 1-hour drive east on a 2-lane road puts me at the crest of the Sierra Nevada Mountains (above timberline) where it's extremely dark. First good snow closes the road for winter. Many other good places to go within 30 minutes that have wide open vistas. My 8"f6 newt is well suited to these sites, and it fits comfortably in the back of a small SUV.

I like to go out every clear night year round though, watch the sun go down while the scope cools, and look at whatever's up that night for about an hour, less if it's cold, a little longer if something special is happening. Smaller newt or small refractor works better for this relaxed style of observing from home.

 

 

To me, it seems like you have the right scopes for your needs.  The AT-72 for quick looks, for terrestrial viewing and just having fun.  The 6 inch Dob for viewing in the difficult terrain around your residence and an 8 inch Dob for putting in the car and driving a ways.. One scope can't do it all.  

 

Jon

 

(I own a Twilight 1, it's not really competent to handle a 4 inch refractor, an 8 inch SCT is beyond it's capabilities.  There are others that would work but might be awkward to carry very far.)

 

Jon,

 

Thanks for the feedback about the mount and SCT. I plan to hang onto the 72mm refractor, one 6"f8 newt (sell the other), and the 8"f6 newt for another year. By the end of the year, i would like to be down to one newt and one refractor. 

 

I am looking into options for lightening the 8" if it can be done without decreasing stability. I once owned a 8"f6 Portaball that weighed less than 35#, but it was far too shaky to be satisfactory for nightly use, so I am skeptical. I want to stick with a solid tube design because there's too much tree sap blowing around on this site for a truss or strut design. If i can get the weght of the 8" down to 35#, it can replace the 6" for home use.

 

If lightening the 8" doesn't work, i am looking into replacing the 72mm refractor and the 6"f8 newt with a larger refractor, perhaps a 4-inch, that comes a little closer to meeting my requirements for a general purpose telescope. A 4" refractor is definite step down in performance from the 6" f8 newt, but i am confident that i can get it down the 35# with acceptable stability for nightly use from home. In this scenario, i would keep the 8"f6. 

 

However, a hand-held binocular a 6" f8 newt would satisfy all my present instrument needs, and a rational person would probably just keep three scopes that I own now and call it done, but it's a hobby after all. 

 

Gary

Edited by gwlee, 20 February 2017 - 02:07 PM.

[Starman1]

 

 

I live about an hour north of Yosemite NP. In summer, an easy 1-hour drive east on a 2-lane road puts me at the crest of the Sierra Nevada Mountains (above timberline) where it's extremely dark. First good snow closes the road for winter. Many other good places to go within 30 minutes that have wide open vistas. My 8"f6 newt is well suited to these sites, and it fits comfortably in the back of a small SUV.

I like to go out every clear night year round though, watch the sun go down while the scope cools, and look at whatever's up that night for about an hour, less if it's cold, a little longer if something special is happening. Smaller newt or small refractor works better for this relaxed style of observing from home.

 

 

To me, it seems like you have the right scopes for your needs.  The AT-72 for quick looks, for terrestrial viewing and just having fun.  The 6 inch Dob for viewing in the difficult terrain around your residence and an 8 inch Dob for putting in the car and driving a ways.. One scope can't do it all.  

 

Jon

 

(I own a Twilight 1, it's not really competent to handle a 4 inch refractor, an 8 inch SCT is beyond it's capabilities.  There are others that would work but might be awkward to carry very far.)

 

Jon,

 

Thanks for the feedback about the mount and SCT. I plan to hang onto the 72mm refractor, one 6"f8 newt (sell the other), and the 8"f6 newt for another year. By the end of the year, i would like to be down to one newt and one refractor. 

 

I am looking into options for lightening the 8" if it can be done without decreasing stability. I once owned a 8"f6 Portaball that weighed less than 35#, but it was far too shaky to be satisfactory for nightly use, so I am skeptical. I want to stick with a solid tube design because there's too much tree sap blowing around on this site for a truss or strut design. If i can get the weght of the 8" down to 35#, it can replace the 6" for home use.

 

If lightening the 8" doesn't work, i am looking into replacing the 72mm refractor and the 6"f8 newt with a larger refractor, perhaps a 4-inch, that comes a little closer to meeting my requirements for a general purpose telescope. A 4" refractor is definite step down in performance from the 6" f8 newt, but i am confident that i can get it down the 35# with acceptable stability for nightly use from home. In this scenario, i would keep the 8"f6. 

 

Of course, a rational person would just keep three scopes that I own now and call it done, but it's a hobby after all. 

 

Gary

 

If you use a shroud on the truss scope, it is the same, in terms of protection, as a tubed scope.  But WAY lighter.

Or rebuild the particle board base of your scope with plywood and it will significantly lighten and stiffen your 8" scope.

I have seen 20# 8" truss scopes, so getting an 8" down under 35# is fairly easy.

The CN poster Danny (Pinbout) can even provide you a blueprint to make one.

[gwlee]

 

 

 

I live about an hour north of Yosemite NP. In summer, an easy 1-hour drive east on a 2-lane road puts me at the crest of the Sierra Nevada Mountains (above timberline) where it's extremely dark. First good snow closes the road for winter. Many other good places to go within 30 minutes that have wide open vistas. My 8"f6 newt is well suited to these sites, and it fits comfortably in the back of a small SUV.

I like to go out every clear night year round though, watch the sun go down while the scope cools, and look at whatever's up that night for about an hour, less if it's cold, a little longer if something special is happening. Smaller newt or small refractor works better for this relaxed style of observing from home.

 

 

To me, it seems like you have the right scopes for your needs.  The AT-72 for quick looks, for terrestrial viewing and just having fun.  The 6 inch Dob for viewing in the difficult terrain around your residence and an 8 inch Dob for putting in the car and driving a ways.. One scope can't do it all.  

 

Jon

 

(I own a Twilight 1, it's not really competent to handle a 4 inch refractor, an 8 inch SCT is beyond it's capabilities.  There are others that would work but might be awkward to carry very far.)

 

Jon,

 

Thanks for the feedback about the mount and SCT. I plan to hang onto the 72mm refractor, one 6"f8 newt (sell the other), and the 8"f6 newt for another year. By the end of the year, i would like to be down to one newt and one refractor. 

 

I am looking into options for lightening the 8" if it can be done without decreasing stability. I once owned a 8"f6 Portaball that weighed less than 35#, but it was far too shaky to be satisfactory for nightly use, so I am skeptical. I want to stick with a solid tube design because there's too much tree sap blowing around on this site for a truss or strut design. If i can get the weght of the 8" down to 35#, it can replace the 6" for home use.

 

If lightening the 8" doesn't work, i am looking into replacing the 72mm refractor and the 6"f8 newt with a larger refractor, perhaps a 4-inch, that comes a little closer to meeting my requirements for a general purpose telescope. A 4" refractor is definite step down in performance from the 6" f8 newt, but i am confident that i can get it down the 35# with acceptable stability for nightly use from home. In this scenario, i would keep the 8"f6. 

 

Of course, a rational person would just keep three scopes that I own now and call it done, but it's a hobby after all. 

 

Gary

 

If you use a shroud on the truss scope, it is the same, in terms of protection, as a tubed scope.  But WAY lighter.

Or rebuild the particle board base of your scope with plywood and it will significantly lighten and stiffen your 8" scope.

I have seen 20# 8" truss scopes, so getting an 8" down under 35# is fairly easy.

The CN poster Danny (Pinbout) can even provide you a blueprint to make one.

 

Don, 

 

At this forested rural site, the outside of a solid tube dob has numerous deposits of sap and pollen at the end of the evening, but the optics are protected. I had a shroud on my Portaball and used it at a much more environmentally benign site in the city, and I never thought the shroud did an adequate job protecting the optics. Because this scope will be used every night if it replaces the 6"f8, it will be permanently set up in my living room, and the shroud and optics will soon be covered in dust and spider webs (comes with living in the country), so i am leary of strut and truss designs for nightly use. If the scope was going to be set up once a month on the telescope field at a club's dark site, i would not be concerned. 

 

I have been talking to Ken Fiscus (on this site) about building a baltic birch base for the 8"f6, which he estimates will weigh about 5# less, getting this scope down to ~36#. I am considering it, but don't know how stability compares. Equal or better stability is an acceptable trade off for reduced weight, but decreased stability is not. Do you have hands on experience with stability (focusing especially)  before and after replacing a partical board base with baltic birch in a telescope of this size?

 

Gary

[Starman1]

Yes.

The plywood is significantly stiffer than particle board, as well as being lighter.

As for the truss design, you could have a decorative cover for the mirror box and keep dust/sap/etc. off the mirror in storage.

It would be as effective as tube covers for a full tube.

Shrouds can be easily removed for cleaning, and are no more prone to getting dusty and covered with spider webs than a tube.

Tubes and shrouds are about equally prone to having body heat enter the light path if you sit with legs under the scope or handle the upper end to guide the scope.

So I suppose lining a tube with interior or exterior flocking might offer the dual improvement of better thermal management AND superior light scatter blocking.

And you can easily add an external "steering knob" to the underside of the front end for guiding without letting your hand get into the light path.

 

It's easy to extend a tube above the focuser a diameter or more for light shielding, too.  Making the UTA of a truss tubed scope this long adds UTA weight and either changes

the balance point of the scope or requires a counterweight in the mirror box.

 

One thing I like about the truss design, though, is that the COG is usually much lower than a tubed design.  I've seen and used 8" dobs with the COG well less than a foot off the ground

compared to a much taller rocker box with a tubed scope.  That low COG results in a radically stiffer rocker box (and lighter) and, usually, a lower eyepiece height.

Here are a couple pictures to compare what I mean:

8" full-tubed dob  http://www.telescope...k539hoCmTvw_wcB

8" truss tubed dob: http://www.cloudynig...ject/?p=5941962   look at the chair for scale.

Edited by Starman1, 20 February 2017 - 04:29 PM.

[gwlee]

Yes.

The plywood is significantly stiffer than particle board, as well as being lighter.

As for the truss design, you could have a decorative cover for the mirror box and keep dust/sap/etc. off the mirror in storage.

It would be as effective as tube covers for a full tube.

Shrouds can be easily removed for cleaning, and are no more prone to getting dusty and covered with spider webs than a tube.

Tubes and shrouds are about equally prone to having body heat enter the light path if you sit with legs under the scope or handle the upper end to guide the scope.

So I suppose lining a tube with interior or exterior flocking might offer the dual improvement of better thermal management AND superior light scatter blocking.

And you can easily add an external "steering knob" to the underside of the front end for guiding without letting your hand get into the light path.

 

It's easy to extend a tube above the focuser a diameter or more for light shielding, too.  Making the UTA of a truss tubed scope this long adds UTA weight and either changes

the balance point of the scope or requires a counterweight in the mirror box.

 

One thing I like about the truss design, though, is that the COG is usually much lower than a tubed design.  I've seen and used 8" dobs with the COG well less than a foot off the ground

compared to a much taller rocker box with a tubed scope.  That low COG results in a radically stiffer rocker box (and lighter) and, usually, a lower eyepiece height.

Here are a couple pictures to compare what I mean:

8" full-tubed dob  http://www.telescope...k539hoCmTvw_wcB

8" truss tubed dob: http://www.cloudynig...ject/?p=5941962   look at the chair for scale.

Don,

 

Thanks for your thoughts. Gives me something new to consider. Thinking out loud:

 

For a truss or strut design, i would need tight dust/spyder covers for the mirror box, and equally tight covers above and below the secondary/focuser assembly (can't remember what it's called on a truss design) to keep dust and nesting critters out. The shroud could be removed/replaced each time the scope is used, and the entire scope could be covered when not in use to keep dust down. It wouldn't add too much to the nightly setup/tear down.

 

Seems like it might be reasonable trade off for the additional optical performance of an 8"f6 (vs 6"f8) that still weighs less than 35# complete and ready to observe. How much less is the question though because it's expensive and the outcome is less certain compared to just replacing the base. My solid tube scope with baltic birch base might come in at 36#, which is almost light enough for my needs, the outcome is easier to predict, and the cost is much lower.

 

Anytime you build a prototype of something (or commission a custom build) you run the risk of unforeseen problems, and you can seldom sell it for anything like your dollar investment, much less your time investment, so it usually makes more sense to buy rather than build if what you want can be bought off the shelf. 

 

Need to think about this some more.

 

Gary

[Starman1]

UTAs will stay clean in drum cases, most of which are now cordura nylon.

In the case of the 8" in the link, the upper ring and secondary nests in the mirror box and the ground board becomes the top of the box.

It is similar to the Sumerian Alkaid scopes: http://www.sumeriano...products-price/

[penguinx64]

If I was younger and didn't have back problems, I'd pick a 12 inch Dob and an AR102.

[gwlee]

UTAs will stay clean in drum cases, most of which are now cordura nylon.

In the case of the 8" in the link, the upper ring and secondary nests in the mirror box and the ground board becomes the top of the box.

It is similar to the Sumerian Alkaid scopes: http://www.sumeriano...products-price/

Don,

 

Keep in mind the minimum requirements are simplicity, portability (35# Max), and the ability to show all the major types of celestial objects (Min 6" aperture) because it's a general purpose telescope that's left set up in my living room and moved outside for a short observing session every clear night. I simply pick it up in one piece, walk it through the door into the yard, set it down, remove two OTA covers, verify collimation with a collimation cap, and I am done. It's not quite grab and go, but it's close. 

 

The 6"f8 Dob that I am using today meets all of these requirements, and it cost $150.00. I don't mind paying 10x for it's replacement, but its replacement must meet all of these requirements and must do significantly better on at least one. Installing/removing additional UTA covers, a cloth shroud, the UTA, and doing a full collimation every time I used the scope wouldn't meet the simplicity requirement. It's going in the wrong direction. 

 

If I went with a 8'f6 truss design, I would want a UTA with two rings and a light shield between the rings to block stray light, and to allow putting solid covers over the top and bottom rings (like Portaball) to too keep dust/spider webs off the secondary and out of the focuser, so I could leave it set up in the living room. I would want it to hold collimation well between sessions, so no more than a slight tweak of one primary adjustment screw is normally required. 

 

Do you think these are realistic requirements for an 8"f6 truss or strut design?

 

Gary

Edited by gwlee, 20 February 2017 - 11:34 PM.

[Jon Isaacs]

Gary:

 

I own several truss/strut scopes. In an 8 inch, I think a tube scope is the way to go, particularly for one that will be transported on a regular basis.. 

 

To lighten the OTA, I would think about an aluminum Tube.. It would be a thicker wall but it could be lighter since aluminum is less dense.  It wold 

 

http://www.hastingsi...laneous-tubing/

 

Jon

[gwlee]

Gary:

 

I own several truss/strut scopes. In an 8 inch, I think a tube scope is the way to go, particularly for one that will be transported on a regular basis.. 

 

To lighten the OTA, I would think about an aluminum Tube.. It would be a thicker wall but it could be lighter since aluminum is less dense.  It wold 

 

http://www.hastingsi...laneous-tubing/

 

Jon

Jon,

 

My 8"f6 Portaball experience left me very leary of truss designs for small scopes. It was a pain to use at home every night, no advantages, several disadvantages. I seldom need to transport a scope, and when i do, a small solid tube scope is easy to transport in a small car. 

 

i think an aluminum tube and baltic birch base would be light enough and simple to use. However, I don't have a feel for how stable it would be, especially while focusing. The 34# Portaball was the worst scope that I've ever owned in that respect, and I don't know much of that was design and how much was simply it's light weight. There's nothing on the market like this, so i would have to build it, which is a scary thought. 

 

Thanks for the link to hastings.

 

Gary

Edited by gwlee, 21 February 2017 - 12:00 PM.

[Jon Isaacs]

 

Gary:

 

I own several truss/strut scopes. In an 8 inch, I think a tube scope is the way to go, particularly for one that will be transported on a regular basis.. 

 

To lighten the OTA, I would think about an aluminum Tube.. It would be a thicker wall but it could be lighter since aluminum is less dense.  It wold 

 

http://www.hastingsi...laneous-tubing/

 

Jon

Jon,

 

My 8"f6 Portaball experience left me very leary of truss designs for small scopes. It was a pain to use at home every night, no advantages, several disadvantages. I seldom need to transport a scope, and when i do, a small solid tube scope is easy to transport in a small car. 

 

i think an aluminum tube and baltic birch base would be light enough and simple to use. However, I don't have a feel for how stable it would be, especially while focusing. The 34# Portaball was the worst scope that I've ever owned in that respect, and I don't know much of that was design and how much was simply it's light weight. There's nothing on the market like this, so i would have to build it, which is a scary thought. 

 

Thanks for the link to hastings.

 

Gary

 

Gary:

 

I am not sure what was up with the Portaball.  I think an 8 inch F/6 with an aluminum tube on a baltic birch base could be very stiff.

 

Jon

[earlyriser]

I'm just brainstorming here, but would it be possible to have a base for your OTA at each observing position?  That way, you would only have to carry the OTA around your property.  The bases would have to be weather resistant, or maybe you could cover them with a tarp.  I've heard of guys having multiple piers on their property, so this would be kind of like that.

[gwlee]

I'm just brainstorming here, but would it be possible to have a base for your OTA at each observing position?  That way, you would only have to carry the OTA around your property.  The bases would have to be weather resistant, or maybe you could cover them with a tarp.  I've heard of guys having multiple piers on their property, so this would be kind of like that.

The problem is extensive tree cover that requires moving the telescope several times an hour to keep objects in view. There no open observing positions anywhere on the property, so i would need a LOT of bases scattered over an acre of rough sloping ground. 

[gwlee]

 

 

Gary:

 

I own several truss/strut scopes. In an 8 inch, I think a tube scope is the way to go, particularly for one that will be transported on a regular basis.. 

 

To lighten the OTA, I would think about an aluminum Tube.. It would be a thicker wall but it could be lighter since aluminum is less dense.  It wold 

 

http://www.hastingsi...laneous-tubing/

 

Jon

Jon,

 

My 8"f6 Portaball experience left me very leary of truss designs for small scopes. It was a pain to use at home every night, no advantages, several disadvantages. I seldom need to transport a scope, and when i do, a small solid tube scope is easy to transport in a small car. 

 

i think an aluminum tube and baltic birch base would be light enough and simple to use. However, I don't have a feel for how stable it would be, especially while focusing. The 34# Portaball was the worst scope that I've ever owned in that respect, and I don't know much of that was design and how much was simply it's light weight. There's nothing on the market like this, so i would have to build it, which is a scary thought. 

 

Thanks for the link to hastings.

 

Gary

 

Gary:

 

I am not sure what was up with the Portaball.  I think an 8 inch F/6 with an aluminum tube on a baltic birch base could be very stiff.

 

Jon

 

Jon,

 

i believe that i owned the last 8"f6 that Peter built. It was built for me. Subsequent 8" scopes were f5ish, which I assume was done to increase stability. The proprietary, low profile, 1.25" helical focuser was also poorly designed and manufactured, which made things worse. It was so shaky that it was very difficult to focus. The scope was limited to a Rigel QuickFinder and was made to balance with the owner's specified eyepieces. Peter was in poor health by then, so i never got to the bottom of it with him. 

 

I think the basic design has promise that was not realized in the 8"f6 version. I wrote to the new owner several times about the stability of the new, faster 8", but he didn't respond. My brother owned an astroscan back in the day, and i have fond memories of it, but I didn't know anything about telescopes then. 

 

This expensive experiment taught me the difference between portability and transportability, and made me a bit wary of ultra-light construction in general and bespoke telescopes. Mark Twain said something like: good judgement comes from experience, and experience comes from bad judgement. 

 

I haven't used a larger Portaball, so don't known if the problems I encountered with the 8" were present on the larger scopes. These scopes could be ordered with a FeatherTouch focuser. It's possible the design didn't scale down well. 

 

I suspect that you are probably right about an aluminum tube and baltic birch base being light and stable, but i would want some hands-on experience with a similar 8"f6 before building one. Bicycles can be both light and stable, so why not telescopes. Maybe I should go to the Riverside TMC this year and look around. 

 

Gary

[Stargazer713]

Would probably keep my 6" sct and add a quality 4" refractor.

[Tony Flanders]

I haven't used a larger Portaball, so don't known if the problems I encountered with the 8" were present on the larger scopes. These scopes could be ordered with a FeatherTouch focuser. It's possible the design didn't scale down well. 
 
I suspect that you are probably right about an aluminum tube and baltic birch base being light and stable, but i would want some hands-on experience with a similar 8"f6 before building one. Bicycles can be both light and stable, so why not telescopes. Maybe I should go to the Riverside TMC this year and look around.

I know several people with larger Portaballs, and they all love them. The only complaint I've heard is that it's very hard to adjust the scope's balance, which can cause problems with ultraheavy eyepieces and binoviewers.

I also know innumerable people with ultralight truss-tube or string Dobs, some commercial, some home-built. Again, almost all of these people love them.

But in some ways the easiest solution to a portable 8-inch Dob is a solid-tube scope plus a handtruck.

Also, if there are handles on both the tube and base, it should be pretty easy to walk around carrying one in each hand. That's what I do with my 7-inch Dob.

[emontano2]

Gary wrote:

"This expensive experiment taught me the difference between portability and transportability, and made me a bit wary of ultra-light construction in general and bespoke telescopes. Mark Twain said something like: good judgement comes from experience, and experience comes from bad judgement."

 

Thanks Gary that explains it all.

EM

[gwlee]

 

I haven't used a larger Portaball, so don't known if the problems I encountered with the 8" were present on the larger scopes. These scopes could be ordered with a FeatherTouch focuser. It's possible the design didn't scale down well. 
 
I suspect that you are probably right about an aluminum tube and baltic birch base being light and stable, but i would want some hands-on experience with a similar 8"f6 before building one. Bicycles can be both light and stable, so why not telescopes. Maybe I should go to the Riverside TMC this year and look around.

I know several people with larger Portaballs, and they all love them. The only complaint I've heard is that it's very hard to adjust the scope's balance, which can cause problems with ultraheavy eyepieces and binoviewers.

I also know innumerable people with ultralight truss-tube or string Dobs, some commercial, some home-built. Again, almost all of these people love them.

But in some ways the easiest solution to a portable 8-inch Dob is a solid-tube scope plus a handtruck.

Also, if there are handles on both the tube and base, it should be pretty easy to walk around carrying one in each hand. That's what I do with my 7-inch Dob.

 

Tony,

 

i don't know which Portaball model people that you know used and for what purpose and where. I can only speak from my first hand experience with one Portaball model (8"f6) that i owned and used for a few years. I have zero personal experience with larger models, but people that i know have said nothing bad about them either. 

 

To me, the key question is who "loved" them for what purpose, used where? if i had owned a 2-seat Mazda Miata and wanted a telescope that could ride comfortably in the passenger seat of a Miata for monthly trips to a dark site, i might have loved my Portaball too because it might have been ideally suited for the observer (me) and my observing site.

 

As it was, i used mine for observing every clear night from my home, and i seldom traveled with a telescope. When i traveled, i traveled in a medium size SUV that could comfortably transport any telescope that i owned. The design trade offs that were required to achieve the ultra-transportability of the 8"f6 Portaball severely compromised this telescope for my use at my observing site. Two other dobs that i owned simultaneously worked much better for me at this site and cost much less. 

 

From four years experience using a 41# 8"f6 dob at my present home observing site, i know that a cart it woefully unsuited for my use at this rural observing site.  Nor Is a 41# scope suitable for hand-carried tree dodging by me across this difficult terrain. However, i found both methods suitable for me at my previous observing site in the city and at my club's observing site, just not here. 

 

By themselves, telescopes don't do anything, but collect dust. To be useful, they must be suitable for the observer and the observer's observing site. 

 

Gary

Edited by gwlee, 22 February 2017 - 11:56 PM.

[Jon Isaacs]

I also know innumerable people with ultralight truss-tube or string Dobs, some commercial, some home-built. Again, almost all of these people love them.

 

 

I have a lightweight strut Dob that I put together from a Dobstuff kit.  I like it well enough but I spent a long time and a number of years achieving a  stable scope that is free of vibration and one that holds collimation from the horizon to the zenith.  I would prefer a classic truss design like my other Dobs but it would be too heavy to easily move.

 

I love my 16 inch but love does not imply perfection, love, by its very nature is accepting of imperfection.

 

Jon