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DocTelescope Review - 16" F/4 Made by Marco Guidi

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#1 jloweva

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Posted 21 May 2020 - 07:46 AM

Background

 

About two months ago I was perusing Cloudy Nights when I came across a thread about a dob builder I hadn’t heard of before – Marco Guidi, owner of DocTelescope, from Castelnova Bariano, Italy, which is just outside of Verona - https://www.cloudyni...pe#entry9963863.

 

I have owned several dobs over the last ten years, including two Starmaster 14.5 hybrids (an f/4.5 and an f/4.3) with Zambuto mirrors (that I no longer own), and a JP Astrocraft Sweet Sixteen f/4 with a Zambuto quartz mirror I had made for it, which I still own.  I have loved my Sweet Sixteen since acquiring it via Astromart about five years ago.  The build quality is exceptional, and I appreciate being able to tilt and roll it out my door without the need for wheelbarrow handles, which I find a nuisance.  The Sweet Sixteen structure, coupled with my exceptional Zambuto mirror (I know, redundant), are about as fine a combination as one could hope for.  Plus, John Pratte, the maker of the Sweet Sixteen, is a true gentleman and has provided fantastic service and support to me, even though I acquired the scope in the secondary market.

 

The only downside for me, however, is the weight of the Sweet Sixteen.  I am now 55, and although I am in good shape and work out regularly, I have noticed the scope becoming “heavier” over the past five years I’ve owned it.  The Sweet Sixteen is equipped with ServoCAT and Nexus DSC, and unlike my Starmaster hybrids, the truss poles and UTA cannot be removed all in one piece for travel.  The scope requires full disassembly, including removing the ServoCAT altitude control wire from the mirror box if I wish to separate the mirror box from the ground board and rocker box.  In addition, the weight and bulk of the ground board and the rocker box, either with or without the 18-pound mirror installed, have become too much for me to safely lift into a car or SUV alone.  This makes me more reluctant to travel to dark sky sites with it.

 

So, while I have not exactly been in the market for a new dob, I have thought about finding something that would allow me to make my fine 16” mirror more portable.  After spending a week or so reviewing the DocTelescope site and strolling the internet for additional information about Marco and his scopes (including finding some great videos made by Marco about them), I reached out to Marco to inquire about purchasing one.

 

Communications with Marco

 

Communications with Marco have been frequent and easy.  Although he speaks excellent English, I believe he prefers to communicate via email and WhatsApp rather than by phone in order to avoid any miscommunication.  His level of service and responsiveness is similar to that of Serge from AstroDevices, which is saying something.  It’s been obvious that he cares very much about his work and his products.

 

The Telescope – 16" f/4 Dob

 

The telescope that I purchased from Marco was one that he had already built and had in stock.  Marco originally built it with ServoCAT installed, but I asked him to remove it because (1) it would have doubled the €3500 price and I knew I could obtain the ServoCAT much less expensively here in the US and install it myself if I so wished, and (2) I wanted to try the structure without GoTo and see if that would work for me.  Marco understood my reasoning and was happy to oblige. At my request, he even took detailed pictures of the scope before removing the ServoCAT so I could see how to reattach it in the future if I desired.  I have since decided that I prefer GoTo on my dobs and have ordered a ServoCAT from Gary.

 

The scope is, in a word, beautiful.  I think the bright blue rocker crescents combined with the silver UTA and the dark carbon fiber-colored truss poles look great.  The blue rocker crescents also match the 10” Portaball that I had made years ago and also store in my home office, which is nice.  By the way, although the truss poles and the cross beam over the crescents appear to be carbon fiber, Marco told me they are actually aluminum covered in high-quality carbon fiber decals.  I happen to like the look, but I can also see how some would prefer it without the decals.  I do not know whether Marco plans to offer true carbon fiber at some point, and I was aware that the pieces were not made of carbon fiber.  Marco also replaced the original single ring UTA with a dual ring UTA, which I understand provides greater stiffness.  This was done at his suggestion and at no additional cost to me.

 

I am most pleased by the ability to separate the scope into several easy-to-move parts.  Marco designs his scopes so that the entire truss/UTA can be removed from the mirror box all in one piece, much like a Starmaster hybrid or a Teeter.  This obviates the need for fully disassembling the scope whenever I want to travel with it.

 

Shipping

 

Marco did an excellent job packing and shipping the scope from Italy.  It was not inexpensive (€700), but I did not find it to be overly expensive, either, given the size of the crates and the distance they were travelling.  Marco built the crate that the dob was shipped in as well as a separate crate for the truss poles.  Both crates were shipped via DHL and arrived in less than a week from Italy.  This was particularly impressive given that they were shipped at the height of the COVID-19 pandemic in both Italy and the US.  All of the items were packed with great care and I was relieved to see that all arrived unscathed and in excellent shape.

 

Performance

 

Of course, the most important issue is how well the scope performs.  It's been very hard to test the scope because of COVID-19.  I live just outside of Washington, D.C. in Alexandria, VA, in the Old Town section near the Potomac River. Complicating matters further is that I live right next to a park. I do most of my viewing right outside my home, and I know from experience that the unusual nature of a scope of this size tends to draw a large crowd.  Consequently, I have only had it outside three times in the six weeks I have owned it, and two of those times were very, very brief.  I have, however, played with it a LOT inside my home because I’ve been stuck inside due to the pandemic.

 

          Fit and Finish - The fit and finish of the scope are excellent.  I’ve never owned a predominantly metal dob before, so I have nothing to compare it to, but to my eye Marco has paid attention to all the details, both from an aesthetic and functional standpoint.  It looks well-made and feels well-made, and to my untrained eye the parts, both off-the-shelf and machined, look first-rate.

 

          Balance - Because the scope was originally designed for use with ServoCAT and a heavier mirror, one of the first things I needed to deal with was the balance of the scope.  I typically use Ethos eyepieces when observing.  I purchased some magnetic weights from Amazon to serve as counterweights.  I found a product called Plate Mate weights, which are magnetic weights typically used in gyms and health clubs as extra weights for the weight machines.  Because the mirror box and rocker box are both made of steel, they work very well.

 

As shipped by Marco, the scope had two 5-lb counterweights installed directly under the mirror to provide some counterbalance, but I found they were not sufficient.  In addition, they were intended to be installed as permanent fixtures with bolts, and I realized that having 10 additional pounds permanently attached to the structure made it that much harder for me to lift it and move it around.  I am happy with the Plate Mate products and especially appreciate the ability to remove them at will.

 

          Mirror Cell - As designed by Marco, the mirror rests on an eighteen-point cell and is kept in place, without a sling, solely by gravity and two roller points that sit at roughly four- and eight-o’clock when the scope is pointed horizontally.  Candidly, this reliance on gravity alone concerned me, so I made three additional “mirror stops,” similar to what John Pratte at JP Astrocraft uses on the Sweet Sixteen, to help prevent the mirror from falling out of the cell in the event of an accident.  I may have placed the two bottom mirror stops too close to the mirror, but I haven’t had an opportunity to determine whether that is the case.  I do not want to introduce any unintended pinching or astigmatism. I do notice, however, that the mirror does tend to float a bit on the cell when being moved but I haven’t done any experiments yet to determine if it always properly “rights” itself once it is fully assembled and ready for viewing.

 

          Secondary Holder and Collimation – Because I had the dob shipped without a secondary, I had to obtain one from Antares Optics (3.1”, 1/30 wave) and install it myself.  The secondary holder is different than the ones I have traditionally seen in that it is two parts: the top parts installs to the UTA via the main screw, and the lower part of the holder installs to the top part of the holder via three hex bolts.  The top part of the secondary holder also has three small hex screws that push into the lower part of the holder in the traditional sense.  However, I found that I needed to manipulate all of six of the bolts/screws to get collimation right.  It may be because I did not properly center the secondary on the holder, or it may just be a function of the design.  In any event, once I figured out how to finesse it I was able to dial in collimation, but not as easily as with the Starmaster or Sweet Sixteen.  Again, it may be the result of my installation of the secondary mirror.  Once collimated, the scope tends to hold collimation fairly well, though I did notice some movement on the Tublug as I worked through taking the scope from vertical to horizontal when I got to the 45 degree point.  Again, this may be related to my installation of the secondary.

 

         Focuser and Finder - The scope arrived with a single-speed Moonlight focuser equipped with an Orion electric focuser, as expected.  I tried it out, and it worked okay, but I prefer to manually focus for visual and so I replaced the Moonlight with a 2” Feathertouch focuser that I repurposed from another scope.  Unfortunately, the baseplate for the focuser installed on the scope was designed for the Moonlight, which is narrower, so I needed to have Marco make a new baseplate for me to accommodate the Feathertouch.  The cost for this was €190 including shipping, which may seem a little high, but then again it was completely custom-made for me and Marco shipped it within a matter of days.

 

The scope also came with a Stellarview Multi-Reticle Red Dot Finder (F002) and an Orion finder base.  I’m not a fan of the F002 because it requires a hex key to adjust it, so I removed the Stellarview and its finder base, moved the placement of the Orion finder base to where the Stellarview was, and use my Rigel Quickfinder with Orion base plate on it.

 

          In the field - The scope is very easy to separate the parts and move to the field.  I purchased a large wagon with 11” pneumatic wheels to transport it the short distance from my front door to the field.  I first load the ground board/rocker box on, then the mirror box on the ground board/rocker box, and the put the truss/UTA next to those pieces, and then reverse the process at the end of the evening.  The wagon also allows me to include my eyepieces, iPad and miscellaneous other equipment all in one trip.  Perhaps not as easy as simply rolling out the Sweet Sixteen, but even then I needed to open both of my screen doors and main doors and put ramps in place, plus make extra trips for the eyepieces and other equipment once the Sweet Sixteen was placed.  I’d say it’s a wash from a time perspective, but again the DocTelescope will be much easier to transport via car.

 

          The Views – As I noted above, I have had very limited time at the eyepiece because of the weather and the pandemic.  My first two brief trips out were solely to explore the scope’s balance and lasted less than 45 minutes.  It was early dusk and the only object visible was Venus, so that’s what I looked at.  Even without giving the mirror time to acclimate, I was very pleased with the view.  Last week, I found myself unable to sleep so I got up and went outside with the scope around 2:30 am to check out the planets, which were relatively low in the sky but moving upward.  After giving the mirror some time to acclimate, roughly 90 minutes, I was very pleased with the views of Jupiter and Saturn.  However, I was still having some issues with balance so I didn’t get to spend as much time as I would have liked concentrating solely on the views.  In addition, my new shroud from Randy at Astrosystems had not come yet, and I was fighting terrible light pollution from the street lights and park lights.  This was exacerbated by the fact that the scope is an open truss structure that has a much lower UTA profile than the Sweet Sixteen and an open mirror box, making it much more susceptible to reflected light.  My new shroud arrived a few days ago, and I have now perfected the balance, so I am eager to take the scope back out.  Naturally, the weather here is now terrible and is expected to remain so for the next week.  

 

Preliminary Conclusions – Before going forward with the purchase, I asked an observing buddy whose opinion I trust for his thoughts about buying the scope.  He was candid and said that I was definitely incurring some risk making a high-dollar purchase like this sight unseen from an international vendor.  I knew he was right, but I still went forward anyway, and I am very pleased that I did.  So far, I am very happy with my purchase.  Marco has been a pleasure to work with and I feel I received a very high-quality structure at a fair price.  What has impressed me most is Marco’s eagerness to make sure that I am happy with the purchase and the scope’s performance.  Even though he is half a world away, I feel like I’m dealing with a manufacturer with integrity who cares about his reputation and his customers’ satisfaction.  

 

I currently own telescopes of varying designs made by Questar, Astro-Physics, Televue, JP Astrocraft and Portaball.  Much to my wife’s chagrin (although she’s a great sport about it), they are all on display in my home office, simply because I have nowhere else to put them.  My DocTelescope certainly holds its own in their company from a look/feel perspective, and my initial observing experiences have been very favorable as well.  I look forward to really putting it through its visual paces someday soon.

 

*Please note that I had no prior relationship with Marco Guidi prior to purchasing this scope and that I am not being compensated by him in any way, nor has he offered me any inducement to write this review.  I did give Marco the opportunity to review this review prior to publishing it because I believe it is the fair thing to do.  He was fine with it and suggested no changes.


Edited by jloweva, 21 May 2020 - 02:55 PM.

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#2 jloweva

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Posted 21 May 2020 - 07:54 AM

IMG_1881.JPG PHOTO-2020-03-28-09-15-06.jpg thumbnail_PHOTO-2020-04-10-12-27-06.jpg


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#3 spereira

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Posted 21 May 2020 - 08:14 AM

Gorgeous scope!  

 

Great review - thanks very much for posting this.  Please be sure to post more as you get the chance to do some observing.

 

smp



#4 Jim45157

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Posted 21 May 2020 - 08:32 AM

that scope is very nice i dont think you could do any better jim45157



#5 jeff3948

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Posted 21 May 2020 - 09:26 AM

Dear jloweva,

 

Great review. I generally do not like all metal Dobsonians, but this one is very good looking. I'm getting older too and weight is a concern when transporting in a car or SUV. Since you have to transport it in your SUV, it's better having a lighter one. However, you say you had to buy a wagon to transport it to the field. That means you have to do a lot of taking apart, then lifting the parts and then bending down to put the parts on the ground, etc., which does not sound good for you. Also, it seems like you had to do several modifications to it to make it work properly. That is also not a good sign. I definitely find that wheel barrel handles, especially if they are long, is much easier to move the whole thing from the garage to a nearby viewing sight like your field, quick and easy. Your Pratte already had wheels on it which must have made it really easy to move to the field. So I'm not sure your purchase was really worth it, especially since you already were so happy with your Sweet Sixteen. Let me ask you two questions and be honest with yourself:

 

1. Which is easier for you to move to your field viewing sight, the Marco Guidi or the John Pratte?

2. Which is easier to use for a nights observing?

3. Is the Marco Guidi easier to put in your SUV to travel to a dark sight than your John Pratte?

 

If the answer to any of these questions was "Marco Guidi" then it was probably worth it. Maybe you'll have to keep both for different viewing sights. wink.gif

 

Jeff


Edited by jeff3948, 21 May 2020 - 09:29 AM.


#6 jloweva

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Posted 21 May 2020 - 12:01 PM

Hi Jeff:

 

Thanks for your questions.  Let me break them down one by one:

 

1.  It seems like you had to do several modifications to it to make it work properly.

 

a.  The only modification I "had" to make was to adjust it for balance.  However, as I noted in the review this particular scope was already made by Marco and was designed for a different, heavier mirror and to be used with ServoCAT.  I knew going in I would have to deal with the balance issue and make my own adjustments.  This was not a telescope that was built to my specifications.  In addition, even my Sweet Sixteen is not designed to operate easily as a push-to without the ServoCAT.  It would have the same balance issues if not for the ServoCAT clutch.

 

b.  I put the mirror stops in because I am generally a cautious person and I figured that with minor effort I could better protect my $5,000 investment in my mirror.  I think Marco would be happy to install them if another buyer wanted them but I don't know for sure.  It took a couple of hours, but was complicated by the inability to go to a hardware store at the height of the pandemic.

 

c.  The Moonlight focuser with electric focuser was perfectly serviceable, but not to my taste.  It's also much less expensive than the Feathertouch, which would have cost me approximately $600 if I didn't already have it laying around.  It was unfortunate that the Feathertouch and Moonlight don't share the same mounting pattern, but again, I bought a pre-existing scope, not a bespoke one. 

 

d.  Modifying the finder setup took 15 minutes.  In case I didn't make clear, the scope came with both the Stellarvue F002 and the Orion mounting base.  Had I ordered the scope custom, I would not have wanted the Stellarvue at all.

 

2. Which is easier for you to move to your field viewing sight, the Marco Guidi or the John Pratte?

 

Definitely the Sweet Sixteen, but I knew that going in and ease of use at home had nothing to do with the buying decision.  I don't think there's anything out there, at least commercially made, that's easier than a Sweet Sixteen to roll from one location to another without having to do anything other than tip and roll it.

 

3. Which is easier to use for a nights observing?

 

I'm not sure yet.  They are also apples and oranges at the moment because one has ServoCAT and the other is a push to, and I live in an extremely light-polluted environment.  I'm not adept at star-hopping, and that deficiency is exacerbated by a light-polluted environment.  Once I have the ServoCAT installed, I could make a fairer comparison.  Although I do use a wagon, Marco does make wheelbarrow handles that I could buy and just roll it out, sans truss/UTA.  Again, however, that wasn't the driver.  As I noted above, the wagon has some benefit because I can load all my gear in one trip and not have to make multiple trips like I do with the Sweet Sixteen.

 

4. Is the Marco Guidi easier to put in your SUV to travel to a dark sight than your John Pratte?

 

Hands down the Marco Guidi will be, though I have yet to do so.  The ground board/rocker box and the mirror box of the Sweet Sixteen are *very* heavy and cumbersome.  It's an uncomfortable dead-lift.  The DocTelescope, on the other hand, essentially breaks down into three very manageable parts, and as I noted above, the truss poles/UTA can remain fully assembled.  It remains to be seen whether this will still be the case after I install the ServoCAT.

 

Additional Thoughts

To be clear, this purchase was much more of a luxury than a necessity, and was motivated primarily by the desire to have a more portable high power setup than I have with the Sweet Sixteen.  So far, it seems very capable of accomplishing that objective.


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#7 jloweva

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Posted 21 May 2020 - 02:52 PM

Additional pics

Attached Thumbnails

  • Truss UTA.jpg
  • Rocker.jpg
  • Separates.jpg
  • Base.jpg

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#8 Bill Jensen

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Posted 21 May 2020 - 06:23 PM

Your scope is a work of art. Being fairly close (Springfield) I can attest to the light pollution challenges you face. I hope you can get it out to some dark skies in the near future. the 16 inch f/4 size is a great balance between aperture and transportability. 

Have a ton of fun with your Italian sports car of a scope. 


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#9 Axunator

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Posted 23 May 2020 - 05:51 AM

Absolutely gorgeous looking scope! I hope you'll enjoy it waytogo.gif

 

And thanks for taking the time to write the review - I've been eyeing Marco's website for some time now...smile.gif


Edited by Axunator, 23 May 2020 - 05:53 AM.

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#10 jeff3948

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Posted 23 May 2020 - 12:47 PM

Dear jloweva,

It sounds like you made an excellent purchase for what you needed it for. As soon as you add the ServoCAT it will probably be a dreamscope for you. I would love to take a look through it with that Zambuto mirror. I've never looked through a scope with a Zambuto mirror. Just out of curiosity how does the Zambuto mirror compare to other 16" telescopes you have looked through? I looked through a Orion 16" Dobsonian and was not impressed compared to my Ostahowski 12.5" F/5 which is really good.

Jeff


Edited by jeff3948, 23 May 2020 - 12:48 PM.


#11 jloweva

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Posted 23 May 2020 - 02:34 PM

Thanks, Axunator and Jeff3948.  
 

I’ve had several Zambuto mirrors and they’ve all lived up to the hype.  I don’t have many points of comparison with other scopes, but my sense is you do get what you pay for.  That being said, I’ve looked through some mid-range commercial and hand-made scopes that have knocked my socks off. No doubt part of what you’re paying for with a Zambuto etc. is a greater degree of certainty that your mirror will be great, versus a more luck-of-the-draw experience. 


Edited by jloweva, 23 May 2020 - 02:39 PM.

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#12 jloweva

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Posted 24 May 2020 - 01:56 PM

Several people have asked me about the weight of the structure and whether I have noticed any vibrations at the eyepiece.  I just took some measurements and share the following.  All are approximate because I was using a bathroom scale:

 

Ground Board/Rocker Box - 24.6 pounds

Mirror Box - 22.2 pounds

Mirror - 17.8 pounds

Truss Assembly/UTA - 19.8 pounds

 

Total - 84.4 pounds with mirror, 66.6 pounds without

 

I don't know how that compares to Ultralights generally, but according to the Obsession website, the total weight for a UC 15 is listed at 65 pounds including mirror, and the Obsession 15" Classic is listed at "about 90 pounds."  Obsession lists the specs for the UC 18 and 18" Classic as 90 pounds and 140 pounds, respectively.  So if we extrapolate, one could estimate the non-existent "UC 16" at approximately 72-73 pounds.

 

Having lived with the DocTelescope for six weeks now, I wouldn't describe it as an Ultralight, but rather a lighter telescope than a similar-sized traditional wooden dob, but whose primary advantage is the ability to break it down into several easily manageable parts.  It's also waaaaaay better looking, but that's just my opinion.  smile.gif

 

 

As far as vibration at the eyepiece, I haven't noticed any at the eyepiece, but I've only used the scope three times and for very short periods of time.  It's worth noting that until someone asked me about it I didn't even think about it, which indicates it wasn't a problem.  I will pay more attention to that during my next session, now that I have the scope finely tuned for my needs.


Edited by jloweva, 24 May 2020 - 02:47 PM.

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#13 Kunama

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Posted 24 May 2020 - 05:55 PM

What are beautiful telescope!
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#14 jloweva

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Posted 24 May 2020 - 06:15 PM

Thanks, Kunama. I’ve admired yours from afar!


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#15 Dougeo

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Posted 24 May 2020 - 08:07 PM

Awesome looking telescope! I wish you many happy nights under the stars with it!


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#16 jloweva

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Posted 26 May 2020 - 07:48 AM

Observing update:

 

Took the scope out last night at midnight to wait for Jupiter and Saturn.  Temp was around 60 degrees Fahrenheit and a very light wind was blowing. 
 

Some have asked about vibration at eyepiece, so I paid special attention to that.  None detected while observing and minimal experienced while focusing manually.  Confirms my earlier suspicion that it’s a non-issue, at least in the above-described conditions. 
 

A joy to use. 


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#17 jloweva

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Posted 11 June 2020 - 10:58 PM

Observing update: Had the scope out Sunday at a friend’s home in Round Hill, Va, about an hour outside of DC.  He had had the scope for about a week and had isolated one cause of the collimation drift I mentioned in my original review: I hadn’t fully tightened one of the truss connectors. 

 

Also, I had ordered a new secondary holder from Randy at Astrosystems because I liked his collimation screw set up better.  We removed the secondary from the original holder and got to work squaring the focuser and adjusting the secondary in its new holder. I also hoped that putting the secondary in an enclosed structure would help correct any potential issues from my misplacement of the secondary when I glued it to the original “open” holder. Total investment was about $50.  
 

The result: Virtually zero drift (as shown by laser) from vertical to horizontal. The beam stayed well inside the center spot at all times and any drift was imperceptible. We also used a cheshire and autocollimator and were easily able to collimate to perfection.   Even though the seeing was bad, the views were what I was used to from my Zambuto quartz mirror when I had it in my Sweet Sixteen. We spent most of the night on globular clusters M5 and M13, the Ring, M81 and M82, among others. Great contrast and depth were evident. 

 

So, with some small mods I have been able to achieve the result I was hoping for in purchasing my DocTelescope: exquisite views in a more portable package. Packing up for the evening was a snap, and best of all I didn’t have the dread of deadlifting the rocker box and mirror box into my car.

 

Nearly two months in I am extremely happy with my purchase. Marco is great to work with, the scope is solid and beautifully machined, and the views are spectacular.  Also, per my post above, once again there was zero vibration at the eyepiece. The structure is rock solid. 


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#18 Bill Jensen

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Posted 12 June 2020 - 08:08 AM

Having seen this scope in person  I can just say that it truly is a work of art, and that is great that you are getting the performance from it that you wanted. Bellissimo! Have fun with it. 



#19 jloweva

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Posted 21 August 2020 - 05:08 PM

Update:

 

Finally had a chance to install the Servocat.  Works like a dream. The best thing about this scope is that it breaks down into four very manageable sections:

 

Ground board

Mirror/rocker box

Mirror

Truss/UTA.

 

This makes it significantly more portable than my Sweet 16.  Bottom line:  If I had a permanent dark sky location, I'd have no need to ever replace the Sweet 16.  It's an amazing piece of hardware.  But given my highly light polluted home location, I need to travel to get the best views.  As I've aged (I'm now 55), I've started dreading the thought of disassembling the Sweet 16 and hauling it to a dark sky site, especially if I have no one to help me load it in the car.  With the DocTelescope, I no longer have to worry.  I highly recommend the scope to anyone in a similar situation.  It's very well made, works beautifully and Marco Guidi is a pleasure to work with.  I've felt fully supported by Marco in the five months since my purchase.  He is always available to answer any questions.

 

Feel free to reach out to me if you have any specific questions about my scope or my interactions with Marco.


  • Bill Jensen likes this

#20 Peter Natscher

Peter Natscher

    Apollo

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Posted 16 September 2020 - 06:36 PM

This is a beautiful telescope!  This type of telescope design subjects the primary to heat radiating off of the ground due to its low position relative to the ground if set up on a pavement which will affect the mirror performance until full mirror equilibriation.  What kind of surface do you set this telescope up on?  Mirror fans really help move the warmer air away from the mirror.

 

How's the telescope structure's stiffness compared to your JPA? I have a 20" JPA and had a 16" JPA and both have very good stiffness with a ~1 second tap settling time at high power. The JPA build quality and mass (weight) helps this a lot. What settling time at the eyepiece would you estimate at 300X?

 

 

Background

 

About two months ago I was perusing Cloudy Nights when I came across a thread about a dob builder I hadn’t heard of before – Marco Guidi, owner of DocTelescope, from Castelnova Bariano, Italy, which is just outside of Verona - https://www.cloudyni...pe#entry9963863.

 

I have owned several dobs over the last ten years, including two Starmaster 14.5 hybrids (an f/4.5 and an f/4.3) with Zambuto mirrors (that I no longer own), and a JP Astrocraft Sweet Sixteen f/4 with a Zambuto quartz mirror I had made for it, which I still own.  I have loved my Sweet Sixteen since acquiring it via Astromart about five years ago.  The build quality is exceptional, and I appreciate being able to tilt and roll it out my door without the need for wheelbarrow handles, which I find a nuisance.  The Sweet Sixteen structure, coupled with my exceptional Zambuto mirror (I know, redundant), are about as fine a combination as one could hope for.  Plus, John Pratte, the maker of the Sweet Sixteen, is a true gentleman and has provided fantastic service and support to me, even though I acquired the scope in the secondary market.

 

The only downside for me, however, is the weight of the Sweet Sixteen.  I am now 55, and although I am in good shape and work out regularly, I have noticed the scope becoming “heavier” over the past five years I’ve owned it.  The Sweet Sixteen is equipped with ServoCAT and Nexus DSC, and unlike my Starmaster hybrids, the truss poles and UTA cannot be removed all in one piece for travel.  The scope requires full disassembly, including removing the ServoCAT altitude control wire from the mirror box if I wish to separate the mirror box from the ground board and rocker box.  In addition, the weight and bulk of the ground board and the rocker box, either with or without the 18-pound mirror installed, have become too much for me to safely lift into a car or SUV alone.  This makes me more reluctant to travel to dark sky sites with it.

 

So, while I have not exactly been in the market for a new dob, I have thought about finding something that would allow me to make my fine 16” mirror more portable.  After spending a week or so reviewing the DocTelescope site and strolling the internet for additional information about Marco and his scopes (including finding some great videos made by Marco about them), I reached out to Marco to inquire about purchasing one.

 

Communications with Marco

 

Communications with Marco have been frequent and easy.  Although he speaks excellent English, I believe he prefers to communicate via email and WhatsApp rather than by phone in order to avoid any miscommunication.  His level of service and responsiveness is similar to that of Serge from AstroDevices, which is saying something.  It’s been obvious that he cares very much about his work and his products.

 

The Telescope – 16" f/4 Dob

 

The telescope that I purchased from Marco was one that he had already built and had in stock.  Marco originally built it with ServoCAT installed, but I asked him to remove it because (1) it would have doubled the €3500 price and I knew I could obtain the ServoCAT much less expensively here in the US and install it myself if I so wished, and (2) I wanted to try the structure without GoTo and see if that would work for me.  Marco understood my reasoning and was happy to oblige. At my request, he even took detailed pictures of the scope before removing the ServoCAT so I could see how to reattach it in the future if I desired.  I have since decided that I prefer GoTo on my dobs and have ordered a ServoCAT from Gary.

 

The scope is, in a word, beautiful.  I think the bright blue rocker crescents combined with the silver UTA and the dark carbon fiber-colored truss poles look great.  The blue rocker crescents also match the 10” Portaball that I had made years ago and also store in my home office, which is nice.  By the way, although the truss poles and the cross beam over the crescents appear to be carbon fiber, Marco told me they are actually aluminum covered in high-quality carbon fiber decals.  I happen to like the look, but I can also see how some would prefer it without the decals.  I do not know whether Marco plans to offer true carbon fiber at some point, and I was aware that the pieces were not made of carbon fiber.  Marco also replaced the original single ring UTA with a dual ring UTA, which I understand provides greater stiffness.  This was done at his suggestion and at no additional cost to me.

 

I am most pleased by the ability to separate the scope into several easy-to-move parts.  Marco designs his scopes so that the entire truss/UTA can be removed from the mirror box all in one piece, much like a Starmaster hybrid or a Teeter.  This obviates the need for fully disassembling the scope whenever I want to travel with it.

 

Shipping

 

Marco did an excellent job packing and shipping the scope from Italy.  It was not inexpensive (€700), but I did not find it to be overly expensive, either, given the size of the crates and the distance they were travelling.  Marco built the crate that the dob was shipped in as well as a separate crate for the truss poles.  Both crates were shipped via DHL and arrived in less than a week from Italy.  This was particularly impressive given that they were shipped at the height of the COVID-19 pandemic in both Italy and the US.  All of the items were packed with great care and I was relieved to see that all arrived unscathed and in excellent shape.

 

Performance

 

Of course, the most important issue is how well the scope performs.  It's been very hard to test the scope because of COVID-19.  I live just outside of Washington, D.C. in Alexandria, VA, in the Old Town section near the Potomac River. Complicating matters further is that I live right next to a park. I do most of my viewing right outside my home, and I know from experience that the unusual nature of a scope of this size tends to draw a large crowd.  Consequently, I have only had it outside three times in the six weeks I have owned it, and two of those times were very, very brief.  I have, however, played with it a LOT inside my home because I’ve been stuck inside due to the pandemic.

 

          Fit and Finish - The fit and finish of the scope are excellent.  I’ve never owned a predominantly metal dob before, so I have nothing to compare it to, but to my eye Marco has paid attention to all the details, both from an aesthetic and functional standpoint.  It looks well-made and feels well-made, and to my untrained eye the parts, both off-the-shelf and machined, look first-rate.

 

          Balance - Because the scope was originally designed for use with ServoCAT and a heavier mirror, one of the first things I needed to deal with was the balance of the scope.  I typically use Ethos eyepieces when observing.  I purchased some magnetic weights from Amazon to serve as counterweights.  I found a product called Plate Mate weights, which are magnetic weights typically used in gyms and health clubs as extra weights for the weight machines.  Because the mirror box and rocker box are both made of steel, they work very well.

 

As shipped by Marco, the scope had two 5-lb counterweights installed directly under the mirror to provide some counterbalance, but I found they were not sufficient.  In addition, they were intended to be installed as permanent fixtures with bolts, and I realized that having 10 additional pounds permanently attached to the structure made it that much harder for me to lift it and move it around.  I am happy with the Plate Mate products and especially appreciate the ability to remove them at will.

 

          Mirror Cell - As designed by Marco, the mirror rests on an eighteen-point cell and is kept in place, without a sling, solely by gravity and two roller points that sit at roughly four- and eight-o’clock when the scope is pointed horizontally.  Candidly, this reliance on gravity alone concerned me, so I made three additional “mirror stops,” similar to what John Pratte at JP Astrocraft uses on the Sweet Sixteen, to help prevent the mirror from falling out of the cell in the event of an accident.  I may have placed the two bottom mirror stops too close to the mirror, but I haven’t had an opportunity to determine whether that is the case.  I do not want to introduce any unintended pinching or astigmatism. I do notice, however, that the mirror does tend to float a bit on the cell when being moved but I haven’t done any experiments yet to determine if it always properly “rights” itself once it is fully assembled and ready for viewing.

 

          Secondary Holder and Collimation – Because I had the dob shipped without a secondary, I had to obtain one from Antares Optics (3.1”, 1/30 wave) and install it myself.  The secondary holder is different than the ones I have traditionally seen in that it is two parts: the top parts installs to the UTA via the main screw, and the lower part of the holder installs to the top part of the holder via three hex bolts.  The top part of the secondary holder also has three small hex screws that push into the lower part of the holder in the traditional sense.  However, I found that I needed to manipulate all of six of the bolts/screws to get collimation right.  It may be because I did not properly center the secondary on the holder, or it may just be a function of the design.  In any event, once I figured out how to finesse it I was able to dial in collimation, but not as easily as with the Starmaster or Sweet Sixteen.  Again, it may be the result of my installation of the secondary mirror.  Once collimated, the scope tends to hold collimation fairly well, though I did notice some movement on the Tublug as I worked through taking the scope from vertical to horizontal when I got to the 45 degree point.  Again, this may be related to my installation of the secondary.

 

         Focuser and Finder - The scope arrived with a single-speed Moonlight focuser equipped with an Orion electric focuser, as expected.  I tried it out, and it worked okay, but I prefer to manually focus for visual and so I replaced the Moonlight with a 2” Feathertouch focuser that I repurposed from another scope.  Unfortunately, the baseplate for the focuser installed on the scope was designed for the Moonlight, which is narrower, so I needed to have Marco make a new baseplate for me to accommodate the Feathertouch.  The cost for this was €190 including shipping, which may seem a little high, but then again it was completely custom-made for me and Marco shipped it within a matter of days.

 

The scope also came with a Stellarview Multi-Reticle Red Dot Finder (F002) and an Orion finder base.  I’m not a fan of the F002 because it requires a hex key to adjust it, so I removed the Stellarview and its finder base, moved the placement of the Orion finder base to where the Stellarview was, and use my Rigel Quickfinder with Orion base plate on it.

 

          In the field - The scope is very easy to separate the parts and move to the field.  I purchased a large wagon with 11” pneumatic wheels to transport it the short distance from my front door to the field.  I first load the ground board/rocker box on, then the mirror box on the ground board/rocker box, and the put the truss/UTA next to those pieces, and then reverse the process at the end of the evening.  The wagon also allows me to include my eyepieces, iPad and miscellaneous other equipment all in one trip.  Perhaps not as easy as simply rolling out the Sweet Sixteen, but even then I needed to open both of my screen doors and main doors and put ramps in place, plus make extra trips for the eyepieces and other equipment once the Sweet Sixteen was placed.  I’d say it’s a wash from a time perspective, but again the DocTelescope will be much easier to transport via car.

 

          The Views – As I noted above, I have had very limited time at the eyepiece because of the weather and the pandemic.  My first two brief trips out were solely to explore the scope’s balance and lasted less than 45 minutes.  It was early dusk and the only object visible was Venus, so that’s what I looked at.  Even without giving the mirror time to acclimate, I was very pleased with the view.  Last week, I found myself unable to sleep so I got up and went outside with the scope around 2:30 am to check out the planets, which were relatively low in the sky but moving upward.  After giving the mirror some time to acclimate, roughly 90 minutes, I was very pleased with the views of Jupiter and Saturn.  However, I was still having some issues with balance so I didn’t get to spend as much time as I would have liked concentrating solely on the views.  In addition, my new shroud from Randy at Astrosystems had not come yet, and I was fighting terrible light pollution from the street lights and park lights.  This was exacerbated by the fact that the scope is an open truss structure that has a much lower UTA profile than the Sweet Sixteen and an open mirror box, making it much more susceptible to reflected light.  My new shroud arrived a few days ago, and I have now perfected the balance, so I am eager to take the scope back out.  Naturally, the weather here is now terrible and is expected to remain so for the next week.  

 

Preliminary Conclusions – Before going forward with the purchase, I asked an observing buddy whose opinion I trust for his thoughts about buying the scope.  He was candid and said that I was definitely incurring some risk making a high-dollar purchase like this sight unseen from an international vendor.  I knew he was right, but I still went forward anyway, and I am very pleased that I did.  So far, I am very happy with my purchase.  Marco has been a pleasure to work with and I feel I received a very high-quality structure at a fair price.  What has impressed me most is Marco’s eagerness to make sure that I am happy with the purchase and the scope’s performance.  Even though he is half a world away, I feel like I’m dealing with a manufacturer with integrity who cares about his reputation and his customers’ satisfaction.  

 

I currently own telescopes of varying designs made by Questar, Astro-Physics, Televue, JP Astrocraft and Portaball.  Much to my wife’s chagrin (although she’s a great sport about it), they are all on display in my home office, simply because I have nowhere else to put them.  My DocTelescope certainly holds its own in their company from a look/feel perspective, and my initial observing experiences have been very favorable as well.  I look forward to really putting it through its visual paces someday soon.

 

*Please note that I had no prior relationship with Marco Guidi prior to purchasing this scope and that I am not being compensated by him in any way, nor has he offered me any inducement to write this review.  I did give Marco the opportunity to review this review prior to publishing it because I believe it is the fair thing to do.  He was fine with it and suggested no changes.

 



#21 jloweva

jloweva

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Posted 16 September 2020 - 09:56 PM

Peter, I typically set it up on grass, so the pavement concern is limited.  It also has a fan directly under the mirror that I leave running, but none over or to the side of the mirror. 
 

As for stiffness, it’s not quite in the same league as the JPA, which I think is overbuilt in a good way, but I haven’t noticed any vibration at the eyepiece at all. Haven’t done a tap test, but I think that speaks for the stiffness because I haven’t felt a need to do a tap test. 


Edited by jloweva, 17 September 2020 - 06:46 AM.



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