Observing Session May 12th and 13th XT10 with Carl Zambuto Mirror

This link to CloudyNights will provide you with the information of this loaner program for the 10 inch mirror that Carl Zambuto has offered.

I was at home, and everyone was gone to activities or such and so I plugged down to CloudyNights and began reading in the reflecting forum. I had been reading about how Carl Zambuto was offering replacement mirrors for Chinese made dobs, mainly the Orion series of scopes. That got my interest because I have an Orion XT10 along with an Orion XX14i and a 20" Obsession that was purchased used.

I followed this thread for several days and then watched as Carl himself signed on and offered to send otu a test mirror for people to try. He stated in his post that it would be a 250mm mirror. Well, that would work in my XT10 so I followed the thread until life got in the way between work, family and other obligations. I thought about putting my name on the list for viewing with the 250mm mirror and putting it in the XT10 to see how well the mirror was. Then I noticed that there were four or five people ahead of me and I thought I had better rethink this as it could be fall before I see the mirror.

Carl then posted and mentioned that Steve Dodds of Nova Optical was doing the coating and Steve only lives and has his shop ten minutes from where I live. So a thought occurred to me. Why not offer to test the mirror over that weekend since the forecast was decent and then ship it to the first person on the list, CityKid or Phil on Monday? I posted that, and Carl thought it was a good idea to get the mirror out and a review done as long as everyone on the list in front of me agreed. Graciously they did agree so I picked p the mirror on Wednesday, May 11th, 2011 from Steve at his shop next to his home. I took it home knowing that Thursday looked very promising and it was the second day after a storm had gone through. Typically the second day after a storm in the fall, winter and spring brings really great conditions to northern Utah.

NOTE: I sketch and I do not claim to be a terrific sketcher or to capture everything perfectly. Errors are mine and mine alone in terms of star placement or any other error. I use my sketches as visual reminders of my experience. All sketches here are not corrected except for the background. I used GIMP and the curves feature to try and capture what I was seeing in terms of the background and contrast. Everything else on the sketch remains as it was sketched.

Also, when referring to the XT10 in this rest of this article, I will mean the XT10 with a Zambuto ten-inch mirror in it.


On Thursday, May 12th, 2011, I have to admit that I anxiously waited for the last bell of school in order to get done with my work obligations and to have a quick exit. I completed my teaching duties and was out the door and on the way home by 4:00p.m. At 5:00p.m. I had the XT10 tube out, and had undone the base screws holding the primary cell in the tube. I have to say, that I had to replace the Orion stock screws about two years ago because I found they stripped far too easily when one had to remove the mirror cell for some maintenance in the tube. I put steel screws in and they work much better and don't strip though they are silver. Anyway the mirror cell cell came out quick enough, and it was on to the clip screws. There are two screws in the clips and you have to remove them to get the mirror out. Watch out for flaking of the black paint off the screw as you take them out. Not an major issue though, just thought I would point that out in case you see it.

The XT10 stock mirror came out easily enough and then I opened up the box that holds the 255mm Zambuto mirror. The mirror has a cover and it is held in place by blue painters tape to protect the top of the mirror. To remove the top simply undo the tape carefully and then the top will just lift right off. Installing the Zambuto 10 inch mirror was a breeze and within ten minutes the scope was back together and ready to go less a good collimation.

I used my backyard for this task since the moon was a nice 66% plus, waxing gibbous and I figured a dark site wasn't going to help in those conditions. Plus there is this thing called work the next day and by using using the backyard this night meant more time viewing with the scope and mirror since I wouldn't have the drive back and the unloading.

The box the mirror arrived in and was shipped to the next trial user in.

The mirror with its cover on.

The stock mirror is on the left, the Zambuto mirror is on the right.

The Scopes: Night 1

Orion XT10

Zambuto 10 inch mirror

Stock secondary mirror.

Stock focuser

9x50 RACI Finder; Telrad

Orion XX14i

Stock Primary; Enhanced Secondary

9x50 RACI Finder, Telrad, Shroud

That is my son in front of the XX14i.

Eyepieces and Equipment

27mm Panoptic, 22mm Panoptic; 14mm, 10mm, 7mm Pentax XW; 6mm TV Radian;

Filter: Orion Ultrablock on Ghost of Jupiter PN; 13% Neutral Density Filter (for the moon);

27mm TV Panoptic, 22mm Panoptic; 14mm, 10mm, 7mm Pentax XW; 6mm TV Radian;

Filter: Orion Ultrablock Filter , 13% Neutral Density Filter (for the moon);

Breakdown of Eyepiece magnification by Scope:

EP XT10 XX14i

Panoptic 27mm 61x

Panoptic 22mm 55x

Pentax XW 14mm 86x 118x

Pentax XW 10mm 120x 165x

Pentax XW 7mm 171x 236x

Radian 6mm 200x 275x

In using eyepieces we really tried to stick with these and to use magnifications that are similar. The field of view was the same with the Pentax, while 68 degrees in the Radian. For example in the Pentax XW 14mm was used in the XX14i at 118x so the Pentax XW 10mm in the XT10 gave us 120x, close enough for a comparison.

May 12th, 2011

Location: Herriman, Utah

Time: 03:00 UT on May 13th, 2011, or 09:00p.m. MDT. Session lasted until around 3:45a.m. MDT or 09:45 UT on May 13, 2011.

Seeing: Antoniadi II

NELM: est. at 5.5 at the beginning and moving to about 6.0 according to Polaris.

I used the XX14i first and used the 14mm Pentax XW. The images were sharp, clear and the seeing tonight was wonderful. It is the second day after a storm and as I previously mentioned, that usually means excellent conditions for observing in terms of seeing and transparency. Tonight, for the whole night, seeing conditions were excellent and transparency was very good. My friend and fellow observing companion, Mat Hutchings was observing this night with me. Mat has made both his own mirrors with exceptional results and has made his own ATM projects for sometime now, having learned the craft from Jeff Baldwin over in the Stockton (CA) Astronomical Society.

Before Mat arrived I had the opportunity to do some lunar observing in the XT10 using my favorite eyepiece, the 10mm Pentax XW. Copernicus was just wonderful and I enjoyed viewing Reinhold and Lansberg as well. The craters showed a terrific contrast between the light and shadows. My reaction was this is the best I have seen the moon and I thought my XX14i did a really outstanding job as did my Obsession 20 inch. In terms of contrast, this mirror was just making me goody for anticipation. I settled down as I didn't want to just buy in right away without testing and observing for the night. On my audio I did give the contrasts available on the Zambuto refurbished mirror a big wow at this moment. About this time, around 45 minutes into my lunar observing Mat showed up and it was game on. Mat asked me what I was doing. I told him to observe the moon in the XX14i giving him the craters and to pick a few items of his own, and then to compare it in the XT10. At this point I really wished I had spent more time practicing and doing lunar observing. I really need to be more consistent with this aspect of my observing. It would add another week to observing.

We both felt that the XT10 with the Zambuto mirror had jut a wonderful contrast between the shades of white, gray and black. The rays from the ejecta from the craters actually seemed to show a variation to their coloring, and it was just terrific to see the black shadows transit through a gray to a white color. The XX14i performed quite well here, actually, it was excellent if not outstanding but the edge in contrast is definitely to the XT10 with the Zambuto mirror in it. Some of this has to be given to the amount of light the 14 inch is gathering over the 10 inch.


Now that Mat was here we decided to do a star test using Regulus and a 6mm Radian. The star test shows, to quote Mat, "A phenomenal mirror with phenomenal smoothness." Mat told me while we were comparing notes on the test that the smoothness of the mirror is perhaps the best he has seen, and he crafted an eight-inch mirror that is just outstanding, and that Steve told him was one of the best he has seen. The eight would go head to head the next night.

Messier 51/ NGC 5194 & NGC 5195 (Sketched)

We next decided to let our eyes undo from the moon and waiting for about twenty minutes to begin to recover. I did a sky hop on both scopes to go and check out Messier 51 in a very moon dominated sky. Here the XX14i showed a brighter inner core area, with some fuzziness around the core with some brightening toward NGC 5195. The XX14i was also not near as dark in its background contrast, but some of that would have to be accounted for from the increased aperture and the increase amount of sky glow from being in an LP area and especially with the moon being so bright. In the XX14i NGC 5195 showed a bright inner core with a hint of fuzziness around it, and it was relatively small. My sketch here doesn't do a good job of showing that detail, and I brightened the fuzziness of M51 to try and convey what we were seeing.

Having said all this, the XT10 had a very, very dark black background that allowed the galaxy to really stick out. There is definitely a hint of structure there that Mat observed first, since he was at the XT10 while I was still viewing the XX14i which he had finished viewing through. With my turn at the XT10 and when we conferred our observations, we both felt that we could distinguish a spiral arm. Also, NGC 5195 in the XT10 was much larger and the core brighter, and the shape was easily distinguished. The XT10 here had the advantage here and that was due to the contrast. The XX14i performed quite well, outstanding again, but could not match the contrast of the XT10. The contrast allowed more details to be observed in the XT10. Again, this has to be a factor of aperture in the given conditions because the 14 is bringing in so much more light. Eyepieces used in this trial were the 14mm Pentax XW in the XX14i, and the 10mm Pentax XW in the XT10. The 10mm Pentax XW was also used in the XX14i and the 7mm Pentax in the XT10. Conditions continues to allow for around 200x to 250x without an issue.

In my sketches here, I attempted to show a darker sky with the XT10 versus the XX14i and the details that reveals. You can decide if they enhance or detract from my observation.

XX14i Sketch

XT10 Sketch

Messier 13, Globular Cluster in Hercules (No Sketch, time)

By now the constellation Hercules was well up into the eastern sky and heading up toward Dobson's Hole. The night continued to be pretty steady so we did a quick Telrad to M13, used the finder to center and then used the 14mm Pentax XW in the XX14i and the 10mm Pentax XW (best views were with the 10mm Pentax XW) and the XT10 used the 10mm Pentax XW and the 7mm Pentax XW.

The XX14i showed a wonderful view of easily defined tendrils and stars showing up through the FOV. The contrast here was terrific and for being such a moon lite night, the globular looked reasonable (not as good at a dark site on a great night). In the XT10 the background again was darker than the XX14i, but it was harder for some reason to view as many stars as in the XX14i, and the detail seen in the tendrils was not as much as in the XX14i. For this object both Mat and I felt that the XX14i got the edge. Perhaps aperture was a deciding factor here?

Epsilion Lyra: The Double Double (No Sketch)

We decided to take a look up in Lyra which had arise and was decently up in the night sky by 12:30 a.m. MDT on May 13th, 2011 or 06:30 UT. The star hope was easy using the Telrad on each scope and we used the 10mm Pentax XW on the XX14i, the 7mm Pentax XW on the XT10 and then the 6mm Radian on each scope for fun. Both scopes split the Double Double easily enough, and did so nicely. However, the XT10 with the Zambuto mirror had a nice dark edge and the black in between the doubles was cleaner. Edge to the XT10 with the Zambuto on this one because the contrast was darker. The XX14i again did an outstanding job just all the LP and the Lunar light is hampering the views I believe.

Saturn (Sketched but I'm not a good planetary sketcher at all so no post)

We now went to Saturn and took a gander at a planet. Saturn showed a wonderful view in both scopes. We used the 7mm Pentax XW on the XX14i and the 6mm Radian on the XT10. Both scopes showed the first northern band and one southern band. The Cassini division was visible as was the A and B rings. The XT10 performed wonderfully here but so did the XX14i. Perhaps fatigue was beginning to set in as we observed Saturn for over an hour to capture as much detail as possible. In the end, the overall view of the XX14i was better, but the contrast of the XT10 showed through also.

Friday, May 13, 2011

Herriman, Utah

Antoniadi IV to III (what conditions moved to)

Spring in Utah! The weather is great one day, and begins to degrade the next. Conditions tonight were not as good as Thursday night. Antoniadi IV moved to a III later in the evening. Clouds were all around when we set up (no rain clouds, just clouds). I'm tired of clouds but that is another story. Let me state up ront that Mat and I and a couple of others got some observing but my 17 year old son (see the picture) came out and spent the evening with us (he is truly deadly with a Telrad) and so did my 18 year old daughter. She spent a lot of time in the early evening/night doing lunar observing. She also made the decision that she wants to get in and do astro-photography! NO!!!!!! I'll have to convert here to visual observing . . . actually no. I'll support her in whatever she does because though not perfect, who is, she is just an incredible young woman as my son is also. It's pleasing to see them growing up and coming to the journey that is their life. Very satisfied as a parent and I just enjoy being able to be in their lives and to share the journey of life together. Sorry, I don't talk much about my family, but they do mean the world to me as do my friends.

Tonight Mat brought over two eight inch scopes that he had built, both the mirror and the dob. The F3.6 (I believe) 8 inch he just finished with his 12 year old daughter and he just finished it a few months ago and it was coated by Steve Dodds. It has an excellent to outstanding mirror in it. So we decided to include that scope with the XX14i. My regret. My friend with a Z12 and another with a Z10 couldn't show. For the first two hours we all did a lot of lunar observing and observing of Saturn because the clouds just came flying in. Clear Sky Clock stated that the clouds would go away around 11:00p.m. and they did. I will state that during this time my 17 year old son who has been observing for about 3 years now, told us that quite frankly, after viewing the Moon and Saturn that "This mirror is much better than the one I have in there normally." I asked why he felt that way and he stated "You can see far more details. . ." Leave it to younger eyes I guess.

Here are a couple of photos of what we called Dob Row that night.

Looking west south-west with several houses in the distance.

Looking south with two light shields which are not needed after 10:00p.m. when the neighborhood goes pretty well dark. You can see the clouds we fought for the first part of this session.

Mat's two ATM 8 inch scopes.

Gamma Virginis (Sketched)

After the clouds cleared out, Mat suggested that we try to split Porrima or Gamma Virginis. This is a tight split of around 1.7 seconds I believe right now and a good test of the scopes. We used the 6mm Radian in the XT10 and the 7mm Pentax in the XX14i. Both scopes split the pair, but the XT10 again had the finer split and showed more of both a black area between the stars and a gap in the split. This to me was due to contrast yet again and the light impacting the 14. We next compared the XT10 to the 8 inch portaball that Mat had made recently. Again the Zambuto mirror in the XT10 won, but not by much. The 8 inch gave the 10 inch a good run for its money.

NGC 3242 The Ghost of Jupiter

I wanted to observe a planetary nebula, one of my favorite objects to view and I knew that The Ghost of Jupiter was still up, and bright enough to view. So both the XX14i and the XT10 and the 8 inch star hopped over to The Ghost, which was relatively easy. Without a filter in all three scopes, the planetary stood out, even in the poor conditions. Conditions would hurt detail though I believe. The XT10 showed a better contrast but the color was better in the XX14i without the filter in. With the filter, both did fine and all it really did in this situation was increase the size of the object. Overall the 14 did a better job on this one. I did not pull out my OIII filter at this time. We observed a little more and did so for the enjoyment and I let others have a go with the scopes now that the weather cleared. I spent some time observing and interacting with my kids/teens, observing and going through the sky with them. The mirror in the XT10 was just outstanding, but man, I tell you, spending time with my kids, with the sky, is just magical. I truly hope it is something we enjoy together til the end of my days because it is what I call, a magical moment. Actually the last two days had been magical in may ways and a terrific learning experience.


So what is my conclusion after spending two nights with my XT10 with a Zambuto mirror? That as I stated it was a wonderful experience, an outstanding learning experience, just wonderful. The biggest takeaway for me is the amount of contrast in the mirror. That contrast allows an experience observer to see more detail and thus gleam more from their experience. No one will go wrong buying that mirror or one like it, or any Zambuto mirror. Regrets? Yep, that I would have loved to have it for a dark sky trip to Notch Peak (one of the darkest areas in the continental U.S.A.) for a two night observing trip, with no moon and excellent conditions.

To be honest, if you buy the mirror its not that it is a huge WOW factor, but it is a major subtle factor. Also, don't expect to perhaps glean details unless your experience observer. It takes time to achieve this and one thing I've learned in this hobby is to be able to really gleam details it takes experience and that means time. When you purchase a mirror like this your buying into your future as an observer and committing to it. An experience eye will see a just a tad more detail with the Zambuto mirror than with their stock primary and the contrast is what helps you to do that. What else? It confirmed to me as Mat and a couple others have that I have an excellent mirror in the XX14i, and I could be very happy observing with it. I will state that as soon as I can get the money together, if Carl is willing, I want a Carl Zambuto in my 14. My brother in law wants to buy me out of the 20" Obsession and I now have a reason to let him buy me out, and I enjoy my 20" views in an observatory in southern Utah! My XT10 mirror is just average, there is no doubt about that. It is a good scope and I'll keep it but it also at some point will have a Zambuto mirror put in there. Not all at once Carl, the 14 is my preferred scope so that is the priority! I also know to give this some time as the wow reaction to the mirror is such that I have to make sure I am thinking through everything here.

Whether it is worth it to buy a mirror like this will be up to each observer and owner of a scope. For me, I will upgrade as soon as I can bring the money together and there is an urgency for me to do so because I have seen the difference. It is subtle but it exists. The 10 inch wasn't that much better than my current 14, but enough that for me, I believe that I want the upgrade. However, it is for everyone? Much like Jason D. at CloudyNights, I am not sure if it is for every user right away. I will not regret spending the money. Conditions will always play a role in viewing and it is up to each observer to determine if the upgrade is the correct thing for them. I could be happy staying with my stock 14 primary, yet on those nights when the seeing and transparency are excellent, a difference would be seen. I guess I'll pay for that opportunity as soon as I can. If fiances warranted that I had to keep the 14 as is, I could do that or I could look to reconfigure but as Mat told me, your mirror is "well configured, both tests and visually we've seen that." An outstanding done 14 will increase the performance but only you can decide if a mirror that is almost equal to the cost of the scope is worth it. Guess I'll strive to get that money together and to upgrade, not because the scope is terrible or I have a terrible mirror, but because I want that opportunity. So if you doubt, get on the list over at CloudyNights by PMing CityKid/Phil and take a test drive. Beware though, it may just wet your appetite for more. The link is at the top of the post.

Thanks to Carl Zambuto and to Phil and others who allowed me to sneak in front of them. It is an incredible opportunity, what in business we once called "The Opportunity of a Lifetime" for some and I encourage you to take advantage of it. Please feel to ask questions or to contact Carl at his website located here. Simply go to contacts or go to Carl's Yahoo group to ask more questions or to CloudyNights.I am in no way employed by Carl or receiving any incentive for the report that I have written. Tests were done willingly and to the best of our ability. I am sure Mat and others would alter some of what I have written based on their experience and views.