Calling all Explore Scientific Ultra Light Dobsonian users

[niallk]

I need to use my shroud on my scope while I store it (fully assembled pointed to zenith) in a spare bedroom. This is because a couple of days after I bought it, I found my 2 yr old had climbed up and in, and was dancing on the mirror box lid inside the scope holding onto the trusses.

After I'd recovered from my heart attack and checked everything was fine, I put on the shroud - problem solved... for now. Probably not a common reason for advocating the use of a shroud

I do live in quiet fear though ... He is very resourceful, and destructive ...

Stunning collection of scopes Quaoar!

[John]

When I had a truss tube dob (Meade Lightbridge 12") I found a light shroud essential for my viewing site where I have some issues with stray light from my house and our neghbours.

Without the shroud the contrast on deep sky objects was poor but the shroud made a huge difference to the usefulness of the scope. I felt it also helped keep my body heat out of the light path and reduced the chances of stray debris getting on to the mirror.

Unless you observe from a really dark site I reckon a light shroud is an essential accessory for these open tubed scopes.

[niallk]

I've experimented with putting my warm hand in front of my scope, while defocussing ... Quite an eye-opener to see the impact of the warm air currents! As John says - body heat/contrast-stray light/and a little bit of safety protection for something falling on the mirror in use.

I do pull up the shroud during cool down, and have had a drip of dew fall on the mirror when taking down - but now I do it more carefully with the scope tipped horizontal without issue.

[Mrbloke]

Well, the new scope arrived on Friday and I thought I'd do an unboxing post to see if anything had changed since earth titan (Tom)'s early production piece of last year. I was at work so the missus was taking the delivery.  Having briefed her on the importance of checking for damage before signing anything, I was more than a bit concerned when I came home to find this.  Grrr

Carefully opening the box, I was happy to see that it looked ok at this point.  The scope is double-boxed so would help to protect it a little bit more in transit.

Instructions put to one side and trusses removed, you are left with two further boxes, the altitude bearings and the light shield neatly packed.

The smaller box contains the mirror box, and here is where the first issue was found.  The catch on the left had pulled so didn't clip as neatly as it should.  Very minor and something a pair of pliers can fix with not much effort. 

Inside the mirror box was unexpected treasure.  A battery pack (Woohoo!) Haven't a clue where it is supposed to go, its not in the instructions at all.

A set of thumb-driven knurled knobs 

I'll work out what this is for later... 

Red-dot finder 

I don't think I'll be getting rid of my Telrad anytime soon!

The mirror is covered with special paper and topped with a circular thin piece of ply. 

Arrggggh my eyes.....

The larger box contains the secondary cage and rocker box.  The focuser is lovely compared to what I have been used to with the Astromaster.  Very smooth with minimal slop.

The rocker box is ok, its actually surprisingly light as it is hollow.   I can hear little bits of metal running around inside it if I shake it.  Probably cut offs from the manufacturing process or rivet ends or something, but there is no way out so they are trapped in there for good. 

Now....where were those instructions?    You have a choice of 2 altitude bearing positions (upper or lower) based on if you are using heavy eyepieces/coma correctors etc.  I went for the heavy option, and the balance works fine for both my 1.25" and 2" eyepieces.

Boxes in boxes.

Here is where the instructions could do with being clearer.  There are 4 knurled knobs on the inside of the mirror box.  I originally thought that this was poor design as you could drop them onto the primary when you remove them.  I was -oh- so careful, gently cupping each one as I slowly disconnected them in turn and removed the washer and the corner wedge.  I then discovered that the trusses have a notch cut in them, so the knobs only needed to be loosened a little bit for you to slide them in.  Good design after all.  Minor swearing as I carefully put them all back on again.

The secondary is fun to put on by yourself the first time, poles all over the place!

This was where I found problem number 2.  I could only get one of the knurled knobs in for holding the mirror box lid in place.  The hole in the lid doesn't quite line up to the altitude bearing.  No matter, it is well secured on the other side with the other one and doesn't go anywhere.

Add on the light shield and you are done!

Finally, a shot complete with idiot for scale.  I'm 6'3" so a chair is a must for observing in this scope.

Am I pleased with my purchase? Yes, very.  The truss design is very secure, it dampens really quickly, the focuser is good, its footprint is actually smaller than my other newt on a eq mount, its light(ish)/portable, only minor tweaks required.  Everything moves smoothly/freely and I have been checking for any other issues top to bottom.  Awesome scope for the money.  First light report coming this way soon!

I also treated myself to a Maxvision 82° 24mm  EP.  Strangely, I didn't have any beans so you will have to make do with spaghetti!  My much loved BST starguiders have taken a back seat to this behemoth.

[John]

Thanks for posting the pictures George. They look nice scopes when they are assembled. I think some of the issues you found are similar to what others have experienced although you have not encountered as many.

I can't see a centre spot on the primary mirror - is there one ?. Actually I wonder if thats what is in the packet you are holding below the phto of the red dot finder ?. Perhaps you have to put it on yourself ?

You may well find that you need to rotate the focuser position so that it does not stick straight out of the side of the tube. I've found a sort of 45 degree angle works best and thats where most dobs have theirs. Don't know why ES put it in the position it's in

Hope you enjoy using it

[Mrbloke]

I think you're right John, I was surprised there was no centre spot on the mirror. I had assumed that the reticule was for the red dot finder screen, but now that I think about it, that wouldn't work when you align the dot to the scope (unless you never ever move it again!). I'm sure I saw a downloadable centre spot alignment sheet somewhere, I'll have a look for it later.

It was part of my plan to move the focuser at some point, although I have had a couple of sessions over the weekend and found that it wasn't as bad as I thought. Getting down low enough for M31 was a bit of a lean on a regular chair!

Job number 1 is to make a light shroud. I have 2 street lights that ruin my view. It's so bright I don't need a torch to read my Telrad maps at night. I now have the Stellerium app on my phone and am using that more now. M40 is oddly missing on the app - not an interesting target anyway!

[niallk]

Congrats! Looks the biz - nice unboxing report with lots of pics

[John]

I wonder where ES stand on warranty if you accidently mark the mirror when putting the centre spot On ?

 

Collimation is going to be a lot, lot easier with a centre spot in place !.

 

It's not a particularly difficult task but obviously there is some delicacy involved. Not that the manufacturers always get it right

 

I believe one of our members, russ.will. did move the focuser position when he had an ES 12" dob. I expect there is a thread somewhere on the forum on how he did it.

[sdkfz181]

The short tube is an extension which goes between the end of the draw tube and the 2" eyepiece holder. I needed to use it to achieve focus with 2" eyepieces.

[Mrbloke]

I went away camping this weekend, so it was the first scope disassembly.  I didn't notice these before, but it looks like there are some pre-drilled holes so you can move the focuser from the 90° position without making any mods.  The truss connectors have a nut back of these phillips head bolts so you should be able to tweak it with ease to your preference.  The angle of tilt is only about 70° rather than the more traditional 45°, but having a look at the offset spider vane design, it would interfere with the supports if they had predrilled at 45°.  I guess you could go crazy and put the focuser on the correct side and have it at 20° also? 

Maybe ES had read some of their feedback and implemented it as an improvement.

[tarotrocola]

Nice report Mrbloke.

Have you tried to place the focuser at 70º degrees? Another possibility is to place the focuser at 180º degrees, especially if you want to observe objects near the horizon. Not that I've tried that, though.