Scope Turbo-Charge: The Mary Rose Reborn!

[Rodstar]

I am a very satisfied man.

The Mary Rose has returned from Santa’s Dobsonian Makeover (SDM) workshop with some fantastic upgrades. In fact, it looks and feels like a new scope!

Santa (Peter Read) has fitted the Mary Rose with new Delrin split blocks, an 80mm Stellarvue finderscope (scope is fully balanced), a new Moonlite filter slide with built in dew strap, a Feathertouch focuser, higher quality finer collimation screws for the primary mirror cell, and a new quieter lower amp fan at the base of the primary mirror with spider web/alien themed grill. He has also replaced the Kydex in the secondary cage to stained Plywood. He has also tidied up some wear and tear, and improved the wiring. What’s more, the Mary Rose now has gold lettering to mark her out on the observing field!

For more info and pictures, read on.....

[Rodstar]

A problem that truss dobsonians the world over that use a wooden split block system to house the truss poles is that the blocks can be very sensitive to environmental changes. In particular, in warmer weather, wooden blocks can expand, meaning that the insertion hole for the poles becomes tighter. In extended warmer weather, it can become a very tight fit to squeeze the poles in. Another problem some have is that the blocks actually split (this has not happened with SDM’s blocks because of their hardy construction).

On a recent week long stay in Coonabarabran, I experienced a major problem with block expansion, and spent a number of hours battling to ease one of the truss poles in so that I could observe.

Peter’s fix, which is now to become standard on all SDM scopes, is to use split blocks made of Delrin. Delrin is an industrial plastic which is entirely unchanged by heat and cold (Peter even tried using a blow torch on it, and it was completely unaffected).

The Delrin blocks are a dream to use in practice, the poles sliding in with an almost lubricated feel. Although the black of the delrin material markedly differs from the appearance and finish of the marine ply of the Mary Rose, the new split blocks have an industrial beauty that does not detract at all from the overall appearance of the scope. More importantly, I now have spilt blocks that will last a lifetime without warm weather bloat!

Peter kindly re-machined the poles so they look shiney and new, and more importantly, so that they fit into the delrin blocks perfectly.

[Rodstar]

As I become a more experienced observer, I want to go more and more off the beaten track. While the Argo Navis computer has a wonderful list of user-objects and can be uploaded with user lists of yet further objects, I rather enjoy opening a page of Uranometria, and searching out objects like unidentified double stars, or little known galaxies. For this sort of work, I am heavily reliant upon a finderscope for star hopping and field orientation. I decided it was time to get a bigger and better finder than the 50mm GSO finder I have previously been using.

I have also been wanting to have greater opportunity to view some of the large scale objects which simply cannot be seen through the narrow gaze of a large dobsonian telescope. Enter the 80mm finder, which with the SV supplied 23mm crosshair EP offers a 4 degree FOV at 13x. The crosshair EP has a detachable red light illuminator.

The finder comes with a helical focuser and can fit any 1.25 inch eyepieces. At f/3.5 the SV will perform best at the edges with a better corrected wide field ocular, such as a Nagler. I am planning to purchase a 13T6 at some stage, which will give me a 3.5 degree FOV at 23x.

The SV80 finder also has a straight through function, which takes 2 inch eyepieces. I am yet to work out how this operates, the but the thought of being able to look at rich Carina starfields through a 31 Nagler in the SV80 has me salivating!

Peter has balanced the scope beautifully to allow for the weight of the SV finder. It required about 4kg of extra weight in the mirror box!
The finder has a lovely black matte finish which I think complements the black of the delrin blocks rather nicely.

[Rodstar]

When I first took delivery of the Mary Rose in March 2007, it had a Moonlite filter slide. I have found this device to be immensely useful (the alternative of changing filters manually on individual eyepieces through the evening can be a real chore). The slide has space for three 2 inch filters to be fitted at once, as well as having an open position (filterless).

The only problem I have encountered with the filter slide in the past is the tendency for it to dew up on particularly wet nights. Placed near the top of the secondary cage, the filters are unfortunately rather more exposed to the elements.

The filter slide now has heating for those wet nights. No more dewy filters. Ah, that is better!:P

[Rodstar]

I originally had a Moonlite focuser (tri focuser style) to marry the Moonlite filter slide. The Moonlite focuser has slowly become less buttery smooth than it was at the beginning.

The Moonlite focuser has bearings running directly on the anodized draw tube and over time the draw tube inevitably ends up with tram tracks dug into the tube. As a consequence, the focuser had developed a tendency to clunk slightly out of focus for some observers if the focus point coincided with a point where the scoring on the draw tube was at its worst. I could probably have replaced the draw tube, but I thought I might take the opportunity to try the Feathertouch focuser instead!

The Feathertouch draw tube rides on stainless steel rails and so I have my fingers crossed that it will be more long-lasting solution. Its feel is truly beautiful and smooth. It doesn’t get any better than this!

Peter has developed a way to couple the Moonlite filter slide with the Feathertouch focuser (there is apparently no solution otherwise commercially available to create this combination). So I can have my Christmas cake, and eat it!:D

[Rodstar]

Since Kriege first built his prototype truss dobsonian at the start of the 1980s, a black plastic material called Kydex has generally been used around the world to line the secondary cage. Obviously this is a light weight and very flexible material, and being black, it is the right colour for the internal lining of a telescope. However, most truss dob users find over time that the Kydex is prone to warping, particularly as it can be exposed to high temperatures at star parties in warmer climes.

The Kydex on the Mary Rose was in reasonable condition after two and a half years, but Peter took it upon himself to overhaul it to a new plywood construction. The end result is superb – it looks almost identical to the Kydex, and will not warp. I am hoping that it will be far more durable.

(see pictures for filter slide!)

[Rodstar]

Bearing in mind all of the heaters etc drawing power on the Mary Rose, Peter has installed a lower amp cooling fan behind the primary mirror. It is whisper quiet to boot!

It also has a groovy golden web design grate with an alien face. Pretty neat, huh?

[Rodstar]

The collimation screws the Mary Rose had a large thread and did not allow well for precision collimation Peter has fitted collimation screws that allow for very fine collimation movements.

I understand that Peter Read has also developed a remote collimation system…..maybe I can afford this next time!

[Rodstar]

SDM has attended to some other fixes for me while in the workshop. It is hard to contain the irrepressible Peter Read from his perfectionist ways…No doubt I will never notice some of the improvements, but here are the ones I have noticed so far:

* changed the primary mirror sling from a black polyester strap to a more convenient stainless steal wire.

*I had broken the heater for the Telrad, so this has been replaced.

* changed the set up of the connection points to take power up to the secondary cage. We now have banana points at both top and bottom.

*colour-coded all of the heaters so that even a technically challenged person like me can work out what goes with what.

* tidied up the scope lid, which had a misadventure coming home from the Pony Club one night, as well as putting a seal around the lid to keep unwanted dust out of the primary mirror box.

* straightened the end of one of my truss poles, and placed identification stickers on each pole so each pole is positioned correctly in the correct delrin block.

*adjusted the azimuth encoder arm so it is easier to remove if necessary

*repaired the wheelbarrow handles (which had become a bit loose), including using stainless steel cord to attach the pin to the handle

*fixed a problem with the secondary mirror heater.

* resolved a problem with some unplanned movements in the triangular base plates under the primary mirror.

* replaced the SDM logo on the secondary cage

*fixed a couple of broken cable attachment points for the Argo Navis

*regreased and improved the operation of the mirror locks (which enable the scope to be wheeled in and out of the garage fully set up).

*washed the mirror (!!!):P

[Rodstar]

SDM is currently converting SDM#8 to a folded mirror design. If Peter Read perfects this system, I am considering using a folded mirror system on the Mary Rose. It would mean being able to observe from a seated position like the old days when I had my hydraulic chair to observe with my 10” LX200.

Then of course there is Servo Cat….but one thing at a time.

I fear I have condemned the Central Coast of NSW to an entire month of snow and blizzards. Please accept my humble apologies. I WILL make it up to you on the observing field, if you want to come and have a look some time!
:scared3:

[erick]

Thank goodness that is over - now Peter can get to work on mine :D


I read with great interest Rod, since I will see some of these features on mine. The heated filter slide is going to be great!

Congratulations on the rebirth!

[Marke]

Congrats on the update its looks like a work of art !
I have an SV 80M finder you should have a threaded backing plate
with the 2" helical attached. When mine came all I had was the helical
focuser , the new backplate was missing and I had to email SV for
a replacement. So assuming you have the bits then you unscrew the
whole backplate (can be a bit tight) and screw on the new backplate
with the 2" focuser attached. No need to undo any screws just undo
the the whole back as it is.
Enjoy :thumbsup:
Mark

[iceman]

Looks great Rod, I can't wait to get some viewing time through it :P

btw I've fixed the photos :)

[gary]

Hi Rod,

Thanks for the excellent pictures and running commentary. She looks gorgeous!

I can relate to what you describe.

Andrew's 25" came back from a makeover by Peter and I looked at it briefly last
month when Andrew pulled the covers off to show me. It also included the refinements
such as the new split blocks and Peter had given the woodwork a nice new stain.
All in all the scope looked like new and was fabulous to look at.

Looking forward to seeing Mary Rose up close and personal and hopefully
we can get together for some observing very soon.

I went and saw the hull of the original Mary Rose there in Portsmouth
many Moons ago when and she was continually being misted with water to
keep her preserved. Nevertheless I think if we left Peter alone with her for
a few weeks, she would come out looking like brand new and would once again be
the pride of Henry's fleet. :thumbsup:

Best Regards

Gary

[Starkler]

Excellent stuff Rod.

I also had troubles with the wooden split blocks and had to return the scope for Peter to rebore them. Delrin blocks make sense.

A filter slide is the one thing missing on mine and something I would like to have.

[xstream]

G'day Rod,

The "Mary Rose" is looking stunning as she always does!

I can imagine the upgrades that Peter has done will be that little bit closer to having perfection in a truss tube dob. As we both know and have spoken about numerous times his work is second to none as I'm sure all other SDM owners would also attest to.

Anna and I are both looking forward to when we pickup "Edwin" with his upgrades on our return from Tassie. I'm sure Peter will also have excelled himself once again.

Looking forward to when "The Mary Rose" and "Edwin" once again scour the skies together in March.

[Satchmo]

Is that design an on-axis fold with a 33% circular flat at the top and elliptical tertiary or just a larger secondary angling the light at 135 degree rather than 90 degree to the optical axis?

Mark

[h0ughy]

LOOKS GOOD ROD - LOL SHOULD BE THE BORG - resistance to additions is futile.....

[norm]

Looks great Rob, now I have mod envy :P:shrug:!!!

The moonlite filter slide is certainly a much more convenient solution and adding dew heaters is a bonus:thumbsup:

I especially like the idea that the UTA is now plywood. I like the idea of the extra durability and the look is very appealing.

Looking forward to checking it out:).

I wonder if I leave the scope outside accidently and warp the kydex, it might be a good enough reason with the other half to get a make over too.:question:.

No Fair!
Cheers Norm

[wavelandscott]

Wow! It looked great before...and can only imagine how wonderful it is now!

Congratulations!

[Kal]

Impressive list of mods/improvements Rod, I love looking at the work Peter does on the scopes he produces, A1 stuff!

[Rodstar]

Thanks erick. I am sure your SDM is not far away. I would be interested to see how you find the filter slide once you have had the chance to use it a bit.

[Rodstar]

Marke - yes I got the 2" end piece etc, thanks for the explanation which reassures me that I do not need to unscrew anything. I will let you know how I get on.

Mike - cheers mate, we must get together to observe in January.

Gary - I saw an exhibition about the Mary Rose at the Maritime Museum in Sydney about 13 years ago, and it had a huge impact on me. Yes, I am sure Peter Read could even restore the original Mary Rose!

Geoff - I very much encourage you to get the delrin blocks at some stage. They are very very nice. I am sure Peter would do a good price for you (as he did for me).

John - I can't wait until Coona in March! I know you are getting the 80mm SV finder fitted. What else is Peter doing for Edwin?

Satchmo - I haven't a clue, but I will ask Peter and report back what he says.

hOughy - beware of Borg references....my wife refers to my family of origin as "The Borg" and their "collective consciousness". Rather chilling really.

Thanks Scott....when are you going to visit Down Under to observe with us again???!!!

Norm - you will want to do more than change to plywood when you see the Mary Rose!

Kal - thanks mate, yep I agree with you totally.

[TheDecepticon]

Wow, she sure is a beauty!! The SDM scopes are definately in a class of their own.
Ive been thinking about a Dob, but I'm just not ever going to be in that league!
Awesome bit of kit!:eyepop:

[wavelandscott]

Maybe in 2010 more likely 2011? I'm ready any time!

[Rodstar]

Decepticon....just save those pennies....one day an SDM can be yours!!

Scott....great news, looking forward to seeing you when you can make it out!

Geoff....I meant to say that I do have split handles...perhaps I did not explain it very well!!

[xstream]

Stellarvue F80M finder
R80S rings riser and shoe
Truss mounting quick release system
mounted on truss tubes
Black fitted Shroud
Black plywood UTA baffle
Convert Secondary Holder to 3 screw system
Adjust drive cable slack
Fine tune tracking and backlash as required

[stephenb]

Well done, Rod. A beaut set of mods. The plywood to replace the Kydex is a great idea. Here is my attempt 18 months ago (image below).

[astronut]

Rod,
I installed a Moonlite Filter Slide on my 12" Lightbridge.
I also made up a heater for the slide.
This a great addition, you'll wonder how you ever did without it.:thumbsup:

[Louwai]

Excelent info Rod. She's a great looking family member.

I'll be taking delivery of my very own 20" SDM in about 6wks time. Can't wait.


I must ask Peter if he's added the heating onto my filter slider. Great idea that..........

B

[Rodstar]

I look forward to seeing how the finder will work on the truss tubes....especially around the shroud. Will the shroud have a velcro slit in it???

[Rodstar]

Stephen, cheers mate. So did you end up finishing the scope? I see in your footer that you have an SDM in the pipeline....when are you expecting her arrival??

[Rodstar]

Cheers astronut. It will be good to wave good-bye to the dew!

[sally1jack]

Looks very nice mate , has given me something to ponder on .It would be great to have another side by side shoot out, i really don't mind coming second.
Merry xmas to you & your family see you in the new year.

P.S. slide is progressing well.

Phil :thumbsup:

[Rodstar]

Congratulations Bryan. You'll love it.:thumbsup:

[Rodstar]

Cheers, Phil. I will give you a call about the slide....kids are ready, willing and able.;)

[Rodstar]

satchmo - I understand you have now spoken with Peter Read about the folded mirror issue, so I will not confuse things by adding to what you have discussed.

I note the weather continues to be crap.....sorry everyone.....it is all my fault....!!!! Hopefully we will all get some clear skies next year.....looks like the rest of December is to be clouded over at least in my neck of the woods.

[Rodstar]

Well I finally had a window of about 90 minutes last night where it was not raining, and there were patches of clear sky! It takes me back to the days when I first took delivery of the Mary Rose....then I had to wait about two weeks as well for a clear night.

Anyway, notwithstanding a rising fullish moon and lights from neighbours on all three sides, I was able to do some simple observing to get a feel for the modifications. Here are some preliminary thoughts:

1. The new primary fan is so whisper quiet, I could hardly detect it...a couple of times I checked to see that it was actually on - it was.

2. The Feathertouch focuser is simply wonderful to use, buttery smooth with objects snapping into focus. All of my eyepieces came to focus without having to use an extender (with the Moonlite focuser I always had to use an extender). The only "issue" is that the focuser drawtube actually hits the filter slide when fully in (a position not relevant when observing, but one needs to be careful when packing up for the night not to tune the focuser too far into the closed position).

3. The 80mm Stellarvue finder is an absolute ripper. I started off with the 23mm SV supplied EP, which gives a nice 4 degree FOV, but then decided for some fun to put in my 9mm Nagler for comparison. Wow! I could see the four stars in the trap, and a nice green glow for the mass of nebulosity of M42. 47 Tuc was a lovely large cotton ball of stars. I could make out M77 (just). I had originally thought that I might get a 13T6 for the finder, but I am now contemplating perhaps getting an 11T6 instead for the slightly higher resolution of galaxies, so it can help with the star/galaxy hopping use I have in mind. I can always pop in the 13E for a slightly wider FOV as the Ethos has a dual 1.25/2 inch barrel.

The finder is not perfect in all respects. On Sirius there was a thin white line of light running across the FOV from left to right. There is also false colour on the brighter stars, with a blue/violet smear of light about them. I suspect a lot of this is caused by the SV diagonal which does not look to be the best. In reality, of course, my purpose with the finder is to star/galaxy hop in fainter fields, and there is no obvious false colour in such fields. As the problem may well be caused by the SV diagonal, in the long term I might consider getting a better diagonal to attach through the 2 inch rear end of the finder if I can get that arrangement to work / come to focus.

When changing eyepieces I noticed that there is a lot of lubricant on the inside off the helical focuser, but fortunately this is well below the point that either the 23mm supplied EP or the 9T6 reach to within the barrel, so it appears to be a non issue.

4. The motions of the scope are as smooth as I can ever remember. Peter has thoroughly redone all of the movements, and it is obvious from the moment I started moving the scope around.

5. I have realised there is one problem with Peter's system of colour coding the various power cords running from the dew heater.....in red light it is very difficult to distinguish the colours. I am going to redo something which John Bambury kindly did for me a few months ago, by making up some printed labels for each line.

6. The collimation knobs were beautifully smooth to operate - very happy!

All in all, the first night out was as good as I could have hoped. I can't wait to set sail with the Mary Rose under some darker skies!

[spacezebra]

Excellent report Rod.

Cheers Petra d.

[Kevnool]

That was all great reading Rod.
You would have to be all smiles after the upgrades.
Great pics as well ,its allways good to see an upgrade in motion as it gives everyone more ideas to think about.
Your clear skies hopefully will return to normal.
Cheers Kev.

[Rodstar]

Thanks Petra and Kev!

I am looking forward to the little adventure planned in March when we head up to Coonabarabran for New Moon. That should give the Mary Rose a chance to stretch its legs!

[StarGazing]

Congrats Rod with the new updated version on Mary Rose :thumbsup:. I too am turbo charging my 14" truss dob through Peter Read at SDM and cant wait for thoose improvements. Best of luck with Rod, keep us informed on it.

Cheers Alex. :)

[Rodstar]

Thanks Alex! And great news about your scope. When will your turbo charge be complete?? What is Peter doing to your scope?

[StarGazing]

G'day Rod, thanks for your response.

Peter wont get it done till March or April so I have a little while to go :(.
I am getting an Argo Navis & a Servo Cat fitted, changing the Helicron focuser to the Feathertouch :D, build a new rocker box and new power ground board with all the battery and wiring done and finaly give a new coat of paint. Not sure as of yet if I should get a dew system, what do you think ?
does it come handy ?.

Cheers Alex.

[RB]

So.....Rod.......does this mean we'll get to see Carina in a 'new light'.
Can't wait buddy, scope's looking magnificent.

:cool:

[gb_astro]

Hi Rod.
Did Peter say anything about not selling Stellarvue and other bits and pieces anymore? His online webshop has disappeared from his site.
Greg.

(Edit: Just looked at the Stellarvue site and see that they now ship direct to Australia, so that might be my answer.)

[Rodstar]

Sounds great, Alex. I thoroughly recommend you get the dew straps etc. On a dewy night, an observing session can easily be ruined by dew. It is nice to have the peace of mind to know that dew will never be an issue.

Thanks RB - talking of Carina, I had a gander at her the other night, and I reckon Eta is ready to blow!!!!

Greg - news to me if Stellarvue and SDM have parted company. Peter is so busy building scopes (his reputation keeps growing, and he is now selling overseas, even to the US), I suspect that it is better for him to focus on that part of his business rather than being distracted by a webshop for another manufacturer's products. He can always fit Stellarvue products if customers want them, whether or not he is a Stellarvue distributer.

[StarGazing]

Thanks for the advice Rod, I will definetly get dew protection......... makes good sense.

Cheers Alex.

[ausastronomer]

Hi Alex,

You definately need as a minimum a dew heater on the secondary and on your finder/telrad. I don't find it quite as necessary on the eyepiece, but it is very nice to have on the really dewey nights. For the small extra cost I agree with Rod and think the full dew package is well worthwhile.

Cheers,
John B

[StarGazing]

Cheers John, thanks for input much appreciated. Your right about the cost and in relation to everything else it makes sense. I am straight on the phone Peter to order one in.

Alex. :thumbsup:

[Deeno]

This is all very exciting Rod....
Can't wait to bludge a peek

[Rodstar]

Mate, I get to bludge the fumes from your cigars all the time, so it is only fair that I share too!

When are you back from the US (or are you back already)??