Keiths next scope modding plans

As some of you may remember, I modded my Orion XT12i 12inch Intelliscope Dob to the max and it was almost as much fun as the actual observing and it also kept me sane during the months of cloud. When I say it was fun, I mean it was very stimulating doing the research, formulating ideas on how to approach certain problems, implementing the ideas etc Its funny that I was never a modder or customiser with any other hobby or interest, ie no interest in modding cars etc. Didn't think I was that type. It looks like I am a bit of a 'Gearhead' astronomer though, ie as much interested in the mechanics and technology as the science and observing.

Well, as I finally got to go to some more SDAS observing sessions I came to the realisation that I picked the wrong scope for the car. (The car came first) Its not that the Solid OTA is too big for any car, its not. A Golf sized hatchback can transport everything, no problem, its just that my particular car presents significant problems with its low sloping roofline. I've borrowed the brothers A3 once or twice to bring the scope to observing sessions but this is not a permanent solution as he is moving home further away, as am I (opposite directions!). Even if I wanted to sell my current car for something more practical, it is not financially feasible at the moment because due to the recent VRT changes the secondhand value of my car has been pushed down a few grand as a result and at the point I am at with the repayments, I would be in 'Negative Equity' with my car!! as funny as that sounds. Also with the current economic crisis, I can't imagine people are prepared to invest in my type of car at the moment. I'd loose even more at resale.

So the car stays, and my current scope goes. I need a truss/strut type scope that breaks down further than my current scope and can be packed more efficiently into my current car. But while I am at it, I can jump to a 16in in apeture. Premium Dobs are out as I don't have that kind of money. ATM is out as I do not have the skills. 16in Chinese Dobs are in!!

Now before I get the new scope, I have a few final mods to do on the XT12i. I have almost got the azimuth motions perfect with my ebonystar mod but my magic slider pads didn't really work out. I am going to do the kriege calculations to find out the optimal pad surface area and replace the magic sliders with the appropriate size Virgin Teflon. Azimuth motion should then be as good as it can be on this scope. The other mod will be dual purpose. Going to use some 1in ply or WP sealed MDF to re-inforce the side forks to finally eliminate base flexure and this will also enable me to use virgin teflon pads for the altitude motions in combination with strips of ebonystar glued around the plastic Orion alt bearings. After that, it will just be a case of touching up a few marks on the base from dings and defunct mods. Then the scope will be ready for sale along with the Equatorial platform. The buyer can then be assured that the one or two inherent flaws in this Orion design have been eliminated and the scope operates as good as it can be and they can then enjoy all the other great features of this scope and platform combo without being bugged by a little too much stiction in the movements and some base flexure. They'll benefit from the full tube flocking I did. The dew/light shroud, The telrad I fit to the scope. The Rear baffled, vibration isolated, boundary layer air removing, mirror cooling twin fan with dual on/off switches for rapid cooling and then ambient temp tracking The big Orion OTA transport bag, the great Intelliscope DSC object locator, the tracking with the Equatorial platform. I'll even transfer the Dual speed crayford focusser from my new scope to the XT12i, (Wont need it as I will be moving my moonlite to the new scope) I'd probably be able to deliver the scope within a hundred mile radius of Bray, and demo the scope features, offer some tips on use and provide email tech support (Not that it would be needed). What more could the prospectve buyer of this 9 month old scope with great mirror ask for!!:laugh: ....and all for a few hundred less than the cost of a new barebones XT12i!!!

But of course this thread isn't a sales pitch :blush: :laugh:

This thread is about the new scope modding journey I am about to embark on in a few months. This is going to be a poormans Obsessionator!!

Has to be a 16in chinese Dob.
Has to be a scope that has a unique feature that will make certain mods easier but that is also the easiest to mod with the best features of other competing chinese dobs.

My scope of Choice??

The GSO 400TDI Strut from Telescope service!

Lets start at the bottom and work our way up.

+ No. 1 The base pieces shape, lend themselves to the addition of reinforcement to reduce flexure without adversely affecting aesthetics and the ability in combination with the re-inforcement to enable the tops of the side pieces that the alt trunnions slot into, to be hinged and thus fold downable. This Large base will then be able to fit under the roofline of my car.

+ No. 2 The Azimuth Lazy Susan bearing and innovative Altitude Trunions while providing smooth motions in and off themselves also with a little bit of modding of themselves and the DSC allow me to use the €50 Orion Intelliscope DSC designed for GEM's on this Dob.

+ No. 3 The same bearing systems also lend themselves to use with the Dob Driver II system from Tech2000. ie the minimal friction of these bearings is perfect for the Dob driver, so I don't have to use the rollers provided with the DDII. This is an advantage in that with the DDII not in use, the motions are the exact same as the basic scope, whereas if I had to replace the teflon pads of other scopes with the DDII rollers, my motions with the DDII off would be worse than the basic scope. I will of course need to fit a disc for the Alt pulley belt of the DDII

Why the Dob Driver II over the StellarCat and why both over the Equatorial platform I already own?? Platform is out due to car space constraints already discussed earlier and also because while the EP height of my current 1500mm FL scope on the platform is well within reach, the EP of an 1800mm FL 16in on the platform would require a step stool.

And why DDII over Stellarcat? €€€. Remember this is a poormans Obsessionator!! :laugh: But also, for GOTO operation the Stellarcat also requires a €400 Skycommander DSC or a €700 Argo Navis even for Laptop Operation. Instead I make a compromise with the DOb Driver II which provides no DSC integration but does offer stand alone Goto without encoders. How does this work in practice? For manual 'Push-to' tracking operation it works like this. I use my €50 Orion Intelliscope DSC to select a target. I slew to the target following the directions of the Intelliscope either by disengaging the clutches on the DDII and pushing the scope manually or I engage the clutches and use the slew buttons on the DDII controller. While Clutch engagement/dis-engagement requires a new star align for the DDII my Intelliscope DSC will not lose alignment. Once on the target, after manually holding the target in the FOV for about 30 seconds, the DDII takes over sidereal tracking. (Or any tracking Vector actually!! ISS/Sat/Comets here I come! :laugh: )

But how about full auto Goto? Well with the stellarcat one can use goto straight from the Sky Commander or Argo Navis DSC. This is not possible with the Intelliscope DSC which cannot integrate with the DDII, but then again my intelliscope DSC was €50 not 400-700!! Also with the Stellarcat, one even needs these expensive DSC's for Laptop Planetarium program GOTO/tracking.
With DDII it would work like this. DDII can do very accurate Goto and tracking using their Propreitry Roboscope Software. Unfortunately this application cannot communicate with planetarium software. Heres how it will work for me though. As some may have read in a previous post, I found the Intelliscope integration with Starry Night Pro+ planetarium software worked in principle but it was not accurate enough to get targets in the FOV. I prefered to just use the bare intelliscope system. It comes back into its own now though. It is accurate enough to get within a few degrees of a target on screen. The telescope controlled crosshair on screen is close to the targets on screen and the planetarium view does pan with the scope. The roboscope software would run in the background and I would just have to type in the NGC number into its little window and then watch the scope slew to this target by itself and the intelliscope tells the planetarium software to move the crosshairs and pan the view. The only difference is, instead of clicking on a target on screen and stellarcat slewing to it and the crosshairs and view panning in SNP, I type in the target NGC number and then watch the aforementioned happen. Not much of an inconvenience when one is saving a thousand or two!!!

What other mods??

Well, as mentioned this GSO lends itself in many ways to the mods above. Its even black!! and requires no painting :laugh: But the one downside is that it uses struts instead of a 6 pole truss like the LightBridge. Unfortunately GSO manufacture Meade LB's and its part of the contract that they didn't bring out a competing 6 pole truss themselves. While the GSO struts do a remarkable job there is reportably still some flexure. I have come up with a plan of using eyebolts at the top of the struts and eyebolts on the Lower OTA end ring spaced between the struts, with Swagged metal cable that quickly at setup can be run through the eyebolts and then tensioned with a turnbuckle. Instant string truss scope with flexure of struts eliminated!!

I am also going to fit a large 120mm PC fan for mirror cooling. The distance between the metal tube and edge of mirror on my XT12i was small enough that the air coming up around the sides of the mirror from the baffled fan created vortices that pulled the boundary layer air off the surface of my XT12i mirror. With this new scope the gap is larger and I don't think the same would work here. Instead I will mount PC PCI fans on the sides of the mirror tub which will blow through slits I will cut in the tube. Well one will blow across the mirror and the other will pull the air out the other side. All fans wire up to a PC fan on/off/speed Controller mounted on the side of the base.

Dew heaters will be a requirment too and those and the fans and the Dob Driver motors would all run off one of those Celestron Lamp/Battery thingies so many of you guys already have. Don't want the slewing scope pulling that around though do I?? So I want to make a powered ground board!!

Can I run this by you? Sheet metal Lazy Susan bearing is fitted to the scope. ie, the roller bearing is sandwiched between two metal sheets one attached to the groundboard and one attached to the underside of the top base board. Could I wire these sheets up to 12v. ie electricity conducted from sheet via roller bearings ensuring constant contact into the top sheet and then through the base up to the gear. How does that sound. Feasible??

[img=http://img519.imageshack.us/img519/1398/lazysusanmc3.th.jpg] [img=http://img519.imageshack.us/images/thpix.gif]

I would glue the metal sheets in position and then with a dremel, create a split in the sheets. If the roller bearing spokes are plastic then great, the inner and outr roller bearings are insulated from each other already. If the spokes are conducting metal then maybe I could sever the spokes and rejoin with glued non conducting plastic gussets. Now I would have isolated in and out DC (don't know the electrical terminology) transmitted through the groundboard to the rotating dob base.

Lots more little mods planned of course! :laugh:




Do I get a prize for the longest IrishAstronomy forums post in history

I'm even getting anal enough to be already thinking about cable management. I have an idea about where I might mount permanently RCA/Phono adapters so that I could quickly attach the bundle of power leads for the dew strips. Those would run down a strut and into the top of the LOTA mirror tub. The fan power leads would run up along the inside of the mirror tub. Both sets of leads could run through one of the hollow Alt trunnions and from there to their respective connectors mounted on the side of the base.

ie. Now I have easily attachable/detachable cable runs that don't hang all over the place because this way I don't need to leave any slack in the cables to account for up and down MOvements in altitude.

I know, I know!! I am mental!! But the advance planning helps me with the astro boredom due to the weather, it helps to write all this down somewhere, so I don't forget anything when it comes to actually purchasing the scope and bits and pieces. And it basically keeps me out of trouble!! :laugh: :laugh:

BTW, None of this is because of Lunartics "I hate Calibos" thread. I am not being competitive with Paul, I swear to God!! Search my posts, I started to talk about this weeks ago. :laugh:

Think about it.

15" Obsession $4695
Stellarcat & Argo Navis $2995
Euro Conversion -> $7690 = €5697 Shipping Customs/Vat +25% = €7121

€7121!!

Versus

16 GSO 400 TDI €2100(with TS discount)
My modded Intelliscope DSC €80(€50 + I paid 20 Shipping and a dew shield for American friend as a thank You for ordering this from Orion USA on my behalf and forwarding it to me)
Dob Driver II €700 (including Euro conversion Customs/tax and shipping)

€2880!!!

I'll have arguably 90% of the Optical performance and even 90% of the Goto performance for about €4200 less!! What I will have is the Knight Rider of 16" scopes with cool black paint job and even flashing lights (Red LED's of course :laugh: ) What I won't have is a piece of beautiful woodstained furniture that could happily live in a livingroom. But thats what happens when you save €4200!!! :laugh:

So the question is. Do I name the new scope

The Knight Rider !

Dya know what. I'm gonna get that stenciled on the base!! :laugh:

Obsessionator....Meet....The Knight Rider!!

BTW, here is a pic of the same scope with a shroud. Mine will look cooler with all my mods and flashing lights obviously :laugh:

[img=http://img370.imageshack.us/img370/2373/knightriderkr8.th.jpg] [img=http://img370.imageshack.us/images/thpix.gif]

PS. The Dob Driver II also has an autoguiding port!! Purchase I nice Stellavue F60 Finder scope and a cheap autoguider camera and wahey!! All connected to my Black Dell laptop mounted on my lovely black articulated laptop stand mounted on the back of the base. Black is the new Black when it comes to scope!! :laugh:

You only want a 16" scope because I said it first.

Thats a pretty good plan there Keith.
One thing about your pricing plan is that you seem to be pricing alot of the equipment new.
I got the 20" from england on the ukastrobuyandsell website at literally a fraction of the price I would have got it in new from the US. These big scopes are hard to sell and sellers will often be happy to negotiate. The electronics I'd buy new as I'm not one for buying other peoples problems.

From your description, I think you are saying you need a laptop for goto operations, personally I'm not a fan of using laptops for this, they're fragile, not weather hardened and can affect your dark adaption, a few years black I destroyed one with the cold, not at my expense thankfully. I doubt that this will be your final scope, why not get the argo and servocat, bite the bullet and go for it, its easily transplantable to any newer scope you might get in the future. Garry Myers of servocat gave me a very generous discount as I got the entire system in one go.

Maplin sell the knightrider left/right red led lights, that would be cool on the front of your scope, "pimp my scope" so to speak. : cheer:
I'm currently looking for a 3 inch terminator figurene and will stick 2 tiny red leds in for its eyes and bolt the thing to the top of the scope, yea, you're not the only one who's alittle mad. :laugh:

Keith...an interesting plan,and I wish I'd half that time to work on my Dob!
One point,though. Have you had a go at getting a 16" Dob into your Golf yet?
I have a 16" Lightbridge and the mere thought of getting it into a Golf made me gulp.
I have a Mondeo with huge boot space, and it's just do-able with the seats down.
Firstly, even carrying the base/mirror section will take two people.
I'm a relatively big guy and I've put my back out twice trying it alone. It's the leaning whilst placing it in the boot that does it.
It's too big to go in via the doors.
In addition, placing it in the cradle whilst transporting it in the car makes it easier on the scope. Otherwise its hard to stop movement of the scope in any other storage position due to the weight, and no matter how careful you are it will get bumped and dinged!
I look back fondly on the 12" Lightbridge I used to have. It was ideal for transport and for carrying, and the upgrade wasn't great enough to make the resulting problems worthwhile.
So, what I'd say is to try to fit a 16" in first, or measure up well in all planes, before purchase. A 16" Dob is about 22" in diameter, and the base cradle will be even wider.
Good luck with the mods, you seem to have the knack for it!

Have you a tow hitch and the space to stow a trailer?
Even a modest one of the dog transporter kind
might suit your needs.
That's what I'd have!