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[Chicago Astronomer - Astro Joe]

90mm Meade FinderScope for the C11 SCT Beast

The C11 Celestron SCT normally came with a straight through 9x50 finderscope. It comes with a quick release dove-tail mount and does a decent job and I use it often...

But I have the 60mm Meade Shorty-tube AZ Series refractor that I not only used for my old 4.5" reflector, but attached it to C11 with my own homemade dovetail attachment. I enjoy it's wide low-powered field and the ability to swap out 1.25" eyepieces - including reticles. I also use it in conjunction with the 9x50 and the Rigel finders and have quite successfully attached the camera to it for low powered imaging.

As astronomers tend to do, I visit Ebay every once in awhile and see what's out there at a good price. I could easily drop serious cash there, but have come across very good deals - including this....

A decent looking 90mm Meade OTA...might make a nice finderscope.

BRAND NEW! Meade 90mm F8.8 or 800MM focal length Silver color achromatic refractor tube assembly with dust caps. This has a 1.25" focuser that can be changed to a 2" focuser with the proper adapter. This is an achromatic high quality Meade coated objective lens so it gives sharp almost false color free images up to 225X. This makes a fantastic giant finder. With a 32mm eyepiece you get 24x or with a 40mm you get 20x. perfect for a giant finder, but you also get the power of a great guidescope. it can handle easily 60x per inch as do fine telescopes. It is clear to 225x so it is very capable as a guidescope too!

This tube is lightweight, under 4 lbs so you won't weigh down your scope. It is about 32" long. The best thing is the price! Buy it right now for only $34.95 and a very reasonable shipping.! You might pay that for a 50MM finder! But this is a finder/guidescope tube and 90MM! all you need to do is add a 1.25" diagonal and 1.25" eyepiece

I outbid another interested individual...and followed the last few minutes of open bidding while at a Chicago Astronomer star party via my Smartphone Ebay app....expecting a last moment bid snipe.

I won...very cool!

It's apparent that the tube is off some packaged Scope & Mount...and a bit of research came up with a Meade DS-2090AT-TC 90mm.

A close match is this...

Meade DS-2090 Refractor Telescope with 4mm Plossl upgrade.
DS-2090, with 90mm aperture, 800mm focal length with f/8.8 focal ratio, and equipped with SmartFinder, not an "official" product of meade, $299.

SPECIFICATIONS:

Clear Aperture: 90mm
Optical Design: Refractor
Focal Length: 800mm f/8.8
Resolving Power: 1.3 arc sec
Max Power: 300X

I think it just might make a decent finderscope, replacing the 60mm, (which I'll add to the C5). I have some rings layin' about that just might fit, but will need to make some sort of base to attach to the C11 OTA.

It arrived this weekend via Fedex and for $35.00...it looks decent....the Dew Shield is very deep - which is good, as the dew shield on the 60mm allowed the objective to mist up too easily. This could be a suitable Grab-and-Go scope on it's own merit, as it's very light and I could attach it to my unused Alt-Az mount that holds the 4.5" reflector. I haven't been able to test it yet, but Sunday I'll mess with it and see if it'll work as a finderscope.

More on the addition as the project develops.

[RobbW]

Pretty cool, Joe! Your C11 beast always looks very mighty with all the different accoutrement attached (e.g. finder scope, Rigel, laser, guide rails, etc.). Almost makes me think you might be compensating for something?!

[Chicago Astronomer - Astro Joe]

Snicker...

It's all about the toys.

[Chicago Astronomer - Astro Joe]

First views of the 90mm Meade Refractor Finder/Guide Scope

23 November 2010

I have had the 90mm Meade layin' around the place for over a week now, won in a Ebay auction for $35.00 - but sidelined by an event that took me away from astronomy for while. But, things are settled now and I was really anxious to test it out.

(It's cold kids...really cold with howling winds blowing hard.)

With the first clear night of recent, I crudely electrical taped the OTA to my GEM mount that the C5 rides on and secured it with a bungee cord. And off we go.

Taken with the Canon Powershot S3 - no scope

The just after Full Blue Moon was high above and a natural first target. The scope delivered a sharp clear orb, filling up about 75% of the FOV...

F.L 800 ÷ 25mm EP = 32 Magnification @ f/8.8

In comparison to the 60mm finder scope that is currently utilized...

F.L 350 ÷ 25mm EP = 14 Magnification @ f/5.8

..which fills up about 25% of the FOV.

Scanning at random, the scope brought out dimmer stars and good center FOV pinpoints...but no airy disks...Hmmm.

The 90mm will not be utilized as the primary finder scope, the field is too tight, but now perhaps pressed into service as a guide scope or just a quick grab & go scope when I don't want to lug the C11/C5.

But there were some problems...

At $35.00, I did not expect an Apochromatic refractor with edge-to-edge clarity, and it shows.

Still aimed at the Moon, the Chromatic aberration was heavy to the yellow hue gleaming off the lunar limb, with less hint of bluish on the other 180 degree limb side of the Moon. The baffling is off I would imagine.

Also, the objective lens is off a bit.

Centered, the Moon is very sharp and clear and good in the North-East-West orientations - but when slewed to the south quadrant of the FOV, the Moon becomes blurry. Re-focusing corrects this, bringing it back to clarity - but when re-centered, it is blurry again. The lens is not perpendicular to the light path of the tube.

I will have to take this apart and see what is going on and perhaps the lens is just not seated properly in it's base. But the claim from the seller:

"This is an achromatic high quality Meade coated objective lens so it gives sharp almost false color free images up to 225X."

...is so off.

Caveat emptor...

This lot of scope must have been quality control rejects and no way worth more than $40,00.

The 90mm scope is an all plastic affair. From Dew cap down to the focuser, it's all lightweight plastic....and that's cool. Being just under 4 bs, it will put less stress on the motor drives.

But...

For pocket change, I am satisfied on this lower end 90mm refractor scope and will come in handy. I might take it out in a few to see how Saturn looks in this.

But....dare I attach it to the C11 - in addition to the 60mm, 9x50mm and Rigel.

Can you say overkill?

But I just may do it, because I can...

And besides....it looks cool and impresses.

More later.

[Chicago Astronomer - Astro Joe]

Update:

I ventured out into the cold again to see how this scope would handle Saturn.

With patchy fast moving clouds and very windy conditions, it was not a fair evaluation of the scope, but it did deliver.

Centering Saturn with a 25mm, I could clearly observe the rings and the familiar yellow shade I have observed over the decades. Popping in a 17mm, the scope was holding resolution well, and it took magnification well.

But still, the planet was small in the FOV.

Used to the performance of the C11 and displaying a large disk, I wanted some more "arc". I slid in a 2x Barlow with the 17mm ( creating a 8.5mm), and got a decent Saturn. The OTA was being shaken by the winds, but from what I could catch, the views were ok and clear.

Tomorrow promises to be clear and we will take the 90mm out again for a calmer, less windy early morning test...and maybe even catch the comet hanging by Saturn, Venus and Spica.

[Chicago Astronomer - Astro Joe]

Assembling parts to attach the 90mm guide scope to the C11

Although it's cold and cloudy, astronomy planning goes on.

Thinking on how I will attach the 90mm Meade refractor guide scope to the OTA of the C11, I think I came up with a workable and economic solution.

I will need to remove the 90mm from the C11 when I pack up, but also would like a quick set-up at the start of the sessions. There are many options for this, but most assemblies are $100.00 and up.

Too much for this urban astronomer.

So I scour the internet, looking at set-ups and parts that are available. Ebay, Amazon and the mainstream telescope suppliers were perused. I even considered making some rigging up myself from odds and ends.

I almost bought 105mm tube rings for $21.00 + shipping, but with only 7.5mm's on each side of the tube within the rings....I feared there might not be enough play for adjustments. I then remembered that I just might have some rings layin' about. In my telescope supply area I found these...

Meant for mounting on to a bar and tripod mount for a primary scope, I could adapt them for guidescope work. Best of all, free and on hand...

I will need to drill adjustment screw holes and tap them. No big. And they also have a threaded hole on top to attach a camera for tracked piggyback astrophotography.

Rings: Free

Next...what to attach the rings to.

I thought about attaching a permanent bar along top of the C11 and attach the rings as necessary, but no. I wanted something that I could quickly and easily mount and detach.

Some suppliers have a 8" and a 13" long dovetail bar...

They both sell for $16.95 each (odd), + $9.00 shipping. for about $27.00 a bar could be mine. Too expensive I thought.

I found this...

It measures at 16" and cheaper, ($14.95 + $6.95 shipping). I don't know why it's cheaper, but I called and the dimensions are the same in width as the 8" & 13" bars... Taking a chance, I ordered it.

Rings: Free

Dovetail bar: $21.90

Now, with rings and bar figured out, I still need a easy way to attach the refractor assembly to the C11.

I came across these...

But everyone wanted $14.95 plus shipping. I need two of these to attach the dovetail bar and it would have cost me $38.90.

Hell...that's more than the 90mm scope cost!

I kept searching and found these little treasures on Ebay...

For two and shipping...$9.50 ;D

I will attach one dovetail base at each end of the C11 OTA, securing them to the end collars, but it means taking the C11 apart to get to the insides. That's ok, since I need to remove the Corrector plate anyway soon and clean it again...and there's a spider web inside the tube...(more on this on a later post... ) I will cut the 13" dovetail bar into segments - two 4" bits to fit into the dovetail mounts on the C11 and a 5" piece permanently attached to the 90mm on the bottom...so I can fit it snugly onto my GEM saddle mount, (where the C5 rides on now), when I just want to use the 90mm on it's own....like this...

...but without the rag and tape...

Rings: Free

Dovetail Bar: $21.90

Dovetail bases: $9.50

Grand total = $31.40

More than I expected to pay for this project, but I think I wrung out the best I could. I estimate that I start this project sometime in January on my kitchen table, as the workshop is not heated and although I have a propane heater...not all that comfortable.

Will it all fit together?

Dunno.

Stay tuned kids.

[patrickm]

Man, are you a geek!!

[Paulie pchris00]

If this weather keeps up, no need to wait until January...

[RobbW]

Meh, I called an end to my scope season a few weeks ago. More than likely, I won't be hauling out the C8 mini-beast again until the Spring thaw. However, during my recent vacation to WDW, I think I may have found my perfect Winter hobby/obsession... hydroponics! I took a behind-the-scenes tour of Disney's "The Land" ride and I am hooked! If everything works out right, I should be harvesting fresh strawberries in my basement garden in 4-6 weeks!!!

Well, not really. I would actually have to start the project before I can begin the countdown. But it was still really cool and I can't wait to try this out while my astronomy passion simmers in the background over the winter!

[Chicago Astronomer - Astro Joe]

Dovetail bases Arrive...

Wow...I'm impressed...! #wha#

I ordered these little beauties early on the 30th of November, about 4:00 am on Ebay. Today, the 2nd of December, there they were in my mailbox...all the way from Las Vegas!

1 1/2 days.

Incredible...!

They are hefty, milled from steel and a little rough. You can still smell the paint that was sprayed on a bit, but it's all cool and I think will do their job very well.

Astro geek, Joe

[Chicago Astronomer - Astro Joe]

The 90mm Guide Scope Mod

April 2011

Winning this 90mm cheapo Ebay refrector, I did not expect Apo scope performance...but it ain't too bad. It was apparent that I could improve this scope before I put it into service - as not only a guide scope for the C11, but as a stand alone instrument. But the workshop is not heated and I needed to wait until spring.

With a bit of a warm couple of days, I started to take apart the scope. I attempted to break the tube apart when I got it last November, but the components just wouldn't budge!

Using these strap wrenches, the objective lens holder just held fast and wouldn't come off. So, I left it for the winter in the workshop for later. Then...coming back to it...the damned thing came apart easily, without the straps and just brute hand force. I guess I learned it good.

Slipping off the large dew shield, brought the objective into proper light for initial inspection...

It needed attention, but looking more closely, there was something else...

There's a palm print on the lens!

Some goof assembling this scope shoved it in place with his/her bare hand, leaving an imprint. And considering that this scope is entirely made out of plastic, (not a bad thing), these must be Meade rejects and why sold so cheap.

And so we start the disassembly..

Inspecting the assembly some more, we need cleaning badly...

There are three screws holding the lens housing to the tube and comes off easy. Three globs of glue secure the lock ring to the lens holder...

I attempt to remove the glue with a utility knife, but a chisel handles it better....

With the ring removed, the glass pops out easily...

It did occur to me that maybe these lenses might be air spaced, but considering how cheap the whole thing is - doubtful...

Glued...and that's fine.

I mark which way is front temporarily...

Using the Giotto air blower and clean brush, we remove loose debris...

There seems to be a smudge of sorts on the lens....

...and the palm print most evident on the backside.

I use the same cleaning formula utilized last year when I took the C11 apart, using many cotton balls and lightly clean in a linear motion...

Works well, but that smudge isn't going anywhere. I bring in the POR cleaner, made for greasy deposits like this - and using several Q-tips, we win....

I buff with lint free cleaning pads, but there is still a hint of the palm print that I cannot remove and suspect after all this time, has eaten into coatings. It only shows up when I fog the lens with my breath and won't make a lot of difference, but still....

I also darkened the edges of the lens with a black marker to increase contrast and limit the bouncing light...

But an odd phenomenon occurred before I was 1/4 done...

The unmarked portion of the lens edge had already become dark...very cool. I complete the edge blackening and making sure a good solid coat is applied.

With some more cleaning with the solution and more buffing, my once filthy dirty lens is now back in the holder and pristine...

Satisfied, I set the lens aside and move on to the next phase.

Attaching a dovetail bar to the tube....

[Chicago Astronomer - Astro Joe]

- Part 2 -

Attaching a Dovetail bar to the 90mm OTA

The intent of getting this refractor was to use it as a guide scope for astrophotography...and really as a crowd pleaser attached to the C11 OTA...it's all about the tubes baby. But also, as a stand alone scope, to grab quickly and start observing.

But...how to attach it to a mount....

I got a 13" dovetail bar, with the primary intent to use to attach the 90mm my C5 mount w/drive. But I didn't need the whole bar, so I hacked off a section..

I centered the bar, leaving about 7" on each side and marking the holes...four to choose from, I selected the ones on the ends. The bolts I choose are 1/4"....

I could have used a hand drill, but used the press instead, adjusting for a slow cutting speed...

Marking my tube with the date, we are ready to bolt this thing on...

Using split and flat washers on the inside, I top them off with a nut - reaching deep into the tube with my hand and tighten firmly.

And there we have it.

Solid and ready for a tight fit on the C5 saddle shoe and took only about an hour.

Next....all night flocking.

[Chicago Astronomer - Astro Joe]

- Part 3 -

The Flocking

I'm a fan of tube flocking, especially for urban astronomers.

Anything to limit the external lighting from bouncing around in an instrument is good and well worth the effort involved. At a dark site location, it isn't as vital, but in cities where street lamps, car lights and the ever present light pollution glow, the flocking makes sense.

Don't let those smugly state that urban astronomy is futile and all you gonna get is the Moon and some planets. Nonsense. With proper actions, one can limit the intrusive light pollution and enjoy city skies - uncovering secrets of the cosmos - and flocking is one of them. The flocking I performed on the C11 makes a great difference in observations, kicking up the contrast nicely.

Although the interior of the tube is painted flat black as shown in the above pic, it's still pretty bright in there. And since the 90mm is already apart, might as well.

Using scraps from my C11 flocking of last year, it looks like I will have enough for this tube without having to cut into my virgin roll of material.


Taking many measurements, I get my dimensions for the first leg of the flocking...

A dry fit looks good...

Spray adhesive is the way to go here, with plenty from the last scope project...

Spraying and waiting until tacky, I ease the material inside and tamp it down using a roller and direct pressure from fingers. And already the welcomed darkness is making it's way into the tube...

And I do the other end too and we have flocking on both sides of the internal baffling...

This is good, but now looking at the focuser tube...it's much too shiny and must cut it down...

I applied the flocking material on all visible surfaces including the movable draw tube and the operator side of the inner tube housing...

Using two scrap pieces, it's quite apparent with only half applied - that the flocking will dramatically cut down on undesired bouncing light.

And now, we have pitch black surfacing...

And as always, I install a Chicago Astronomer business card...

This is great and I hope that this additional mod will make a cheapo refractor...a better one. But wait, I'm not done yet. I peek at the inside of the dew shield and the objective lens holder...and they too are a reflective plastic surface...not good. With scrap pieces still at hand, I flock them as well...

I use sticky tape to remove any fuzzies and other debris, over and over again...

Reinstalling the pieces all back together now, looking down from the dew shield to the focuser end - it's pretty dark in there now...

...as opposed to what I started out with.

But, some of the adhesive got onto the outside of the dew shield by my clumsy fingers and looked nasty. How to remove the glue? I tried some Turpentine and WD-40, but it made a splotch - even if it did remove the glue. I decided to refinish the surface with rubbing compound and finish it off with the polishing compound...

Meade put on a matte finish on all the black parts. The polishing made the surface glossy, which made a nice contrast with the matte.

So now, with a cleaned objective lens and total flocking, I was anxious to try it out. Chicago Astronomer Bill called for a brief session the day after the project was completed and I was a go...

Sky conditions were not optimal that evening, but enough to peek at the crescent Moon and Saturn...sorta. The clouds were thickening and didn't look hopeful.

The tube, now with a dovetail bar, fit smartly into the saddle mount and was rock solid. Very cool.

The performance of the 90mm refractor is good. With the added flocking and cleaning, the contrast is better than what I observed during the winter, (when I attached the telescope to the mount with bungee cords and tape!... )

I caught a brief glance at Saturn, and although small, with only a 25mm, ( I forgot my 1 1/4 eyepiece case), and a 32mm of Bill's - I observed a sharp ring system. Slewing to the Moon, which was battling clouds and near the horizon, it too was sharp, but with a slight chromatic aberration - skewed slightly to the yellow. I bet I could knock this out with an adjustment to the internal baffle for a color balance, but I'll live with this.

Before the Moon vanished behind the skyline, I took a crude handheld pic through the 90mm of a bubbling sphere...

Testig FOV sharpness, there is a drop-off near the edges, but acceptable - getting about a 80/90% sharp center focus.

It was not a true test of performance that evening, but it was good initial trial run nevertheless. More later, including a star test.

The next phase is to craft the tube rings and base configuration in order to attach the 90mm cheapo Meade refractor to the C11.

(With a 60mm wide field finder scope already on the C11, Meades riding atop a Celestron is sacrilegious... )

Perhaps during the weekend I'll work on the next phase, but I am very satisfied in this modification project.

[patrickm]

Meet the Flockers!

I do so love your projects.

Can't wait to check it out.

[Chicago Astronomer - Astro Joe]

Patrick....

It's 3am now, Saturday morning.

Perhaps I go work on the next phase now...but first some leftover pizza.

[Paulie pchris00]

I'd forgotten how much work you'd already done on this little scope.

[Chicago Astronomer - Astro Joe]

Paulie,

It ain't no Taki, but it'll do.

[Paulie pchris00]

It's not like it's your primary instrument. It will be a handy finder/guide scope, or an auxiliary scope.

[andrewgilhooley]

On the advice of Dion over at AstronomyShed, I checked out his Guide Scope Rings tutorial.

So I picked up a set on 100mm rings from ModernAstronomy, some plastic bolts with wingnuts from fleaBay, and an ST80 from Rother Valley Optics.

Here's the result ...

Now I've ordered a prism-type vixen dovetail clamp from Wolfi at TelescopeService, a pair of 14" vixen dovetail bars from First Light Optics, and a SkyWatcher SynGuider, also from First Light Optics.

I have the 8" imaging reflector - it's made by GSO, but sold as Astro-Tech in the US, and as Altair Astro in the UK.

What's left? EQ6 Pro to sit it all on and a camera to take some pictures. Camera will probably be a modified Canon DSLR.

This imaging malarkey is a mess of bits and pieces to get things all hooked up together isn't it? ;D

[andrewgilhooley]

SkyWatcher Synguider arrived today, but due to a picking-and-packing error, the supplier only shipped one of the 2 dovetail bars I ordered. The other should arrive tomorrow.

[Chicago Astronomer - Astro Joe]

Carrying bag for the 90mm

or

Everything comes in handy one day

I collect astronomical stuff from all aspects of opportunities. Gifts, castoffs, finds and buys. I have been carrying this 90mm refractor in a foldable chair bag. Worked, but so uncool.

A well known institution was cleaning house and among the many goodies I was gifted with...was this elongated blue Meade bag. I had no use for it at the time and thought perhaps I would use it for auxiliary equipment and such. But instead I just threw it in the C11 floppy carry bag, (also a gift of the clean out), and forgot about it.

While replacing a stripped visual back attached to the JMI motor focuser, I came across this bag again, empty and calling out for some usage. The same day, I done some minor solar observation and while putting things away, I noticed the bag laying to the side...and a marriage was at hand. Fit's perfectly and could have been originally paired together.

The bag is padded, velco secure straps around the tube and a handy side pocket.

Everything comes in handy...everything.

And we hang it on the pedals of a bike.

The belly of astronomy revealed....

[Chicago Astronomer - Astro Joe]

We ain't done kids...

Just a hint of the next stage.....

60mm and 90mm machined rings - crafted by a master for the Chicago Astronomer.

More soon.

I'm so excited...... #Yay#

[RobbW]

Holy crap! Personalized rings! The Chicago Astronomer IS going big time!

[patrickm]

Well, I'll be anodized. How cool is that?

8-O

[Chicago Astronomer - Astro Joe]

Attaching the 90mm Meade Finder Scope to the C11

Dovetail Bracket Problem Resolved

Earlier, whilst cleaning and modding the C11, I had attached the two dovetail brackets and gave the 90mm refractor a test run...

astronomer.proboards.com/index.cgi?board=ATM&action=display&thread=3208

The brackets seemed to hold ok to the great looking Marzec rings, but during the shake-out session for the C11, the 90mm ring bases slipped out of the cheapo brackets and fell to the ground...cracking slightly the dew shield and a dimple on the tube.

Not cool, even if is a $30.00 scope.....

Rick's crafted rings and the generic dovetail bases I got months before, just don't mate as good as they should - and slip out...

The bases of the rings tilt a bit and there isn't much of a bite from the hold down screw. I thought to drill a small set hole, so that the screw could set into and prevent the base from slipping out...

...after the drilling, the screw did in fact set nicely in the hole, but it tilts the base and there is a bit of a wobble. Not good for a guide scope.

What I need for this un-natural couple is a stop, to prevent it from slipping out. And since the stars are above, there's just one angle to deal with.

I drilled a small hole in both dovetail bases...

...and installed these two pieces of metal I had laying around.

Not a prefect fit, but it will work and is solid...

I eased the corners of the metal bits, because you know a finger or palm is going to get dragged across those corners at a star party. I should have contoured the bottoms to fit the curvature of the OTA...but whatever...

I slide a ring bases in and it's a good fit...

I painted the two little metal stops the same color as the bases while I was at it.

But, I still ain't digging the two little hold down screws. One cannot provide enough torque to lock the rings down, so I install these nice chrome wing nuts I have in my assortments of nuts, bolts and washers. (Never throw anything away...it'll all come in handy one day.)...

(Garage division... )

With these, I can bear down properly and tighten them securely.

I attach the refractor...

...and it all feels solid. No wobble, tilt or movement...and it all looks good.

Also...

I covered the dew shield with pleather material to hide the chip from the fall it took at the shake out session...and I like it. It's removable and I can change colors at a whim....like the varied materials I will wrap the C11 with.

I'm thinking about painting the refractor the same as the C11...and possibly doing a warp on it too....to keep things uniform.

There are star parties this coming weekend and let's see how this fix works. The 90mm Meade provides surprisingly decent and sharp images for being such an affordable scope and I think will serve the Chicago Astronomer well for astrophotography pursuits.

[wwpierre]

Hi Joe, I took a some test photos with my 90mm Meade refractor. You can read about it here: www.telescopejunkies.com/forums/thread-view.asp?tid=5705

[Chicago Astronomer - Astro Joe]

wwpierre,

I think that the 90mm will come in very handy for quick images - with out the hassle of a long set up and alignments.

I have yet to try it out on a longer tracking session for DSOs...but I think it will deliver the goods well.

I'm thinking about getting another one...the blue one!

[Chicago Astronomer - Astro Joe]

Replacing the Cheapo focuser on the 90mm Refractor

I'm digging this little inexpensive scope bunches.

It displays objects well and sharp, with little aberrational distortions.

But...

The weak link here in this scope...is the focuser.

There is some wobble play in the draw tube guides and the rack & pinon is all plastic. (I already have a missing tooth in the rack, making focusing with a little pause in the action.)

If I am to use use this scope for imaging and guiding, I need to swap out this focuser with something more substantial.

There wasn't much out there in terms of a better replacement, but tons of the exact same focuser. I came across a seller that had a 90mm refractor focuser - made from metal for $49.00. I wasn't prepared to spend big for a Crayford...so I look this one over...

Focuser
This rack & pinion refractor focuser allows the use of 1.25" and 2.0" eyepieces. The primary feature of this focuser is the smooth action and tight tolerances that permit the use of this focuser for visual observing as well as CCD astrophotography. The low cost is a plus when upgrading the focuser on your telescope. The base of the focuser fits to the inside diameter (ID) of a 3.785" ID optical tube to provide an integrated look.


Eyepiece Usage: 2" & 1.25" Adapter
Focuser Travel: 5.4" (137mm)
Travel per Revolution of Focuser Knob: 0.935" (24mm)
Racked-in Length Overall: 6.25" (159mm)
Racked-out Length Overall: 11.65" (295mm)
Fits Tube ID: 3.785" (96mm)
Weight: 2.0lbs. (0.91kg)

Materials: Die cast metal body (powder coated paint black), aluminum draw tube, metal rack and pinion gears, aluminum eyepiece holder (1.25" & 2.0"), plastic knobs, stainless steel hardware.

Other features:
Extra length travel.
Focuser lock holds focuser in position.
Integrated finder scope dovetail slot. Fits base of RD-ASM and RBA-ASM.

I like it and the ability of using either 1.25" or 2" Eyepieces.

Done.

Now, my cheap $35.00 refractor is costing me $80.00...!

Astronomy is not cheap.

It arrives soon and I size it up next to the OTA and original focuser...

It's got heft and is solid....but damn it.....no fit....

It's almost the same diameter as the 90mm OTA - and no matter of twisting and manipulation will set this focuser in place. What is needed, is an adapter collar of sorts.

They make a nice adapter for times like this...

It's a handsome piece of anodized metal. But at $42.00.....Uhm, no.

There has got to be something around Astro Joe's estates that I can make a mating collar out of. I search for quite awhile. Pipes of all sizes and materials...but nothing. Not even my local hardware store was of any help. Coming back home disgruntled at the thought of having to buy the collar - pushing the economical 90mm $35.00 scope now over $120.00.

Damn.

But....I grabbed a PVC coupler and it looked promising. Too small of a I.D, but...I got tools and know how to use them. I'm gonna make this work.

It's too wide as well and I grabbed a hacksaw, but I know the cut won't be straight all the way through. Removing the safety cover on the Radial arm saw, I trim me out a hunk. and sand it smooth on the belt sander...

Now, I have a nice piece to work with and the proper width..but the I.D. is still too narrow. I use a small drum sander attached to the radial arm saw to grind away the insides until I get a nice tight fit on the focuser...

PVC dust flies everywhere and probably settled in my lungs in piles, to be coughing up bits of plastic years later...

But now, I have me a coupler adapter = free...

I drill the necessary holes and good for paint...

I have been using this Rustolium Hammered paint extensively throughout this spring ATM/rehab season..and it looks especially good here...

I want to swap out the straight head screws with others, but for now, it's cool. It all holds solidly together as I mount the 90mm on the C11...

The option to use a right angle or straight through viewing is a plus. I pop in the reticular 35mm 2" Rini without a 45 degree...

...and I dig it.

I think I will keep this configuration for the time being, as it works well in testing in the daylight..

I think this project will work out well. The only mis-step, was the diameter of the OTA and the focuser are not exactly the same...and the fit is a little loose at the OTA end. Some double-sided tape squares snugs it up, but I should have brought the tube to the workshop for fitting. If I have to, I'll make another one, but for now, I think it will work well.

My neighbor stops by to see what the hell am I looking at...

Nothing but chimney Johnny, nothing but chimney.

[andrewgilhooley]

Finally got around to doing some pictures of my guidescope mount ...





The whole thing is a reversed dovetail arrangement so I can mount the one guidescope onto any vixen dovetail bar.

[Chicago Astronomer - Astro Joe]

New Dovetail brackets coming for the 90mm finderscope

April 2012

The dovetail bases that has carried the 90mm Meade refractor on top of the C11, (above), has served hundreds since first installed. But, since the inception, they were less than optimal, loose and even one time early one, enabled the refractor to slip out and fall to the ground. The clumsy generic bases did not rest on the C11 tube well and were not a good fit for the precise machined aluminum Marzec© rings/stems that held on to the scope.

Chicago Astronomer and master metal craftsman Rick saw this -and told me he would care of the situation...

...and they are done!

Now, with his rings, stems and matching bases, I will have a rock solid set-up for the 90mm. He even took into consideration the height differential between the thickness of the rear cell casing and the OTA, (which the two bases rest upon), ...a measurement of .1546...!

He's too cool. ;D

We will soon meet, in which we will have a beer and laughs. After I get them, I will take apart the C11 for it's annual clean up and mod.

More later.