Posts Made By: Mike Pupeza

Hi;
At an Astro Swap Fest, I bought a Galileo G-102 Maksutov-cassegrain Scope - OTA only, with the little "Mars'Eye Finderscope".
The OTA has 2 threaded holes for tripod mount and is 115 mm wide and about 283 mm long - to the flat back. It appears to have the front corrector lens at 102 mm dia.
Does anyone know the actual fl or f ratio for this scope, or any other details.
It appears to work well as a spotting scope but I haven't had a decent mount to really check it out.
I can't seem to find anything on the web.
Any info would be appreciated.
Thanks.
Mike.....>

Hi,
I will be receiving a 7 1/8" OD .083 X 40" formed and welded aluminum tube from a local fabricator for my 6"f6 home made scope, to replace my old home-made fiberglass tube.
I want to paint the inside with Krylon Ultra-flat Black #1602 paint and the outside with another Krylon Paint, probably a high gloss white.
I do wish to ensure the best bonding, and Preston Engebretson had recommended a Phosphoric Acid wash, then a primer.
I have some Phosphoric Acid used to wash Teak, as part of a Teak Cleaner with a separate Sodium Hyroxide rinse - will that Acid be OK?
WHAT PRIMER should I use for these products?

I have painted aluminum in the past and was NEVER totally successful. They peeled and flaked, usually.

All help from successful aluminum painters would be appreciated.
Also, if anyone could get Preston Engebretson to drop an e-mail to me at [email protected], that would also be good.
Thanks all.
Mike.....>

OK Guys (?);
I finally got my 7" ID .081" 41" LGTH Aluminum tube (Fred Hook - Midland, Ontario) for the price of $110 CDN (US=$80 approx), and it looks fine (6"f6)!
However, the welder of this tube, left the outside weld visible, and I want to file/grind it flush!
There are are a few inside 'incursions' but I can use my "Dremel" to clean up those.
However, there's a LOT of extra weld on the outside of the tube.
I did use my various files and 'wood' rasps to try to get the bulk of the welds down.
Most of the 'grinders' that I use clog up - quick!
Grindstones, sandpaper, work fine, for moments!
Is there anything that works well for clearing out a lot of aluminum welding seam?
Mike 6"f6 - the costliest HB reflector in History!

Well Gang,
I finally ground down the welded seam of my new 40" long 7" OD aluminum tube of .081 thickness with a 3/8" back fold at each end. Thanks for the advice and help for the techniques. It still needs final sanding and polishing but I want to make all the holes before I go ahead with the final preparations.

HOWEVER, it looks so good and durable that I have second thoughts of mounting the focuser that I did get for it! My old focuser was 1 1/4" all the way through, causing some vignetting on my fiberglass tube, while the 'new' one is 1 11/16" ID. Unfortunately the design and construction of this one is pretty marginal for the quality of other parts that I have (Novak spider and diagonal holder, and Novak aluminum mirror cell). This 'new' focuser only has about 1" in travel from 6" till the tube starts to protrude into the telescope tube. That's pretty crummy since it will get right into the light path!

SO, what is a decent, but reasonably priced durable, all metal, focuser to use with this 'ultimate', and high priced, 6" f6, built like a tank, telescope??? One that won't protrude into the light path, and that is wider than 1 1/4" at the tube end?

As before, all opinions would be appreciated.

Mike Pupeza.....>

OK Gang;
I need more informed information.
I now have my 7” OD Aluminum (Aluminium) tube, 40” long ready for establishing my 6” f 6 Newtonian telescope. I had made an aluminum tube rolled and welded (.08”) and with folded over ends (3/8”).
I’ve got the seams ground down and filed, and am ready to ‘finish’ the tube!
I did get info for the interior – cleaned, primed and sprayed with ‘ultra flat black krylon’.
No disagreement, no problem. (Flocked paper would be better – not for me!)
But now, I am getting conflicting info on the exterior!
I thought of getting it painted in an auto-body shop, with a paint that they were using for whatever was going through - white, if I could get it cheap!
But, at ‘Starfest’ last weekend, in Ontario, I was advised to just buff up the exterior of the tube, by several people.
They said that it would “Dew less” and “Not get as hot” in the sun.
Also, apparently, after the oxide forms, it will be clean to handle, and not give off any ‘dirty’ marks when I am moving, twisting, working with it!
There are a lot of recommendations to use a “Scotch Brite” pad to scrub up the aluminum, to leave a random swirled pattern as the final buffing.
So, what are the opinions of the ATM people on this group?
My personal though is to ‘Try It’! There’s nothing to lose. I could have it painted later!
Thanks,
Mike Pupeza 6” f6 – most expensive homemade 6f6 in Canada!

I had an aluminum tube made (Rolled and Welded - with a foldover at each end - $80) to replace my home-made fiberglass tube for my 'Most Expensive' 6" f6 to be ready for Winter Star Party (WSP)!
I tried to make it bare polished aluminum to prove out the theory that bare aluminum, with it's very low IR Emissivity, would be less likely to Dew Up. I really wanted to try that out!
However, after grinding, sanding, and much more wet sanding down to 600 grit, and achieving a nice smooth satin finish that looked pretty good, I gave up.
The material (.083) was too soft!
Every time it touched, or pressed against any hard surface - watch strap, ring, plastic pieces, etc., it would leave a mark. Not Acceptable!
I phoned a few Powder Coat Shops, and got a price of $35 for a white powder coat job.
I picked it up today!
What a beautiful job!
DON'T paint your tubes, or struts, or metal pieces. Get them Powder Coated.
Cheaper (in many cases) and DURABLE.
I gave up the low IR emissivity, but what a surface.
BUT, phone around and tell them how much prep you've done and pick the White or Black for cheapest prices.
You won't be sorry!
C U at WSP!
Mike in FL.....>

How do I set my DEC=0 for great alignments?

I'm just back from the Winter Star Party and it was great. I had good
observing for at least 4-5 hour on 3 nights, clear but breezy all of
one night, and great for all of 2 nights.

However, I noticed that I am getting inconsistent alignments.
I am using a Tangent Box (Orion Discovery MIII ver. 3.66) with a GEM. I
use a reticle eyepiece to center my guide stars. On some nights,
using Castor and Sirius as my 2 stars - I get Warps of 0.0, and I was
Bang-On with ALL my objects, even when I have to flop over the tube.
I then left my scope without moving it, later do a restart of the DSC,
resetting DEC=0 and the Guide Stars.
I am sometimes then off with my Warp and my objects are just around my
view, not Bang-On. The ONLY thing that changed was the DEC=0 adjustment!
It MUST be the DEC=0 set-up.
I, usually, get Polaris in my eyepiece (Not the reticle one - it's far
too hard to do this) for my Polar Alignment and adjust my latitude
pivot and my azimuth rotation close enough for adequate visual
tracking.
I rotate my DEC setting circles, with my RA at the top of travel, and
the DEC parallel to the RA, and set for 90 degrees!
I then rotate the tube declination east, till the analog setting
circles read 0 degrees.
Then I set my DEC=0 on my DIII.
My first star MUST be in the east (Castor), then Sirius.

Is there a way to use a bubble level, as in the Dob, or Alt-Az mounts to get a consistent accurate DEC=0?????

I would like to have something less subjective, and more accurate,
than the couple of degree errors inherent with my preliminary DEC=0
set-up.

How can I do it?

Thanks.
Mike .....>

After 2 very dewy nights at StarFest in Ontario this last weekend, I realize that I must finally make up some heaters for my 6" f6 (1" thick) primary and my 1.83" (1/2" thick) secondary mirrors!
The powder coated aluminum tube did little to slow down the dew, and, even though my mirrors are both recessed at least 4" from the ends of the tube, they both dewed up after several hours. Not a pretty sight, and the skies were great!
Kendrick uses 2 Watts Max. for that size secondary, and his 8" primary heater is about 20 Watts Max.
I plan to use small resistors glued to the backs of the mirrors in a distributed pattern.
I also plan to use small PWM controllers, or, I may make the Don Clement automatic feedback controllers, fed from 12 VDC batteries!
I am planning on mounting 17 of miniature 2W 0.47 Ohm resistors on the 6" primary and 4 of 15 Ohm 1 Watt resistors on the secondary!
Do these seem sized right? Any other advice?
Mike

Gosh Guys (and Gals, I guess?)
Do I yearn for a BIG scope? For sure!
BUT, I made a darn good 6"f6, and I've taken it to a bunch of places and Star Parties, including the WSP06 in the Keys, where I have had a great time.
I am convinced that a good scope (any size) that you enjoy, and can use regularly, is the BEST scope for you.
My 6" began with a pyrex blank that I tortured into a pretty fine optical mirror, more by luck than skill. Ken Novak, when still supplying parts, supplied the mirror mount and secondary spider. I forget where the secondary mirror came from!
I then built, using mail-order for many items, the OTA, several mounts, several tubes, several focusers, several bases, and have now evolved a really useable, for me, SYSTEM!
The heavy aluminum pedestal, which looks like it came from a fold-up artillary mortar piece, holds an old Meade Starfinder 110VAC 1" dia. shafts GEM. I 'found' some 7" ID rings at a Swapfest!
A sheetmetal company made an aluminum tube for me, using my Rings.
A powdercoater in Melbourne, FL did the tube for $40.
Astromart for the DAR focuser and the DSCs and SDI for some gears and a astronomer machinist for some of the other gears and a few hours with some wood and power tools and! VOILA! Here comes a humble 6"f6!
I can comfortably say, and my WSP friends will agree, that I ALWAYS am enjoying my finding, viewing, and studying through my scope!
While I do have trouble on some nights, seeing 6 stars in the Trapezium, and I DO have problems finding some of the Herschel (sp?) objects, and some of the really faint objects, I, almost always, can find those objects that the 'BIG' boys can see!
To me, finding, and seeing, is the challenge! Internet has the Hubble pictures, the dynamics, the science. BUT MY SCOPE has the immediate view! AND I MADE IT!
DON'T BE DISCOURAGED IF YOU'RE NOT MAKING A GIANT SCOPE!
Small is nice too!
Mike 6" f6 .....>

I just received a 12" Dia X 4' aluminum tube of .094" thickness from Hastings Pipe Company for $119.36. This is to replace the irregular fiberglass/aluminum lousy tube that I have on my 10" f4.5 Newt.
It arrived in good condition in a cardboard box, with a square of plywood at each end by UPS Ground. No nicks, crimps, folds, punctures, nor any other damage that I could see, whatsoever. The ends are clean and cut square.
At .094" thick, I didn't need any stiffening at the ends and the tube is quite round. The welded seam is well finished and shouldn't even be visible when I'm finished. My previous locally made welded tube for my 6" had a very thick irregular weld and took mucho grinding and work to clean it up. It cost me the same as this tube!
I had my other tube powder coated and used Krylon Ultra-Black spray paint for the interior. It worked well and looked very good!
I'm still debating on the way to finish the exterior! I'll check the powder coat places again down here and see if I can get a 'deal' again! This time I'll make the holes for my Novak fittings, FIRST!
I thought that I'd share this with you ATMers, as, in the archives, I saw some problems with other people and Hastings Pipe Company. I'm extremely satisfied!
I should have this finished and together for my week at the Winter Star Party in Feb. 2008.
Mike
6" f6 Newt on GEM
10" f4.5 Newt on GEM