Alan64
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Posts posted by Alan64
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I soak the areas first with 100% acetone. I then scrape as much of the now-softened paint off and out with a blade. Next, sandpaper of varying grits, along with a little acetone, and to remove even more paint. Lastly, varying steel-wools down to #0000, and lemon oil, to tidy up and polish. The mating surface...
There, the paint has been removed, but what's that greyish coating; primer for the paint? Did they actually go to that much trouble there at the factory? I then sanded it some more with finer grits; this kind...
...and polished with the aforementioned...
No, I did not cause those scratches seen there. That was the factory's doing, with an industrial wire-brush possibly, and to make the primer and paint stick better, perhaps. The scratches are, at most, only cosmetic.
On the flip side...
Where washers for the bolt come in contact with that surface, and forward of the lock-nut, that was prepared as well. Beforehand, all surfaces were gritty, rough, like sandpaper itself, and which had scratched and "boogered" up the surface of that large nylon washer. I then smoothed and polished the washer out with the fine wool and oil, and in preparation...
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The altitude axis...
Without and with flash...
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The mount, an ES "Twilight Nano"...
...no slow-motion controls, nor clamps or locks for the axes.
The knob there, to clamp the head to the hub, was loose within the box; not a big deal.
Who paints bearing surfaces, I ask. I know that Synta and Ningbo Sunny do; so why break up a set, as JOC is also complicit...
At first, I thought that this large washer might be of PTFE(Teflon), but no, it's of nylon, and adequate for this design I suppose...
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Second-light...
I observed Polaris straight-through, without the diagonal, and threw the star out of focus; no change, the patterns were identical to the image shown previously. I now know that my roulette-wheel star-prism is indeed collimated, as I had renovated and tested it a while back. I tried to take snaps of the pattern, and with seven shots this time round, but all seven were duds. Of course, it was more difficult to attempt without the diagonal in place. I brightened each one even, and nothing appeared.
In focus, at 190x with the 10mm, on both mornings, I could see the Airy disc of Polaris sharply, and at least two diffraction-rings encircling it, but the seeing, at Pickering 6, from fair to good, mucked the view up a bit, with annoying rays dancing within and about the rings. On this second night there were a number of cloudlets rolling across the sky, but the haze was gone.
Jupiter was brighter this time round as a result, like a 40-watt bulb, at 190x. There would be no seeing any spots this night however, I knew, but it was a good show nonetheless.
I didn't wait on the Moon, as it was due to appear even later than the morning before.
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8 minutes ago, johninderby said:
Sounds like you like the new scope. 🙂
By leaps and by bounds, I do. I just hope it doesn't disappoint in future.
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First-light continued with Polaris, the North Star, at 190x...
...most impressive. Incidentally, I've had my camera, again, since 2002, but it's only now that I've discovered how to adjust the shutter; pathetic, I know. But as a result, I may now take sharper afocal shots through an eyepiece, and in a split-second. Right afterwards, I threw Polaris out-of-focus and took ten shots. All but one were duds. The one...
It's there. Look sharp.
Here, I've brightened the image...
The extra-focal and intra-focal sightings were identical.
Now, that's with my Celestron star-prism diagonal integrated, and as it was throughout the first-light.
I had thought about this at the time, although not pertaining to this exercise: "Can a mis-collimated diagonal cause a mis-collimated telescope to appear collimated?"
Lastly, the Moon...
The Moon appeared there in the sky as though it had fallen into a bowl of chicken broth, floating just beneath the surface, glowing. It wasn't very high up above the horizon...
The live view, of course, was sharper, as always. I do want this telescope to exhibit what it's capable of, but that's not going to be forthcoming for a while I'm afraid. There's been too much water around here. The Mississippi River, the largest in the U.S., is about ten miles to the west of my digs. Currently, it is at a level and longevity approaching that of its infamous Great Flood of 1927.
By the way, the mount's been sorted, mostly, and to where it's usable. I'll be showcasing that in a bit.
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"Like the way the inside of the OTA has micro baffles all the way front to back. So much better that just a painted surface."
Yes, I had seen those online, but not as clearly as this...
And here I have this new box of Protostar...
Alternately, I have to wonder if JOC's factory-black is as black as my rattle-can of chalkboard-black. That stuff is almost as black as a black hole...
There's got to be something or other within to flock. I might at least flock from the meniscus almost all the way back to the primary. The baffled surface would have to be high-glossed, for improved adhesion. However, I do suspect that in that the telescope will sport a flocked dew-shield 24/7/365, then perhaps said enhancements would be to no avail.
Incidentally, whilst mucking about inside with the camera, it seems that JOC's clean-rooms, if equipped, aren't up to the task.
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39 minutes ago, johninderby said:
On the “baffling” subject have you read this? Some very usefull info.
http://mirrorworkshop.mtbparker.com/cassegrainBaffleStory.html
One of the Orion type finder mount fits directly Using the original holes. Be aware that the rear dust cover of the scope that covers the metal back plate is plastic and the finder screws strip easily. I taped the holes to M5 and it seems solid. You could always remove or just parially remove the dust cover enough to put nyloc niuts on the inside for a really solid job.
Like the way the inside of the OTA has micro baffles all the way front to back. So much better that just a painted surface.
Thank you for that most useful link, John.
Yes, I see...
And here I thought it was of metal. Why am I not surprised. Incidentally, the focussing knob was loose upon arrival. It takes a 1.3mm hex-key, but I'm fresh out of those, so I used one of those tiny flat bits from a mini magnetic screwdriver.
Also, might I integrate a 2" visual-back to this, please? Would it be worth it, given the diameter of the primary's bore?
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First light...no, not when I took that image of the leaves during the day...
The very first celestial object I saw through my new and only Cassegrain was old Jove, and at 190x...
Of course it's blurred. I used a 2002 Minolta 4MP point-and-shoot, and with a manual mount. Still, you can see a single moon at upper-left.
All four were seen quite well during the live view, naturally. When I first had the planet in view, I saw one moon emerging from the side of the planet. It appeared as a little bright dot, and sharp. That was nice.
The image brightened, and now two moons are visible...
The moon closest to the planet there was the one that had emerged earlier.
The whole night I was bothered by cloudlets and haze wafting across the sky. It's nigh summer. But the haze did have a beneficial effect. Jupiter was dimmed slightly in consequence, its lovely colouring revealed, as shown.
The only detail seen on the planet's surface were the usual equatorial bands; and perhaps, just perhaps, a spot that I think I saw, but cannot say for certain. This is the eyepiece I used: a 10mm 70°...
...and with these strange, amber-like coatings...
...much mysterious, that one.
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Despite the 1900mm focal-length of this telescope, I have little to no trouble in quickly bringing the objects that I view regularly to bear within an eyepiece: Polaris, the major planets, and the Moon; even in the absence of a finder. I simply sight alongside the tube. Here, under Bortle-4 skies, which might easily become -5 in future, there are a number of globular-clusters that I can readily locate, but not by sighting down the tube.
This is the base for the red-dot finder, and similar to that of a Meade...
At first I thought it was of metal.
I have a couple of Vixen-type bases, but I'll need longer screws to attach one; and yet another trip to my local hardware, to where I've suggested a cot in the back of the store.
I have this 8x50 straight-through...
That will do for the time being, and another red-dot that I have in addition. I'll try both and see which performs best for my purposes.
The dovetail-bar is of white-painted metal, and with a steel strip fastened onto one side, as a clamping surface. That of the Bresser is identical, but painted black...
I'd like to replace it; perhaps tube-rings in addition. That would add extra weight however.
The plastic dust-cap has two locking tabs...
The meniscus is multi-coated and uniform...
...and very much like that of my Meade 90mm achromat...
The secondary-baffle, and flared, like a vortex,...
That will be altered, or ripped out altogether, albeit ever so gently. As I understand, the telescope as it sits is optimised for daytime/terrestrial use. That won't do. Its presence also increases the size of the obstruction, and that won't do either.
The primary-baffle...
The reverse of the Gregorian "spot", and facing outwards...
I've thought about a matte-black disc. Schmidts don't seem to have that problem....
https://www.flickr.com/photos/140554065@N05/47962213786/in/dateposted-public/
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The collimation appears bang-on fresh out of the box...
I made a dew-shield straight away, in a pinch, and with these sheets of art-paper...
As I had said before, the bundled mount, an ES "Twilight Nano", cannot be utilised at present, notwithstanding the fact that it's not ideally supportive. My only recourse was to place the telescope upon my Astro-Tech Voyager I, a GSO product...
I didn't dare take it out of the house without a dew-shield, with the micro flora and fauna whizzing round.
The only thing I could point it at were tree leaves in the distance, lots of them. So I did, and at 190x...
The live view was sharper of course, as the eye and mind can follow an object more easily when a breeze ensues.
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Undoubtedly it has experienced slow sales, which is how I got it for a song; a promotional I suspect: US$299(£236), and from a vendor in New York. I've been aware of its presence within the marketplace for quite some time, but so little information has been forthcoming.
I came close to deciding upon the Orion-of-California model, a Synta, as are the Celestron and Sky-Watcher models, at f/12, and all three apertures actually at 118-121mm. I did find this out about the Jinghua: it has a full 127mm of aperture...
...and at f/15, a slightly smaller secondary-obstruction. That, combined with what I thought to be a promotional, made it a no-brainer.
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Many times in the past, I have also stated...
"A 127mm Maksutov is the 'sweet spot' among the varying apertures of the design; not too small, not too large, just right rather"...
A Jinghua Optical Co.(JOC) 127mm f/15 Maksutov-Cassegrain...
It is identical to that branded "Bresser", and perhaps the Meade 127mm as well.
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The big box is almost emptied, save for this last box...
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"I've never had one of those before..."
I take that back, as I do have this 2" mirrored-star...
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The telescope came with accessories, and a mount to boot. But the mount, an alt-azimuth, will need renovating straight away. I have some material on order for it, although it will not be described nor illustrated until it's righted.
Out of the box, the threaded end of the altitude handle was crooked...
I "warmed" it up with a mini-torch and straightened it as best I could. I was fearful that it might snap off altogether. Perhaps the torch tempered the soft imported steel, I can only hope.
One eyepiece was provided: yet another kit-25mm, and a Plossl. I've never used my 25mm eyepieces, a total of four now from kits, and in preferring a 20mm instead...
The red-dot finder...
The battery's good, but the chassis shakes and wiggles like a bowl of gelatin. Elsewhere, someone who has one just like it suggested adding springs to the cross-screws. I do have a box of assorted springs, but do I really want to go to the trouble? I have other means.
What is this? I've never gotten an accessory quite like this before...
Why, it's a dumbphone holder; bizarre to say the least.
An empty box...
Not unexpected; although as I fished it out I did have high hopes that it contained something lovely.
A mirrored star-diagonal...
I've never had one of those before, but I now have one with which to experiment and play.
I suppose we now know that it's not a Newtonian; drat. But still, what could it be?
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Practically all of my life, since I was about nine years of age, I've owned and enjoyed telescopes designed in the 1600s. All I might add to that is: when you've got a good thing going, and for over 400 years and counting, then quit whilst you're ahead.
This latest acquisition is one for which I've been longing, and for quite some time. On more than one occasion I've stated...
"I plan on getting one of those myself in future."
The future has arrived at last...
Double-boxed, and expected...
<creeeak>...
What in the name of James Gregory could it...oops.
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4 hours ago, Philip R said:
Bit late for the party.
What a fantastic restoration/'re-mod' you done @Alan64.
Many, many, years ago, I purchased a Prinz Astral 500. I could not get on with the EQ1 mount. In the end I gave the whole setup away to a neighbour. I said to them that I would never ever get a 'scope with an EQ1 again.
Twenty years ago I purchased a TeleVue Ranger and used to mount it on a camera tripod and various heads. Then I purchased a Tele-Optic Giro ten years ago and about four years ago I purchased a secondhand Vixen GP.
How wrong was I...
Thank you, sir.
If your kit was identical to this Prinz Astral 500...
https://www.youtube.com/watch?v=eQ0wdFSFZ1o
...then that's an EQ-2 rather, but only a little larger, not by much. I had a Towa EQ-2 myself once...
I had given mine to a relation.
As far as I know, the telescope houses of Japan never produced an EQ-1. If they did, they certainly weren't as commonplace as the EQ-2. Back then, the 60mm+ achromats were of a considerable length, at f/13 or f/15, and required the stability of an EQ-2, at a bare minimum. The 50mm and even 40mm achromats of that age generally if not exclusively came with alt-azimuth mounts, like this 50mm f/12 of my own...
In any event, you should've kept that one, and just as I should have kept my own. Hindsight is indeed 20/20 in that.
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6 hours ago, SteveBz said:
What an amazing amount of work you have done. And the final product looks great. But you still have the plastic wing nuts! Mine split as soon as I tightened them.
Very good luck,
Steve
Thank you, sir. I'm not quite done with the mount however. There are a few more things to do, and one of those may be in the getting of stainless-steel hardware for that very thing. When I had fastened that hardware, it did feel as though it were in a pinch.
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The final images to conclude this thread; I used my relation's Celestron C90 for the photo-shoot. The mount is practically finished. I do plan to eventually to make an eyepiece-tray for the tripod, but not at this time...
I'm also wanting to fit a knob onto the RA worm-shaft in lieu of the slow-motion cable.
There, the sunlight illuminated the bottom of the front leg; rather lovely...
Clear skies to all, and thank you for looking...
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On 19/05/2019 at 08:13, palazer said:
Hi everyone just made an account. I'm going to buy a Skywatcher 8" Dobsonian (https://www.astroshop.eu/telescopes/skywatcher-dobson-telescope-n-200-1200-skyliner-classic-dob/p,4440)
I mainly want to look at the moon, Jupiter and Saturn. The telescope comes with a 25mm and 10mm eyepiece, but everyone says the standard ones are pretty bad?
So I was thinking one of these two for Jupiter and Saturn? What's the difference with the ultra wide angle one? And which one would you recommend? https://www.astroshop.eu/eyepieces/omegon-eyepiece-cronus-wa-6-mm-1-25-/p,32982 OR https://www.astroshop.eu/eyepieces/omegon-ultra-wide-angle-eyepiece-6mm-1-25-/p,5087
I'll also be buying a moon filter (https://www.astroshop.eu/moon-filters-polarizing-filters/orion-moon-filter-13%25-transmission-1-25-/p,14458)
Please let me know if these items are decent and the right choice!
Lastly I want a decent eyepiece to look at the full moon in full, so not just a small part, but the FULL moon. What do I need for this? The standard 25mm? Or do I need a different ?mm or just a better quality 25mm one?
Just want to keep it as "cheap" as possible but still decent quality
Thanks!
I would choose a variable-polariser, rather than one with a fixed percentage, the 13% in question...
There are also other fixed-percentages available, up to 25% I believe.
You'd have all the fixed percentages in one unit with the variable-polariser. A variable polariser acts as an indoor light-dimmer, but for the telescope. You simply twist the two halves together to adjust...
Now, I'm not suggesting it so much for the Moon, although if the light from same bothers your eyes, by all means. Where I found great success with my own was when observing Jupiter, particularly during its opposition. I was observing Jupiter with a 150mm f/5 Newtonian, the next step down in size from your own. The planet was simply too bright, even at the higher powers, to see any detail. I then integrated the variable-polariser...
I could at last see wondrous detail on Jupiter's surface. The filter also eliminated the flares caused by the Newtonian's secondary's spider-vanes. During Mars' fairly recent opposition, the filter eliminated those as well...
But there was no detail to be seen on Mars' surface at that time, as the planet was experiencing a major dust storm.
Those are digital drawings of what I saw live, and from Bortle 3 or 4 skies here at my home.
Those 66° wide-angle eyepieces are sold on eBay, if you have access, and for considerably less outlay; for example, here's the entire set...
A pair of the 6mm and 9mm... https://www.ebay.com/itm/SVBONY-1-25-6mm-9mm-66-Deg-FMC-Ultra-Wide-Angle-Eyepieces-For-Astro-Telescope/362586394038?hash=item546bd54db6:g:UJ4AAOSw64tbnPqE
The full Moon is not usually observed, as there's little detail to be seen. It's during the Moon's phases that drives us wild...
But then, why not, as I've observed the full Moon on several occasions...
...including that big "strawberry".
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On 19/05/2019 at 11:04, Anthony1979 said:
any critics please so i can improve thanks
Not bad, not at all. When I take snaps through my telescopes, I sharpen them with a paint programme, but only to match the sharpness seen when observing with the eye and an eyepiece. I also adjust the contrast, and again, only to match what was seen live. For example, I took this shot of the Moon through a 60mm refractor...
Now, you may think that sharp and clear, but I saw the minutest of detail within this area of that image during a live view with my own eye and eyepiece...
...craterlets and rilles, hills and dales, seemingly tens if not hundreds of them, but the camera could not capture a single one. Therefore, I think that you've got a very nice telescope there.
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10 minutes ago, Philip R said:
At least I am not the only one that has a had mishap/accident with a Mak!
Mine is too, I think, is slightly off a bit. My ETX105 hit grass/lawn and damaged two mounting points and cracked the ABS flip-mirror cell.
One thing you could try, you can give it a gentle shake and if you hear a slight knock. The locking ring that slides the primary mirror on the baffle tube sometimes work loose. If you can remove the meniscus cell/corrector plate, (making note of its orientation for re-assembly), may need a slight tightening up. This is what I did with mine, before the 're-mod', (photos in my earlier post), and have not touched it since. If in doubt ask someone at your local astro-society/club who can fix it.
Sorry to hear of that. Have you either repaired the flip-mirror cell or bypassed it with the camera-port?
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New Telescope
in Discussions - Scopes / Whole setups
Posted · Edited by Alan64
But before I reveal the final result, the azimuth axis...
That was easy enough. But this, not so much...
I cannot reach the lock-nut for the azimuth's bolt, due to that glued-in plastic disc with the two holes and the threaded brass insert, and without comprising it. Thoughts...
Okay, I'm done thinking. I will leave it alone for now, as it, unlike the alt had upon arrival, operates quite smoothly actually. But it will be revisited in future, as I do have bronze, PTFE, and Formica #909-42 laminate perhaps, waiting in the wings.