Celestron PowerSeeker 127EQ Renovation

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Sky Tinker
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Re: Celestron PowerSeeker 127EQ Renovation

#41

Post by Sky Tinker »


notFritzArgelander wrote: Wed Jan 01, 2020 8:13 am
Sky Tinker wrote: Wed Jan 01, 2020 7:59 am
notFritzArgelander wrote: Wed Jan 01, 2020 6:17 am Truly an epic makeover!

Your photos tell me that my recollection (posted earlier this week) that the "corrector" isn't a proper Jones-Bird optic but rather Barlow lens pressed into service was correct. The difference in thickness of the lenses in the doublet gives it away.

See the single doublet (3) in the figure under the heading "Conventional Barlow lens"
https://www.telescope-optics.net/miscel ... optics.htm

A double doublet is shown in the figure at the left with a single doublet to the right.

A true Jones-Bird has a doublet that is more equal. See figure 154.

https://www.telescope-optics.net/sub_ap ... htm#bottom
I can't be certain if the doublet-lens does or does not correct for spherical-aberration until I observe and test further. The images I've seen after collimating have been great; other than comatic views at the lower powers, and in that it's behaving as an f/4 Newtonian should. Do you think it's possible that someone at the factory was having a good day and decided to go ahead and parabolise my mirror? Definitely stranger things have happened. Perhaps Synta is now parabolising all of them.
That would be one explanation. :shrug: I just don't know about that.

To evaluate expected coma https://www.telescope-optics.net/newton ... ations.htm

I would not rule out that you, yes YOU, did an outstanding job of rebuilding and permitted the optics to perform well.
To me, the coma is inconsequential, as I didn't get the telescope for low-power observations, not with its 1000mm focal-length; no, only for the medium to high, and highest, powers. You can see the coma in this afocal shot of the Moon via a 30mm Plossl(33x)...
071119 - 30mm.jpg
See that stretching? Why, it appears as taffy.

No, ne'er to be an all-rounder, I'm afraid.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

"Desserts tend to corrupt, and absolutely delicious desserts corrupt absolutely." - Chef Acton

Alan :Astronomer1:

Apochromat: Takahashi FS-102 4" f/8 - Achromats: Meade S102 102mm f/5.9, Antares 805 80mm f/6(flocked & blackened), Meade "Polaris" 70mm f/12.9, Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion 6" f/5(flocked & blackened) - Catadioptrics: Explore Scientific 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened, and collimated!) - Mounts: Meade LX70(EQ-5), Astro-Tech Voyager I alt-azimuth
Sinerjee
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Re: Celestron PowerSeeker 127EQ Renovation

#42

Post by Sinerjee »


Awesome right up sky tinker.
I’m especially looking at the secondary mirror modifications as my Astromaster 130EQ has a very similar setup albeit plastic.
D78F9F3B-18E8-47C2-A46A-C3F835D16B36.jpeg
2BA2619E-5693-4E47-BC45-E7C9EE9A9833.jpeg
It has a lot of reflection so I’d at the very least paint it once I learn how to properly Collimate but do you think I could get away with removing the other 3 veins like you have and just having one plastic one?
Scope: Celestron Astromaster 130EQ Reflector
Astromaster Lens and Filter Kit
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Re: Celestron PowerSeeker 127EQ Renovation

#43

Post by Sky Tinker »


To conclude, images and descriptions from the telescope and myself, outdoors under the night sky last August...

I usually test my telescopes with Polaris, the north star; mainly because it doesn't move, and given that my mounts are manually-operated. I couldn't take an afocal-shot of the star at high power, but upon returning indoors I immediately created a virtual sketch of the sight with my PC's paint-program. Polaris, at 167x, and through a 6mm Vixen NPL Plossl...
Polaris - 081919b.jpg
Polaris - 081919b.jpg (6.22 KiB) Viewed 2035 times
I think, there at the top of the star, that that's a diffraction-effect from the single stalk; flare-like, and jutting upwards. The seeing was off an on, and as the primary-mirror was acclimating to boot. The Airy disc presented itself regularly, and had a rather tight first-diffraction ring round it, with successive rings shimmering, dynamic, as they emanated from their host. Polaris' companion, Polaris Ab, was a little below and slightly to the right. Also, Ab did not disappear when staring directly at it. I observed the wonder for about fifteen minutes, as I had used lemon-eucalyptus spray instead of that deet-based.

On another night, I took the Bird out as soon as it became dark. First, I observed Jupiter for a bit...
082319 - Jupiter.jpg
082319 - Jupiter.jpg (7.65 KiB) Viewed 2035 times
Actually, all four moons were visible. That afocal shot is by no means indicative of what I saw, as my Minolta DiMage F100 is a bit dated. For the very first time ever, I saw the Great Red Spot. It was tiny, but there it was. I even saw it rather clearly with the bundled 4mm(!), and at 250x. I don't know what to think of this 4mm symmetrical-Ramsden, save that I apparently got one where the lenses were well ground and polished. How is that possible given the usual reputation of these kit-eyepieces? I guess I'll have to chalk it up to having been 2019, and now 2020.

I then directed the telescope towards Saturn...
082319 - Saturn.jpg
082319 - Saturn.jpg (6.81 KiB) Viewed 2035 times

Again, that afocal shot is by no means representative of the tack-sharp view I saw. Through the 4mm, the image only slightly softened, but not by much at all.

Lastly, I aimed the Bird at the star Ascella, within the "Teapot" of Sagittarius...
082319 - Ascella.jpg
082319 - Ascella.jpg (6.3 KiB) Viewed 2035 times

That afocal shot, and the telescope and eyepiece, revealed the beautiful blue colour of the star; and no, I didn't increase the colour's saturation with the paint-program.

I then disengaged the axes, popped in the GSO "Super View" 20mm, and scanned in the area right round the top of the "Teapot". It wasn't long before I spotted M28(I think); a lovely globular cluster. I did have to use averted vision to see the "diamonds" within, but not that far away from the cluster; almost adjacent thereby.

In July, when I had collimated the telescope for the first time, I took this afocal-shot of the Moon, and with the bundled 4mm, at 250x. The mount was shaky, so I set my camera's shutter to 1/45th of a second to compensate. As a result, the image had to be brightened later with the paint-program. Imagine my surprise at what was then revealed...
071119 - bundled 4mm.jpg
Now, it's a bit blurred there within the image, but during the live view I was floored by the tack-sharp view. I definitely have that 4mm slated for continued use with this telescope, and others.

I haven't observed with the telescope since, as I've been working on another. In addition, it suddenly started to become cold at night shortly after those shots, and I'm not too fond of cold weather.

Thank you for looking.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

"Desserts tend to corrupt, and absolutely delicious desserts corrupt absolutely." - Chef Acton

Alan :Astronomer1:

Apochromat: Takahashi FS-102 4" f/8 - Achromats: Meade S102 102mm f/5.9, Antares 805 80mm f/6(flocked & blackened), Meade "Polaris" 70mm f/12.9, Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion 6" f/5(flocked & blackened) - Catadioptrics: Explore Scientific 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened, and collimated!) - Mounts: Meade LX70(EQ-5), Astro-Tech Voyager I alt-azimuth
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Re: Celestron PowerSeeker 127EQ Renovation

#44

Post by Sky Tinker »


Sinerjee wrote: Thu Jan 02, 2020 4:12 am Awesome right up sky tinker.
I’m especially looking at the secondary mirror modifications as my Astromaster 130EQ has a very similar setup albeit plastic.
It has a lot of reflection so I’d at the very least paint it once I learn how to properly Collimate but do you think I could get away with removing the other 3 veins like you have and just having one plastic one?
I've sent you a couple of private-messages. Please check your inbox.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

"Desserts tend to corrupt, and absolutely delicious desserts corrupt absolutely." - Chef Acton

Alan :Astronomer1:

Apochromat: Takahashi FS-102 4" f/8 - Achromats: Meade S102 102mm f/5.9, Antares 805 80mm f/6(flocked & blackened), Meade "Polaris" 70mm f/12.9, Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion 6" f/5(flocked & blackened) - Catadioptrics: Explore Scientific 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened, and collimated!) - Mounts: Meade LX70(EQ-5), Astro-Tech Voyager I alt-azimuth
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