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Alan64

Zhumell Z100 100mm f/4 Newtonian

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The dust-cap was masked-off where needed...

1352273619_dustcap3.jpg.c18d01c6a6ef8f6b04746afaf71ae9a1.jpg

...then painted matte-black(chalkboard-black, as usual)...

528558108_dustcap4.jpg.93cc6a569fc984a7edceea58f74bdc86.jpg

669983308_dustcap5.jpg.e93f1f8d49779ced9c36d3368c9fecc3.jpg

The recessed rim round the stopped-down aperture was blackened(left), and the reverse was blackened utterly.  I will not be fitting the plug until after a day or so, and to allow the paint to dry/cure completely.

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After the matte-blackening, the dust-plug became a bit tighter-fitting, but no matter as now the entire cap can be removed with the dust-plug's single knob, and both the cap and plug as one.

To cushion the dust-cap as it's inserted, shimming with felt or other could occur only here at these two areas, and between the aluminum-braces...

1790983374_dustcap7b.jpg.a74da7eae7292eda579353a7dd0b6475.jpg

Through trial-and-error over the course of a day or more, I finally arrived at the ideal combination of materials: one 5mm-wide strip of double-layered aluminum-foil tape, then one 9mm-wide strip of flocking, and for each side of the flange...

1178276791_dustcap7.jpg.30c3ac496e14505e4434eda55b056ebe.jpg

Perfect fit...

1354697431_dustplug14.jpg.2b7d1956bd865586078b5a9dd1b8f50e.jpg

1616591804_dustplug14b.jpg.1c30c20c74a75f19c069a41c3ef43c4c.jpg

The altered dust-plug now allows ample clearance for the secondary-hub's thumbscrews...

1587572124_dustplug-clearance.jpg.2cbeb7bb1dc274d8aaa2823f9eed5887.jpg

Other than the collimation yet to be performed, the telescope is completed.

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Looks fantastic Alan, nice job.

Hope it performs well now! 👍👍

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Just now, Stu said:

Looks fantastic Alan, nice job.

Hope it performs well now! 👍👍

Thanks Stu.  The next step will be to collimate it, then to take it outdoors for an afocal photo-shoot, through this eyepiece and that.  Although, this winter has been wetter than usual, but I'm still hopeful for a clear, dry night soon.

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I imagine that the telescope has gained a bit of weight over the last three years, but for kicks and giggles I placed it onto its original mount...

Before...

kit2b.jpg.42f331128792f95e20e0519eb38f4f49.jpg

After...

finis.jpg.46c8c43898c3d4a74ee3885506bd8b02.jpg

I will probably use that mount when collimating the telescope.  I may also give it another whirl round and under the night sky, at least once.

Edited by Alan64
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For better, or for worse, and through a collimation-cap...

1205207344_collimation-011720.jpg.886d8d921f1ebf06c83fd3a8b97e8393.jpg

All I need now is a clear, night sky, and that will come in a day or two, but it's going to cold, cold, cold outdoors.  But I won't need to be out there long.  I hope the Moon will be out.

I tried to use my Cheshire initially, but I don't think that it likes the visual-back of this telescope.  I'll need to investigate that further, for it seemed to work well enough when I took this shot three years ago...

011417e.jpg.d7b9f255eab4b479885ef3eda65f4557.jpg

Then this, the view through the collimation-cap three years ago...

011417d.jpg.b7a3cfe773e8a626050fe567fbf28173.jpg

I did tweak the off-setting of the secondary-mirror in relation to its stalk during the renovation.  Oh well, time will tell.

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I do know now that the telescope is collimated quite well.  Sirius, extra-focally, and through a 12mm 60° Konig(33x)...

1407188862_Sirius-12mmK-011920.jpg.6a2b24dc05c9fb103ca0de6032d94a52.jpg

I then observed the star with this, my SR4mm(100x) from my Celestron 127mm f/8 "Bird Jones" kit...

SR4mm2.jpg.c6c3ac7061791742d1abd072c1d6ed8a.jpg

The star was tight, yet as expected somewhat colourful due to the type of eyepiece.

Afterwards, I used the 12mm to zero in on the Trapezium within Orion, then popped in the 4mm.  I could just see the main stars, and sharply as well.  It was difficult however to find the sweet-spot of sharpness as I racked back and forth.  

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The Moon, at 33x through the 12mm Konig...

99302050_011920-12mmK.jpg.a32863e85d91a8d98a337ff48888107f.jpg

Now, it was at freezing, I was using the original mount, with my old(2002) Minolta point-and-shoot, and with the shutter at 1/30th or 1/45th of a second.  I did have to brighten the image to match what I saw during the live view.  I never enhance these afocal-shots otherwise, never have, as that would be dishonest.  During the live view I saw Earth-shine on the left side, but this old camera couldn't pick it up.

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Hi Alan.

Just thought I would say I had a read of this  thread a couple of months back before I was a member of the forum. I really enjoyed it. Top job you did improving this scope and it also inspired me to flock my 200p which improved the contrast greatly.

Keep up the good work

Regards

Baz

 

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