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PREVIEW The William Optics GT81 Triplet Refractor

Deneb

By Deneb
in Member Equipment Reviews

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Deneb

Deneb

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Okay, here's some more images of the scope with rings...

Mounted using WO 90mm Rings on an ADM Losmandy Dovetail.

P1010254.jpg

Now here's a surprise, only for you Handle Lovers :)

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Front shot of lens.

P1010259.jpg

Mounted on mount.

P1010260.jpg

There's one more image remaining of it mounted on a dual bar system, i'll post that later... Im a bit tired now from the rest of the day, I'll give the rest of my synopsis after i've done a image test on it with & without using a flattener, as Im sure all would like to know, does it deliver the performance what it's mean't to deliver. If Saturday night holds up, fingers crossed expect to see some images on Sunday...

Cheers

Nadeem.

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Tim

Tim

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Looks v nice indeed Nadeem.

Can you do some star test piccies? Ideally on a red and a blue star and in each corner of the frame and centrally, bright star, short exposures, with and without reducer.

Cheers

Tim

Tim

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AndyUK

AndyUK

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I second Tim's comments - It does look VERY nice indeed... (and my wife would certainly approve of your reading material in the background of your last picture - She's also a great Winnie the Pooh fan :))

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Deneb

Deneb

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Looks v nice indeed Nadeem.

Can you do some star test piccies? Ideally on a red and a blue star and in each corner of the frame and centrally, bright star, short exposures, with and without reducer.

Cheers

Tim

Tim

I was thinking of doing the same, short exposures meaning 30secs, 20 secs or 1min?

Nadeem.

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Deneb

Deneb

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Focuser Update :

While looking over the scope again just in case I might have missed something, I found some slop when rotating the focuser, don't worry it can be fixed very easily.

Around the rotating edge of the focuser there are 3 screws positioned one at 11 o clock, 4 o clock & 8 o clock. I turned those screws 1/2 mm clockwise & the slop tightened up, now the focuser has a nice firm rotation.

Tonights a bit naff for testing, fingers crossed for tomorrow night...

Nadeem.

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Deneb

Deneb

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Round Star Update:

As the rain departed, I thought i'll get a clear break, but was not the case, you could say high cloud. But anyway I managed to get off a few lights using the LUM channel 1min exposures guided.

Below is an unprocessed jpeg from a fit file taken with 383 while I was checking out how round the stars would appear in this scope. I certainly did not want a replication of the star shapes which appeared in the Quadruplet I had previously.

Edit: No Reducer/flattener was used.

Nadeem.

post-15111-133877631782_thumb.jpg

post-15111-133877631789_thumb.jpg

post-15111-133877631797_thumb.jpg

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gbealnz

gbealnz

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Looks good, and I accept that the weather was against you, but they need to be in focus. Some coma as well, which is contrary to what I found with the AT2FF, and also the TRF2008. I used mine very briefly tonight on M8 with ha, and the TRF2008, and have decent stars to the corners.

Gary

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gbealnz

gbealnz

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Nadeem.

here is the Ha Lagoon from about an hour ago. It was a 5 minute break between thunder showers, and in fact I had to hurriedly pull the gear down as the next shower approached.

Single 300 second sub, with the GT-81, SXVR-H16, Astronomik 12Nm Ha filter.

Saved as a JPEG and reduced in CS5 with Curves to bring out the nebulosity.

Gary

post-17751-133877631821_thumb.jpg

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Deneb

Deneb

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Looks good, and I accept that the weather was against you, but they need to be in focus. Some coma as well, which is contrary to what I found with the AT2FF, and also the TRF2008. I used mine very briefly tonight on M8 with ha, and the TRF2008, and have decent stars to the corners.

Gary

I would expect so with a TRF2008...

Nadeem.

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Deneb

Deneb

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The Coma is a concern to me, even at imaged in a small area, especially if WO is touting this scope as something special. As it's showing more coma then my SW 80ED DS Pro, even without a reducer. :D

Anyway it needs another star test with a full frame with the 383. Unfortunatly in the rush last night i forgot to select the full frame option on the control panel of the Artemis software, thus having a smaller fov.

Nadeem.

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Deneb

Deneb

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I really do wish im wrong in this testing & that maybe I have missed something, but other testing opportunities will dictate that... I've uploaded a shot of my guiding graph just in case there's some doubt regarding any guiding issues which may cause the elongated stars.

Nadeem.

post-15111-133877632426_thumb.jpg

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Deneb

Deneb

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i'll download a demo & run it next time i'll get a decent night, hopefully blinkin soon... unless it can be done just importing the data as you suggesting Peter...

Nadeem.

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