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William Optics Star71 - A First Impression...


PhotoGav
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The wonderful package arrived on the 16th October and we all know full well what happens when you open the box of new astronomy gear. I apologise to all, though I didn't realise that there would be so much gunk in such a small box...

Anyway, it hasn't been a total cloud out and I have now had a few chances to play with the new William Optics Star71 on my HEQ5 Pro with my QSI 683-WSG connected up. This seems to be a very popular little scope, but I thought it might be of use to post a report to aid those who are still unsure whether this could be the right next scope.

First up, I purchased this scope as I was becoming increasingly frustrated with the focuser on my SkyWatcher 80ED, a superb scope, but the focuser lets it down. I had considered a simple focuser upgrade, but decided that a bit more field of view and a bit more speed would be worth the extra expense. As far as the focuser on the WO is concerned, it is a dream to use, even with the heavy camera pulling down on it, no problems at all. I have now discovered what focussing should be like! Very big plus point to the WO.

So, on to actually capturing an image. I dived straight in once I saw that it all worked properly and fired off an 1800s sub on The Soul Nebula. Excited to see what it would look like, I was concerned, upset and disappointed with the result. Here it is, click to see the full size image and you will see what I mean:

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Very bad star shapes... Not what I had hoped for. Anyway, the cloud rolled in and I packed up, scratching my head...

It dawned on me over the next day or so and after a bit of internet research that perhaps it is just down to poor polar alignment. This looks like field rotation and not dodgy optics. I had always thought that PA didn't really matter tremendously when guiding for imaging. How wrong I was. The next clear night came along and my first task was to check PA. Indeed, it was about 45' out or so. Bad, but not that bad I thought. Anyway, a couple of iterations with Alignmaster and I had the error down to a few seconds. I cautiously went for just 600s on The Soul this time. Oh my, what a difference accurate PA makes... Phew, the scope wasn't to blame. So, on to an 1800s sub of The Soul Nebula:

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Looking good! This is the file as it came out of the camera with no calibration, just some stretching so that the detail can be seen. Lovely contrast coming through, great field of view, round stars across the whole frame and generally making me feel very optimistic about this scope and camera combination.

Just by way of comparison, here is an 1800s sub of The Soul Nebula through the 80ED:

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All the images are through the Ha filter.

So, in conclusion, this little scope is living up to my expectations and beyond. It's a dream to use, so light and easy to carry in and out of the house. The focuser is solid and makes focussing a doddle. The field of view is going to be really useful for those large areas of sky. Mosaics are great for detail, but in this country it takes an eternity to complete one image, let alone two or even four panes of a mosaic! I have shot some subs through the OIII filter and immediately the speed of the scope can be appreciated, the detail coming through compared to the subs with my 80ED is hopefully going to make processing less of a battle. I really look forward to some dark clear nights (or even afternoons at this time of year!!!) and to building my first complete image with this little gem of a scope. If you aren't sure whether this scope is going to be right for you, but are looking for something with a reasonable price tag that will cover a good chunk of sky, just hit the buy button - you won't be disappointed!

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Nice image...well done, good to hear you have sorted the issues out. I have the w o zenithstar 70ED, for me I had to use the focal reducer, stars were naff around the edges of the field of view, but perfect once fitted.  there great scopes, have fun!

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Looking good Gav, got the same setup but only managed a few 10 min HA subs so far but delving in at pixel level stars are nice and round into the corners so I'm a happy camper, just need some clear sky now as usual, can't get rid of this damn fog ATM.

Had to amuse myself doing a set of calibration frames so now I'm leaving the camera on the scope.

Dave

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I think because everyone ordered a WO star 71 at the same time so many cloud points have been generated that it turned into Fog!

Glad you got the stars sorted out PhotoGav, now if we could just get a week of no moon and clear skies....

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I think because everyone ordered a WO star 71 at the same time so many cloud points have been generated that it turned into Fog!

Glad you got the stars sorted out PhotoGav, now if we could just get a week of no moon and clear skies....

I had wondered where all this fog came from its either the Star 71 or Star adventurer thats done it in my view.

Great report Gav.

Alan

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A polar alignment which will give nice results at 15 minutes most certainly will not do so at 30 minutes if it isn't good enough. It's surprising how exacting the 30 minute sub really is! Nice when you get them, though...

This is a potent little scope, one of the most remarkable ever offered for sale, I think.

Olly

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Thanks folks, indeed a neat little scope. Martin - good to hear the positive reports regarding RGB work, I have many projects of that nature on the list!

So, all this fog, whoever is responsible, has led to me having a peak fiddle with the four 1800s subs...

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A noise fest really, it certainly needs a load more subs, but it definitely shows promise!

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Glad that you have sorted the issues out. As matter of interest I never trust the error figures that PA aligning software gives. In the first image the rotation is indicative of errors well above one degree of arc given the short focal length of the scope. None the less a few iterations of the PA routine always bring the error down to an acceptable level as you have discovered.

Regards,

A.G

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Excellent initial results with the new scope Gav. Ref the PA, didn't you have an Obsy on the wishlist? Best thing I ever did. Once that alignment is nailed just a check every now and again to ensure nothing has moved is bliss. Good luck with the weather and I'll look forward to seeing more images from this fine little scope.

Pete

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