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Megrez 90 arrived today!


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Like a child on christmas...

I got my 90 today from FedEx. I bought it straight from WO and they shipped it the same day with delivery in less than a week.

It was US$ 1346 including two mounting clamps, the new digital readout focuser and a soft bag. Also, the field flattener 4 is included in the amount.

It gives a very solid impression and I took upon me to get it ready for the promised clear skies.

Right now it is ticking away 10-minute shots of M101 as a test. Unfortunately, the wind is blowing straight at us with gusts up to 20 knots. We'll see...



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Thanks all!

Yes, it looks nice and it is a very neat scope.

So far, either the wind or the flattener is giving me strangely shaped stars, almost like nuclear symbols... Go figure...

All report back tomorrow. The scope will take the darks while I sleep :hello2:


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As a potential purchaser of the 90 with DDG I'd be very interested in how the new DDG focuser performs. I tried one last year wth the PL focuser and it appeared to have a "notch" every 120° - any thoughts?

Great set up BTW!



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I think the star shape you describe is quite well known but I just cannot remember the cause. It might arise from the clips retaining the lens. Ths has come up before with WO and one suggestion was to mask down the outer rim of the objective very slightly. Anyway, it may be nothing and just go away, as things sometimes do.


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About the focuser...

It is great if you need a guage. I do not, but I have noticed that if you rush it, it will miss some "ticks". Apart from that it is very accurate. So, turn the knob slowly :)

The front lens assembly is on its way to WO for adjustment...

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  • 3 weeks later...

Got the front lens assembly back today and have - lo and behold - clear skies.

The optics are still pinched. I don't know what to do, but I guess the first thing would be to try to loosen the collimation screws just a litle bit, wait a few days and the try again.

I have about two weeks left before the skies get too bright to do any astronomy, and that situation then lasts until early August.

An artificial star is also on the list in order to be able to collimate indoors. I guess a LED of a watt or two and a microscopic pin-hole will do.

As a last resort I will mask off the outer 5mm of the lens and see what goes.


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Yes, it is a beautiful scope, but the optics are not well collimated and pinched. Just check the quickie I just took. 4 10-min lights at ISO400, no flats, no darks - all from the balcony :)

Tomorrow I'll start with de-pinching tests.


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I have tried loosening the collimation screws on the M90 and have still not been able to get a non-triangular star image.

The people at WO are extremely polite and very forthcoming and I have reached the conclusion that I will return the M90 first thing tomorrow morning.

I am giving William Optics another go because I feel that the service and the general build quality of their stuff is really good. Also, their telescopes come out very well in tests. So, I will move up in their range and try the FLT 98 instead. Any comments on that?

The last couple of nights have been clear and I mounted the Explorer 250 Newtonian back on the NEQ6 and shot some stuff from my light-polluted balcony. Last the nights have yielded this (note: round stars :)):


M101 4x10min, darks and flats


M51 4x15min, 15 darks, 30 flats


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Now I'm double jealous! The FLT 98 is pretty much my dream imaging scope :)

I couldn't understand why the FLT 110 was less money, though. At least at FLO. Is Ohara FPL-51 glass not as good as Ohara FPL-53?

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I'll see what I can come up with that will double it again. Give me some time...


Yes, the FLT's seem nice, and from what I have gathered, the 53 glass is a bit better than the 51.

We'll see how it performs, and I'll keep you all posted. Right now it's 21:06 and I'm waiting for the first hint of Polaris in the sky so that I can check the polar alignment of the Explorer 250 and go on with some lights of M101.


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Hi perfrej

Also v jealous of your purchase - congrats.

I note with interest in your current equipment list you say ETX 125 - 'scrapped the mount'. I am considering doing the same on my ETX 90 as I feel there is life in the tube but massive frustration in the mount. I assume you mounted it on a different (equatorial?) mount? How did that work out for you and was it difficult to disassemble?


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I tried it on my NEQ6, but then the mirror gor all loose. I took it apart and noted that the whole design is prone to problems. The mirror slides up and down on a center thingy when you focus, and the focus screw is about half-way out to the edge. It just doesn't work. If you want mine - which was frightfully expensive when I got it - it comes pretty cheap this week :D


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