Megrez 80 mini report

[grandpanancy]

For those interested I thought I would do a small report on this scope and the eyepieces I have been using.

The telescope is a Megrez 80mm ED Triplet refractor, the eyepieces include 2" 33mm Swan, 1.25" 9mm UO HD ortho, 1.25" TV 8-24mm Zoom and a William Optics x2.5 barlow. And it's mounted on a microstar basic altaz mount -- pictures of the setup can be found previously posted in this forum.

Keep in mind that I'm relatively new to astronomy so this is a beginners point of view.

The 33mm swan gives a nice low mag wide field view. Stars are pinpoint about 2/3 to the edge -- in the final third there is seagulling which i personally find a bit distracting but probably to be expected from an ep in this price range. This ep has provided amazing views in the eta carinae region of the sky.

The 9mm HD ortho gives nice bright views of jupiter and saturn at x62 mag. The two brownish cloud bands on jupiter are clear, with saturns shadow cast onto the rings also visible -- at times the cassini division is also visible. The images are very sharp and aesthetically pleasing. Teaming this up with barlow to give x155 has generally been a fraction too much magnification except in moments of good seeing. There is noticible softening of the image at this magnification but i suspect the poor coditions have also had something to do with this.

I felt the TV 8-24 Zoom was a bit of a risk purchase given some of the poor reviews it has recieved. However, from what I did read a small refractor seems to be the best companion for this ep. I have found it to be a brilliant acquisiton and it is easily the most used ep. I get powers from x23 to x175 (with barlow) and everything in between! Without the barlow it has been perfect for star clusters and glob clusters in scorp. and sag. It is nice to be able to find exactly the right mag and field of view to frame the cluster without changing the ep. I'm particularly fond of the butterfly cluster (m6 I think?) in this region. Stars are pinpoint sharp all the way to the edge of the field of view. With the barlow I found this ep to be excellent on the planets and lunar. Again, it enables you to select the right mag for the conditions easily. Remebering that I'm only a beginner (which may have something to do with it), I found image quality using this ep comparable to the ortho -- maybe not quite as bright but certainly as sharp and it provides just as much detail. It also has the advantage of far better eye relief.

The barlow itself isn't too bad but I certainly wouldn't recommend it. As far as I can tell it doesn't introduce any chromatic abberation but it has a very small clear aperture for a 2" barlow at a very expesive price. In fact, the clear aperture is less than most 1.25" barlows. In hind sight, TVs big barlow would have been better but I will admit I was stung by brand loyalty!

Overall, the scopes performance has been pleasing and what I expected from the positive reviews. Chromatic abberation is noticible only on bright stars such as sirius. Star tests in good seeing have showed a nice airy disc in focus, and nice circular concentric rings outside focus. My only concern is that inside focus the concentric rings have a slightly jagged and hazy appearance (particularly the outside ring) -- if anyone has read this far and knows what this might be or might with a better description your suggestions would be appreciated.

To finish, the biggest advantage of this scope is its portability. I have been able to get this scope out for short sessions in between clouds when I just wouldn't have bothered with anything bigger -- this is the primary reason why I got this scope as I felt it would maximise use. Don't get me wrong, more aperture on nights when i have lots of time and patience would be nice, but I figure 3" of frequently used aperture is better than x" of unused aperture.

Feel free to ask any questions.

Cheers,

Dan

[atalas]

Hi Dan nice report, the star test is revealing a problem for shaw . Getting softening at 155 x with an 80mm triplet ED. I would take a punt and say you have spherical aberration . Should you worry about it?
maybe send it back under warranty for a better corrected one?
These are probably questions you are asking your self!
I think It all depends what your happy with, but the first thing I would do is get a professional evaluation but hey thats me !
I hope that I have not depressed you Dan, that is not my intension,I could be wrong.
I believe that when you buy quality you should get It !

Louie

[grandpanancy]

Yeah, I must admit i'm not sure what to do about the star test. Since I'm pretty new to this, it would be nice to get someone with more experience to take a look first.

I agree that when you pay for quality you should get quality. The only problem I have with sending it back is that it could be a very very long wait to get a better corrected scope. WO seem to have quite a few people on waiting lists for these scopes and I can't imagine the turn around time would be great.


Dan

[grandpanancy]

I just did a quick search on the net -- from memory (I will confirm this after i star test again) the star test images appear on the following site http://www.willbell.com/tm/tm5.htm as a combination of "turned down edge" and slight atmospheric turbulence. I must admit I have no idea what "turned down edge" means or if there are serious practical implications when using the scope?

Dan

[atalas]

Yeah Dan same book I have , its a good read and you do start expecting more for your money but you know thats ok too.

Louie

[beren]

Dan thanks for the report on your scope , star testing can be influenced by weather variables on a given night so try again on a few different nights {this download might help http://aberrator.astronomy.net/html/download.html} i think turned down edge is more of a Abberration that affects mirrors . The ED should be able to push to the boundries so if it is a indication of a problem definetly dont accept it get onto the dealer and send a direct to william yang through the WO site or the WO williams yahoo group and try the gurus at the Cloudy night forums .

[iceman (Mike)]

Great report Dan, i'd love you to combine it with some pictures into a review for the IceInSpace Reviews page!? It might be better after you've had it out a few more times too, to be able to tell if there are any defects, or whether it was just conditions etc.

Teaming this up with barlow to give x155 has generally been a fraction too much magnification except in moments of good seeing. There is noticible softening of the image at this magnification but i suspect the poor coditions have also had something to do with this

I'm sure the softening has more to do with the seeing than anything else. What's the focal length of that scope?
150-200x magnification is pretty normal for a high power eyepiece.. In my 10" (FL 1250mm), some nights the planets can be soft with my 9mm GSO plossl (139x). Other times I can barlow my 14mm to get 178x and still be sharp, but unless the seeing is really good, I rarely get the chance to barlow my 9mm (277x) because the image just goes soft and very unfocused looking - not sharp at all.

Thanks for the report, sounds like a nice scope with some nice accessories.

[mch62 (Mark)]

Hi Dan , I should think that the Williams will be capable of 60x per inch on a night of good seeing.186x
That's the trick getting a night of good seeing with stable air.
My cheaper (Chinese) Celestron 80mm ED doublet is quite often able to go to 192x with a UO 12.5mm ortho and 4x powermate.
Can you take an AVi of the star test and extract some frames to post so we can see what they look like.
Also one of Sirius would be nice to compare chromatic colour at high powers.
I note your in Brisbane, you should come along with all the Brisbane guys for a night at my place in the Lockyer valley.
About 6-7 of us do regular get together and I have nice dark sky's within 3/4hr from Brissy.
PM me your e-mail address and I will let you know the next night if your interested.

I am curious as to the colour correction of the WO triplet and have included a frame of Sirius at 192x. a bit over 60x / inch from my doublet.
A blue haze is visible around the star but from the Achromatic refractors I have had in the past both long and short focal ratios it is vastly superior and images snap to a focus.

Any one with other ED and semi-ed able to post a similar pic for comparisons of color corrections?

Mark

P.S. Dan if your unsure of the star test bring your scope out and I will check it for you.
We can throw the ToUcam in if you don't have one and get some frames to analyze.

Mark