Excelsis - Display Vote

Intes Micro MN-56

The clear skies all day today were too much incentive. The winds came later - gusts over 30mph. Kinda shook the 'ole MN56 tube - but at dusk and up to about 9pm or so not unbearable.

This was only the second time out for the new MN56. I got it on sale from ITE for $599 ($200 savings).

OK - did star tests and put the MN56 through it's paces with cool down time of an hour or more. Cool down made a huge difference. Stars focused through most of fov - extreme edges show coma but - hey - its an f/5
fast mirror.

I question those who state stars are sharp all the way to edge - seems kinda hard with the f/5 mirror. The big brother MN61 is I think f/6 or longer - that probably makes a big difference.

With good eps (32mm UO 1.25", a 20mm TV plossl, and a
12mm UP ortho - all 1.25" barrels) - scope showed nice images. For a while Jupiter showed remarkable details - I could see striated bands in equatorial
regions - the image equaled what I saw with an MK66 albeit smaller with the 12mm ep and at f/5 compared to f/12. Seeing condits broke down later as clouds rolled into area.

Saturn was fantastic for a while - planet was too small to show details but you could see subtle shading on planet and Cassini Division - but again a tiny tiny image even with the 12mm ep. It was tack-sharp but teeny weeny little.

M42 Orion Nebulae was nice even though there was a full moon - stars in trapezium sparkled like diamonds. I could only see 4 n the bright moon-lit sky. I anticipate a great view and lots of nebula details with an actual dark sky.

The final image was Venus in the Pleidaes. It was beautiful. That's when I decided the scope is a keeper. That eautiful wide field view of the open cluster with Venus was dreamy.

I did several star tests. Lots of circular concentric rings with
outer ring bright and distinct. Central obstruction was well imaged as perfect circle. It was ever so tiny off-center - but all rings were very circular and concentric. I suppose this would be a good star test.

So - for now I think I will keep the scope. The views with proper cool-down in bright sky with full moon and lots of wind were pleasantly good - I can't wait for a still dark nite to check out the Milky Way star fields with that wide f/5 field of view. It's just such an easy scope to use at that aperture.

Improvements - however - will have to be made in my scope. The finder is OK and adequate but hard to focus - I need a better finder to help find faint fuzzies on those dark nites. A right angle may also be needed.

The focuser on this Mak Newt scope also needs to be swapped out with a JMI multi-speed. It needs a fine focus option to zero in on targets - the stock Crawford is
functional but not very subtle.

I also need a few more quality eps and especially eps more powerful than a 12mm for planetary views. Planets are way small in 12mm or larger.

I also need a dew shield - if for nothing more than to protect the front corrector.

I guess the lesson I learned is patience - this scope is much better that I first realized. I gave it another try with proper cool-down and better conditions (albeit not perfect with wind and a full moon) and it proved a good good scope. The fast primary mirror makes pinpoint stars across entire fov through edges impossible - but with proper cool-down it's only apparent at very edges. They're not comets or anything gross - they just go out of focus as you near the edges. That's why I gave the optics only a 9 rating.

I use the scope on a Vixen GP with wooden tripod. It's a great combination. I can find a small object in scope, loosen rings, rotate tube so ep and focuser properly lined so I can use easily - and object will still be in fov. Now - that's a good scope/mount combo!!!

Overall Rating: 10
Optics:9 Mount:10 Ease of Use:10 Value:10
Weight: 1 (Unreliable Vote)
Date: 04/03/2004 04:46:56 pm PST
By: Anonymous (xxx.xxx.234.249)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=351399

> Stars focused through most of fov - extreme edges show coma but - hey - its an f/5 fast mirror. 

The MN56 is not f/5, it's f/6. This reviewer repeats his "f/5" error several times in his report. 

> The fast primary mirror makes pinpoint stars across entire fov through edges impossible - but with proper cool-down it's only apparent at very edges. They're not comets or anything gross - they just go out of focus as you near the edges. That's why I gave the optics only a 9 rating.

Sounds like field curvature and/or astigmatism/coma in his *eyepieces*. Maks are reknowned for wide _flat_ fields. The official specs of the MN56 include:
-- photographic field = 13.5 mm diameter;
-- spotdiameter at edge of photographic field = 11 micron.
This is superb sharpness at a considerable distance off-axis. It would have to fall apart completely, further off-axis, at a rate faster than coma becomes apparent in normal f/6 Newtonian paraboloids, to match the decription given by this reviewer. I doubt that could be the case, so I would suspect the eyepieces or collimation, rather than the telescope optics themselves.

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