Konus MotorMax 90 Muskatov Cassegrain Telescope Review

Author: Robert Geake robert@thegeakes.co.uk
Subject:Konus MotorMax 90


Telescopes and Mounts:
Skywatcher Evostar 150
Konus MotorMax 90
Orion(UK) Europa 250
Skywatcher EQ-6
Meade DS2114
Orion(UK) OMC 140
Meade ETX-90EC
Skywatcher Startravel 80
Synta Skywatcher EQ-6 EQ6
TAL 100R Refractor
Film Astrophotography
Minolta SRT100X
Canon IXUS 330
Other Stuff:
Baader Fringe Killer
My Latest Astro Picture
Star Hopping Guide
Stacking images
Bits and bobs

My astronomical experience

I have, in the last 3 years gained more and more experience with telescopes and all fields of astronomy. Although i am hardly a professional i do have a very good working knowledge of telescope types and use as well as observing practices. I have been using all the equipment mentioned on this site along with other equipment at star parties. My reason for buying the Konus is simple. I wanted an equatorial camera mount for my slr, having tried unsuccessfully to locate a BC&F mount i turned to relatively cheap equatorial mounted telescope. After a few days of searching i found the Konus at Green Wich. Read on for the first section of my review.

Konus technical specification

Aperture = 90mm
Focal Length = 1200mm
Focal Ration = f/13
Aluminum tube assembly
Two eyepieces, 10mm and 17mm
Equatorial Mount with motor drive to RA axis

Konus Motomax 90 and EQ-1

Out of the box

As expected for a measle 200 quid, there is alot of plastic. 2 eyepieces a 10mm and a 17mm. Both of which appear to have plastic lenses, not good. I have yet to even try these ep's simply because i have a collection of my own. An EQ1 mount with after market RA drive which, unfortunately is not even capable of moving the RA axis of the scope! The scope its self is a pretty little fully coated Muskatov Cassegrain with a erecting prism for terrestrial viewing(i think). It appears to have an aluminium tube although i have yet to scratch it to find out(wont take me long though). The back half of the scope is of plastic construction and contains a central threaded hole for the erector and a top hole for 1.1/4 EP's. This part also contains the flip lever for terrestrial/astronomical viewing. Altogether the scope and mount is pretty much what i expected for 200 quid, usable but not that great a quality.

Assembly of the mount and scope was relatively simple and required only a single look at the badly translated manual. Knowing the way EQ mounts function aided in assembly and it only took about 30 minutes. Once assembled i realised how fragile and wobbly the EQ1 is compared to its biggest brother the EQ6. There was a bunch of boxes inside a box inside a box inside another box so the "i want to see my new toy" excitement was greatly extended. Having said that though once opened i had the scope up and running within the hour.

My first observing session

As with all my other astronomical purchases and completely conflicting to the law of Murphy, the sky was clear on the day of purchase!!! I did a simple polar alignment by pointing the scope along the polar axis of the telescope and using ALT/AZ adjustments to center Polaris. This is good enough for visual observations. I have yet to try using the setting circles as im sure they will be pretty useless. Visually the scope is much more contrasty than i am used to. I own a Orion Optics Europa 250 that runs at F4.8, given that the Konus is almost F13 that makes for an incredibly dark sky in the background of the image. I have yet to try the scope on anything larger than stars as the moon and planets are still below the horizon until 3am.

Using a TAL 25mm Plossyl I have viewed M31, as expected i got the grey blob with a brightening towards the center although the outer arms where visible as nothing more than a haze of grey. M13 again was really no more spectacular than a pair of decent 10X50 Bins(Some thing to do with the 10mm aperture advantage i guess). No points of light where detectable but the distinctive shape of M13 was easily spotted as well as the hazing effect of all those tiny point sources combined into a single glow. I also viewed the well know sword handle double OC in Perseus. This objects familiar pattern of stars was visible but the reduction in visible points was greatly reduced to what i am used to..

Altogether i believe the scope would make a good quick point an shoot toy for a serious observer i doubt it could be used for anything but that on a regular basis. I look forward to viewing Saturn and Jupiter in a month or so when they begin to rise at a more reasonable time of day.

One must also bear in mind i did not buy this package for the telescope but instead for the EQ1 mount!!
Check back for updates soon!!!

Recent observing sessions

Update: 2004-09-19

Set up mount and did simple align by lining the scope to the polar axis and using the scope to center Polaris, centered Alcyone returned after 5 mins turned the RA slow motion control to find the star in same position in the FOV. Did it again but waited 15 mins this time and noticed slight movement in DEC. Dont think this will matter given the wideness of camera angles.

Attached camera, took 20 odd pics. Mostly milky way, Cygnus first, then Perseus then M31(200mm) then Casseopia(100mm) one or two of Vega through the scope. I now have the resulting images back from the lab and some are ok, the longer telephoto lens has very little light grasp and will need exposures of over 30 minutes!! As i guessed the images of Vega where well and truly out of focus but, hey, it was worth a go!!!

I re-attached the Konus to the mount and viewed M45 for about 30 mins, just stars, colours looking good but not so good as to challenge Europa 250. Using both scopes on the same object really teaches one to appreciate the quality and light grasp of the 250, along with its masively faster F ratio.. Although one downside is the light grey background to the image. The Konus with its slower F ratio(and smaller apature) produces a much more contrasty image with a jet black background.

Saturn high enough to view although it is still very low on the horizon, just above trees to the east. Using 20mm TAL plossyl saturn's rings are, as expected, clearly visble although there is very little/no detail to be seen in the rings or on the planets surface to that matter. This is a very small scope compared to the Europa i am used to using and quote cheap too, i was not expecting anything better than i saw. I did try using a 12.5mm Orion Optics plossyl too but it was all too much for the little scope to deal with. For now i will stick to the 20mm. I can however clearly see 2 of Saturns Brighter moons, Titan and Rhea. This proves the scope can do point source down to MAG 9.8, not bad at all for a 90mm F13!

Venus is now rising throught the trees and i cant be bothered to wait so i will track through the leaves and branches in the hope of getting a fleeting glimpse. DISCO, got about 60 seconds of clear viewing, plenty of time to see venus at approximately half phase!

4am now, im going to bed!
Good Night


Author: Robert Geake robert@thegeakes.co.uk
Subject:Konus MotorMax 90
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