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Anyone know about Astronomica's 152mm Maksutov

philsail1

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GazOC

GazOC

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http://babelfish.altavista.com/babelfish/tr

Gurkerltest - DS Maksutov 152/1900 - sourly like never

Some weeks after our recent starting seminar I was contacted by one the participant. It has to adjust me again asked, its DS Maksutov 152/1900 after a dismantling for improvement. Always curiously on me, I assured unknown telescopes immediately.

When I had the equipment finally in hands, I examined it only once from the outside. The mechanics made a quite solid and confidence-arousing impression. That focus-rubbed ran softly and without jerking. The made improvements were tubus an inner lining with Veloursfolie - actually an unnecessary task of diligence, as I tightened, the equipment later is day blind-free, thus is reflections of the tubus inner wall rather insignificant, because the central screen pipe prevents any scattered light from the outside. If one does somewhat meaningful in this regard had wants, the screen pipe had to be lined inside. The second improvement concerned the main mirror adjustment screws: they are accessible in the original state only if one removes the telescope rear wall. Then one has however no more okularauszug - not straight favorably for an adjustment... Therefore the made drillings were in the rear wall, in order to be able to reach the main mirror adjustment screws from the outside, a meaningful thing.

By means of a laser I controlled first the adjustment of meniscus lens and sekundaerspiegel. Since the laser had somewhat much play in the 1.25"connection, one was not allowed to wedge it. If one "agitated" now in such a way with the laser flat resting upon, found one for instance in the center a position, where the laser beam of the sekundaerspiegel dropped back again accurately. That looked thus so far good.

Then I was a adjusting eyepiece in the 1,25"connecting pieces, and regarded the adjustment of the hauptspiegels. That looked already to some extent strong "beside it". It cost however only a few minutes, until once everything looked concentric here. I wanted to make the fine adjustment at the star.

In this condition I wanted to accomplish now the first tests on the day. In addition placed I mean FR-DX installing onto the terrace, put the telescope on, and began on the east horizon antennas, freileitungsdraehte, to examine roofing tiles and the like. The picture was not completely so knackig quite sharply, in the contrast, as I had already often seen with other telescopes. I attached only once no so great importance to that, since the screen pipe with look through without eyepiece very probably touching light reflexes showed. After something search I found at an insulator sun reflexes, and thus I could study the first diffraction patterns. There I saw equivalent once little coma, an indication that the adjustment still Feintuning would need to be seen and in addition I determined Pinching - the diffraction rings were only in three places. My "stars" were however so faintly, thus were a regular start not possible. Which I positively took to the knowledge: no Bildshifting when focusing.

The following night brought only blunt sky also a few stars, enough however to adjusting to the optics and for a test at the star. In the absence of the polar star, which was not visible from my location, I took Arktur in boat as a goal. My first attention applied for the adjustment, those was a Stueckl off. So far I would not have expected it. Therefore the pipepipe pipe would have to sit actually inclined to the Z-axis of the hauptspiegels... No matter, I made myself to the work, kneeling, and with threatening neck rigidity. Emigrating the star could the star by the adjusting movement always observe itself and had afterwards again in the image field center. After some tracing, in order to ease the neck again, I had the optics so far, it was missing only more probably little for perfect collimation. Coma was practically no longer visibly, only when very high enlargement (approx. 300x) saw one an approach of it. The whole time I had extrafokal worked, now turned I once when this enlargement by the focus through on the intrafokale side. Which I can see thereby, struck me the breath. Honestly, I had to out-climb under the telescope, to lean me to the wall and breathe deeply deeply. I had seen Pfui, so a bad optics never before! Extrafokal completely sharp, high-contrast diffraction rings, but extreme ring much too narrowly, against focus too - where one wanted to assume that - at one time a thick Knoedel became draus, turned one far direction intrafokal, became "nearly" a diffraction wafer draus, which "swam" however in a bright halation, and if one continued to turn intrafokal, was only more the halation to see, without structure, and only much, very late the shade of the sekundaerspiegels showed up. Thus a spherical over correction, which washed itself. In the best focus compromise, if one wants to designate in such a way, Pinching was to be recognized, and evenly that bissl fine adjustment would be necessary still. In view of the cruel illustration I gave this unjustified demand up however - hopeless case...

I communicated my adjusting and test results to the owner, and marked that I would classify this telescope for astronomical purposes as useless. A few days later the owner announced itself again to me. It had contacted the dealer and had addressed the case. As answer quasi would have come, one may this telescope nevertheless so hard test, it would not be exclusively suitable for Deep Sky observation within the range of maximally 60 to 70-facher enlargement... , one knows Hoppla on the part of the dealer easily from this grauslichen illustration? This is emergency A nose, just A feature? Pushes such a thing sourly up, at least with me.

However, on the test with low enlargement I wanted to let it arrive. Equal the next night offered opportunity to me in addition. As the first visierte I the globular star cluster M3 on. With approx. 50x: Ok one, which one saw here, one can call stars. I increased the enlargement on approx. 80x. That also still went through at M3. With scarcely 120x the illustration of the weak stars degrees was still tolerable. Against 190x the illustration was then noticeably too soft. I made the same play also at M13. I found the best compromise between still tolerable illustration and dissolution with approx. 120x. However, a tired sight...

Then visierte I Epsilon Lyrae on. With approx. 120x the close components with much trouble were to be dissolved. It was already very difficult to find the best focus compromise and the stars were surrounded by the halation already mentioned. Tja, the components of the four-fold star are already brighter stars, there showed up the optics errors already clearly. With the weak stars of M3 and M13 still the bad resolving power of the eye helped, whereby degrees point-fine stars are also not noticed still as points. Also M57, was the ring fog, worth an attempt. Actually only a bright Patzen was to be seen there, I had to against 190x to go, so that I could suspect the darker center at least.

At brighter stars the optics could convince not once with approx. 50x. There it was to be found already with difficulty the best focus, and the halation around each star was already clearly visible. With a word said, also in the low extension area the illustration this telescope was more bad than quite. Really, so a miserable optics did not find accomodation me to date ever.

It still came to a further test, on the occasion of the return of the Gurkerls to the owner. Was also walter present, and it could only confirm my results. Besides now thermal effects became apparent, which let the diffraction pattern appear hufeisenfoermig extrafokal. Intrafokal was to be seen anyway nothing except the halation. Walter found this effect extremely strange, I could him however "calm down" that this was only thermally conditioned. Tja, with my tests at home were the thermal conditions saw I such effects more favorably, there only for approximately a half hour. Now however the telescope was in the car, on a sunny day there already meets all day long some at temperature. And as result the Gurkerl Mak fought practically the whole evening and did not become the thermionics effects not loosely. That is a further point, which limits the fitness of the instrument still more. Without would be hardly to be gotten to exhausts the thing also with good optics.

It falls me here very heavily a summary to pull. I concern myself now long enough with telescope optics, than that I could let this go through as quality dispersion caused by production at the lower end. Here possibly somewhat rougher must have happened. Looks nearly in such a way, as if one with center drilling would have provided a Newton mirror, and inserted. Different this really bad spherical over correction is not explainable. Stutzig makes me however the alleged statement of the dealer that this optics is meant for low enlargement only. Does this insanity have easily method that one blocks not fitting optics components here? The price of 358 euro must make actually already stutzig - charms cannot the Chinese finally also - cheap wage country for one or ago. If it were the case the fact that this DS Mak would have "in series" this bad illustration might not offer it a respectable dealer at all - then it is simply not even the 358 euro worth, only a verschwendung of raw materials. The market should regulate such a thing, so that the really useless products disappear automatically.

Should this Gurkerl tested by me be "however really Ausrut" more glaringly? We should interpret it in this direction, because for the owner it nevertheless still another Happy gave ends: the dealer took the telescope back, confirmed the dreadfully bad imaging capacity, and offered to the owner credit note or disbursement. That is at least very fair.

For me it was anyhow a completely new experience. I did not see I already many Optikgurkerl, such a sour however ever.

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John

John

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The attitude I take with online translators is that whatever information I can glean from them is better than my other option, which is no information... :D

I agree entirely Gaz - thanks for posting it :D

I just can't help but grin at some of the phrases that come out !.

John

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Neon

Neon

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I just can't help but grin at some of the phrases that come out !.

Yep, they always tickle me as well, the worrying thing is that it starts making sense after a while!! :D

If you guys enjoy online translations then you'll love this touching love-story on Youtube:

I thought it was a clever idea :D

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  • 2 weeks later...
philsail1

philsail1

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Well, not necessarily (I hope!)....... I'm prepared to give anyone the benefit of the doubt......once only!

The issues I experienced with the first scope could have been due to poor quality control (at the Chinese end of the supply chain) where you get the odd "poor" quality item coming through which has nothing to do with the integrity of the local supplying company. For example, I had to return the head of HEQ5 mount to FLO some weeks after I bought it earlier this year, (it had developed a "kick" which made using high powers impossible). Steve had it collected, and replaced straight away, so from the point of view of the local supplier (in that instance FLO) I had nothing but very high praise.

In this latest "venture," and to maintain a sense of fairness to the the supplying company "Astronomica, "until I get the scope back, and give a good test I cannot reach a conclusion.

I am awaiting it's return in eager (hopeful) anticipation!

Regards,

philsail1

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John

John

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In this latest "venture," and to maintain a sense of fairness to the the supplying company "Astronomica, "until I get the scope back, and give a good test I cannot reach a conclusion.

As Astronomica are now represented on SGL, will presumably have at least seen this thread, and will be aware that you are going to share your thoughts on the scope with the forum, I reckon you've got more than a 50:50 chance of getting a good one this time :(

John

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philsail1

philsail1

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Well I hope so John! I did tell Richard & Ian that I intended to do a "write up" on their 152mm Mak, when I initially ordered it - I told them that i was going away from my usual "reliable" choice of the "Skywatcher" brand to give them a try.

I may as tell you all now, that the first scope delivered a couple of weeks ago had a very bad focusing fault, rendering the scope totally unusable, so back it went, initially with a request from me for a complete refund. In fairness to Astronomica, Richard (their director) immediately agreed to this. However, by the next day, I had calmed down a bit, and after having a chat to Ian Latus (in their Hull shop) I agreed to send it back for them to repair or replace. Of course, if this next one proves the same as the first, I will then ask for my money back. I do like the look and feel of the scope - it does look and feel "the goods." It's got a very good 8x50 finder scope to - something like the quality of a "Tal" finder. Good "Synta" type dovetail for fixing to any Synta mount. Nice finish to the tube too. Either side of the focus its collimation appeared spot on too. (The focuser problem, was just that - the scope would not hold it's focus, and there was tremendous mirror shift too. The Focuser knob was very loose - as if something had come adrift inside the mechanism). I was bitterly disappointed I can tell you!

However! In the grand scheme of things its not the end of the world!! I feel confident that they (Astronomica) will be able to sort the problem out.

Both Richard & Ian from "Astronomica" have said that they obviously want me to be totally happy with any product supplied by them - and if I am satisfied (and produce a positive write up - despite the initial problems experienced - then it will benefit their "standing," and their future sales to others on SGL.

I believe I cannot be fairer than that John.

Regards,

philsail1

Oh! here are some photo's of the scope on my HEQ5 mount.

2535_normal.jpeg

(click to enlarge)

2536_normal.jpeg

(click to enlarge)

2537_normal.jpeg

(click to enlarge)

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