SW 180mm Mak Quality
Posted 09 January 2013 - 04:17 PM
I'm looking for thoughts on the quality and overall user experience of Sky-Watcher's 180mm Black Diamond Maks. I get the impression the old gold Pro series scopes were very well made. Curious if the hardware coming out now lives up to that reputation.
I'm looking for a good quality, preferably sub $1k (used), high power planetary scope. Feedback (and alternatives - EdgeHD 8?) appreciated.
Posted 09 January 2013 - 05:26 PM
It appears that Synta is producing serially high quality equipment these days, so I would have to expect the 180mm version to be as good.
On the other hand, the recent Celestron SCTs seem to also have excellent quality.
The difference on planetary performance will likley be very small, but the difference on deep sky and all around use will favor the EdgeHD 8".
What's most important to you?
I don't use it much (along with my 6" APO), but when I do, I love the EdgeHD 8. I think I use my 6" APO even less than the EdghHD 8" because the view in the EdgeHD is so superb. If it fits into the field of the EdgeHD 8" in generally looks as good or better than the 6" APO (deep sky targets).
But honestly, I don't use either of these scopes much. 90% of my observing is with a C14.
But the EdgeHD 8" impressed me more than any SCT I have ever owned. It lacks the aperture of the C14, but for its aperture, it presents beautiful, sharp fields from center to the field stop when good quality eyepcies are used.
So, planetary I expect them to be close, but for all around use, the EdgeHD 8" is a truely wonderful SCT. The best I have ever owned (adjusting for aperture of course).
That doesn't mean that this should be a slam dunk. If you can get a used 180mm MCT for a great price, even the performance on deep sky is not so greatly different that I would turn away from a 180mm MCT that someone was selling one cheap.
Posted 09 January 2013 - 06:11 PM
A local vendor has a gently used Mak180 for $800 CAD, $300 off retail. Apparently in good shape.
It's a tough call, the wider FOV and positive reviews of the EdgeHDs make them an attractive option.
I should add that I plan to use it primarily for visual and maybe tinker with webcam AP from time to time. Seriously considering a binoviewer with this one as well.
What's got me on the fence is the variable quality in these mass manufactured scopes. Scanning recent threads it does seem that the quality is more consistent now than it was in the past, particularly with C's SCTs. That's encouraging.
Posted 09 January 2013 - 06:24 PM
The only lab test I have seen was for an Edge HD 11 (Astro-Foren.de has this test). Sthrel was .95.
Now in my book, .95 is in the excellent quality. You can make a telescope better, but at .95, it is almost impossible to see the difference at the eyepeice between this and a perfect one.
I cannot guaranty that the quality of all of them will be this good, but on the other hand, they are made by the same company yes? Why would they make one better than the other?
So, no guaranty that an EdgeHD 8" will be made as well as mine of the one Rohr tested, but there is no guaranty that the 180mm MCT will be either.
And if you are going to image either deep sky or planets, it is a slam dunk to get the EdgeHD in my opinion, especially now that the focal reducer is in the pipeline.
Posted 09 January 2013 - 07:05 PM
I do give the 150 and 180 a big thumbs down for the narrow-diameter baffle tube and 1.25" focuser that prevents all efforts to effectively use 2" eyepieces.
Posted 09 January 2013 - 10:13 PM
I may ask the vendor if he's up for a brief comparison of the Mak and an EdgeHD if he has one. It would be interesting to see how they fare side by side with my EPs on an average night here.
Thanks for the input guys.
Posted 10 January 2013 - 11:43 AM
Posted 10 January 2013 - 12:16 PM
Posted 10 January 2013 - 01:22 PM
Posted 10 January 2013 - 02:12 PM
A good test is against a decent 8" Newtonian.
Posted 10 January 2013 - 02:50 PM
I dont see much, if any, coma or astig, but I added a tiny bit to be conservative (and about the amounts shown in Rohr's SW test.) No zones were obvious. Aberrator places RMS at about 0.038 and I'd guess the correction to be about 1/6th PV SA or a little better. Its the best I can figure without a bench test.
Yea, they are pretty good with very smooth surfaces.
Posted 10 January 2013 - 08:19 PM
C11 will trump only for aperture giving more detail of the planets clouds. The C11 and Mak 180mm are very close to having the same Focal Length C11 2800 /Mak 2700. However If I am only planet viewing/videoing I will use the Mak due to the smaller/lighter size and excellent contrast.
John59, seeing you own a C11, how does it compare against the 180mMAK on Jupiter?
A good test is against a decent 8" Newtonian.
Posted 10 January 2013 - 09:09 PM
I have a SW 180mm "Black Diamond" Mak for lunar & planetary which i bought as a compromise for portability vs a larger aperture (C11 EdgeHD or 10" ACF LX200 Meade were the alternatives).
a) Straight out of the bag, the chances are the image will be badly degraded by internal tube currents. If you are patient and wait for it to come to equilibrium in good seeing, it will give good Airy disks on bright stars so at high powers it can show all that an f/15 Mak should.
A C11 or 10" Meade might show a bit more detail on some occasions but that's going to be only on the rare nights with excellent seeing. Whether you want double the weight and cost for a larger scope, for not much gain; that is your call.
but it has no fan, so cooling down takes a while. Stirring up the air inside by quickly rotating the OTA or pointing it down while cooling also helps significantly.
c) At f/15 you may need to rethink your eyepiece collection. My favourite eyepiece is a Vixen 13mm LVW, and sometimes in good seeing 8mm. At the long end it will easily fill the field of a Vixen LV50mm.
In 2" eyepieces with no field stop you will lose the outer 5mm of the field due to vignetting, so really big eyepieces that have no field stop such as the TMB 40mm Paragon are a bit pointless. Maybe the C11 can fill such a field, though i haven't tried.
d) obviously it only have the light-gathering power of the bigger scopes, whether this matters to you is your call.
Posted 11 January 2013 - 02:33 AM
Posted 11 January 2013 - 04:54 AM
Dzukielis, sweet clip, thanks for the link.
John59, saemark30, Asbytec, iluxo, bobmarleyou812, great feedback, thanks.
Some background info: I have a 127mm SW Mak equipped with a GSO dual speed crayford and use either a cheap Celestron 1.25" or Orion 2" dielectric diagonal (when it's not in our AT72ED). EPs are 31, 24, 13 & 8mm Hyperions and a Celestron Ultima 2x barlow.
What I hope to gain with 7"+ for planetary observing is larger image scale, more detail and I guess what amounts to a larger exit pupil with my existing EPs without pushing the scope too hard. Portability is important. 8"-9.25" is probably the largest SCT I'd consider.
The 127mm usually breaks down around 187x on most nights. The calculated exit pupil is 0.68mm with the 8mm Hyperion. Floaters are a nuisance, decent focus is tricky at best and the image is dim. Floaters are minimized around 115x / 1.10mm exit pupil with the 13mm.
A 17mm EP with the 7" should land around 158x / 1.13mm exit pupil. That should be comfortable for me for general purpose use.
I'm constrained to a pretty bad location most nights. There is a possibility the image breakdown in the 127 is a combination of scope thermal issues, radiant heat from the parking lot/vehicles/furnace flues etc, below average seeing, collimation (seems off) and a relatively small amount of light reaching my eye. I haven't been able to determine which factors are at play and which is the main culprit with any certainty.
There's a chance a larger scope won't improve the situation, hence the question about the quality of the scopes being shipped by Synta. I should be able to control the environmental variables to some degree with a bit more effort. I'd really like to score good optics though!
Let me know if my reasoning is out in left field or if I'm missing something obvious. Maybe my expectations need recalibration?
Posted 11 January 2013 - 09:41 AM
Posted 11 January 2013 - 10:05 PM
Nice photos on your site Panagiotis!
I have this scope permanantly mounted at my rooftop. It is an amazing scope ! When the seeing is not terrible it delivers excellent views at the planets and the moon . Under dark skies it is very nice for small fields, with very nice contrast and details ! small planetary nebulas or galaxies are very nice and double stars are splitting very nice! I also have a maxbright bino and the views are awessome !! Like you, I am living at the center of a big city, Athens, Greece. But I am using it not just for viewing and photograph planets but I am using it for deep sky narrowband imaging ! I love this scope !
Posted 11 January 2013 - 11:23 PM
Posted 12 January 2013 - 03:25 AM