Did a quick comparison between my two Maks tonight. Results were interesting.
The Intes Mk-65 is somewhere close to 20 years old but is in great condition. It's a Gregory design, just like the Skywatcher, with a focal length of 1500mm (f/10). The primary mirror is fixed. It has an unusual diagonal with built-in helical focuser. Although the focus travel is limited, it has sufficient range for my collection of eyepieces which include Televue, Pentax and Explore Scientific. The helical focuser is very smooth and precise. It takes 1.25" eyepieces only.
The Skywatcher Black Diamond is only around two years old and in mint condition. It has a focal length of 1800mm (f/12). It focuses by moving the primary mirror, so it can accommodate any eyepiece. The visual back is 2" so allows the use of all 2" accessories. So far I've only used 1.25" eyepieces.
From my light polluted home it wasn't possible to compare the scopes on faint fuzzies, but I did compare views of stars and globular clusters, especially 47 Tuc which is conveniently placed from my balcony. Both scopes were collimated and allowed plenty of time to cool down.
I couldn't match the magnifications in the two scopes but used a variety of eyepieces to get as close as possible, switching around so that neither scope was always at an "advantage" due to higher or lower power.
The results were interesting, if perhaps unsurprising. At low powers, using a Pentax XL 21mm in the Intes and Panoptic 22mm in the Skywatcher, globular views were very similar. The Skywatcher seemed a bit brighter, perhaps due to its more modern coatings and being a 'younger' scope. However, the views in the Intes were still very good.
I swapped around my eyepieces, moving up to a Delos 14mm, Pentax XW 10mm, Explore Scientific 8.8mm and 6.7mm and switching them between scopes.
After using all the eyepieces, I confirmed that the Skywatcher is indeed slightly brighter than the Intes, as you would expect. Contrast seemed similar between two scopes, which might mean the Intes is slightly better in that regard, but losing out on the brightness factor. This seemed to be confirmed when the Intes reached its limit of observable detail at a lower magnification than the Skywatcher.
In summary, the Intes is still a very good scope, and is only just overtaken by the "youth" of the Skywatcher. The side-by-side comparison shows the Skywatcher to be a slight but clear winner. However, if I hadn't done the comparison I'd still be pretty happy with the Intes.
Of course, there's no point in having two such similar scopes, so I reckon I'll be selling the Intes soon. The question is whether to sell the Skywatcher as well and go for a modern Russian model such as an Intes Micro, which is kind of my dream scope. Decisions...
Hi Morton,
That was a very good littel review, something many might be interested in.
Your setup looks very sleek, ideal fo these kind of comparisons.
I have a similar setup, just intead of the DSV-3 I have the AYI II with Nexus+iPod.
Something about the Maksutov that can't be beaten IMHO. The BEST visual views I EVER had of galaxies was through my Skywatcher Mak. I saw more in one night with that scope than I had seen in 20 years.
The only problem with mine was eventually the focuser seemed to become floppier, and I could not find a way to remedy that.
Be interested also to know if other SW Maks have the "issue" mine had - they wrote on the meniscus during assembly with a chinagraph/grease pen, then erased it. I could still read the assembly number 253 when it either fogged up or I blew on it Check yours Morton
Something about the Maksutov that can't be beaten IMHO. The BEST visual views I EVER had of galaxies was through my Skywatcher Mak. I saw more in one night with that scope than I had seen in 20 years.
The only problem with mine was eventually the focuser seemed to become floppier, and I could not find a way to remedy that.
Be interested also to know if other SW Maks have the "issue" mine had - they wrote on the meniscus during assembly with a chinagraph/grease pen, then erased it. I could still read the assembly number 253 when it either fogged up or I blew on it Check yours Morton
I breathed on mine yesterday to give it a quick clean. No number visible, thankfully.
Thanks Morton , just goes to show the quality of the SW Mak I have not looked thru one yet but I have looked thru a MK-65 and was very impressed with what I saw , great review buy the way .
Brian.
Thanks Morton , just goes to show the quality of the SW Mak I have not looked thru one yet but I have looked thru a MK-65 and was very impressed with what I saw , great review buy the way .
Brian.
Thanks. The Chinese scopes are continually closing the gap on the premium scopes, but the gap is still there. Was a bit unfair to compare the Skywatcher to a 20-year-old Intes. I'm sure the current Intes Micro scopes would still have an edge. If only someone would sell me their M603
I had a Skywatcher 150 MAK. It was terrific. It clearly showed Antares'
companion, a beautiful pale green. My Celestron C-8, Skywatcher 8"
Newt, and 10" Flex dob show no sign of it, no matter how many
times I try. It had some image shift, but after re-lubeing the focusing
mechanism it was almost eliminated. A fantastic scope for the money.
raymo
I had a Skywatcher 150 MAK. It was terrific. It clearly showed Antares'
companion, a beautiful pale green. My Celestron C-8, Skywatcher 8"
Newt, and 10" Flex dob show no sign of it, no matter how many
times I try. It had some image shift, but after re-lubeing the focusing
mechanism it was almost eliminated. A fantastic scope for the money.
raymo
The trick to seeing Antares "B" is infinitely more dependant on the prevailing seeing conditions and thermal equilibrium state of the telescope, than it is on the telescope type or design, provided all telescopes compared are of decent optical quality.
Under decent seeing conditions and with all scopes properly cooled and collimated, be rest assured if you see Antares B in a 6" mak, you will also see it under those same conditions in any 1/2 decent 8" or 10" newtonian. Under good conditions with my Suchting powered 10"/f5.3 SDM I can drive a truck between A and B.
I have seen Antares B on many occasions in a 4" Takahashi FS102 under good conditions. I have also seen conditions on many occasions where I couldnt pop it in a 25" newtonian due to stars bloating to the size of soccer balls under poor seeing conditions.
Thanks. The Chinese scopes are continually closing the gap on the premium scopes, but the gap is still there. Was a bit unfair to compare the Skywatcher to a 20-year-old Intes. I'm sure the current Intes Micro scopes would still have an edge. If only someone would sell me their M603
Morton,
Those 1980's/1990's Intes scopes usually have exceptional optics. I am sure with mirror recoats it would outperform the Skywatcher, although probably not by a huge amount due to the improvements in corrector coating technology, over the past 20 years. At high power under good conditions it also should come out slightly ahead, as a lunar / planetary scope.
Depending on your need for 2" eyepieces and accessories it's probably easier to sell both and go with a new Intes Micro as you suggest. Of course there are still the 9" AP maks which I here are pretty good too
As an happy owner of an 180 Skywatcher Mak I was interested in your comparison of the 150mm Skywatcher and the Intes MK65 and was wondering if the difference in image brightness is partly due to the size of the central obstruction being smaller in the Skywatcher.
The trick to seeing Antares "B" is infinitely more dependant on the prevailing seeing conditions and thermal equilibrium state of the telescope, than it is on the telescope type or design, provided all telescopes compared are of decent optical quality.
Under decent seeing conditions and with all scopes properly cooled and collimated, be rest assured if you see Antares B in a 6" mak, you will also see it under those same conditions in any 1/2 decent 8" or 10" newtonian. Under good conditions with my Suchting powered 10"/f5.3 SDM I can drive a truck between A and B.
I have seen Antares B on many occasions in a 4" Takahashi FS102 under good conditions. I have also seen conditions on many occasions where I couldnt pop it in a 25" newtonian due to stars bloating to the size of soccer balls under poor seeing conditions.
Cheers,
John B
I've seen Antares B in my 8" F/6 newt without difficulty in average seeing. Personally I find it a harder target than Sirius B.
As an happy owner of an 180 Skywatcher Mak I was interested in your comparison of the 150mm Skywatcher and the Intes MK65 and was wondering if the difference in image brightness is partly due to the size of the central obstruction being smaller in the Skywatcher.
Jeff
Good question. Don't know the answer! Guess it has some effect but no idea if it's enough to be detectable.
As an happy owner of an 180 Skywatcher Mak I was interested in your comparison of the 150mm Skywatcher and the Intes MK65 and was wondering if the difference in image brightness is partly due to the size of the central obstruction being smaller in the Skywatcher.
Jeff
Hi Jeff,
I think this has a minor impact only. For example assuming the Sky Watcher has a CO of 32% to the Intes CO of 37% this would amount to a difference in light collecting surface area of only 3.84%. A 5% difference in light transmission is considered the human detectability threshold.
I would think of far more importance is the fact that the Intes uses 20 year old coating technology, on both mirrors, 20 year old coating technology on the corrector plate and its coatings are in fact 20 years old and would have without question lost some reflectance/light transmission.
If we assume the reflectivity of each mirror in the Intes has dropped from 87% when new, to 80% at 20 yrs old; and we assume transmission on the corrector has dropped from say 97% to 94% after 20 years, the overall drop in light transmission drops from 73.4% when new, to 60.1% at 20 yrs of age, or a decrease of 18.1%.
Lets assume the Skywatcher with its newer technologies has 90% reflectivity on both mirrors and a corrector plate transmission of 98%. This gives an overall light transmission for the scope of 79.4%. This is a 6% increase over the Intes when it was new and a massive increase over the Intes with its aged coatings.
Yep I have seen Antares B with my 127mm Istar, small and close , inside the very faint 2nd diffraction ring and definatly green looking , not easy to find but once you have found it , its easier to see and it has to be a very good night .
Brian.
Quote:
Originally Posted by pgc hunter
I've seen Antares B in my 8" F/6 newt without difficulty in average seeing. Personally I find it a harder target than Sirius B.
Check yours Morton 
Thanks Morton , just goes to show the quality of the SW Mak I have not looked thru one yet but I have looked thru a MK-65 and was very impressed with what I saw , great review buy the way .
