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Orion 180 Mak-Cas vs Celestron C8 EdgeHD

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#1 bcolenj

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Posted 21 January 2013 - 11:30 PM

Looking to branch out into a new scope. Right now I have been doing some general visual observation with an Orion ed80t. My interests mainly lie in lunar and planetary viewing however cluster and DSO would be fun too. Given the similar prices in my budget the two tubes I am looking at are the Orion 180 Mak-Cas or the Celestron C8 edge. The 9.25 edge was also a consideration but I am unsure I can swing the cost. Any recommendations either way or possibly other options in the 1000-1500 range?

#2 watcher

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Posted 22 January 2013 - 02:53 AM

Tough question. I have a 180mm Mak, and I don't think I would trade it for any 8" SCT, but the Edge scopes have been getting nothing but good reviews either.I don't think you can go wrong either way. It probably just comes down to which one "speaks" to you.

#3 Mirzam

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Posted 22 January 2013 - 07:24 AM

I had an Orion 180 mm Mak and was happy with it until I compared the views to my 6" f/10 newtonian. The contrast in the Mak when observing the Moon was noticeably inferior to the newtonian. Lunar shadows were much blacker in the newt. This made me think that the baffling in the Mak was not quite up to snuff.

Although I don't have personal experience with the new HD's I would be inclined to try one.

JimC

#4 azure1961p

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Posted 22 January 2013 - 07:32 AM

I think the lack of contrast versus the newt isn't so much a Mak inferiority but cassegrain scattering light in general. The off axis light shing down that long baffle coming out of the primary can throw a flare across the image. But cassegrains are so much better for other reasons too so its a toss up I think. An aside, this forum in particular seems to have had the consensus the 18o Mak outdoes a C8 . Wether that includes the HD would be interesting to know.

Pete

#5 rg55

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Posted 22 January 2013 - 11:12 AM

Here is a quick comparison of an orange tube C8 and a much newer 180mm Orion maksutov.

Attached Files



#6 Traveler

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Posted 22 January 2013 - 11:56 AM

:gotpopcorn:

#7 Bill Barlow

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Posted 22 January 2013 - 11:58 AM

Given the Orion MCT is f/15, the FOV will be narrow as well as a narrower rear cell opening. I would get the Edge 8" as at f/10, it will be a better all-around scope for multiple target's and it will give additional light grasp.

Bill

#8 bcolenj

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Posted 22 January 2013 - 01:45 PM

rg55, have you done visual through both? Which do you prefer?

#9 rg55

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Posted 22 January 2013 - 02:38 PM

I haven't looked through a EdgeHD, but can speak to the old C8. It's a little brighter but not quite as sharp...of course the latter is partly a collimation issue, and I sometimes struggle with that. From my location I do little but lunar/solar/planetary, so the Mak is a pretty strong choice.

#10 bremms

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Posted 22 January 2013 - 03:56 PM

Comparing a SCT or a Mak to a good long focus newt is never good. My 6" F8 newt has better contrast than any 8" SCT I've had or looked through. Some are about the same on resolution but not on contrast. Looked through a Q7 and that was about the same as my 6" in contrast. Little better on detail. 'Maybe Y'all have really good examples of SCT's. Maybe all the ones I looked through were just not very good.
I even collimated some at star parties. My friends early orange tube is the best I've seen.

#11 Mirzam

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Posted 22 January 2013 - 05:14 PM

I agree that it is an apples to oranges comparison. However, any telescope design can be properly baffled to give maximum contrast for that design. The rather dramatic difference in contrast that I observed made me doubt that Orion had accomplished this. Orion would not be alone among manufacturers having this problem.

Azure mentioned glare coming from the baffle tube, which admits off-axis light directly to the eyepiece at near grazing angles. The baffle tube should be flocked or designed with internal annular rings to minimize reflections from light sources that are slightly off-axis. The bright limb of the moon is one such light source.

JimC

#12 Itz marcus

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Posted 23 January 2013 - 10:26 PM

Would an edge scope improve plannetary and double star views or is its advantage mainly that extended objects appear better at the edge?

#13 Mirzam

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Posted 24 January 2013 - 08:51 AM

If the baffling is done correctly then it will improve performance versus a poorly baffled scope on all types of objects.

Consider this--With any telescope where the eyepiece is at the rear, one must prevent direct skylight (i.e. unfocused light) from contaminating the focused light that forms the image. Otherwise, you will have unwanted glare or simply an unnecessarily bright background that degrades contrast in such things as lunar shadows, subtle planetary detail, faint nebular detail etc. Baffling is a critical element in telescope design.

Now I can't say for sure whether the baffling of an Edge HD scope is better than that of the Orion. However, Celestron does have a pretty good track record of knowing what they are doing.

JimC

#14 Asbytec

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Posted 24 January 2013 - 10:07 AM

Having the Orion 150, I can tell you the baffling is light tight. In fact, I removed my secondary baffle and flocked the inside of the primary baffle. I still see absolutely no glare resulting from poor baffling. None at all. Just came in from some double star work and observing the moon, I gotta tell ya, after tonight's observation, get the friggin Mak. :)

Actually, get either - I am just still on a stoked high from observing the moon. I mean, we have all seen the moon where it looks like you can actually see dust on the surface. I just had one of those nights. And with the secondary baffle removed, the diffraction effects are much improved (less CO by about 10% aperture.)

On Richard's images above. At first glance, it looks like the older C8 is putting up a brighter image while the Mak is dark. But, on closer inspection, the Mak image is actually sharper (in worse seeing?) Not sure what that is telling us, though, many things can affect the image in some way. Anyway, I am not surprised the image in the Mak is sharp.

#15 Tank

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Posted 24 January 2013 - 03:52 PM

Ive have a 180 Skywatcher MAK and have looked thru a few 8" SCTs side by side. Generally speaking the MAK was the more pleasant image by far.
Also owning a C11 looking thru another C11 looking thru a 9.25 owning a old LX5 10" etc. i can say with confidence the MAK design is much shaper and more APO like image than most SCTs.
The Meade ACF and Celestron HDs however might be closing in on the MAK.

#16 doug mc

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Posted 24 January 2013 - 07:07 PM

I own a celestron c6 sct. I flocked the main baffle tube because its inner walls light up when observing the moon and day time observing. It was not possible to see the dark limb of the moon against the night sky before flocking. I give my vote for flocking, it makes a big difference to contrast. I also had to flock two narrow surfaces in my William Optics 1.25 diagonal. Sighting through the scope without an eyepiece with the moon in the field after flocking shows a completly black tube. DO IT!!!. It will make a definite improvement.

#17 skyjim

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Posted 25 January 2013 - 12:15 PM

I have been for many years pro MCT's over SCT's, the flater FOV and contrast just seemed to always be better plus the detail on lunar was always great. My last MCT was a Intes Micro M703 with close to 1/8th wave optics and was an excellent scope (I always wanted an M703 for years and finally got a good one) but I had a chance to look threw a C8HD and everything changed. The C8HD had a nice flat FOV, no coma could be detected, stars were sharp and the focus was the same regardless of were the object was in the FOV, contrast even on lunar and planetary was better than anything that I have seen on for an SCT and IMO spanked the MCT (the Intes Micro MCT's are very well baffled), detail was even sharper on every target plus on DSO's it was soo much better. Both scopes are F10's and some say the F15 MCT's would be better, I am sorry I fail to agree that its gonna make that much difference cause the F15 scopes seem not to perform all that well on DSO's compared to F10's. My call would be with the C8HD, I have owned way too many MCT/SCT's in the past and the HD scope has done everything I would expect from the scope, its easy to mount and very portable too, the optics are spot on, celestron has done a real excellent job.
I used to have maybe anywere from 3-5 scopes, now I have just one and very happy with it.
Jim

#18 Illinois

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Posted 26 January 2013 - 08:29 AM

Here is a quick comparison of an orange tube C8 and a much newer 180mm Orion maksutov.


Both pictures is different so cant compare! Look at different shadows!

#19 Illinois

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Posted 26 January 2013 - 08:36 AM

I cant tell you how good HD is but I know its good! I used C8 for years and donated to Observatory. I have Orion 180 Mak-Cass for 2 years and I love it! Power is different. 2700mm and 2000mm 10 mm eyepiece for 180 mm Mak Cass is 270 X and C8 is 200 X. 70 power different but for high power is not much different however I see Juipter, Saturn and Moon at 270X is great. I use my 180mm Mak Cass for planets and Moon while I have 16 inch Dobsonian for deep sky objects and planets. I use my 100mm f9 refractor most of the time for general view and bright deep sky objects like open clusters and double stars.

IF you not sure which 180 mm Mak Cass or C8HD then I think C9.25 would be good for many years to use.

#20 tomharri

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Posted 26 January 2013 - 08:53 AM

Chinese Maks just are not that good. Can you say 'Diffraction Limited'. They cannot compare to the Russian Maksutovs that usually come with an optical certificate that states '1/6 to 1/9th wave'.

So get the Edge!

#21 Julio

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Posted 26 January 2013 - 12:54 PM

Whos to say the HD series scopes are not just diffraction limited as well. I keep reading that perhaps Celestron hand picks their HD scopes ensuring perhaps a 1/6 PV. I really hope these rumors are correct.

#22 Traveler

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Posted 27 January 2013 - 04:12 PM

When these rumors are correct, why isn't Celestron make this part of their marketing?

#23 jrbarnett

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Posted 27 January 2013 - 10:44 PM

Why Edge?

Why not either a standard C8 OTA ($799 brand spanking new) or a standard C9.25 (about the same price as an 8" Edge, new)?

If you're not imaging, I'd save the dough and get a standard SCT unit.

- Jim

#24 Patrick

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Posted 27 January 2013 - 11:48 PM

Why Edge?

Why not either a standard C8 OTA ($799 brand spanking new) or a standard C9.25 (about the same price as an 8" Edge, new)?

If you're not imaging, I'd save the dough and get a standard SCT unit.



I used to have that opinion too, before I began observing with my EdgeHD. If you keep your object centered in a standard SCT, the view will be very similar between the scopes, but the point is that with the Edge you don't have to keep the object centered in the scope. I realized after using the EdgeHD how often I would fiddle with the object placement in other scopes. With the Edge, I don't have to fiddle anymore because the image looks good just about anywhere in the eyepiece.

Between the two scopes listed, the C8 Edge is a clear winner, imo...more aperture, f/10 vs f/15, flat field and well corrected.

Patrick

#25 Illinois

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Posted 28 January 2013 - 08:32 AM

Why Edge?

Why not either a standard C8 OTA ($799 brand spanking new) or a standard C9.25 (about the same price as an 8" Edge

If you're not imaging, I'd save the dough and get a standard SCT unit.

- Jim



Good idea but what about pin point stars and tight double stars? Is it good? If good then it should be good for planets and moon.






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