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5" APO verses BEST 7" MAK CASS

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#51 Asbytec

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Posted 21 January 2019 - 08:56 PM

Asbytec,  Would the A37 OCS make the difference in not losing light?   Would start off at a much higher power but that's ok with me. 

I'm not familiar with binos, adapters and various configurations. Maybe ask the bino forum. Some form of Barlow might help, it seem so intuitively. 

https://www.cloudyni...hout-binotrons/

https://www.cloudyni...or-apo-and-sct/


Edited by Asbytec, 21 January 2019 - 08:59 PM.


#52 De Lorme

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Posted 21 January 2019 - 08:59 PM

That I will do right now.  Thanks for the help,

 

Clear Skies,

 

De Lorme


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#53 chuckscap

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Posted 21 January 2019 - 09:48 PM

The skies are not great here either.  But not having to deal with the snow any more is just great. Moved to Killeen 2 years ago.

Though it's cold here in January I can still look up  but not in Colorado Springs.

Have you ever tried using binoviewers with your TEC?  If so were you able to come to focus?

 

Clear Skies,

 

De Lorme

 

I tried using binoviewers on my Orange C14 seven years or so ago and never felt comfortable with them, which is weird since I use binoculars a lot hunting.  Not sure why.  Haven't tried since.   They were the original Denk binoviewer with two 19mm Panoptics.



#54 Bomber Bob

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Posted 21 January 2019 - 10:00 PM

I am always sceptical when people brag about magnifications greater  than 300x.***

 

Why does this bragging claim often come from people who own refractors?

 

 

***It is a fact of live that for us mere mortals atmospheric seeing for most of the time is stacked against us.

You answered your own questions:  Seeing, and refractors.  A quality refractor should stay sharp 60x / inch in average seeing -- not beneath a jet stream.  My backyard would make a DSO fan cry.  But the stagnant air is great for high power planetary, and fracs like my fluorites, EDs, and hi F-ratio achros will deliver at 80x / inch.  On the very best nights, my Questar Standard is frac-sharp at 300x; and, I used 275x often with that vintage ATM 6" F23 Mak-Cass (its views of Saturn were awesome with all those subtle belt colors).  Gotta have the seeing.  And, with small fracs (and Maks), your eyes have to be sensitive enough for the dimmer views.


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#55 Asbytec

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Posted 21 January 2019 - 10:24 PM

That I will do right now. Thanks for the help,

Clear Skies,

De Lorme


Just to be clear, my Orion is the older version I got at a steal on closeout before they went off the market. I understand they have been redesigned, apparently, and reintroduced with an improved baffling system for additional unvignetted back focus.

#56 Peter Besenbruch

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Posted 22 January 2019 - 12:01 AM

How Good or bad are the Sky Watcher and Orion Mak Cass?   I can easily hit 300x with the 5" FCD100. Looking for much higher power on the moon and planets.  Is the optical quality of the Sky Watcher or Orion of excellent quality that it would take me to 500x with a cooperating sky of course?

Mechanically, they aren't as good. What others say about their 7" Maks vs their 5" apos I agree with, though I ran my comparison with a 120mm doublet. I have taken my Maksutov to 540x.



#57 De Lorme

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Posted 22 January 2019 - 12:33 AM

Thanks Peter for letting me know how well your Mak Cass performed.  So far I haven't found any bad reviews or serious

problems that would turn me away.  Looking forward to trying one.  My main concern was the consistency of Sky Watchers

manufacturing.   I would not buy one if that was the case. Hope to find a used one a little down the road.


Edited by De Lorme, 22 January 2019 - 12:34 AM.


#58 barbie

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Posted 22 January 2019 - 12:45 AM

I've had Synta Maks from 3.5 to 7 inches in aperture and they've all been excellent.


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#59 De Lorme

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Posted 22 January 2019 - 04:10 AM

Thanks Barbie,  for telling me.



#60 Magnetic Field

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Posted 22 January 2019 - 02:54 PM

300x to me is just getting warmed up. And i sure do have the seeing that supports crazy powers.  Even with my 3" APO's 300x is no problem on the moon and doubles. Planets start to dim at 300x in 80mm and smaller scopes. But i have used 400x with a FS78 on doubles without breaking a sweat.

 

With my bigger Newts at around 14.5" and 15" i have done over 1000x on Jupiter on my best dead still nites.  I have a 10" Cave with super refigured Cervit blank that gave me the best view of Mars about 10 days ago at 500x.  Super well made optics and super seeing can show some crazy stuff.  It is not like every nite i can set up a scope and use crazy powers, most nites are not that great. But Feb seems to be my best month for steady seeing when we have super warm air and no temp drops at nite and sea fog rolling onshore.  I am right on the gulf in FL.  Summer nites never come close to very warm winter nites for high power work.  My very good SW150 Mak would do 600x on doubles and the moon, the moon was dim but still sharp. 350X on Jupiter was easy. Past 400x and Jupiter gets dim in the Mak. But Venus could take much higher powers since it was much brighter.

By any chance are all the headquarters of department store manufacturers located in Pampanga?

 

This would explain their  magnification promise of 600x imprinted on the box.

 

A 3" apo has an exit pupil of 0.25 at 300x.


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#61 Asbytec

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Posted 22 January 2019 - 07:23 PM

By any chance are all the headquarters of department store manufacturers located in Pampanga?

 

This would explain their  magnification promise of 600x imprinted on the box.

 

A 3" apo has an exit pupil of 0.25 at 300x.

Pampanga is me. Good seeing here, too. :)

 

I agree, a less than 0.3mm exit pupil is problematic for a whole range of objects. You can do doubles easily enough, and the moon should be very dim. Depends on the planet, it may be sharp at the limb but you can bet most low contrast detail and probably color are gone. A good refractor will have better throughput, I suppose that allows a little smaller exit pupil than a CAT. But, IMO, 0.3mm doesn't have a lot of utility. It's not the scope, the image is still as good as it is at 1mm exit pupil, but the eye begins to fail at small exit pupils on most things other than high contrast double stars. 

 

"My very good SW150 Mak would do 600x on doubles and the moon, the moon was dim but still sharp."

This is my experience, too. Doubles are no problem. But the moon is dim with noting more to see up that high. 

 

"350X on Jupiter was easy. Past 400x and Jupiter gets dim in the Mak."

I spent years observing Jove exclusively. About 240x (~0.6mm exit pupil) range is the best I could do on Jove. By 0.5mm exit pupil, the fine detail is washed out, but the broader detail (belts and zones) are still visible. Again, it's not the scopes fault. It's the same nicely resolved image we saw at 240x, but they eye struggles more when the object is dimmer. 



#62 CHASLX200

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Posted 22 January 2019 - 08:19 PM

Pampanga is me. Good seeing here, too. smile.gif

 

I agree, a less than 0.3mm exit pupil is problematic for a whole range of objects. You can do doubles easily enough, and the moon should be very dim. Depends on the planet, it may be sharp at the limb but you can bet most low contrast detail and probably color are gone. A good refractor will have better throughput, I suppose that allows a little smaller exit pupil than a CAT. But, IMO, 0.3mm doesn't have a lot of utility. It's not the scope, the image is still as good as it is at 1mm exit pupil, but the eye begins to fail at small exit pupils on most things other than high contrast double stars. 

 

"My very good SW150 Mak would do 600x on doubles and the moon, the moon was dim but still sharp."

This is my experience, too. Doubles are no problem. But the moon is dim with noting more to see up that high. 

 

"350X on Jupiter was easy. Past 400x and Jupiter gets dim in the Mak."

I spent years observing Jove exclusively. About 240x (~0.6mm exit pupil) range is the best I could do on Jove. By 0.5mm exit pupil, the fine detail is washed out, but the broader detail (belts and zones) are still visible. Again, it's not the scopes fault. It's the same nicely resolved image we saw at 240x, but they eye struggles more when the object is dimmer. 

300x in my FS78 and Jupiter gets too dim. Moon is fine and Venus and even Mars when big and close.  Jupiter and Saturn don't take high power as well when it comes to brightness.  So yes, the image is not as sharp and dimmer, but i can't see much detail on a small disk like i can when i blow it up.

 

200x seems to be about right for most people in a 3" on good nites.  I have always pushed scopes to crazy powers. So my taste is for a bigger image.  


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#63 Asbytec

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Posted 22 January 2019 - 09:33 PM

Me, too. I tend to operate at the higher end of the magnification scale with my 6" MCT in nice tropical seeing. I understand, it is amazing what we can see. At 300x, which is pretty "standard" magnification for me, the MCT hardly breaks a sweat on a lot of objects. But, that's too much for others, like bright NGC galaxies. I've been to ludicrous power on smaller bright planetaries and doubles, no problem, and about 100x per inch on a single bright star...just for a look see. I wish I could take my Newt up higher than that. It can, but at f/6 I need a better Barlow to get there. Magnification of 1000x is too much, though, for my 8" aperture. 


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#64 De Lorme

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Posted 22 January 2019 - 11:40 PM

Asbytec,

 

Have you{or any body else here}pushed the powers of your Mak Cass using binoviewers?  I'm hooked on the Binotrons.  To me they making looking up so much more fun. 



#65 Asbytec

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Posted 22 January 2019 - 11:47 PM

Asbytec,

 

Have you{or any body else here}pushed the powers of your Mak Cass using binoviewers?  I'm hooked on the Binotrons.  To me they making looking up so much more fun. 

I have not done any bino viewing. No yet. I might try it in my 8" Dob. 



#66 Magnetic Field

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Posted 23 January 2019 - 01:27 AM

Pampanga is me. Good seeing here, too. smile.gif

 

I agree, a less than 0.3mm exit pupil is problematic for a whole range of objects. You can do doubles easily enough, and the moon should be very dim. Depends on the planet, it may be sharp at the limb but you can bet most low contrast detail and probably color are gone. A good refractor will have better throughput, I suppose that allows a little smaller exit pupil than a CAT. But, IMO, 0.3mm doesn't have a lot of utility. It's not the scope, the image is still as good as it is at 1mm exit pupil, but the eye begins to fail at small exit pupils on most things other than high contrast double stars. 

 

"My very good SW150 Mak would do 600x on doubles and the moon, the moon was dim but still sharp."

This is my experience, too. Doubles are no problem. But the moon is dim with noting more to see up that high. 

 

"350X on Jupiter was easy. Past 400x and Jupiter gets dim in the Mak."

I spent years observing Jove exclusively. About 240x (~0.6mm exit pupil) range is the best I could do on Jove. By 0.5mm exit pupil, the fine detail is washed out, but the broader detail (belts and zones) are still visible. Again, it's not the scopes fault. It's the same nicely resolved image we saw at 240x, but they eye struggles more when the object is dimmer. 

Sorry I meant Florida.

 

I don't know what came over me. I was repyling to CHASLX200. I had to look up were Pampanga is and thought what the heck it cannot be Florida.



#67 Stopforths

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Posted 23 January 2019 - 03:09 AM

I have a superb Vixen fpl53 115eds and a sw180.  The 180 easily puts away the refractor in good seeing on Jupiter.  The refractor produces images of Jupiter that resemble an etching and in average seeing possibly shows more at times.   But when the seeing gets better the view is better in the mak cass more colour more detail and more magnification possible to advantage.   

 

The sw is very good optically however I once owned a 715 intes micro which was even better and easily better than a 5 inch f-15 D&G I owned as well.

 

A friend has a 7 inch questar and the views on jupiter were something to behold I recall that clearly however the IM715 was better than that also.  It was a delux and had a 27% obstruction.   I think it would be very close indeed a quality 6 inch apo versus the IM715.

 

I regret selling the IM715 and have tried to buy it back twice .............................


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#68 De Lorme

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Posted 23 January 2019 - 03:41 AM

Thanks Stopforths for sharing this.  Looking forward to buying the 7" Sky Watcher.  Just can't grunt hard enough to get the 715 Intes.{LOL}.

 

De Lorme



#69 Stopforths

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Posted 23 January 2019 - 04:04 AM

The sw is no lemon very nice optics very sharp contrasty images wonderful coatings IMHO falls short in 2 minor areas focuser and cooldown.

 

both can be sorted ie setting up before observing and a crayford focuser.  715 even had astrosital optics.  wonderful scope can't believe I sold it.    

 

Phil Barker

owner Stopforths



#70 Erik Bakker

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Posted 23 January 2019 - 04:17 AM

A bit late to the party, but here are my 2 cents, coming from the best of both worlds, a Broad Band multi coated Questar 7 and Astro-Physics EDF 130 f/6 and 4" f/8-f/8.8 Tak and Celestron fluorites.

 

A classic 7" f/15 MCT is a medium to high power telescope. 90x and up, with the sweet spot between 120x and 230x, occasionally doing wonderful at 300-375x on the best nights. No wide fields to be found, no Pleiades in one view. That's were the refractors come in.

 

On Jupiter, Saturn and Mars, my A-P EDF 130 f/6 with Zeiss prism and Zeiss Abbe 4mm at 195x could not hold a candle to the Questar 7 with internally barlowed 24mm Brandon at 190x or 12mm Brandon at 233x on good nights. It opened a new planetary world for me. On wide field observing and cooling, the Tak 4" f/8 fluorite did much better than the Questar 7, while still putting up a good fight on planetary images on many nights. But alas, on the best nights, the Questar 7 was in a league of its own.

 

In my opinion, 7" f/15 MCT and 4-5" refractors are complimentary scopes with some overlap in the 120-160x range. Under 120x, you'll likely prefer the refractor (it better be a good one for some realistic overlap!), over 160x the 7" MCT will pull away. Cooling behavior is different, so depending on your observing spot/climate and how you store/use your scopes, differences may be bigger or smaller in real life under the stars.


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#71 CHASLX200

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Posted 23 January 2019 - 06:21 AM

Seems no scope can do it all. Nothing beats the faster APO for sweeping at lower powers and a Mak seems to do best on the moon and planets at higher powers.



#72 luxo II

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Posted 23 January 2019 - 07:31 AM

But you don't need an APO for low powers - a cheap f/5 achro doublet will do that fine ! So will a 6" f/5 newtonian for that matter. I have a 70mm for that but I regard it as a large finder  - even though it happens to be a quad APO.

 

But where I live (big city, Bortle 3-4) low power is pointless.


Edited by luxo II, 23 January 2019 - 07:32 AM.


#73 Magnetic Field

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Posted 23 January 2019 - 08:39 AM


 

On Jupiter, Saturn and Mars, my A-P EDF 130 f/6 with Zeiss prism and Zeiss Abbe 4mm at 195x could not hold a candle to the Questar 7 with internally barlowed 24mm Brandon at 190x or 12mm Brandon at 233x on good nights. It opened a new planetary world for me.

In bold.

 

Okay the Questar has proven optics and I guess it costs as much as the AP EDF 130.

 

Anyway one more anecdote that a Maksutov is indeed a very good choice for observing planets.


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#74 Erik Bakker

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Posted 23 January 2019 - 08:48 AM

In bold.

 

Okay the Questar has proven optics and I guess it costs as much as the AP EDF 130.

 

Anyway one more anecdote that a Maksutov is indeed a very good choice for observing planets.

Let me elaborate on what I meant: a superlative 7" Mak with 40% more aperture is better at high power planetary observing, under great seeing conditions and fully acclimatized, than a superb short focus 5" APO.

 

Size for size, the superb APO wins. And not many MCT's or APO's are of superlative quality. Although marketing people seem to think differently.


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#75 Asbytec

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Posted 23 January 2019 - 08:56 AM

"...Questar 7 with internally barlowed 24mm Brandon at 190x or 12mm Brandon at 233x on good nights. It opened a new planetary world for me."

 

 

My MCT did the same for me...on good nights. The word "etched" was used earlier, it's really the first time I began to understand what that meant. Sometimes it would be nice if we could look through each others's scopes and see just what the other is seeing and what they call good. In response to that, I lay myself bare for criticism of what I see because I have only a vague idea how good someone else see's the same thing.

 

In that light, a picture speaks volumes. Here's what I see though my cheapo Orion 150 MCT eyepiece (admittedly embellished in terms of saturation and contrast so it shows well on your monitor and you do not have to "observe" the sketch as I did the actual image of Jupiter.) 

 

Jupiter 6 Feb 1330UT Final.jpg


Edited by Asbytec, 23 January 2019 - 09:01 AM.

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