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AP 178 f/9 Questions

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#1 stevenwav

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Posted 23 April 2013 - 10:33 AM

Hi Folks - I have turned over my fleet of scopes and am about to take delivery of an AP 178 f/9 - white tube. I have a couple of questions about the 178 in particular and big refractors in general as well.

For the 178, I know that some of them were air-spaced. From what I have read, all blue tubes are oil spaced, and the only air-spaced were white tubes. But - I am not sure if ALL white tubed 178's were air spaced or if just the last few produced white tubes were. Can anyone tell me?

I just took delivery of an AP152 f/12 as well. These two refractors represent by far the largest I have ever seen in person and while I have a G11, I am wondering if I should get something bigger and use a portable pier as opposed to the G11 tripod. I do not have the option of a permanent set up so these are grab and go scopes for me!

Any tips, recommendations and advice from current or past owners of these rare beasts would be much appreciated. Cheers! :help:

#2 Mike Clemens

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Posted 23 April 2013 - 10:48 AM

Did you buy the 152/12 from Astromart recently? It was mine before and it was a superb scope. I have a few pics of it online.

The 152/12 is a lot for a G11, the moment arm is healthy. It will work though. The 178/9 is over the line for the G11 (IMHO) it will flex the mount for sure.

#3 stevenwav

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Posted 23 April 2013 - 10:59 AM

Yes Mike! I was told it was your scope and I was very happy to hear that. I saw your pictures online before I found out it that this particular scope was yours. It is in terrific condition and I am very psyched to use it.
As for the mount question, I was thinking I might be able to pick up an old AP 800 for the 178 if I found out the G11 was borderline. I am open to and interested in any recommendations.

#4 Joe Bergeron

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Posted 23 April 2013 - 11:57 AM

The G11 will be overwhelmed by the 178. The 6" f/12 won't be much better. Also be prepared for the eyepiece to be too low for comfortable use when aimed high, even if you have a 5' tripod.

#5 Mike Clemens

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Posted 23 April 2013 - 12:07 PM

Congrats on getting the best version of a 152/12 that AP ever made. I had some real modern-APO FPL-53 snobs sit down at that scope expecting to see the "Best Of 1994 Planetary" and they always came away thinking - "OH - that's serious. Wait a minute! This is really quite excellent !!"

If you could find an AP900 QMD (probably hard to find now) or an AP900 GTO at some new post-1100/1600-GTO pricing, it would be an ideal kit.

#6 stevenwav

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Posted 23 April 2013 - 12:31 PM

LOL! I love it. That'll teach those FPL-53'ers a lesson!
I will look into obtaining a 900. I take it the G11 aluminum tripod can handle it with an extension. I am not going to take any chances and I don't want to under-mount these fine scopes. I should mention that I am strictly visual and have no intention at this point to get into any astro-photography (famous last words). Thanks for the advice!

#7 stevenwav

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Posted 23 April 2013 - 12:34 PM

Thanks Joe - I am getting a 12" extension but even then I anticipate I will be on my knees - not only because the views will be so great! As a lone observer it'll take some technique to sling these tubes around and prop them up high on the mount. I am glad I asked about this subject and appreciate all this feedback.

#8 TG

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Posted 23 April 2013 - 12:37 PM

The G11 will be overwhelmed by the 178. The 6" f/12 won't be much better. Also be prepared for the eyepiece to be too low for comfortable use when aimed high, even if you have a 5' tripod.


If the G11 is in the same class as a CGE, it should be fine for visual use for the 178. Losmandy sells a 12" pier extension for a very reasonable price ($125, IIRC), which incidentally fits the CGE as well. It makes the 178 clear the legs of my CGE with ease but I did have to put a counterweight on the eyepiece end made from (1) A 7" ScopeStuff ring, (2) a AS-GT counterweight bar extension (0.75" OD), and (3) a 5lb AS-GT weight, as the scope is very front-heavy. Its normal balance point is 2/3rd of the way toward the front.

I've also noticed that viewing from a wooden deck is less stable because the slats flex and introduce a slow jitter. I suppose it depends on the construction but placing the mount on the ground is far more stable.

One thing you might want to be careful about if the white-tube has the same screw-in dew-shield as the blue tube is that the threads on the lens cell are hard to engage because of their size. Having a large piece of metal slip near glass is a heart attack waiting to happen :grin:. I'm thinking of storing my metal dew-shield and using a home-brewed Reflectix one. Apart from being more effective, it also lightens the scope and reduces the moment.

Congratulations to the OP on his new scope. The white tubed StarFires are supposed to be the best of the pre-ED AP scopes.

Tanveer.

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#9 stevenwav

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Posted 23 April 2013 - 01:12 PM

Thanks Tanveer! Very helpful. I like the counterweight system you put together. I have a 5lb counter weight ring being given to me by the previous owner so I will see how well that works to achieve balance in the meantime. Your pics do a good job illustrating the repercussions of the front heavy design.

#10 Joe Bergeron

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Posted 23 April 2013 - 01:21 PM

The G11 tripod is not the issue. It's strong enough. The native height of the tripod is 48". Add the extension and you have 5' tripod. This is a good height for my 6" f/9, but is pretty short for anything substantially longer.

I have a different experience with the G11 head. It's good for visual use with my scope, but if it's even somewhat windy it's frustrating at high powers. I've also used a 6" f/12 on a pier-mounted G11 under a dome. It was quite wobbly and unacceptable to me. A 178 would weigh close to twice as much and be unacceptable to me on a G11. Of course different people have different tolerances for that sort of thing. In my opinion a 900-class mount is optimal for these scopes, and mandatory for imaging.

#11 Mike Clemens

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Posted 23 April 2013 - 01:28 PM

I used a 175/8 on a G11 and it could best be described as "squirrely" and "spaghettified"

#12 stevenwav

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Posted 23 April 2013 - 02:03 PM

I am leaning towards finding an old AP900 QMD. The cost is reasonable and I like the fact that it's still pretty portable.

#13 TG

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Posted 23 April 2013 - 02:35 PM

The G11 tripod is not the issue. It's strong enough. The native height of the tripod is 48". Add the extension and you have 5' tripod. This is a good height for my 6" f/9, but is pretty short for anything substantially longer.

I have a different experience with the G11 head. It's good for visual use with my scope, but if it's even somewhat windy it's frustrating at high powers. I've also used a 6" f/12 on a pier-mounted G11 under a dome. It was quite wobbly and unacceptable to me. A 178 would weigh close to twice as much and be unacceptable to me on a G11. Of course different people have different tolerances for that sort of thing. In my opinion a 900-class mount is optimal for these scopes, and mandatory for imaging.



I agree that a 900 class mount would be ideal but the blue tube 178 is only about 30lbs (IIRC) and unless the white tube 178 has the newer CNC machined tube, it should also weigh the same. I doubt the 6" f/12 is only 15lbs so your estimate seems off. The f/12 does have a longer moment arm and that I think matters more than the weight. I have no experience of the G11 but supposedly the CGE was built to be a G11 replacement (Celestron had been using Losmandy to source their high end mounts), and I find it perfectly adequate for visual use. At my viewing site, it's almost never windy when it's clear but I can imagine wind being a problem. But just to give a concrete example, I find that vibrations damp down in 2-3 sec if the mount's on the ground and 5-6 seconds if it's on a ScopeBuggy. And I can still focus precisely down to Airy-disk precision without any problems using the standard A-P 2.7" single speed focuser while using a heavy Zeiss Mark V binoviewer + 2" AP barlow.

The CGE has its electronics in a "half pier" that gives a 18" total extension to the tripod but the extension that Losmandy sells is stackable and quite solidly built so if necessary, once could always use two. However, it's always a balancing act between viewing comfortably at zenith vs. viewing comfortably at a lower altitude. The best results, IMHO, are obtained by pushing the center of gravity of the scope toward the eyepiece end by weighing it down (a heavy binoviewer + finder helps here as well) so that the majority of the tube length is forward of the mount.

But if the OP has cash to spare, now that AP has come out with the 1100GTO for $8.8k, I suspect there will be plenty of 900 mounts on the used market soon for nice prices.

Tanveer.

#14 TG

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Posted 23 April 2013 - 02:40 PM

I used a 175/8 on a G11 and it could best be described as "squirrely" and "spaghettified"


If that's the new AP scope you are talking about I don't doubt it given that it weighs 43lbs. The old 7" pre-ED scopes had regular Al tubes with the OD same as the aperture: 7" and weighed only about 30lbs.

Tanveer.

#15 Mike Clemens

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Posted 23 April 2013 - 02:43 PM

no it was a TMB175/8... 30 lbs is a lot better but the moment arm will get ya

#16 John M.

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Posted 23 April 2013 - 02:55 PM

Regarding the original question... I had a 152 f/9 (received 4/92) that was made just prior to the introduction of the 155 f/9 EDTs. Mine was air-spaced. That was not true of all the 152 f/9s, however. So, I'd suspect that not all of the 178 f/9s were air-spaced........... John

#17 EddWen

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Posted 23 April 2013 - 03:00 PM

I am leaning towards finding an old AP900 QMD. The cost is reasonable and I like the fact that it's still pretty portable.


I have a 900QMD I am not using. Pm me if you're interested and I'll dig up some details this evening.

#18 Eddgie

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Posted 23 April 2013 - 03:12 PM

Sometimes you can find a used Meade LXD 750. These are pretty stable mounts with a large refractor.

You can often find them cheap, but parts (should you need them) are difficult to find.

This was the mount Meade shipped with their 178ED. It is much more stable than the CGE.

#19 stevenwav

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Posted 23 April 2013 - 03:28 PM

pm sent - thanks!

#20 stevenwav

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Posted 23 April 2013 - 03:29 PM

Thanks Eddgie - I am open to all viable options. I appreciate it. -S

#21 Paul G

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Posted 23 April 2013 - 03:33 PM

I am leaning towards finding an old AP900 QMD. The cost is reasonable and I like the fact that it's still pretty portable.


That's what I would do. There will probably be some coming up for sale, including GTOs, when the 1100 starts shipping.

#22 rfic1

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Posted 23 April 2013 - 03:40 PM

Hi Steve,
Congrats! The other less expensive option would be a older AP 800 mount but agree that a AP900 would be a excellent choice.

#23 Joe Bergeron

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Posted 23 April 2013 - 04:03 PM

According to a previous owner, the 6" f/12 Superplanetary OTA weighs a whole 18 pounds. That sounds about right to me. My scope weighs 23 pounds, and while it has less tube it has a much heavier cell and focuser than those old scopes. So I think my estimate was pretty good.

As I said, different people have different tolerances. You are satisfied with the performance you're getting, and that's great. I wouldn't be.

#24 Ziggy943

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Posted 23 April 2013 - 07:01 PM

Yes Mike! I was told it was your scope and I was very happy to hear that. I saw your pictures online before I found out it that this particular scope was yours. It is in terrific condition and I am very psyched to use it.
As for the mount question, I was thinking I might be able to pick up an old AP 800 for the 178 if I found out the G11 was borderline. I am open to and interested in any recommendations.


Steve,

A friend also recently purchased a AP 178 recently through Astromart. We tried it on my AP 900 mount and it was fine visually but would have benefited from a 1200 class mount. He didn't have a finder yet so our targets were limited but Jupiter was very good.

#25 Mike Clemens

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Posted 23 April 2013 - 07:17 PM

I didn't expect that, Ziggy. My TMB175/8 was about 50 pounds dressed and it was a great match with the AP900QMD I had at the time. Of course, I just came from a G11 so I might have had stars in my eyes at the time.






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