Author Topic: HDX110 or AP1100 for my Cave 10" f/7?  (Read 500 times)

neaubigvapec

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HDX110 or AP1100 for my Cave 10" f/7?
« on: December 30, 2017, 01:13:37 PM »
Hi, everyone. A couple of weeks ago I introduced myself and asked which mount would work best with my Cave 10” f/7 Newtonian for primarily visual use (as well as my C8 and ES 80ED Triplet APO primarily for photography) – the G11 or the CGX-L. There were a few comments and recommendations, but practically everyone agreed neither of those 2 mounts would be sufficient for my needs. So, after additional research (based on those recommendations) and more contemplation of my desire to utilize my Cave telescope once again (with GOTO ability), I’m now looking at the Orion HDX110 and the AP1100. My original budget of $3500 wasn’t based on my ability to pay for it, but on my hesitancy to spend any more than that just because “I want it” when I could use the “extra” money to save for retirement, etc…but I’ll save that discussion for another time. Anyway, I don’t really have a max budget, but I also want to be wise and not overspend just because I can. So, yes, there is no argument that the AP1100 is a better mount than the HDX110. However, do I “need” the AP1100 or will the HDX110 suffice for my needs considering the equipment I have and how I'm wanting to use that equipment? My primary concern is the GOTO accuracy for the 10” as well as the ability of the mount to keep my 10” steady while tracking well. I know I need to learn the night sky better, but when you have the technology that is available nowadays, why not use it?



asexdalo

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #1 on: December 31, 2017, 01:05:03 PM »
Putting a 10" f7 Cave Newt on an AP1100 is an interesting idea. You would have to come up with a very low tripod or pier setup if you want to get to the eyepiece without a ladder. It would be a very effective combination.

I have an AP1100 that I usually put a C14 on top of and it works great. I have a 16" SCT OTA I could put up there if I felt better about getting it on top of the mount.

I have a hand-made 10" f3.8 Newt that is the same vintage as the Cave scopes and it looks like a Cave. I have put it on top of a G-11.

My 10" f3.8 Newt has a lot of internal flexure when moving around the sky, just like the old Cave OTA's. It could be that in spite of having a rock-solid mount like an AP1100, the combination will still have a lot of flexure and pointing unpredictability without a pointing model.

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esrescioripp

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #2 on: December 31, 2017, 11:43:29 PM »
Dennis:

I've learned from direct experience that the slop or lack of it, in the rotating ring assembly will be the thing that first limits your go-to accuracy, regardless of the mounting. Spending the time take that slop out and aligning the system with the mount axes will pay big dividends in polar alignment accuracy and therefore goto accuracy.  Been there, done that...still doing it to a degree. But rotating rings are soooooooooooooooooooooooooo nice with a GEM'd newt.

Regarding the AP1100. It's build is first tier and when accurately aligned its goto's are very accurate. It's a bit of a tall mount physically so you need to take that into consideration for pier height. It's servos are awesome, very robust. If your rig will be portable in any way, I highly recommend a RAPAS and take the time to align the RAPAS to the mount. If you buy the mount and RAPAS new from AP, they may be able to do that for you.

Now something else to consider, is a used AP 1200GTO with the CP3 or CP4 controller (or no controller if you're going to use a computer). They are completely awesome mounts, cheaper than a used 1100, greater weight capability and look really cool too. I made the swap and glad I did.

Jeff

David Pee

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #3 on: January 09, 2018, 11:07:57 PM »
Thanks Christopher and Jeff. Your replies make a lot of sense and Christopher your hand-made 10” Newt is impressive. I do have a few questions, though:

Christopher when you say, “the combination will still have a lot of flexure and pointing unpredictability without a pointing model”, what do you mean by a pointing model—are you referring to a GOTO alignment or something totally different?

Jeff, I hadn’t thought about the slop in the rotating rings. Mine seems to be tight, but I’ve not actually used it with a computer for GOTO or tracking yet. Would I need the RAPAS if I already have a Polemaster?

So, will the HDX110 not work for the Cave (weighs about 50lbs)? I’m not expecting to be a world-class astrophotographer, but if I’m going to spend thousands on a mount, I want it to be enjoyable to use rather than frustrating. At the same time, I don’t want to spend more than is necessary.

exjeraca

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #4 on: January 10, 2018, 09:32:11 AM »
Quote
Would I need the RAPAS if I already have a Polemaster?
You don't *need* the RAPAS if you use the PM (PoleMaster) - they are both used for polar alignment. I don't yet own an AP mount, but I'll be purchasing one over the next couple of months. So, I am not in a position to say whether the RAPAS is better/easier/etc. when compared to the PM, but you would really only use one or the other. If you got the RAPAS, you may find it easier, in which case you can sell your PM on Amart.

I have a PM, and I mounted it piggybacked on my scope because there was no real place to put it on my mount (an MI-250). My adapter was one of these which was screwed to one of these (or roughly equivalent) where I drilled holes to match the PM adapter holes. I then attached this setup to a harness that is piggybacked on my scope (along with a few other items like a USB hub and focus controller). You could actually attach this setup directly to your scope, like a finderscope.

guisamcipen

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #5 on: January 10, 2018, 12:49:41 PM »
Quote
Thanks Christopher and Jeff. Your replies make a lot of sense and Christopher your hand-made 10” Newt is impressive. I do have a few questions, though:
Christopher when you say, “the combination will still have a lot of flexure and pointing unpredictability without a pointing model”, what do you mean by a pointing model—are you referring to a GOTO alignment or something totally different?
Jeff, I hadn’t thought about the slop in the rotating rings. Mine seems to be tight, but I’ve not actually used it with a computer for GOTO or tracking yet. Would I need the RAPAS if I already have a Polemaster?
So, will the HDX110 not work for the Cave (weighs about 50lbs)? I’m not expecting to be a world-class astrophotographer, but if I’m going to spend thousands on a mount, I want it to be enjoyable to use rather than frustrating. At the same time, I don’t want to spend more than is necessary.


If your OTA isn't carefully collimated so the optical axis is exactly centric with the optical tube, rotating the rings will change the GOTO pointing. I discovered this with my Newt. It isn't clear in my photo but my custom machined rings allow the OTA to rotate. The rings are spring loaded and I installed small roller guides on the OTA.

As for "pointing model" that is a feature of Astro-Physic's APCC Pro. Some other mounts have similar capabilities. Either in the mount's firmware or in external PC control software. Basically, a pointing model figures out the flexure and flop of a OTA on top of the mount at various pointing angles and applies pointing and sometimes tracking compensation in software to make the mount+OTA perform (GOTO and tracking) more accurately.

Personally I have accepted that my old Newt has a lot of internal flexure and rotating the OTA effects the GOTO pointing accuracy. That is why I have put my Newt on an old G-11 and a short GM-8 tripod. Putting it on my AP1100 would prevent my AP1100 from really shining to its fullest capability. So basically if you are willing to accept that the combination of a premium mount like the AP1100 and an old Newt OTA with rotating rings isn't going to have the same GOTO accuracy as a modern OTA without rotating rings, then you can be happy with the combination. Otherwise get a less expensive mount or maybe convert your Newt to a dob mount configuration. You could even make a dob mount full GOTO using a Sidereal Technologies servo controller and drive parts to both axes.

I hope this helps.

calfkommomu

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #6 on: January 10, 2018, 02:43:41 PM »
Thanks guys. I really appreciate the clarifications. I love my Polemaster and would really like to use it on whatever mount I decide to get. Also, thanks Christopher for explaining the pointing model. As I said when I first introduced myself a couple of weeks ago, a lot has changed in technology since I first bought my Cave in 1975. I'd read a little about the APCC Pro, but didn't really understand it. You've explained it very well. I didn't realize that kind of technology existed until now.

So it appears the consensus is the AP1100 over Orion's HDX110 for my situation. I'm not sure if that is because the HDX110 won't work well with my telescopes or if nobody really has experience with it. If you have any thoughts about it, please tell me.

Eric Shaffer

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #7 on: January 10, 2018, 06:06:59 PM »
The HDX is actually pretty popular right now since its combines high capacity andgood tracking with a price tag that is significantly lower than AP or the other premium mounts. Thissame mount is also being sold as the EQ8 under the Sky-Watcher name. A good number of imagers here on CN now use it and are generally reporting good results.

If your primary concern is budget, then the HDX is a clear winner here. It can manage the load you intend to carry and can be made to perform very well. There are some known issues that have come up for some users, an odd sort backlash problem is one (mine does that). Other users report flawless operation.

So its not perfect and may take some fiddling to get best results but I believe it can do the job you would be asking of it. But before buying one, its worth checking out the EQ8 yahoo users group for tips and potential pitfalls. The lower price tag is there for a reason...

For visual use the biggest weakness in the HDX is probably the GOTO accuracy. The HDX uses the SynScan handset which can be quite inaccurate if the mount is not very carefully aligned. Good mechanical polar alignment along with good star alignment and properly aligned opticshelp quite a bit. SynScan does support a rudimentarysystem for adding extra stars to its model. This can help a bit but even the most basicCelestron mounts are usually more accurate. (and yes I know, the word "model" is a stretch when talking SynScan but for lack of a better word...).

For much better goto accuracy the EQMOD package is the preferred option. EQMOD is a PC based package and has similarities to APCC, T-Point and other modeling systems. Among other things, with EQMOD you can build a sky model using large numbers of points. Its perhaps not the most sophisticated system out there but it does work and the end result is near-perfect goto accuracy. It also has a number of other functions besides modeling and is very easy to use.

As for its suitability for carrying a large newt, the HDX will have the same basic issues as the AP or any other EQ mount. Eyepiece height and placement will be a concern. Rings can address this but canbring in their own problems as well. I have experience imaging with an 190mm mak-newt on my EQ8. The mak-newt is as heavy and long as most 10 inch regular newts. The EQ8 just laughs at the load and carries on like its nothing. But its awkward for visual no doubt about that.

Mark Patterson

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #8 on: January 10, 2018, 09:43:55 PM »
Quote
Thanks guys. I really appreciate the clarifications. I love my Polemaster and would really like to use it on whatever mount I decide to get. Also, thanks Christopher for explaining the pointing model. As I said when I first introduced myself a couple of weeks ago, a lot has changed in technology since I first bought my Cave in 1975. I'd read a little about the APCC Pro, but didn't really understand it. You've explained it very well. I didn't realize that kind of technology existed until now.

So it appears the consensus is the AP1100 over Orion's HDX110 for my situation. I'm not sure if that is because the HDX110 won't work well with my telescopes or if nobody really has experience with it. If you have any thoughts about it, please tell me.


APCC and APCC-Pro are like jet aircraft instrument panels for AP mounts. The pointing model capabilities in APCC-Pro are just one of the many things that they do. They are really-fun programs to work with but unless you are a serious imager or remote-imager, they might do a whole bunch of stuff you don't really need.

The AP1100 (actual part number is 1100GTO) is an awesome mount that will hold its value for a very long time and will work with whatever OTA you might come up with in the future. It is rated for OTA's up to about 110 pounds. Less if the OTA's are excessively long. It is certainly the Maserati of telescope mounts.

If your passion is imaging and you have the budget then maybe what you should consider is getting a premium 130mm-160mm refractor with an AP1100 or Mach1 mount and find a used Cave-Astrola mount for your existing Cave 10" f7 Newt. Keep your Cave for sentimental reasons but focus your imaging desires on newer equipment and technology. I sold my old Cave-Astrola mount and upgraded to the G-11 because I wanted GOTO for my Newt but now I sort of wish I had kept it closer to the original configuration for sentimental reasons.

I now use a AP Mach1 with AP 130mm refractor for imaging. SBIG STF-8300M camera with FW5 filter wheel and an OAG and STi for autoguiding. And APCC on my imaging laptop.

I use an AP1100 with C14 for outreach.

I have my 10" f3.8 Newt on a G-11 for sentimental reasons. But I don't use it much. More fun to just look at it than use it.

I have a Meade 16" LX200GPS on wheels that I use for visual work in my driveway.

I hope this helps.

opalytun

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #9 on: January 11, 2018, 04:45:31 PM »
I would say the EQ-8/HDX if you are mainly visual and relatively undemanding imaging. The only real draw back to the mount is that it's fairly heavy.

thesaroha

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #10 on: January 13, 2018, 01:18:38 AM »
Thanks again, everyone, for your informative posts and advice. You've given me a lot more to consider. I must confess, given what everyone has said about the 2 mounts in this thread, I'm now leaning toward the
AP1100. Considering that my original intended budget of $3500 has now grown to perhaps $10,000 or more in the last 2 weeks, I better make a decision soon if I get to retire when I've got planned! Clear skies.

frenafverbi

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #11 on: January 13, 2018, 11:13:05 PM »
The 1100GTO is awesome...very portable for the weight class, optional pass thru cablingfor a clean setupand optional RAPAS is great. I've now set mine up about 70+ times and it just runs well. You pay more but get rewarded with a lifetime-like mount.

Best of luck with whatever you choose. cheers, DJ

Woody Boelkens

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #12 on: January 20, 2018, 06:02:26 PM »
I too think you will be very happy with the AP1100. I don't have anyexperience myself with one so didn't comment on it, but from what I've heard its an excellent mount. And DJ is totally right, owning a lifetime mount is something special for sure.

witchcycsuti

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #13 on: January 21, 2018, 02:20:22 PM »
I have the Orion HDX-110. It is very good for imaging. I have the PE down to 0.66 arc second peak to peak with correction. The guiding is great at >0.4-0.7 arc second RMS. I have posted a bunch of posts on it and everything I have experienced. I have a 10" SCT and a 110mm APO and the mount doesn't seem to notice. Is it better than the AP1100 clearly not. But it costs 1/3 as much. If you have the Bucks, get the AP no question. But do you need it? From a weight perspective the EQ8 can handle it and it is a fine imaging platform. I can get very good guiding and 8-10 Minute subs with about all good. The mount is not the issue in the imaging. I have a pole master for rough alignment and us PHD2 drift for polar alignment. My only recommendation would be to get it from skywatcher USA for an EQ8 and not ORION since they have better service. I have never used a Newtonian so I don't know if there are any quirks that are an issue.

prehconbubun

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Re: HDX110 or AP1100 for my Cave 10" f/7?
« Reply #14 on: January 23, 2018, 12:54:26 PM »
Thanks for your post, cfosterstars. While I'm leaning more now toward the AP1100, I've still not made up my mind yet. So, your info is much appreciated and gives me more to think about. I did email SkywatcherUSA about the EQ8. They told me they didn't sell the EQ8 at this time. So if I decide to go that route, I'll have to either order it from an international source or buy the HDX110 from Orion.