Enconders...why do I want them?

[nmoushon]

So in  the search for a mount that will support my want to image at long focal lengths. I'm planning on a C11HD as my intended scope. My first thoughts for a mount to support this were possibly the EQ8 or a used AP900. Both would easily support it by weight alone and both have good accuracy. Talking with others and reading other threads mounts with encoders keep coming up a lot. I know from my own research and just seeing what others have done that encoders offer a good advantage over non-encoded mounts. Now this is relatively new tech, for the amueture at least, so these mounts are very expensive. Starting at $10k and climb.

My budget right now can not support this kind of purchase in the slightest. Put the suggestion of purchasing the new AP1100 and then when I get the fund buy the upgrades to install encoders on it. Which is much better than shelling out both my arms at once to pay for it and can do one at a time. Much more duable.  Then I realised that once I purchase the encoders the price almost doubles!!!!!!!! This brings up several questions:

1.) Why are they so blumming expensive?!

2.) At that doubled price the 10Micron is now much cheaper and come with encoders. So why is the AP + encoders so much more than the 10 Micron that comes with encoders? Is one that much superior to the other? They are in the same weight class.

3.) Also at that doubled price the new AP1600 (w/out encoders) is cheaper and is also in the same price range on the 10Micron. So why would I choose a 10Micron over the AP1600?

4.) I have a basic understanding of encoders and from that I understand how they work. So with that if I plan on guiding with OAG and guide cam then aren't encoders useless? They only come into play if I want to do unguided imaging and dealing with wind gust (like the ASA mounts). Or am I missing something?

[perfrej]

HI!

1) Encoders are expensive because they are very complicated to manufacture and install. The precision needed is close to ridiculous. In fact, I do not subscribe to the thought of retrofitting encoders of that magnitude to any mount and have a hard time understanding how AP can even consider this as a viable option.

2) The 10Micron mounts have a magic encoder solution that apparently is different and very innovative. I do not know the specifics but they do work. AP encoders are placed in such a way that they need homing after power-on. Not so with the 10Micron ones. You can move it around, clutches off, power off, whatever, and it will know where it is on power-on.

3) More modern stuff and will let you do unguided imaging.

4) Not necessarily. When you go robotic or when you want reliability you benefit from having encoders (at least in the 10Micron version). They are not in play just for unguided imaging, instead they are part of the motor control loop, thus removing close to all traces of periodic errors and other mechanical stuff. Regardless of whether you guide or not, dual axis tracking is more accurate an can go with pretty large polar errors.

As you see, I have two of them

/per

[ollypenrice]

If you want to enjoy imaging at C11 focal lengths buy a good mount. If you don't, you won't enjoy it. I've seen Per's 10 Micron in action quite often and it does indeed work like a charm. Velvet is mobile with a 10 Micron in the UK and is doing very well, too. Long focal length and budget mount is not a recipe for certain happiness.

Olly

[Velvet]

yes i have the GM1000 with Tak 106 and am mobile... no home pier.  10 Micron mount is excellent and  after a learning curve I get on with it very well.  10  min unguided is easy and 15 takes a little more effort. in the field this quite good I think.  i have done a 30 minute

unguided too. I would recommend the mount to anyone, they will not be disappointed.  Not felt the need to guide as yet.

I have recently purchased a Tak 130 but have had some issues with the tripod (geoptic Hercules) so no trial of the 10 micron with the 130 yet.  My problem is that with a long image train on the 130, it fouls against the legs of the tripod with high targets.  I am just investigating this.

I have had an extension made for the tripod which has worked to an extent, but with the huge extended train i need to look at something else I think.

Velvet

[nmoushon]

Thanks for the comments peeps. 

I have no intention of trying to go cheap on my mount. Well aware of the compounding problems when you do.  I'm just trying not to over buy on my mount and leave me with little money left for anything else. No need for me to buy a Paramount for my ED80 when an HEQ5/NEQ6 works great. But as I said I know I can't go cheap and expect easy and great results. Which is why I first had the EQ8 and AP900 on my list as I've seen them both used with the C11 for imaging. 

Thanks Per for explaining my questions. I do understand their complexity enough to reason with why it drives the price so high. What I didn't understand is why the AP1100 with the addition of encoders is over $16k while the 10Micron starts with encoders and is just under $9k. And with your comment makes me wonder even more why the price for the AP is so high in comparison. The only thing I see different is that the capacity is 110lbs vs 55lbs. But AP does state that "Remember also that imaging requirements are more rigid than visual observation."  so if I go by the rule of thumb of half then  they have the same payload. Assuming 10Microns is stating its imaging payload capacity since it doesn't clarify. So for the $16 of the AP1100 I could get the GM2k for the same amount. Maybe its the name that has pushed its price up so high and the fact that 10Micron, though it has a great track record, is still young in comparison. 

I have no doubt that the 10Micron would make my life easier its just hard to get past that the price tag....well I wouldn't have a hard time getting past it. I'm pretty sure I'd get over it by the time it showed up on my door step. I'd just have a hard time getting it past the wife.   

[perfrej]

Oh, them spouses

The GM2000HPS is a better mount than the GM1000HPS. It has a better clutch solution and, as can be expected, is more rigid. The payload of the GM1000HPS (for imaging) is as qouted. I run the 190MN on mine right now and it is a heavy beast with a long tube and with misplaced balance. 20 minute unguided is no problem.

I have recently belt-modded my NEQ6 but I do not have a scope for it. When I find something to put on it I will have to get my guider out of the closet. I haven't used it for ages 

/per

My babies:

[nmoushon]

Those are two beauties  right there for sure! Very jealous .

What would be the max size scope you would put on the GM1000? With all the imagin equipement to?

[perfrej]

Maximum load depends on the properties of the scope. SCTs and the likes have mirror flop problems so they do not do well on mounts that require a steady OTA (anything that models the sky, 10Micron, ASA, Planewave). Long tubes have momentum... The 190MN is a bad beast in all respects; mirror cell needs modification, you need a steady Losmandy bar and you need to balance everything off pretty good. It is also a very long tube. Still, it works wonders on the little GM1000HPS.

The bigger brother, GM2000HPS, is much less sensitive as it is a substantially larger mount. Give it 50 kg of whatever and it will deliver

/per

[nmoushon]

My goal in upgrading is to do long focal length imaging(2m+ FL). I have planned everything on that point. I had planned on the C11HD to be my scope. So with that I wanted to pick a mount to properly match the scope.

I thought that the Edge had mirror lock to prevent the mirror flop problem? If it doesn't then you are saying that the 10Micron actually isn't a good mount to pair with the SCT?

[perfrej]

I do strictly automated stuff and hence rely on auto-focus. Auto-focus has a strict conflict with mirror locks

/per

[nmoushon]

I do strictly automated stuff and hence rely on auto-focus. Auto-focus has a strict conflict with mirror locks

/per

Ah that make since. I totally forgot you went automated. I won't be doing that anytime soon. My obsy will be in my back yard so I'll be out there focusing myself. Thanks for the advice....I think I'll need to be rethinking my budget .

[perfrej]

And I have one fully automated (apart from the hood) on the balcony I seriously do not like being up at night. For my astrophotography. the hobby has three really nice ingredients;

• Fiddling, designing and building
• Fire and forget to get the data
• Image processing

The "sitting by the scope watching the guide graph" routine doesn't appeal to me at all, simple as that. And the cold! Not that I mind cold, we regularly get -25°C in the winter-time, but sitting still... So apart from my remote rig in Provence, the balcony too is fire and forget. Hood off, ACP on, dinner, quick gawk at the screen, bed. Love it!

What I really tried to say was that even a backyard rig needs automation in my world

/per