Mount choice! Big & basic (EQ8) or Smaller & sophisticated (EM200)?

[johngwheeler]

I'm looking at two used mounts with a view to upgrading my Celestron AVX mount for imaging. One is a Tak EM200 Temma2 of unknown vintage (but great condition) and the other a SkyWatcher EQ8 (Orion HDX110) about a year old.

These are obviously two quite different mounts - the EQ8 is a heavy-weight semi-portable mount and the EM200 is an lighter more elegant (but older) design, and hopefully very well engineered.

Is anyone using an EM200 for imaging, and are there any "gotchas" I should know about? Is interfacing it with a computer straightforward and does it support ASCOM or similar? What is tracking accuracy like? I understand it has no PEC - but maybe it's so good it doesn't need it!

I don't need to the capacity of the EQ8 (a whopping 50kg/110lbs) for my 8" Newt, but I like the idea of something considerably more accurate than my AVX.

Given the prices of both mounts are similar (used), which represents the better deal?

My thoughts on the choice between EQ8 & EM200 are these:

1) The EM200 probably has the capacity I need - as long as I can mount a 10-11" SCT / 8" Newt / 5.5" Apo on it without overloading, it will be enough for any future scope I envisage. Opinion on an 11" SCT (e.g. C11) is divided - some say it will handle it for imaging, others say it's too much.

2) The EM200 seems to be an old design, and it may be harder to interface with modern equipment - although I understand it has ASCOM drivers.

3) The EQ8 would allow very large scopes to be mounted, so gives a few more options for the future.

4) The EQ8 is not really portable - maybe "transportable" is a better description. It would live in my garden semi-permanently. The EM200 is still field portable, which might encourage me to go dark sites more often. In any case I would keep the AVX as a light-weight imaging option & for visual use.

5) Bits of the Takahashi design may make imaging a little bit trickier (some manual selections required for tracking in the southern hemisphere), and no GoTo features without a computer (or at least SkyFi + tablet)

6) The mechanical accuracy of the EQ8 may be as good as or better than the EM200 (quoted +/-3" PE for the EQ8 vs +/-5" for the EM200, which has no PEC capability. I'm not sure what the reliability of these figures is in the real world.

So it's quite hard to decide between them based on accuracy and price!

Which would you choose?

John.          

[ollypenrice]

I have an EM200 and fairly regularly use another as well. There is more difference between the EM200 Temma and the Temma Junior than Takahashi would have you believe because the Junior has some plastic gears which have a bad reputation. In mobile use the polar alignment routine is simply sublime and build qualtiy is good. The lack of a handset is irritating to me.

I did try an EQ8 but, like a lot of people, I found I had a major problem with backlash in Dec and sent it back. I think I can now say this without being shot at because it is very widely documented. There's an EQ8 strip down video on here which looks into the cause.

Which would I buy? Neither. You should be able to pick up a used Avalon Linear Fast Reverse for around £2000. I have no vested interest to protect, here, because I have an Avalon which I am not aiming to sell and an EM200 which I am!

Olly

[cfpendock]

I have an EM200 which is about three years old.  I use it with a Takahashi FSQ106 and a C11.  For the C11 the weight is probably on the limit at around 15 kg, but it does track extremely well.  I like it because it is extremely well made, I regularly transport it, and as Olly says, polar alignment is superb - very quick and accurate.  Unlike Olly's, mine has a handset.  I have no experience with the EQ8, but for me portability is the key and in this respect the EM200 fits the bill perfectly - not too heavy, quick and easy to set up, and extremely accurate.

 

Chris 

[Beeko]

Is it best to start from a position of 'what do I want from a mount?' and go from there? In my recent search, I prioritised easy setup, portability and persistent reliability (have an AVX - some nights it behaves, others it doesn't). This helped me find the mount I want (Avalon). There is quite a difference in the two mounts you are looking at. 

[johngwheeler]

13 hours ago, Beeko said:

Is it best to start from a position of 'what do I want from a mount?' and go from there? In my recent search, I prioritised easy setup, portability and persistent reliability (have an AVX - some nights it behaves, others it doesn't). This helped me find the mount I want (Avalon). There is quite a difference in the two mounts you are looking at. 

Thanks! My principle criterion is to improve consistency and accuracy compared to the AVX, so I'm looking for low PE with a consistent pattern that lends itself to correction via autoguiding. A secondary requirement is to allow me to use a heavier OTA - I currently use a Tak FC100F, which only weighs about 6kg with camera. I'd like something that can easily carry an 8" Newt, 9-10" Cat or 130-140mm f/7 refractor.M

Portability is "nice to have" but not a pre-requisite; the mount will be used 99% of the time in my back garden and will stay set-up under a cover.

Of the two choice, I am now leaning more the EM200 because of its simplicity and (hopefully) more consistent tracking accuracy compared to an EQ8.