Skywatcher EQ6 Pro Equatorial Mount

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Meng Lee
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Skywatcher EQ6 Pro Equatorial Mount

Post by Meng Lee »

Hi all, I will give a partial review of this EQ6 Pro mount (also is Orion Atlas EQ-G mount).

Part 1:

Appearance:

It arrived in 2 boxes. One containg the mount head and controllers, the other one contains the 2" Steel tripod. Pictures later.
I also ordered the full pier for EQ6 with wheels!

The metal peg on the tripod is between 2 legs, hence half pier for EQ6 is not needed! Good news for all everybody seeking the ultimate 3 legs to hold your GP and variants mount head. Installation is very simple, the manual is not needed. But the mount head is very heavy! And another good news is, take out the front screw and the latitude adjustment can reach 0 degree.

The bad point is that the counterweight bar is slightly thinner than the vixen one and it retracts loosely not like the sphinx one. New vixen counterweights need to get longer screws to use the counterweight.

Ok, watch out for upcoming pics and part 2 reviews on GOTO electronics and part 3 on Autoguiding and imaging on this mount.

Thanks!
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Meng Lee
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Location: NTU, Woodlands

Post by Meng Lee »

Hi, I done some tests on its GOTO.

First, note that
2-star alignment compensates polar alignment error but does not compensate cone-error

3-star alignment compensates both polar alignment and cone error.

At least 2 star alignment is highly recommended.

There is a PAE function in the GOTO that enhances GOTO in small areas of the sky. Highly recommended for imagers.

Tracking of the mount is simply accurate. Almost as good as my Skysensor.

Cons: if you don't use the stars they recommend for alignment, then alignment is usually unsucessful. But all the star names leaves one to wonder what they are ! So get a starmap book nearby such as "Pocket sky atlas" or get the Meade "The Sky", hehe.

This is really a mount definitely worth its price.

Next I will try imaging, pray for good skies first.

That's all for now.
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Meng Lee
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Post by Meng Lee »

Hi all, just some updates.

I have done the full 3 -star alignment for EQ6 and at magnification around 100x, its GOTO hit rate (in the eyepiece view) is very high. I slew to 5 objects, M13, M3, NGC 3372, Omega Centauri, M4.

All objects are seen in the eyepiece view. Using the PAE function, the slew gets the objects very nearly to the centre of the eyepiece view. This is important for CCD imaging.

I would actually recommend it over the Sphinx mount for beginning-intermediate imagers.

But lets not forget its bad points:
1) Star names needs to be referred to, in order to do alignment.
2) Date and Time are not stored. Maybe a later firmware might help, but there's no battery inside the controller.

Thanks for reading :)
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VinSnr
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Post by VinSnr »

does it do alt-azi tracking like the skysensor?

Or must you do a good polar alignment first, if not tracking will be out, although GOTO is ok?
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Meng Lee
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Post by Meng Lee »

You can think of EQ6 having the mount mode "Unaligned equatorial" only. So rough polar alignment is needed. It does not have AZ mount mode. In 2 star alignment, the algorithm corrects for error in polar alignment, (same as Skysensor).

Yes, so tracking will be out (maybe 10mins only in EP view around 100x)
Robin Lee
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Post by Robin Lee »

Hello Meng,

I wonder how long you can track without star trailing by just implementing the 3-star-alignment? (No drift alignment)
Clear skies,
Robin.

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orly_andico
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Post by orly_andico »

I will guess no more than 2 minutes at short FL (600mm).

The reason being the EQ6 has a huge periodic error of around 30 - 40 arc-seconds (normally) but as bad as 120 arc-seconds.

http://lambermont.dyndns.org/astro/pe.html

Although with PEC it can be reduced to 6 arc-seconds which is pretty darn good. Still 2 minutes maximum.

My Vixen GP has a 20 arc-seconds PE (+/- 10) although it has two large spikes that I'm trying to get rid of. With this GP and a measly 30-seconds exposure time, only 1/3rd of my subs are perfect (2/3rds have elongation) at 336mm focal length which is very short. This is with a drift alignment so I know my polar alignment is pretty good.
Last edited by orly_andico on Thu Apr 28, 2011 12:57 pm, edited 1 time in total.
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Post by Robin Lee »

orly_andico wrote:I will guess no more than 2 minutes at short FL (600mm).

The reason being the EQ6 has a huge periodic error of around 30 - 40 arc-seconds.
How well can it be corrected with EQMOD and guiding? Any idea?

Cheers.
Clear skies,
Robin.

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orly_andico
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Post by orly_andico »

Since EQ6 PE is fairly smooth, guiding "should" remove all or most of the PE. 20 minutes per sub should be doable at short-ish focal length.

But the thing is.. you can't use really long exposures because light pollution skyglow will swamp your sensor.

I've seen really amazing DSO shots taken with 30-second to 2-minute subs. So I'd stick with that range unless doing H-alpha. Besides if you do a 20-minute sub and something goes wrong (e.g. plane flies overhead) you throw away the whole 20 minutes.
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Post by Robin Lee »

orly_andico wrote:Since EQ6 PE is fairly smooth, guiding "should" remove all or most of the PE. 20 minutes per sub should be doable at short-ish focal length.

But the thing is.. you can't use really long exposures because light pollution skyglow will swamp your sensor.

I've seen really amazing DSO shots taken with 30-second to 2-minute subs. So I'd stick with that range unless doing H-alpha. Besides if you do a 20-minute sub and something goes wrong (e.g. plane flies overhead) you throw away the whole 20 minutes.
Thanks for sharing.

How short is short (focal length) by your definition?
Clear skies,
Robin.

Cyclops Optics - QHYCCD, William Optics, Televue, STC & Optolong filters
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