Skywatcher Flextube 400 Goto performance

[Pingster]

Last night i met up with a SGL regular. To introduce him to a dark site i recommended in Sussex.

I bought my newly flocked 16in Flextube and was excited and nervous because it was my first chance to try the star align and goto feature. I have a Celestron 8se and am familiar with goto features .

The flextube has a very interesting feature,

"patented dual-encoder design allows you to manually move the telescope anytime and to anywhere you wish - with no need for realignment. Slewing to an object on the opposite side of the night sky no longer feels like watching a kettle boil. Simply push the tube close to the object and let the computer do the rest of the work."

Thats what the manufacture claims and to be honest when i received the scoope and built it, i thought... theres no way this duel encoder will work! Theres far to much slop in the scope.

'Slop'? First time i tested the scope in daytime, i placed in a 32 Nagler... and to my shock the scope would not raise when using the hand controller. The gears are running and under strain, the scope stars to rise, then as it reached 10 degrees it just stops rising and you can hear the motors running. Releasing the slew control button, the scope then drops a bit, this is what i mean by 'slop'.

I fixed this by placing a counter weight on the rear of the optical tube. As Televue eyepieces are very heavy. The telescope does not have problems slewing electronically with the default supplied plossls which are very lightweight.

Then a second problem. When the scope was place at an angle, for example 45 degrees. Changing heavy eyepieces, especially when adding a powermate + eyepiece, the scope can be easily nudged out of alignment to your target. And if not sufficent counter weight is applied or too much... then the scope will 'slop' either up or down by about 3inches! The goto version costs about £500 more than without. So naturally i thought... oh well wasted my money again, should have got a push to go... should have known a new model at this giant size by a 'budget' manufacture would fail with goto.

BUT... yesterday i had a chance to try it . Level scope, point scope at Polaris, then lowered to horizontal. Set GPS location and time, and star align. I will add, i found the alignment so much easier than my Celestron.

Punch in M13... slews.... omg... the monster is moving... and pow! Almost bang on centre. Wow i was impressed! :hello2:Ok another item, my viewing buddy suggest veil neb... ok... i'll try find this manually using the movement inputs... i think i see it... oh yes without a OIII filter it was faint, my buddy confirms my find. So then i thought lets try the goto again and get it to slew to the other side of the Veil.... pow! its almost centred! WOW!

M81,M82, Jupitor, Moon, every time the goto got the item almost perfectly centered! I would then manually centre a target, then have a chat to my buddy, go back to the scope 5 mins on and wow.. the target is perfectly centered. I am amazed such a big scope can track so well.

Now for the good bit... every so often i would forget to move my observation ladder clear of the goto slew and the scope would get 'stuck' on it... grinding to a halt, yet gears still trying to move the scope. I move the ladder out of the way and think blast, i have just messed up the alignment, i'll have to reboot and align again. But no... the scope carries on and ends with target almost centered! If this had happened with my Celestron 8se, the tracking would need to be rebooted and star aligned again.

And it gets better

At times when changing eye pieces i would forget to adjust my counter weights... resulting either in the scope not being able to move up or down and i would have to give it a helping hand by pushing gently on the scope to help it move while quickly adjusting my counter weight. Surely it won't land on target now? Thats got to mess up the tracking? NO The scope continues and lands almost bang on target. it still hands on target when i change eyepieces and cause 'slop'. I just select the object from the menu again and the scope does a few adjustments and pow almost bang on target!

And now the best it....

Patented Duel encoder.... ok i must admit... having perfect goto for my first 1hr of observing... i was actually confident it would work. So i call out to my buddy and tell him i'm going to move the scope by hand to a target... do a few random spins and up and down movements. Ok, breath... input M13....slews... almost bang on target! I LOVE THIS SCOPE! ITS AMAZING!

I even made a video where i move the scope about by hand, get scope to goto the moon, bang on target... move the scope by hand again, get scope to goto moon... again bang on target! I'll try to find a way to attach the video asap.

The hand control is much easier and faster for inputting targets than my celestron. Its amazing how this budget scope, out-performs my 'premium' celestron in both views and technology... and has a focuser that actually lets you focus without bouncing the image all over the place!

To sum up, this scopes goto and duel encoder work extremely well. I used the scope for a 5hr observing session. Using a combination of goto, hand slewing, caused lots of 'slop' when changing eyepieces, caused the scope to get stuck on ladders/and myself, did not adjust my counter weights thus causing the scope to get 'stuck'... yet it landed targets almost perfectly every single time! I am sure it can do it perfectly if i had taken my time with alignment.

Its tracking - perfect. At one point i used a 6mm + powermate (x600) just for fun on Jupiter and it tracked perfectly. A bit wobberly due to wind.

I would highly recommend this scope for amateurs and clumsy people like myself. As the duel encoder allow you to make normally catastrophic errors and it will simply 'pick up' from the last point and continue landing on target.

And to finish, the views are stunning.

I am sure my viewing buddy will chime in to confirm my report

[ChrisEdu]

Wow! Sounds impressive! Where abouts in Sussex did you go? As I live on the coast, I'd be interested to know.

[Veracocha]

Superb write up. I wondered where it was leading at first but it looks like you are well impressed.

[John]

Thats a very interesting report of what is clearly a very impressive scope !.

The Nagler 31mm is a bit of a monster and at just over 1 kg will impact balance as you have found. You might be interested in a device that Tele Vue makes called The Equaliser. It's basically a solid brass 1.25" - 2" adapter which adds weight to the smaller eyepieces so that they are around the same as the larger ones - so you should not need to adjust your counter weight system much, if at all, when you switch from 1.25" to the heavier 2" eyepieces.

[Pingster]

Hi Chris check your PM.

John. Sounds good. Might get one if they are charging a reasonable fee. As Tevelue like to charge £100s for simple stuff xP

[John]

Hi Chris check your PM.

John. Sounds good. Might get one if they are charging a reasonable fee. As Tevelue like to charge £100s for simple stuff xP

Don't know if this is a saving over the new price or not (not my ad):

U.K. Astronomy Buy & Sell

At least you know it will be well made

[Pingster]

Thanks John. Thats a great price. I think ill get it

[swamp thing]

When you see that big cannon flying round on its own it's a pretty impressive sight to say the least.

I can confirm all that Pingster wrote.

It tracked very well indeed IMO and the views were terrific. It even handled the weight of a 17mm Ethos + 2" Powermate with no problems.

The Goto worked faultlessly except when switched off by mistake.

Was very nice having two 16" scopes side by side viewing different objects. This kind of observing I could get very used too.

Great evening that I hope we can repeat at the new Moon, weather permitting.

Regards Steve

[Pingster]

Haha. It was so funny when i got to the site. Steve was ready set up and waiting to cool down. I was keen to setup as it was supposed to be all clear, yet steve pointed out the clouds. I thought best align quick just in case the weather turns on us. Generally it was clear with occasional light thin clouds. Milky way was suprisingly well visible, not spetacular, evening considerig half moon. And 90% humidity which prob did not help seeing. I went home very happy as i got to see many targets far better than from my bakyard.

First attempt to align, as it was slewing to the second star i pulled out the power cable! Second attempt, again on second star slew i someone pushed off the power switch as i put the hand controller into its cradle. So i taped over power switch and taped over the power switch and thrid attempt was perfect and stayed that way till i packed up at 4am.

Now Steve hurry up and finish your new scope that would be an evening.

I really enjoyed having company and checking out targets in each others scope. Steve is a very good observing buddy and allowed me to try his equipment. Lookin forward to our new moon session.