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Nexstar Evolution possible achilles heel !!

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Hi fellow star peeps

As some of you know I am in the midst of deciding what to buy my good self for an early xmas prezzy and the Celestron Nexstar Evolution 9.25 has my name written all over it !!! or so I thought ?

As a GO TO scope it looks the biz for a strictly eye to eyepiece type of observer, no hassle EQ's no extra power tanks needed....spot on.

BUT

It seems I may have trouble powering a dew heater / control system from the mount as the output supplied is 12v 2amp via a small jack plug and all the dew controllers I have sourced so far

are 12v 5amp and have a dirty great big cigarette lighter plug on them......

SO,

I have emailed Astrozap for some info on plug changing along with amp difference and i have also emailed Celestron for their view on this.

This post is just a heads up so far as letting others know that there is an issue here and hopefully upon return emails we may get an answer as to how to remedy this without having to succumb to

getting an external power source just for the dew controller, after all what’s the point of a self powered mount if you can’t power something from it to stop due thus allowing to actually use the scope !

One of the biggest things that sells this Evo series for me was NO WIRES hanging around at floor level !!

Lets hope we get some ideas how to sort this.

Lee.

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How do you intend to power the scope when outside?

I have 2 smaller goto's and they are powered vis an extension lead with at least a double socket on the end,

If I am away from home then I use the power output from the car to supply power 12v/10A, and recently bought a Tracer battery for when really isolated.

My scopes are less the 1/3 the diameter of your intended item and the power requirements are a lot less.

If the thought is batteries then I suspect they will last 20 maybe 30 minutes, if they have sufficent power to get the scope operating at all. Slewing the Evolution from A to B requires a fair amount of power and if it drops then the scope will simply need a realignment again - it loses the data, settings and corrections.

One alternative is to make your own dew heater such that the current drawn is no more then 1.5 amp and have an anti-surge fuse in the line. It may be that the heaters have been slowly increasing in their power consumprion over the years. Which sounds better a 20 watt dew heater or a 50 Watt dew heater? One would work on your scope the other would not.

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Morning Ronin, thanks for the input. I intend to power the EVO via its onboard rechargeable lithium battery that supplies the unit with upto 10hrs of continuous power. It has said jack plug for external aux power, 4 aux ports plus a usb to recharge your mobile device for keeping your sky portal going. So i assume it is capable of powering a dew controller although reducing the 10hr observing time but as I only observe for maybe a couple of hours I don't see this an issue, finding a controller that will use only 2amps is however

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A dew heater, really does use a lot of current. 

I have got a spare car battery, that I use for that.

I would not attempt to run it from the on board

battery. It wont last long.

Steve.

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Another clever little aspect of this scope is that it uses dual encoder technology so after alignment is done you can release the clutches on both axis and manually move the scope to a new position and then resume tracking as it remembers it's position thus reducing massive unnecessary electrical movement. I think I may need to look into your idea about a DIY solution though...I will see what AstroZap and celestron suggest

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That must be one heck of an on-board battery.

The Tracer I bought was the smallest available and I suspect I am looking at 3 hours on an ETX-70. Battery says 4 but even if half I will be happy. Like you an hour or two is generally adaquate.

10 hours on an Evolution is a different matter.

Not sure if relevant but have a search for "trace heating", you might find something to use if you make your own up. It is used to keep pipes from freezing and such applications. Some are self regulating in the current drawn. I suspect they do not actually need to generate a lot of heat, but I do suspect that the cry of "More is better" has taken over.

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Thanks peeps...I will find a solution somehow...would be a real shame to have to get a power pack.

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I have gone with a power tank for the astrozap dew heater with mine - so very interested if you do find a solution...

It is a great scope but really does act as a dew magnet!

I also suffer from dew forming on my EPs.

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Another clever little aspect of this scope is that it uses dual encoder technology so after alignment is done you can release the clutches on both axis and manually move the scope to a new position and then resume tracking as it remembers it's position thus reducing massive unnecessary electrical movement. I think I may need to look into your idea about a DIY solution though...I will see what AstroZap and celestron suggest

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Built my own power tank out of a stanley tool chest (the wheelie one). changed all the cig plugs to XLR's for a better connection....mind you I do a bit of imaging as well, and the tool chest acts as a desktop to put the laptop on with a little desk extension that slots over the pull up handle. Also just added USB to it as well...75 mah leisure battery does the trick ;-) Before I built the box I used a mains power pack with a cig lighter female socket....but it looks like you would like it all self contained.

Not sure what battery you have in the Evo, but do they supply a charger to go with it? if its a Lipo, you usually have to balance change them (or I do with my airsoft rifles).

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Spot on blazar, I want to be sell contained...no extra bits to carry lol the scope even tells you the power level etc plus there are led adjustable lights on the eyepiece tray so I would like to think this litho battery packed a punch, certainly for my needs.

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Id be very interested to see what the reply from Celestron and Astrozap is. I just bought a 6" Evo to travel around Europe with me, and the inbuilt battery was a big bonus. First night out with it was amazing. No wires anywhere, till the corrector Dewed up. I ran a hair drier off an extension lead to keep it clear. So, wires everywhere!

Next night I fitted my dew controller off my LX90 and a spare heater band . Worked great, but again, wires everywhere, no point having a built in battery through the winter if you have to supplement it with power tanks or mains leads.

I just bought a Tracer 10ah battery to power my LX90, if dew heaters can't be run off the EVO battery, then I will use this.

But, in the ads for the EVO range, they do state that the onboard battery will run the scope and a corrector plate dew band. Or did I dream this?

Suppose I ought to Google Celestron Dew bands......

I don't think it has dual encoder technology though. They have manual clutches, but once powered up, if you release the clutches, you lose alignment.

That was the only thing that almost put me off buying the EVO.

Allan

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Hey thanks Alan, I am with you here...why have a self sufficient unit if you have to add power to use the scope viewing wise

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Oh forgot to mention....AstroZap categorically said NO MEADE OR CELESTRON SCOPES CAN POWER A DEW CONTROLLER ! That was from Joe. I am still waiting to hear from Celestron.

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Good luck with hearing from Celestron...good scopes but poor customer service.

I have the 9.25 on a AVX mount and it is nice and sturdy, it will be interesting to hear how the tube performs on the EVO mount. It is quite a massive OTA.

Definitely needs dew straps, backed up by a dew shield. It might be worth seeing how long you can go without the strap just using the shield.

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In all honesty - I wouldn't try and run dew heaters from the mounts internal battery...

The Celestron servo based mounts are pretty power efficient compared to the stepper motor based offerings from other manufactures.

I certainly wouldn't open up a brand new mount and modify it to take power straight from the battery pack - that's your warranty straight out of the window...

The 925 SCT's front corrector is a big bit of glass and the dew heaters will use a fair bit of "power"... When it comes to dew on SCT's I found prevention better than cure so used a dew shield and dew heaters on low from the start of the session...

I have run smaller lower power dew heaters from smaller battery packs..

Peter...

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Thanks guys...i am now pondering the idea of a different scope now the EVO can't be self sufficient. This idea is dead thanks to all the great advice here. I have started a new thread on scope choice and have pretty much decided on a goto dob which eliminates this problem massively plus saves me over a grand to put to more aperture and quality ep's. Thanks everyone for helping realise this mount powered dew idea is a no go for now.

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I have a Celestron 9.25 and just use an ordinary dew shield.  Haven't had any problems with dew so far, but this winter has been relatively dry and dew-free and I don't tend to be out for more than a couple of hours.

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Thanks guys...i am now pondering the idea of a different scope now the EVO can't be self sufficient. This idea is dead thanks to all the great advice here. I have started a new thread on scope choice and have pretty much decided on a goto dob which eliminates this problem massively plus saves me over a grand to put to more aperture and quality ep's. Thanks everyone for helping realise this mount powered dew idea is a no go for now.

The beauty of a GOTO Dob is the battery can sit in the mount ...

Good luck with your choice

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That's right knobby...I checked out tinkers on his same scope...looks perfect and he gets 16 hrs between charge

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Have you managed to get your scope yet? 

I've got a non-heated dew shield with mine, I've used the scope about 8 times about 3-6 hours each time and never had any dew forming. 

It came with my scope and I fully intended to buy a heated dew shield however each time I've used it it's done the job perfectly so I've had no need. 

Regards,

James 

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I have a Celestron 9.25 and just use an ordinary dew shield.  Haven't had any problems with dew so far, but this winter has been relatively dry and dew-free and I don't tend to be out for more than a couple of hours.

Me too - I've got the 6 inch with a standard dew shield and haven't had any problems

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