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markclaire50

Opinion on 250px goto flextube Dobsonian

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Has anyone got experience of using on of these scopes? 

If yes, could you give me your thoughts on the good and bad points. 

I'm assuming the mirrors are good, but what about issues of dew? Any goto or tracking issues? 

Thanks 

Mark 

 

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I have an 8" flextube goto.  It does what it says on the box.  They don't track like the tripod scopes the imagers use, but if you want to keep something centred for 15-20 mins at a time they work.  Mine is quite sensitive to being un-balanced and drives better if I remove heavy EP's first - no issues with dew.  I made a perfectly adequate dew shield from some fabric, but it works well without it.

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14 minutes ago, JOC said:

I have an 8" flextube goto.  It does what it says on the box.  They don't track like the tripod scopes the imagers use, but if you want to keep something centred for 15-20 mins at a time they work.  Mine is quite sensitive to being un-balanced and drives better if I remove heavy EP's first - no issues with dew.  I made a perfectly adequate dew shield from some fabric, but it works well without it.

Hi JOC

Thanks for replying. Can you tell me which eyepieces work best? Obviously I appreciate the F ratio may give different results in the 8" vs 10" and balance would be different. Would you upgrade to the 10" version or are you happy with what you see? 

Thanks 

Mark 

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To be honest as a beginner I am more than happy with what I see at 8" - it is as well to consider the portability of larger versions too, even if just lugging them 20 yards into the garden as I do.  

It really depends on what your interest is.  If you are desperate to go and hunt faint grey fuzzies (FGF) - where you think the fainter something is the more blown away you are to see it then of course mirror width is everything - every inch or two bigger is some mathematically improved massive light gathering jump that will let you see fainter objects.  If on the other hand you are like me - just wanted to sort of see what's up there, see all the planets, the moon, the sun, the more knock your socks off FGF Messier objects, double stars, clusters and the showyier bits up there then I find my 8" more than up to seeing that.  The extra width and with it extra Focal length will allow you to get a tad closer to things like the planets, but they don't all respond to being as close as you can get to them - views are sometimes more rewarding at less that than what you can practically achieve.  However, I don't think this extra closeness and what you can effectively use it on becomes that significant between the 8"/10" and 12" SW Dobs.  AAIK its the extra light gathering where the difference is appreciable and so a FGF hunter will benefit from the larger mirror.

I am not a huge FGF finder - it's nice when I see them, but I am not going to expend hours on the hunt for them.  As such the 8" Dob has been just fine for me and I don't hanker after anything else, esp. as it does have the Goto.  I hope this helps

 

NB.  All the eclectic collection of EP's in my signature work well - the telescopes seem pretty forgiving and for my use and experience I don't need better (mind you I've been lucky and picked up some pretty OK glass from SGL classifieds!)

Edited by JOC
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I owned the solid tube Skywatcher 250PX for a while (same optics as the Flextube). It was a pretty decent scope with good optics for the price they charge for them. 82 degree and wider eyepieces show some coma towards the field edges (scope rather than eyepiece generated) and I would have probably invested in a coma corrector if I'd held onto the 250PX and used 100 degree eyepieces with it.

Eyepieces need to be fairly well corrected to be sharp across the field at F/4.7 but things like the Explore Scientifics, UWAN / Nirvanas etc can cope pretty well with it.

I had some great views through my 250PX and others that I've observed through.

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You’ve got power for the GoTo, so some simple dew heaters are no hassle. Invest in a light shroud. The Astrozap ones seem pricy but live on the scope and improve the contrast (and they stop you dewing up the secondary if you breath too heavily)!

Paul

Edited by Paul73
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PS. I’d ditch the GoTo and spend the money on decent eyepieces and a Telrad Finder.

I spent the first 6 months wishing that I had GoTo, and the next 4 years being glad that I didn’t. Who needs to extra weight and faffing about getting set up?

Others may disagree .....

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Before you ditch the idea of the Goto (I personally think its brilliant!) maybe read this thread? 

 

 

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1 minute ago, JOC said:

Before you ditch the idea of the Goto (I personally think its brilliant!) maybe read this thread? 

 

 

Hi JOC. 

I created that thread. ?

I think goto and tracking are essential for me, personally. 

Thanks

Mark 

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Just now, markclaire50 said:

I created that thread. ?

LOL!!  So you did!  I didn't spot that obviously Ha, Ha!

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Another thought is that with the cash you save by getting an 8" you can buy some EP's for it!

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Hee hee ?. I knew the “ditch the GoTo” option would get some responses. My opinion is just that. GoTo suits many people. I enjoy hunting down fuzzies. Others like to spend their time observing their intended targets!

On a serious note. Check out the weight of the GoTo Flextube. If you can’t easily carry it. Observing will become a chore rather than a pleasure. I speak from experience (bought a 16” Dob).

Paul 

 

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15 hours ago, John said:

[...] I would have probably invested in a coma corrector if I'd held onto the 250PX and used 100 degree eyepieces with it. [...]

Thanks, John. That's also my thought about f4.7 and uwa eps. A CC is not required, but can be desirable to someone's eye.

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