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Achieving focus with skywatcher star discovery 150p and dslr

Bprezzle

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Bprezzle

Bprezzle

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56 minutes ago, happy-kat said:

Is that the right mount for what you want it to carry to image with?

Yeah the 150PDS comes standard with the EQ3-2, just not sure what Motor drive I need because I here a lot about dual motor and it doesn't mean much to me 

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wimvb

wimvb

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Now I'm confused. Is this thread about the skywatcher star discovery 150p on a goto alt/az mount or the explorer 150p on an eq3-2 mount without motors? Or is this thread wandering off? I don't think the above mentioned motor upgrade kit is compatible with anything other than the eq3-2 mount.

I have always found the eq3 mount underdimensioned for the 150pds. My eq3 pro (= goto version of the eq3-2) with aluminium tripod, is very much at the load limit with this scope. The mount doesn't have ball bearings in the ra axis, so any load affects the ra assembly directly. I even suspect the infamous chinese gunk (grease) to be needed for proper operation. Any thinner lubricant may not be up to the job at higher load. The mount works fine for a short fl light weight setup, and is a great grab 'n go equatorial mount. I've had lots if fun with this mount and a 135 mm lens + dslr, but also a lot of frustration when trying to use it with my 150pds, losing too many subs due to poor tracking. If you go for it, at least get the steel tripod with it.

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wimvb

wimvb

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Exactly. Add to that the general rule to load an imaging mount to only 60% of its rated load, and you have a serious limitation. But with a sturdy tripod and good balancing, it can perform quite nicely.

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  • 2 months later...
happy-kat

happy-kat

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A member fitted a GSO unit off top of head (still to long to achieve prime focus with dslr and can't recall their name right now).

I remember his name was Lee I'll find the post later.

Found the link. But the GSO focuser is still to long for prime DSLR focusing.

link here

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Nigel G

Nigel G

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46 minutes ago, kiloran said:

I know this is probably uneconomic to do (considering a 150 PDS is around £175) but is it possible to upgrade the focuser on the Star Discovery?

I could not find a focuser that would do the job.. For a guide the front edge of the t ring needs to be 50mm from the ota. See photo.

Also personally I would go for the 130PDS, purely a weight thing.

Nige.

20160507_171501.thumb.jpg.0e09020be7e305bccad89e8a26638b26.jpg

 

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  • 10 months later...
Nigel G

Nigel G

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1 hour ago, mislav said:

what if i change focuser with this one?will i be able to reach prime focus??

Skywatcher Dual-Speed 2" Low Profile Crayford Focuser for Newtonian Reflectors

It looks like it will do the job though it says for 8 to 12 inch aperture, note that on the Star Discovery 150p the camera needs to be within 50mm of the OTA pictured 2 posts before this one.

Nige.

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Nigel G

Nigel G

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2 hours ago, mislav said:

what if i change focuser with this one?will i be able to reach prime focus??

Skywatcher Dual-Speed 2" Low Profile Crayford Focuser for Newtonian Reflectors

At the cost of that, I think you would be better off getting a 130PDS, only about £40 - £50  extra and designed for AP. Better focuser, and no modification needed. It also comes wit tube rings for better balancing.

https://www.firstlightoptics.com/reflectors/skywatcher-explorer-130p-ds-ota.html 

Nige.

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  • 4 weeks later...
Nigel G

Nigel G

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1 hour ago, mislav said:

just to check before i bucher my poor telescope. Questions are on picture... Please help..Nigel? i dont want to ruin my scope...

focuser.jpg

All correct :) have you got a bush of some description to fit the T ring to the focuser after the eyepiece clamp has been removed, you will need one. Its possible a low profile T ring will be enough but I am unsure. 

I would cut the the ring with a hacksaw, better control to get a square cut.

Remove the focuser from the OTA to stop dust getting into the mirrors, careful not to drop the nuts inside.

The draw tube is easy to do, remove the 2 screws and you will see nothing special in there, when putting back together, those 2 screws will be the focuser tension screws ( not too tight not too loose ) 

Any further questions, just ask :) 

Nige.

 

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mislav

mislav

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thnx..i will try firstly with just cutting ring and low profile adapter..i am using canon 350d... i also have nikon 90 but dont have low profile... for that i will probably have to do something...is it same lenght to mirror or nikon could manage with this setup?we will see...ok, i will listen to you and buy hacksaw, i need it anyhow... so i dont need to cut this little part under the eyepiece clamp if low profile t ring manages to do focus??

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Nigel G

Nigel G

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4 hours ago, mislav said:

thnx..i will try firstly with just cutting ring and low profile adapter..i am using canon 350d... i also have nikon 90 but dont have low profile... for that i will probably have to do something...is it same lenght to mirror or nikon could manage with this setup?we will see...ok, i will listen to you and buy hacksaw, i need it anyhow... so i dont need to cut this little part under the eyepiece clamp if low profile t ring manages to do focus??

Do 1 job at a time and check the focus on a distant object :) 

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mislav

mislav

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i have cut this ring and put eos 350 with lowprofile m42, and i can nicely focus something about 200-300m far, but i feel that something what is faraway needs just a bit (mm or two).. is it possible? doest anyone know is focus in canon and nikon same,or maybe nikon has focus few mm outer??? any more idea to do???or this 200-300m is ok and far is just my imagniation that it isnt good...but....

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