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Focuser Upgrade for am 8SE

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#1 David Allen

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Posted 05 January 2010 - 11:30 PM

I am looking to upgrade the stock focuser and would love to have some recommendations from those that have already tried things. I looked back through the posts a long way and could not find anything on this.

First, I plan on trying the coffee cup ring (From Bob I think?) to see if that helps. I may try something a bit more high tech and go with a rubber washer or something. But, since I have the cash left over from Christmas (a fool and his money :lol:) I was looking at either a Starlight Instruments Feather Touch 10:1 manual focuser or some kind of rear cell mounted Crayford-style arrangement.

The feather touch seems simplest. Just replace the stock know with a new one.

But, I have heard the Crayford-style is better. But, I just bought a 2” diagonal that screw on to the rear cell. Would the Crayford make that useless? Does it add focal length? Will it make it too rear-heavy?

So many questions, so little experience. Any suggestions out there?

#2 iceberg

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Posted 06 January 2010 - 12:34 AM

But, I just bought a 2” diagonal that screw on to the rear cell. Would the Crayford make that useless?


You can use 2" SCT thread adapter like this one.

http://www.focuser.c...uct=SCT-adapter

#3 mbaier

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Posted 06 January 2010 - 06:35 AM

David - i am sometimes using a crayford focuser with my 6SE. The only drawback is that due to its size, it will hit the telescope's base when observing objects high up in the sky. But it allows for really fine focusing.

I don't use it very often though because i always have to change the backlash settings on the scope due to the added weight.

I'm also planning to use the coffe cup solution with my focuser and also thought about using some sort of rubber washer or something. I'd be interested in what you come up with !

#4 Tel

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Posted 06 January 2010 - 07:24 AM

Hi Dave,

As an alternative, have you considered the Celestron or perhaps preferrably, the JMI "Motofocus" ?

Both will give you fine focusing with the added advantage that there is no vibration when achieving such due to the fact that the 'scope is not touched at all and, certainly the shorter JMI unit will give you the necessary clearance you may require with a 2" diagonal.

Best regards,
Tel

#5 Pastor Shaun

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Posted 06 January 2010 - 08:33 AM

My JMI "Motofocus showed up last night and I have installed it on my 8SE. I haven't had the scope out yet but have played with focusing. The wired controller has two settings, slow and (what i would call) normal. With both settings if you hold down the button for a few seconds the speed increases. I was able to focus in an object very easily. The thing I like about the MotoFocus is that you need not touch the scope when focusing. To me that is a plus over the Starlight or other manual knobs.

#6 Peter9

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Posted 06 January 2010 - 08:55 AM

I would like a new focuser for my 8se and on the recommendation of Tel and the others, the JMI motor focuser seems to be the one to have. The thing that puts me off is the price here in the U.K. A Skywatcher Motor focuser made up of a control box, cable and mechanical bit at the end cost £50 ($80). The JMI for the SE range of scopes made up of the same bits cost £151 ($241).
I know if I want one I will have to pay the price but I hate being ripped off.

Peter.

#7 GizmoDave

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Posted 06 January 2010 - 09:08 AM

The JMI unit is great for viewing, as pointed pointed out it does not require touching the scope which greatly reduces vibration. My only complaint is it moves too fast when attempting to achieve fine focus with a SLR attached.
Hitting the mount with a Crayford Focuser could be reduced and posibly eliminated witt Eddie's or Ron's rail mods, and they make a moto focus for the Crayford Focuser too.

#8 mbaier

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Posted 06 January 2010 - 09:11 AM

Peter - it's a shame how us poor europeans generally get ripped off by the companies that import anstronomy items. My local celestron dealer wanted to charge me double the price for the 6SE and the same goes for all other accessories.

I just got my finderscope from http://www.agenaastro.com/ they have good prices and also reasonable shipping costs if you can accept shipping times of 2 weeks or so.

#9 Bob Griffiths

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Posted 06 January 2010 - 09:27 AM

Scope and stuff sells a Commercial version of the Coffee Cup focusing aid...its is just a more expensive version that works the same way...

I have a Celestron MF (same as one of the JMI models) ...use it on both my 8i and my CPC and to be honest I really like it EXCEPT its way way too big and long..

I will say however that it took me a few nights to get the hang of using it..changing speeds, learning how to Bump it along as I get real close to focus etc...

Major advantage is naturally you never have to touch the scope which eliminates the shakes rattles and rolls I used to induce in the scope
Plus the battery seem to last forever ...with heavy use I know mine will last for 2 years easily

Bob G.

#10 brmillsy

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Posted 06 January 2010 - 09:45 AM

Another vote for the JMI unit. I feel it's better than the Celestron because it poses no clearance issues.

Having a motor focus is a huge advantage on a single fork mount which vibrates a lot even on grass.

At $160 US I found it to be very pricey for what it does (really a pretty simple device), but still a must have.

$214 USD for our European friends seems a bit like robbery. Why is is it so much over there? Taxes? Something else?

#11 Midnight Dan

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Posted 06 January 2010 - 09:48 AM

What exactly is the "coffee cup solution"?

-Dan

#12 Tel

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Posted 06 January 2010 - 10:03 AM

they make a moto focus for the Crayford Focuser too.


Hi Dave,

I'd respectfully suggest either a Microfocuser or a powered "Motofocus" - but not a combination. A powered Crayford sounds to me like an unnecessary and expensive "double fix". (?)

Best regards,
Tel

#13 Peter9

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Posted 06 January 2010 - 10:13 AM

What exactly is the "coffee cup solution"?

-Dan


Hi Dan, It's something similar to what you see on my focuser knob.

Peter.

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#14 Tel

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Posted 06 January 2010 - 10:20 AM

What exactly is the "coffee cup solution"?

-Dan


Hi Dan,

This stems (I think), and is certainly mentioned in Mike Swanson's Nexstar book under a section entitled "Improving Focusing Sensitivity".

In it he states that focusing at high magnifications can be frustrating due to the much greater sensitivity required. To achieve this (economically) therefore, the trick is to use a large circular object with a hole in the middle to fit over the existing focus knob. He then goes on to advocate the use of plastic jar lids, toy car tyres, and as Bob has often mentioned, the bottom of polystyrene coffee cups ! As MS points out : "The possibilities are endless" !

Best regards,
Tel

#15 mbaier

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Posted 06 January 2010 - 11:11 AM

...i'll look through my son's LEGO box tonight. I think he has alot of those big black plastic tires in there that should be big enough and should provide a nice grip too : )

#16 bcuddihee

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Posted 06 January 2010 - 11:26 AM

I've done the plastic knob improv, and it does work ok but..
the feathertouch is a dream to use. First of all the stock focuser on the c8 had too much resistance. Mine also had some areas of more resistance through the rotation. On an se model, any more resistance adds up to vibration at the ep. The feathertouch at the 10/1 knob takes only the lightest finger pressure to turn. Do not get the crayford as you will have clearance issues at the base well before you hit zenith.
bc

#17 mylatestwhim

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Posted 22 January 2014 - 01:45 PM

Made one from a camera adapter and plastic discs. Works well and nice press fit.

May end up buying a feathertouch but this is ok for now

Posted Image

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#18 Crazyhorse1876

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Posted 22 January 2014 - 03:29 PM

+1 for the JMI Motofocus. It does cost a bit but as far as I'm concerned it has paid for itself over and over again. It is small and stays well clear of the mount when near zenith.

Here is a image of my 8SE with the JMI MF installed.

Attached Files



#19 maugi88

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Posted 22 January 2014 - 05:32 PM

I spent the money for a feathertouch and boy is that baby butter smooth. Its not free though, so to each their own.

all the best

#20 herrointment

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Posted 22 January 2014 - 06:08 PM

Yup, I'm posting this link again.... LINK

#21 maugi88

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Posted 22 January 2014 - 06:33 PM

Yup, I'm posting this link again.... LINK


Um, Ok that's pretty cool.

What was I thinking :foreheadslap:

I kid, I still really like the feathertouch.

#22 mylatestwhim

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Posted 22 January 2014 - 06:38 PM

Can you lend me £190 please? :roflmao:

I may as we'll not delay he inevitable but I've had a new scope and loads of bits, Christmas, blown central heating, car tax, 4 new run fiat tyres AND car service in December/ jan. I daren't look at my bank balance. :bawling:

#23 ben2112

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Posted 22 January 2014 - 07:05 PM

You build one yourself for $70. I don't have access to Google+ here at work or I would post a pic of what I built.

#24 maugi88

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Posted 22 January 2014 - 08:24 PM

Can you lend me £190 please? :roflmao:

I may as we'll not delay he inevitable but I've had a new scope and loads of bits, Christmas, blown central heating, car tax, 4 new run fiat tyres AND car service in December/ jan. I daren't look at my bank balance. :bawling:


Blown central heating? Ouch, what does that run in the UK? Two years ago we lost the heat exchanger in our furnace and $3,500 later we had a new furnace.

And No, on the 190 Euros (257.00 US) sorry.

All the best

#25 mylatestwhim

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Posted 23 January 2014 - 04:11 AM

The heating has cost £600/ $1,000 so far and it's ongoing..

Tires just cost £660/ $1,095






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