What a difference a Feathertouch microfocuser makes - to tracking!

[g__day (Matthew)]

It arrived today and I attached it to my C9.25. I noticed immediately when focusing and changing directions - stars jumped a tenth of what they used to.

But the real pleasure was tracking and pointing - both really improved. I would say my tracking error that has bugged me for a while now is at least two to three times better. So it was the mirror flopping that caused the majority of my tracking errors.

Meaning it might have thrown my polar alignment out too. (yep 36 star model shows Az 3' 22" sec and Alt 1' 24" - so knowing this I can switch compensation off and use PEMPro to tune alignment far better)

So of course its cloud central now - but I feel like I have had a breakthrough in my search for better tuned gear! Raw pointing MaxPoint tells me is +/1 134 arc second vs +/1 40 arc seconds with correction enabled. Guiding with MaximDL I see stars move in RA about +/- 1 pixel before corrections and PEMPro thinks PEC is +/- 2.1 arc seconds. So if I can just finalise alignment then collimate the mirrors - I'll be as ready to image as I can ever be!

Thanks very much to the folk who suggested these microfocusers to improve mirror flop (I already use a basic Meade focuser to electronically focus - but it didn't do a thing for flop). That advice was really a big step forward for me!

Yippee!

[avandonk]

Just shows how sad we are when a minor incremental improvement gives us joy! Yep lock down the lot and only adjust a stable variable!


Bert

[acropolite (Phil)]

I noticed the same with my LX90, the mirror movement was only a fraction of the amount that had been there with the old focusser. I suspect that's because the feathertouch is more rigid, the slop in the bearings of the stock focusser contributes a proportion of the movement. I also noticed that with the stock focusser just touching the focusser was enough to move the mirror.

[Domol (Domenic)]

i have not heard of this, so I quickly looked up the product on google. How does the Feathertouch microfocuser reduce mirror flop in SCT when the mirror cannot be "locked down". Moving the mirror is still used to focus image?

[g__day (Matthew)]

My thoughts are how this works are as follows.

The threaded focus shaft to the mirror is not well designed to ensure it is secured so the shaft can only turn - not shift laterally up or down. Such shifting - even if only very minor would be a big worry. Push the focuser up or down while not rotating it an see stars move significantly. Only a 1/2" diammeter bearing restricts lateral movement. Here's a simply confirming test - focus in then out half a turn of the focuser. When you change direction focusing you may see stars jump 5 - 10 arc minutes, that's shaft shift!

The Featerher focuser is bolted at three points to a thicker steel plate, and the shaft passes through a tighter fitting hole in this plate, and the shaft fits along way into a narrow and very rigid focuser - making the shaft much more secure and greatly restricting stray lateral movement. When I first tried to attach this focuser to the shaft I was worried the hole in the attachment back plate wasn't machined in the right spot. Unscrewing it all and gently pushing the threaded focusing shaft upwards caused the shaft to suddenly move more that 5mm upwards - definitely changing mirror position!

By simply re-designing attachment points to the focusing shaft or inserting one of these microfocusers - it appear one can greatly eliminate lateral focusing shaft movement - mirror stability is greatly improved - meaning all of polar alignment, tracking pointing benefit substantially too!

I'm delighted!

[asterisk (Geoff)]

Originally Posted by avandonk

Just shows how sad we are when a minor incremental improvement gives us joy! Yep lock down the lot and only adjust a stable variable!


Bert

Sad, but true. My Feathertouch microfocusser arrived last week. I installed it and used it this weekend. Thanks very much to Matthew (g_day) for his advice and directions.

An amazing difference to the stock focusser - smoother, finer adjustments, spot-on focussing and, surprisingly, less mirror movement.

I had tried an SCT Crayford-style focusser previously - the Feathertouch is lighter, less bulky and one less thing to have to attach.

A friend of mine used it and immediately added it to his list of things to get.

[alch3my]

Where abouts can I pick one up from? Goggle Australia isn't showing any Australian sellers

And any ideas of a superb electric microfocuser? JMI Motofocus?

[g__day (Matthew)]

Mine costed about US $197.50 including posting from - check your pm's - I did reply!

Ping Brigitte Schmidt of Starlight Instruments, Inc.
www.starlightinstruments.com

PS - I'd ignore their we don't accept credit cards - just send them an e-mail confirming details of what you want to starlightschmidt@wowway.com Phone : 847-985-9595 M-F 9 AM to 6 PM CST, they accepted my credit card about 3 weeks ago!

[asterisk (Geoff)]

Originally Posted by alch3my

Where abouts can I pick one up from? Goggle Australia isn't showing any Australian sellers

And any ideas of a superb electric microfocuser? JMI Motofocus?

I got mine from OPT:

http://www.optcorp.com/productList.a...-175-1041&pg=0

Cost US$139.95

They do not automatically provide an estimate for shipping overseas. I emailed them:

"Can you please provide me with a shipping cost for
Starizona - Feathertouch SCT MicroFocuser - C8 [S6-FTFSCT2S] to Sydney, NSW, Australia (postcode 2560)?"

They replied:

"Below are the USPS shipping options, costs and delivery times:
USPS Express Mail International: 3-5 business day delivery, traceable, fully insured: $35
USPS Priority International: 6-10 business day delivery, traceable, fully insured: $31"

These prices are all in US$. Total cost (incl shipping) US$174.95

Cheers

[g__day (Matthew)]

OPT are cheaper for basic unit - and the USPS are the cheapest option - be it from Starlightinstruments or OPT. But both were stock out when I called - OPT with a 6 week probable re-stock date, Starlight with a 2 week definite - so I went the slightly more expensive and more immediate route with starlight.