Focusers - How good (or bad) ?

[Robert9]

Hi, I'm considering purchasing a focuser for my SCT. Interested in comments on how good or otherwise are the cheaper units (~$100-150). I know Moonlite have an excellent reputation, but would I be that much worse off with a cheaper unit:question:

[GrampianStars]

Lower price option
http://www.optcorp.com/product.aspx?pid=319-327-342-343-11757

[tlgerdes]

What are you using it for? If imaging pay the extra. If visual then you may have more tolerance. Eyepieces generally don't weigh 1kg.

[allan gould]

If you are going to be lifting heavy loads then the WO, GSO, Bintel etc are not worth it in my opinion. They are ok with visual but a moonlight focuser will never disappoint and you will never regret it's purchase. I have three of them and the only thing to remember is get the options you want from the start.

[UniPol]

I use Starlight Instruments "Feather Touch" focusers exclusively nowadays. For viewing I use the Crayford style and for heavier loads use the rack & pinion version. The beauty of these apart from their precision are the many and varied adaptors available from SI to suit just about every scope on the market. I've amassed quite a few adaptors over the years so one or two focusers can be fitted to my various OTA's. Have a look here (http://starlightinstruments.com/)

[tlgerdes]

What are you using it for? If imaging pay the extra. If visual then you may have more tolerance. Eyepieces generally don't weigh 1kg.

[Robert9]

Hi Guys. Thanks for all your feedback. :thanx:
I am intending to go down the astrophotography path so will accept your recommendations to go a bit upmarket. As weight will be a consideration (HEQ5 mount) I'll have to have a good look at the specs. of what's on offer. But I'll also have to consider the cost. Oh to have won Ozlotto!

[g__day]

Hmmm, I do more imaging then visual - off a 9.25" SCT I put a Feathertouch fine focuser (reduced mirror shift / flop considerably too) but put a meade motorfocuser -> Lumicon OAG with a DSLR and a Meade DSI II Pro guide camera (and run the meade focuser via a JMI -> USB converter into a PC). So I focus never having to touch the tube with an Bhatinov mask.

That's a bit of gear a fair way out from the focuser. I routinely do 20 - 30 minute subs and see no issue in flexure of the focusing rig. My scope is Carbon fibre - and it holds focus across significant thermal range. Basically I could probably adjust focus once a week and find things have barely changed unless the weather soars or plumets - it amazes me.

I am unsure how you judge the calibre of gear you need for the tasks you envisage. But the rig I have does keep half a kilo of gear about a foot from the rear of the OTA securely bound.

So thats a $300 unit plus a $100 USB converter to give you computer controlled focusing.

http://www.bintel.com.au/Accessories/Focusers/Meade--1209-Zero-br--Image-Shift-Focuser/1143/productview.aspx

plus

http://www.bintel.com.au/Astrophotography/Focusing-Aids/Shoestring-Focus-Motor-Controller/760/productview.aspx

If you wanted to go all out - ask Mike Sidino what he uses - or consider http://www.optecinc.com/astronomy/catalog/tcf/tcf-s.htm the TCF temperature compensating focuser have a pretty big reputation.