Electronic focussing suggestions for my dob

[davidpretorius]

After a frustrating night trying to manually focus my 10" dob which was imaging saturn at f38.5 or 9625mm, when the slighest sniff or foot step would shake the image off the screen, i am again looking at focussing.

I have an analogue motor kit and a stepper kit that if I can find the time, can make one, but I would like to look at all options.

So off the shelf, from our esteemed local seller of fine astro gear, I would appreciate suggestions as to what is the right electric focusser to buy.

So details, 10" x 1250 dob that is driven by a dob driver II. It already has the 2" crayford manual focusser.

I would like to link to the laptop to drive the focussing from there if possible. I can easily write a program to talk to a driver etc in windows. BUT if I have to go a second hand controller then that is fine.

FUture consideration:

1. Compatibilty of the focusser on a 16" GSO or 16" LB
2. Compatibilty with a colour filter wheel for programmed different focus points for the separate colours

Thanks guys, I value your input

dp

[iceman (Mike)]

Get the Orion Accufocus - it can be adapted to fit the GSO crayfords.

I've got one on my new/old 12" GSO dob.

[davidpretorius]

thanks ice, i had thought they were only for rack and pinion, that is great they can be adapted.

[Astroman (Andrew Wall)]

I have one (accufocus) on my JMI NGF-DX3 Crayford focuser, had to make an adapter for it though. U could go the Robofocus method if you have money, or with the stepper program you should be able to tell it how many steps to go for different focusing positions. I think Jaycar sell kits which could do the job.

[davidpretorius]

https://www.bintelshop.com.au/Product.aspx?ID=7411

I have ordered the orion from bintel sydney as a stop gap until i follow bird and look at these beasties.

thanks guys

[bird (Anthony Wesley)]

The JMI focussers are very good, I bought one in 2004 and I'll probably buy another one from the same place when the time comes.

The computer interface is easy, uses a serial port and simple control codes, highly accurate.

PS for the computer interface you have to also buy the "Smart Focus" PC control unit.

regards, Bird

[ballaratdragons (Ken)]

Here ya go Davo, how to fit an Orion Accufocus to the Crayford Focuser, and how to fit it all to the scope. To control mine from a distance I just got a cable made up. 10m phone cable with the correct ends on it. Cost me $7 I think from memory.

Adaptor: http://www.iceinspace.com.au/forum/s...ight=accufocus

Mounting: http://www.iceinspace.com.au/forum/s...ight=accufocus

[davidpretorius]

can't wait for June to check out in more detail your scope bird!!!

thanks for the links super platinum member!

[ballaratdragons (Ken)]

Originally Posted by davidpretorius

thanks for the links super platinum member!

That's OK 'Mega Gold Member'

[Yogie-One (Paul)]

I have a setup for my scope, which uses only a battery, a 12 position switch, 8 diodes, a 5 or 6 wire stepper motor, a mounting plate and a few gears.

The conection causes the stepper motor to follow the switch, forward or backwards, enabling it to be used as a driver for a focuser.

[netwolf]

The Accufocus is awesome, could not live without it on my dob. However there is one drawback, you have to loosen the shaft coupler to do manual focus when you wish to. I would recommend replacing these screws with something easier to loosen without any tools. Aside from that quirk its a modification I would not go without. I am looking at seeing if it can be modified to work with the LX90.

I am also sure it could be adapted for PC control.

Regards