Electronic focusers

15 years 6 months ago #5897 by dmcdona
Electronic focusers was created by dmcdona
Folks - does anyone here use an electronic focuser? If so, I'm interested in your experience.

I'm currently looking at:
Finger Lakes DF-2
Optec TCF-S
JMI NGF series
Van Slyke - still need to decipher their website....


Cheers

Dave

Please Log in or Create an account to join the conversation.

15 years 6 months ago #5899 by albertw
Replied by albertw on topic Re: Electronic focusers
I have a JMI Motofocus on the LXD55.

The 10" scope is really pushing the limit of the mount and touching the focus knob can cause a lot of wobble at high magnification. The electronic focuser is a godsend, easy quick focusing without any wobble.

Cheers,
~Al

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/

Please Log in or Create an account to join the conversation.

15 years 6 months ago #5901 by michaeloconnell
Replied by michaeloconnell on topic Re: Electronic focusers
Dave,
This is something I looked into a while back. I went the cheaper route and bought a Borg non-rotating helical fosuser (1.25" - manual version). I find it superb especially for webcam imaging where focus is so critical.
One issue I have from my very limited experience of electric focusers is the lack of "feel" in them. It takes a bit more time to gauge how much the focus has actually changed. However, they are very useful. If I were getting one I'd get one that could be electrically controlled from the PC.
Clear skies,

Please Log in or Create an account to join the conversation.

15 years 6 months ago #5902 by dmcdona
Replied by dmcdona on topic Re: Electronic focusers
Michael - good point. Whatever I choose will need to be electronic, PC controlled and preferably temperature compensated (Optec TCF-S). That would be for the astrophotography setup. So I wouldn't be wanting to touch the 'scope at all!

For visual, how does the Borg perform? And do you have to purchase a particular type for a particular scope? And assuming you did the research, was there anything similar in that price range? I think the Van Slykes can be bought as manual focusers but they seem to be on the expensive side. But the quality seems good...

Cheers

Dave

Please Log in or Create an account to join the conversation.

15 years 6 months ago #5904 by michaeloconnell
Replied by michaeloconnell on topic Re: Electronic focusers
Here's something I wrote about it on another website previously. Saves on the typing when I can just link! :wink:

http://tinyurl.com/59xh7

Please Log in or Create an account to join the conversation.

15 years 6 months ago #5905 by michaeloconnell
Replied by michaeloconnell on topic Re: Electronic focusers
Dave,
I had been looking into getting a JMI NGF-S but the price was a little high. I then decided to go the manual route. However, I didn't see many fousers in the same price range as the Borg. I find it really really good. The focuser has markings down to 0.05mm travel, which is nice. It also has a very smooth but secure feel to the focuser.
The focuser comes in two two parts which must be ordered seperately so to speak. The first part id the focuser body which actually has a screw-on fit for some ccd cameras. The other bit is actually the 1.25" adapter which allows for it to fit into a 1.25" fitting. However, various sizes of Borg focusers are available at a variety of price ranges.
Clear skies,

Please Log in or Create an account to join the conversation.

15 years 6 months ago #5909 by eansbro
Replied by eansbro on topic Re: Electronic focusers
Hi Dave,

I use three electronic focussers.

These were each bought depending on the level of application.

The JMI NGT-S is quite good with its hand push button controller. However, I discovered it has some sluggishness when putting on a camera and filter system. I also discovered it was slightly off axis from the principle axis. I think this was due to ratching out to far with such a weight. It also depends on the orientation of the OTA and weight of the camera. However, if you are using light accessories it's fine.

Optec TCF - S has the added automatic facility of conpensating for temperature drop during a nights observing. Actually I use it both manually and automatically. It can take alot more weight than the JMI NGT -S. I like the DRO lit up in red, easily seen at a distance. Ratcheting I/O shows a very slight rotation in the image. ie. slight movement of target within the FOV. Not really important unless you are at high magnification doing webcam work on planets. The focusser is a solid piece of engineering. It also has the added feature of PC link up. to available software like Maxim DL for remote access.

Van Slyke. The focuser is absolutely amazing, the Rolls Royce of focusers. Of course the price is huge.

Again, it depends how serious you are in doing observational work. In my case I am serious. In fact Van Slyke didn't have what I was after so I had to send him a specific design that had a much wider entrance hole for the steep cone of light that would be passing through. This cost me alot more.
In what I have read in your previous mail you may not need this type of focuser for the type of telescope you are thinking of purchasing and camera/ filter system. BTW you can do remote access by adapting the focuser with ROBISCOPE. You then can use Maxim DL. I use a Mititoya DRO for focussing read out. There is no backlash in the system.

Out of the three I would go for the Optec TCF-S

I hope this helps

Eamonn

Please Log in or Create an account to join the conversation.

15 years 6 months ago #5911 by dmcdona
Replied by dmcdona on topic Re: Electronic focusers
Michael - nice review of the Borg! Might take a look at getting one for my new ETX-70 :shock: Seriously though, for the kinds of prices on the board you posted, looks like it'll be nice addition to the armoury!

Eamonn - thanks for the feedback. Like anything else in this hobby, one pathway soon splits up into three or four! I've simply been researching focusers that out there without currently looking at matching it up to a particular scope/camera/filter wheel outfit. This is where the level of complexity starts getting a bot hairy and even the websites have a paucity of information. But if I at least narrow the field down, the final choice(s) will start to become clearer.

Van Slyke - the images on their site are truly objects of immense desire! I'd even just put it on the mantlepiece and gaze at it all night!

Once again folks - thanks for your invaluable and much appreciated feedback. The journey continues....

Dave

Please Log in or Create an account to join the conversation.

15 years 6 months ago #5925 by dave_lillis
Replied by dave_lillis on topic Re: Electronic focusers
Hi Dave,
I'd have to agree with all above, an electronic focuser is a godsend.
I have one for the SCT, its a dedicated meade focuser and it really helps with webcaming as it prevents image wobble.
Since mine actually moves the primary mirror, I get about 20-25 arcseconds on image shift, which isn't alot, but it could have been worse.
I might go to a helical microfocuser in the near future, I'll have to make sure it has a scale on it for repeatable focusing.

Programs like astrosnap help you focus the webcam, this program is used for capturing images images and does the focusing as a side fuction.

DSLR focus is used with the digital SLR camers such as the 300D.

So there are many programs out there to help you along.

Have fun.

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor

Please Log in or Create an account to join the conversation.

Time to create page: 0.082 seconds
Powered by Kunena Forum