Dobsonian tracking

Sheap · #1 17-05-2006, 06:35 PM

What does it cost to have my dob start moving?
Something that can work through my LPI (using k3CCD tools which im going to have to register or autostar suite) is preferable but not vital.
Also, who actually sells them? ive seen them mentioned, but never actually on a store's site. myastroshop and bintel as far as ive seen dont have any.

I can see that this hobby is starting to pull me in...

Chrissyo (Chris) · #2 17-05-2006, 06:55 PM

At the moment, it seems the two main options are a tracking platform or EQ mount.

A new tracking platform has recently become available at Bintel for about $1,050 (I think). These platforms are not that available in Australia, but can be imported from overseas - but customs seems to be quite costly!

The other option is an EQ mount... and the cost depends on the size of your dob. An eq5 can just handle an 8" newtonian (I believe?) and an eq6 (costing about $1,500) is required for anything larger. I'm not a real expert in the actual specs of these, so I might be a little off

I have also seen many cool ideas for improved manual dob tracking, such as the dob wedge that was posted in a thread a short while ago. I wouldn't mind having a go at that myself if I wasnt useless at woodwork

I hope this is useful to you! Many dobbers are also interested in tracking (myself included

)

fremanwarrior · #3 17-05-2006, 07:13 PM

This website has a nice 'how to' on the DoB driver 2 install.

http://webpages.charter.net/jparticle/rasddr2.htm

iceman (Mike) · #4 17-05-2006, 07:14 PM

Chrissyo's pretty much on the mark.

EQ Platform:
Sits under your scope, so you still use it like a dob (alt/az push to). But once you're pointing at something, the tracking of the EQ platform keeps it pointed there.
I've got one from Round Table Platforms that is great. The cost was fairly minimal compared to an EQ6, but postage was a killer. Cost me about AU$700 to get it here.
Bintel sell one now called the "Johnsonian" platform, looks like a very good unit with a hand controller. $1150, so quite pricey, but if you still want to use the dob like a dob, it's great.
You can see a picture of my imaging setup in the attachment below. The platform is the wooden stuff under the dob base

Great for solar system imaging, not suitable for DSO imaging.

EQ Mount
You don't say what size dob you've got. You'll need an EQ5, HEQ5, or EQ6. Cost ranges from $800-$1500 or so I think. More if you get the SkyScan upgrade for full "goto". That is, enter the object in the hand controller, and the mount points your scope to it.
So you'd use your existing newt OTA and put it on the EQ6 mount.
You have to polar align the mount, but you'll get much more accurate tracking for lengthy periods if you do it accurately.

Great for solar system and DSO imaging.
Eyepiece can get in weird spots though, and not as portable or quick to setup as a dob mount.
Obviously more pricey too.

Dob-Driver/Servo-Cat
These are solutions that fit inside your dob base in some way and actually drive it for you. DavePretorius has the Dob Driver, and big dobs usually have ServoCat. They're great solutions.
Can be costly, and some DIY required.

Hope that helps.

drmorbius (Randall) · #5 17-05-2006, 07:21 PM

If you're a bit handy with wood, there's a few plans on the Internet for building your own EQ mount. http://dbpeckham.com/EP/Don-EP.htm

I intend to build one myself... it looks like fun. Mind you, I should probably buy a scope first...

davidpretorius · #6 17-05-2006, 09:51 PM

I picked my dob driver II up 2nd hand for $600, an absolute steal, thanks mr beal!!

It works fine for planetary, but i will need to do some serious work on the ALT bearing ie enlarge it to allow it track without intervention for 10's of minutes.

This makes DSO stuff hard, But planetary is fine with the hand controller as i can adjust as i go along.

I believe a decent eq6 down the track will be essential, but then again this dob driver will work fine on large diameter mirrors as well!

Sheap · #7 18-05-2006, 05:04 PM

Thanks for all the info, but its souding a bit out of my price range to buy one at the moment.

davidpretorius · #8 18-05-2006, 05:17 PM

I still hold to my original plan for getting into astronomy and the levels you progress through.

For the first 5 months I had no tracking. I could image planets and do heaps and heaps of viewing. Along came the 2nd hand dob driver in december 2005 and since then I have hardly seen anything apart from jupiter and saturn.

Tracking is great, but by no means the be all end all. I am really starting to miss viewing Messier objects etc.

So don't rush things, you have all the time in the world to progress slowly.

Even if you have a d1ck smith scope, there is 1 - 2 years worth of stuff to study up in the sky.

The same with eyepieces and the like. You appreciate the better quality eyepieces once you actually have quite a lot of experience in picking out the "bad" things. How many newbies would look thru a $100 eyepiece and a $500 eyepiece and notice a difference???

I spose I am saying, don't rush it.

I still have a 5yr plan to get a celestron 14" on a decent mount. $10,000 - $20,000. I can't afford it now, but it in no ways detracts from the fun i am having now playing with my toys!