Author Topic: SCT vs DOB  (Read 110 times)

acbacema

  • Active Astronomer
  • ***
  • Posts: 126
  • Activity:
    20.67%
  • Reputation: +0/-0
    • View Profile
SCT vs DOB
« on: December 24, 2017, 03:37:40 AM »
I've got a 12" fork mounted SCT with go to and I have really enjoyed the ease of finding objects.  One thing that I don't enjoy about my SCT is setting it up by myself (lifting the scope on the tripod).  I'm thinking about moving into a Dob because a number of them can be moved just like a wheelbarrow, therefore less lifting.  But, I don't have the expertise to star hop, so I want some kind of go to.  Also, I reside in Idaho in which it tends to be windy.  How sensitive are Dobs to wind?  I would love any suggestions of Dob/ go to combinations I should consider.   Thanks.



caheadhilldea

  • Active Astronomer
  • ***
  • Posts: 129
  • Activity:
    12%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #1 on: December 24, 2017, 09:31:28 AM »
There are GoTo variants available.  A part of my club just got a
SkyWatcher 10" GoTo Dob.  I haven't looked through it but another club
Member has and stated it was a wonderful scope.  A number of ways to put wheels
On a single.  A cart and bungee cord may be the simplest.  Mine is on a dolly
With 4" caster wheels which rolls nice on a tricky surface.  Wheelbarrel handles
And bigger pneumatic wheels work best on soft surfaces such as grass.
Dave Y

Clyde Duke

  • Active Astronomer
  • ***
  • Posts: 124
  • Activity:
    9.33%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #2 on: December 28, 2017, 10:58:54 PM »
Finding a GoTo Dob is a bit more difficult and expensive than you might think. However, there is also an arrangement called a "Digital Setting Circle" that is much easier to find and much less expensive on dobs. "GoTo" means there are motors that will take the scope where you tell it to go. "Digital Setting Circles" on the other hand merely tell you exactly where the scope is pointing (once properly aligned), and where you need to PUSH the scope by hand to get to where you want to go.

12 inch SCTs are very large instruments that must be lifted onto big tripods, with big mounts. But if you are talking about a dob big enough to need wheelbarrow arrangements, you are talking about a big operation also. Unless you can leave it permanently assembled, you will need to mount the secondary assembly on top of the truss tubes at some point. It is lighter than a twelve inch SCT, but still a considerable issue.

Yes, Dobs have more sail area land are therefore a bit more of a problem in a wind. But a 12 inch SCT has problems of its own.

I strongly suggest you play with some other people's dobs before you make the switch. ----At least for the reasons you are switching. With big scopes there is no free lunch.

Alex

Rick Nocturnum

  • Active Astronomer
  • ***
  • Posts: 109
  • Activity:
    12%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #3 on: December 29, 2017, 03:18:35 AM »
If you like your SCT why don't you put wheels on the tripod like scope buggy (http://www.scopebugg.../UntitledH.html) or JMI wheelie bars <a>(http://www.jimsmobile.com/buy_wheeley_bars.htm).[/url] Both of these products work well.

If your floor is relatively smooth you could even try a set of 3 wheel dollies like these : http://www.homedepot...-9299/100193474 - one on each leg.

I'm thinking of making a set of 3 wheel doles using larger pneumatic tires (locking) so that I can roll across rougher ground.

AS for wind - yes I think Dobs can be blown around if the wind is hard enough or at least the UTA can be wobbled.

adrajacte

  • Active Astronomer
  • ***
  • Posts: 121
  • Activity:
    16.67%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #4 on: December 30, 2017, 09:41:53 PM »
My 1st scope is an Orion XT10i that I still have in a very upgraded state and use for outreach and driveway observing from my white zone locale. My intro to larger aperture came via the club's 16" LX200 SCT and I wassold! My 16" Dob gives better, brighter views. It is full go-to/track and much less complex than the SCT. It is easier to use and very much easier to maintain.

Last Monday night at the Oklahoma dark site the sustained winds were @ 5-8 mph but gusting to easily 15-17 mph all night. I commented to another club member who'd come by to see what was in the eyepiece that shaking the tube was automatic tonight but we were able to observe 6 of 7 members of Copland's Septet despite the turbulence.

Reasonable winds are notdebilitating. A wind high enough to really interfere will have degraded the observing conditions badly anyway. Granted, the Starmaster is relatively massive and robust.

I respect the strengths of SCT's but I would never own one. A Dob is so much easier to use - for me.

Another club member's Orion XX12g is a very nice scope to which he downsized, taking advantage of the strut configuration so he doesn't have to lift heavy components. I have looked through it. It's nice and the go-to/track works well.

Leave off the motors and use something like the Nexus DSC in a push-to configuration on a Teeter compact Dob for the ultimate lightweight powerhouse scope. When the Starmaster becomes too massive for me, I hope to be able to end up there.

Gabriel Green

  • Active Astronomer
  • ***
  • Posts: 107
  • Activity:
    16%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #5 on: December 31, 2017, 05:48:21 PM »
Those dob suggestions sound good to me.

But if you really like the optics on your Meade, another potential solution is to put it on a simpler, lighter altaz mount, and look into getting encoders for a push-to set up.

Those can be very expensive, but there are alternatives. I use the skytee 2 with my 11" Edge, and plan to look into encoders at some point (I use this 99% of the time on moon and planets, so there's no real need). This is a fairly light and effective set up, but it does require tweaks--a bigger saddle being mandatory. Another issue is that you'd probably have to get it from Europe, e.g.,http://www.firstligh...muth-mount.html

Stargazers lounge has some good reviews.

ovisimmus

  • Active Astronomer
  • ***
  • Posts: 127
  • Activity:
    18%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #6 on: December 31, 2017, 08:31:48 PM »
I have both an 11 inch go to SCT and a 14 inch go to Orion Dob. As far as weight goes, the main difference is that you shift the heaviest weight from the SCT (top) to the Dob (base) where the motors are. The truth is that any scope with 10 inches or more in aperture is going to have at least one fairly heavy component. If go to is important to you, I don't think you would gain anything by switching to a Dob.

Gary Allen

  • Active Astronomer
  • ***
  • Posts: 128
  • Activity:
    16.67%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #7 on: January 03, 2018, 12:11:56 PM »
As Taosmath pointed out there are options from a couple of vendors to put wheels on your SCT tripod. You just keep it assembled with a dust cover on it and roll it out when you're ready to view. If you keep it stored in a garage or shed you'll have the added advantage of it being cooled or shortening the cool down time substantially.

unoritvie

  • Active Astronomer
  • ***
  • Posts: 120
  • Activity:
    14.67%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #8 on: January 10, 2018, 08:53:50 AM »
They'll have to pull my 10XTi from my cold dead paws.....

calfkommomu

  • Active Astronomer
  • ***
  • Posts: 130
  • Activity:
    10.67%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #9 on: January 10, 2018, 09:26:57 AM »
Quote
I have a 12" fork mounted SCT with go to and I have really enjoyed the ease of finding objects. One thing I don't like about my SCT is setting it up by myself (lifting the scope onto the tripod). I'm thinking about moving to a Dob because some of them can be moved like a wheelbarrow, so less lifting. However, I don't have the expertise to star hop, so I need some form of go to. Also, I live in Idaho where it tends to be windy. How sensitive are Dobs to wind? I would appreciate any suggestions of Dob/ go to combinations I should consider.  Thanks.

As others have said, it seems to make more sense to put wheels on your SCT than to custom-buy a Dob just because you've seen Dobs with wheels.

That's assuming that you're staying in the same aperture class. The real benefit of moving to a Dob is if you want to go up a notch in aperture. At that point SCTs become really awkward, while truss-tube Dobs are still quite manageable.

As for Go To, have you considered learning to star-hop? Just because you can't do it right now doesn't mean that you're doomed never to learn it.

halespbourvi

  • Active Astronomer
  • ***
  • Posts: 118
  • Activity:
    13.33%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #10 on: January 11, 2018, 02:55:39 PM »
Orion XT12G go to with wheelbarrow mod.Attached Thumbnails


tiogeroligh

  • Active Astronomer
  • ***
  • Posts: 112
  • Activity:
    9.33%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #11 on: January 12, 2018, 06:37:54 AM »
Just put wheels on it and leave it set-up.

I like Taosmath's idea.3 of these and a couple of 1X3s and you have a cart.
http://www.homedepot...-9299/100193474

My dob lives on a cart in the garage. If you have room to store a Dob set-up you should have room to store an SCT on wheels.Attached Thumbnails


Charles Marin

  • Jr. Astronomer
  • **
  • Posts: 97
  • Activity:
    12%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #12 on: January 12, 2018, 07:16:11 AM »
Orion has a truss Dob that has the Push to Computer for $1699.00. It is about what you could sell your Meade 12" for.
Orion has been known for having very good mirrors, but even better excellent Customer Service!
If you talk to some of the folks that have had to deal with the CS of current SCT manufacturers you will find out just how valuable it is.
The 12" with object locator in a solid tube is $1249.00
 BUT, A small Dob without the Computer where you can learn to Star Hop, and inexpensive set of Star Charts will make you appreciate the Sky above beyond what ANY computer can ever do. You will also find you will be observing out MUCH more often because of the weight difference of a smaller scope.
A friend here Jon helped me realize that for a fact. I was using a Go-To C14 until Medical issues made that impossible. I soon remembered how much I truly loved finding objects by myself, and how much more satisfied I felt.
My observing sessions last 3X as long and time flies. The fact is GO-TO made me lazy and after 30-45 minutes I was bored sick!
 Orion has their XT 6 and XT8 scopes on sale right now with a Solar Filter and eyepieces starting at $349.00
That way you could keep the 12" for those nights when you want to go really DEEP.....
 It feels mighty nice without those motors sounding like a Coffee Grinder going off in my ears.

Chuck Johnston

  • Active Astronomer
  • ***
  • Posts: 118
  • Activity:
    14%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #13 on: January 12, 2018, 06:11:04 PM »
Quote
Quote

I have a 12" fork mounted SCT with go to and I have really enjoyed the ease of finding objects. One thing I don't like about my SCT is setting it up by myself (lifting the scope onto the tripod). I'm thinking about moving to a Dob because some of them can be moved like a wheelbarrow, so less lifting. However, I don't have the expertise to star hop, so I need some form of go to. Also, I live in Idaho where it tends to be windy. How sensitive are Dobs to wind? I would appreciate any suggestions of Dob/ go to combinations I should consider.  Thanks.

As others have said, it seems to make more sense to put wheels on your SCT than to custom-buy a Dob just because you've seen Dobs with wheels.

That's assuming that you're staying in the same aperture class. The real benefit of moving to a Dob is if you want to go up a notch in aperture. At that point SCTs become really awkward, while truss-tube Dobs are still quite manageable.

As for Go To, have you considered learning to star-hop? Just because you can't do it right now doesn't mean that you're doomed never to learn it.

Like Tony, I am a big fan of Dobsonians and a big fan Star hopping, I just enjoy it.

But if one want's GOTO and has no particular reason to want Newtonian optics, I think the SCT GOTO is more robust. As a mechanical engineer, particle board and precision drives just don't make a good match.

Jon

coreanoguf

  • Active Astronomer
  • ***
  • Posts: 132
  • Activity:
    16%
  • Reputation: +0/-0
    • View Profile
Re: SCT vs DOB
« Reply #14 on: January 13, 2018, 03:38:51 AM »
If the primary issue is carrying your scope and lifting it onto your tripod/wedge then a sling might help. Take a look at my sling about 1/3rd of the way down this thread...

http://www.cloudynig...-or-fork-mount/

This made a huge difference in the useability of my 10" SCT.