Which, of course, would negate one of the Dob-mounted Newt's
primary attractions: cost, or rather the lack thereof.

Alan

For some that might be the primary attraction, and for me, it is part of it.
But the cost is only the iceing on the cake.

The compactness, ease of setup and tear down, freedom from vibration,
comfortable viewing postion, intuitive star hopping, these are some of the
attractions.

The most often cited drawback is the lack of tracking. An EQ platform will
allow you to retain the other advantages while adding tracking capability.

While for an 8 inch scope, an EQ mount is quite doable, though one substantial
enough to handle an 8 inch F6 scope with the same stability and freedom from
vibration as a DOB mount with be quite substantial. And for a Newtonian 12.5
inches the EQ mounts are getting into the huge range, and of course for large
scopes like being discussed here, they are essentially impossible for a scope
that is portable.

On the other hand, the equatorial platform retains the low profile compactness
and portability of the Dob design while providing good quality tracking. And
when the scopes get to the sizes being addressed here, it is really the only
option. It is nice that they are also affordable but that is of less
importance to the owner of a 20 inch DOB than the fact that the mount can be
lifted easily by one person and does not require a huge counterweight.

So, yes it is nice that DOBs are inexpensive, but it that is the primary
attraction, then one will probably soon move on. On the otherhand, if the
attractions are the elegent simplicity and ability to work as a close knit
team, then it is likely that one would choose a DOB even if it were the more
expensive route.

And of course sometimes it is. A ELT 12.5 inch Starmaster will run about $3800
without Goto and another $2300 for the GOTO+ tracking, around $6000.

jon