Posts Made By: John Biretta

Not sure. Maybe some sort of removable or interchangable
"feet" for the legs?

If you only need a couple mm more back focus,
one fix is to insert 48mm filters into
the light path. Typically one filter will
gain about 0.7mm backfocus. Using clear (or UV)
filters with multi-coating will have very little
impact on brightness. You can thread them
on to the diagonal (preferred) or the eyepiece.

Another fix is to find a prism diagonal instead
of a mirror diagonal. That will gain about 0.7"
of back focus, but will also add some (probably
minor) spherical and chromatic aberration.

I've had a Teeter 16 inch for a couple years.
About as well-made as any of the premium Dobs.
Well-engineered with features like diagonal
heater and large fans installed and wired-in.
Wood work and finish are very nice -- not
quite fine furniture quality, but very pleasing
nonetheless. Scope frame (upper tube, truss
assembly, mirror box) are well-designed and
very rigid -- more so that some other makers.

The scope arrived in relatively good collimation.
I've seen some other makers where proper collimation
was somewhere outside the available adjustment
range -- requiring some mods to fix. Rob seems to
have paid attention to proper optical alignment.

Mine did have a couple "warts" like it would
not quite reach the horizon -- elevation bearing
placement was a little off. On the other hand,
I almost never observe that low.

Also primary mirror cell was a little loose --
did not have a positive lock-down like some
others -- Rob's cell bolted-in from the sides
rather than from the bottom.

Rob used a tilt-out mirror cell
on mine -- you tilt out the rear cell and pull
out the mirror for transport. Some scopes
I've used were designed so that the mirror+cell
were removable, and I think I like that design
a little better -- less chance of touching the
mirror front surface. But its a relatively
minor point.

Virtually all premium Dobs I've used had some sort
of minor issues as delivered from the factory. Or
needed some sort of mods, like adding fans to the
mirror box, wiring, etc. Or needed mods to the
truss structure to make it more rigid.
In this respect Rob's scope was very solidly
engineered and relatively "complete" as delivered.

I can't really comment on Rob's optics, as I had
already bought the optics before I approached
Rob about building the scope. But his mirror
providers do have good reputations.

I have not tried either unit, but I think it comes down to
importance of day vs. night. If night is important, I would
get the 25x100. The 5x difference (25x vs 30x) is not very important
in terms of what detail you can see.

Not sure. You could check the links on the left
Account Menu > Unused Ratings
and see if its listed there. If not, another option
is to find some other ad from the seller, respond to it,
and then you will be issued a new "Unused Rating" and
you can leave feedback for that. It will be for the
wrong ad, but you can leave a rating anyways.

I once put a 4" APO up against a 6" Russian Mak-Cass side-by-side. The
high-power views were pretty much identical. Except that the Mak
took much longer to cool-down. I eventually sold the Mak,
because I just didn't see any point to it. I think Mak-Cass
in this 5" - 6" size range are a good alternative to much more
expensive 4" APOs. But if you've already got an APO you
are happy with, it just doesn't make sense.

What about something like a Celestron C8 SCT? They are pretty
light weight, MUCH more aperture than a 4" APO, and they are
making some pretty nice ones these days. There are still
some cool-down issues, but its about the same as a 6" Mak-Cass.
I think thats a more interesting alternative. Recent model
used ones can be had for maybe $400 - $600.

Superb!! It is interesting how much subtle cloud detail the
eye pulls out from the animation. I can't see 80% of that
stuff in a single frame.

Impressive!! Much better than trying to carry it outside.
Maybe add some red lights or reflectors before hitting the street.

Superb! Nice detail.

Very sorry to hear it!!! I suspect you are not alone.
The number of ratings I have received from others has been
steadily dropping in the past few days -- no doubt a
sign that accounts are being purged, or some computer
glitch at AM, etc. -- who knows.

I recall you had some interesting posts about refractors
maybe 6 or 7 years ago. All gone now. Pity.