D&G Optical/classic achro refractor YahooGroup?

I'm in the planning process for purchasing on of these long focus achro
refractors and noticed the lack of an "online community" for this
excuisite line of classic telescope. I have met a bunch of super
helpful refractor enthusiasts in the Refractor Group (including some D&G
owners), but, maybe I'm just suffering from
specialization-discussion-interuptus as seemingly every manufacturer and
line of scopes has a Group of their own. Is there something somewhere
out there I'm missing or maybe long-focus classic refractors fit nicely
nestled in Refractors in general?

Pat Kelly in Maryland

"PKelly" wrote in message
...
I'm in the planning process for purchasing on of these long focus achro
refractors and noticed the lack of an "online community" for this
excuisite line of classic telescope. I have met a bunch of super
helpful refractor enthusiasts in the Refractor Group (including some D&G
owners), but, maybe I'm just suffering from
specialization-discussion-interuptus as seemingly every manufacturer and
line of scopes has a Group of their own. Is there something somewhere
out there I'm missing or maybe long-focus classic refractors fit nicely
nestled in Refractors in general?

Pat Kelly in Maryland

Refractors were very popular in the so called good old days (1950's) and
before. Unfortunately they were rather expensive especially when over 4
inches. Unitron comes to mind. I had the pleasure to use a 4 inch Brashear
(1910) vintage when I was a member of the Regina Astro Society. It is now
in a museum. My intro to astronomy was observing a transit of Mercury
through this fine instrument. I guess they fell out of disfavour when
aperture fevor hit the amateur community. Also, easily transportable
Schmidt Cassegrains hit the seen. With the two element achromat colour
becomes a problem with lenses in the 6 inch and larger range. Also they
weren't very portable and were more suited to permanent installations
Apochromats hit the seen but these were expensive but well suited for
photography. I still love the refractor but unfortunately don't own one.
Properly mounted they are well suited for double star work with a filar
micrometer. Planetary and lunar observations are superb. They are great
for solar work also if fitted with proper filters especially an Ha filter
for viewing prominences etc. I hear that the D&G refractors are very good
but I have never looked through one. This is the classical way of doing
astronomical observations! Why not start your own refractor group on
yahoogroups.com!

Ed Majden
Courtenay, B.C.
Canada.

I had a 6"F20 special order lens from D&G. The 3 months order turned
into 10 months, but when the lens finally arrived, it was worth the
wait. I folded the lens newtonian style, a "fold-hoffer", if you will.
At 100x per inch, the star test was flawless. This lens provided
stunning images of the Jupiter "comet-crash".

I too would like to see a discussion group about these classic long
focus refractors. An OTA with a Aries Chromacor is still 1/3 the cost
of an APO.

"Doug Peterson"
I too would like to see a discussion group about these classic long
focus refractors. An OTA with a Aries Chromacor is still 1/3 the cost
of an APO.

Isn't the Chromacor designed for low f-ratio achromats? Have you tried
one on your 6" f-20? If so, what were your results with it?
Ed

On Sun, 09 Nov 2003 09:47:53 -0500, PKelly wrote:

I'm in the planning process for purchasing on of these long focus achro
refractors and noticed the lack of an "online community" for this
excuisite line of classic telescope. I have met a bunch of super
helpful refractor enthusiasts in the Refractor Group (including some D&G
owners), but, maybe I'm just suffering from
specialization-discussion-interuptus as seemingly every manufacturer and
line of scopes has a Group of their own. Is there something somewhere
out there I'm missing or maybe long-focus classic refractors fit nicely
nestled in Refractors in general?

Pat Kelly in Maryland

Why have you settled upon one of those, notwithstanding
the commensurate enormity and consequent expense of the
mounting that MUST be coupled unto it?

Alan

I sold the lens to Detlef Schmidt before the Chromacors were
available. I now use a D&G 8" F12 with a Chromacor-N and the results
are simply astounding on Jupiter. The color correction is very good,
certainly the-good-enough-that-it-doesn't-matter level, equaling or
exceeding the performance of two element EDs and fluorites. The only
way I know to get better is to spend 16-24K for the 8" true zero color
APOs.

You haven't lived unless you have seen planetary detail through a
large unobstructed refractor. Yes, the MTF can be equalled by a
larger, obstructed system where the effective aperture is equal to the
primary minus the secondary diameter, however the larger aperture is
also subject to greater turbulance under all but the most exceptional
seeing conditions.

"Doug Peterson"
I sold the lens to Detlef Schmidt before the Chromacors were
available. I now use a D&G 8" F12 with a Chromacor-N and the results
are simply astounding on Jupiter. The color correction is very good,
certainly the-good-enough-that-it-doesn't-matter level, equaling or
exceeding the performance of two element EDs and fluorites. The only
way I know to get better is to spend 16-24K for the 8" true zero color
APOs.

How well does the chromacor work using film or a CCD camera?

Ed

Alan W. Craft wrote:

On Sun, 09 Nov 2003 09:47:53 -0500, PKelly wrote:


I'm in the planning process for purchasing on of these long focus achro
refractors and noticed the lack of an "online community" for this
excuisite line of classic telescope. I have met a bunch of super
helpful refractor enthusiasts in the Refractor Group (including some D&G
owners), but, maybe I'm just suffering from
specialization-discussion-interuptus as seemingly every manufacturer and
line of scopes has a Group of their own. Is there something somewhere
out there I'm missing or maybe long-focus classic refractors fit nicely
nestled in Refractors in general?

Pat Kelly in Maryland


Why have you settled upon one of those, notwithstanding
the commensurate enormity and consequent expense of the
mounting that MUST be coupled unto it?

Alan


- I'm a visual only observer.
- Can no longer afford the apo route...hit the "fluorite ceiling" so to
speak and just sold my dream AP and other high end eps etc for available
cash.
- Can use my existing G-11, jacked up with minor modifications, to
comfortably accomodate the 5" f/12 and f/15 (and maybe the 6 f/12) D&G
refractors and for observing.
- Enjoy those "classic" refractor-like views that refractors throw out
and the simple yet high performance optical system.
- Can achieve almost-apo (ie. close enough) performance at a fraction of
the cost and more bang for the buck (very important right now).
- Modern technology = minus violet filters and Chromacors to clean up
remaining false color
- Observing close to the Ocean and Chesapeake in the Mid Atlantic is
attrocious for seeing and quickly falling night temps...perfect for
refractors
- I don't travel so portability is not an issue.
- My back yard is not windy.
- I'm all thumbs and don't like to fidle with my scopes.
- I always wanted a Unitron and this is as close as I'll ever get g.
- Double stars, planetary, lunar, deep sky clusters are my fav targets.
Refractors are notoriously under rated for deep sky observing within
the capabilities of their aperatures.
- For quick peeks I get by with an old Questar I got used and cheap.

Pat

Ed Majden wrote:


I hear that the D&G refractors are very good
but I have never looked through one. This is the classical way of doing
astronomical observations! Why not start your own refractor group on
yahoogroups.com!

This notion has crossed my mind more than once g!

"Ed Majden" wrote in message news:0Cwrb.355372$9l5.330621@pd7tw2no...
"Doug Peterson"
I too would like to see a discussion group about these classic long
focus refractors. An OTA with a Aries Chromacor is still 1/3 the cost
of an APO.
Ed

If any of you have any interest in Unitron refractors (and Polarex,
their European equivalents) we have a very viable UnitronTelescopes
Yahoo Group. It has been up and running for about 3 years and has 157
members at present. Lot's of historical info and photos. The web
address is:

http://groups.yahoo.com/group/UnitronTelescopes/

Regards,

Barry Simon, Founder and Moderator
UnitronTelescopes