Coronado PST

Dave Jessie wrote:

Paul Hyndman wrote in message:

...Ummm, B & H seems to have tapped a steady supply of PSTs, and currently
show them as "In Stock" (though they run through them quickly):


http://www.bhphotovideo.com/bnh/cont...=324412&is=REG

Hi Paul,

IT'S HERE! Thursday, August 26, 2004 at 1:55pm EST (that would be 5:55UT)
After ordering on the evening of 8/23 from B&H's web site.

Thanks, Paul! Without your post, I'd still be waiting. And waiting. And
waiting...

Of course, the current weather conditions are clouds - from horizon to
horizon...


Congratulations! That's how I got my PST in July: Saw someone post that
B&H had stock and ordered it 2nd day air on the spot. Most fun I've had
in years.

Problem with all the PSTs is that they are affecting the weather: We may
end up with a global ice age :-)

Phil

Mark Rosengarten wrote:

Great review, David! By the way, what small tabletop mount are you using? It
looks like an Orion slo-mo head, but I don't recognize the tripod.

I was thinking about getting a Bogen 410 geared head and a tabletop tripod as
well as using it on my Slik 400DX tripod.


Let me add my kudos for the review.

I have the 410 head and would like a small tripod, too (use a Manfrotto
475 as primary, but a tiny one would be nice for air travel). Please
keep us posted.

Phil

On Thu, 26 Aug 2004 19:57:49 -0400, "Paul Hyndman" nospamma-mia
wrote:

The etalon is an important part of the system, working in concert with a
blocking filter to restrict the frequency to sub-angstrom levels. To put the
level of precision in perpsective, consider this: an angstrom is one
hundred-millionth of a centimeter, and this filter's passband is "tighter"
than that!

Even small changes in ambient temperature could be fatal to solar H-a image
quality, if proper engineering provisions have not been implemented. Some
solar H-a designs require heaters to maintain "on-band" performance while
others use tunable stages that are adjusted throughtout the session, but the
etalon design as employed here requires no heaters or continued fidgeting.


Yes, I remember using one with a little "tilter" knob on it. Don't
remember the brand.

Non-etalon, rear-mount filter configurations usually require long f/ratios
(f/30-f/32 is not uncommon), making full-disk views less accessible. I
believe the PST works at f/10.. another benefit of an etalon design (the
filter can be mounted in front of or behind the objective).

Increased aperture can impart greater resolution (no secret there) and a
decrease bandpass can enhance contrast. For either though, the cost climbs
logarithmically! Given the price-point of the PST, there is currently
nothiing on the horizon that even comes close to the amount of
bang-for-the-buck it delivers.

One last thought... you can easily spend far more than $499 for an eyepiece
(been there many times over!)... but this little puppy even includes that in
the package price!

Paul


Yes, it is amazing. I can see greater interest in solar observing now
these have hit the market. It's nice to see things have come this way
for Coronado, remembering the beginnings of the company.
-Rich

Richard posted:

Does anyone know which piece in the scope accounts for most of
it's cost? Is it the etalon? I'm curious as to why the prices for
solar scopes/products haven't really dropped below $500.
Also, despite the fact I've owned hundreds of conventional scopes,
eyepieces, etc, I'm not really up on the workings of the solar
products. Is there a great benefit to increased aperture (the filter
or the scope) when viewing the sun in H-alpha?

Yes, the Fabry-Perot etalon is the most expensive part of the filtering
system, and the larger the etalon the greater the cost. There is some detail
resolution benefit (if you have good daytime seeing) to using a larger
aperture, but in that case, the filtering system is a smaller etalon located
just beyond the focal point of a long f/ration system (usually longer than
f/30). The larger aperture will allow resolving finer scale detail as long as
the seeing is good enough. I do get to see physically smaller surface detail
with my 87.5mm aperture Makstuov + Powermate + Daystar T-Scanner, but the PST
still shows a lot, and with slightly higher contrast. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

Paul Hyndman wrote:

Non-etalon, rear-mount filter configurations usually require long f/ratios
(f/30-f/32 is not uncommon), making full-disk views less accessible. I
believe the PST works at f/10.. another benefit of an etalon design (the
filter can be mounted in front of or behind the objective).

Most of the sub-angstrom passband rear-mounted H-alpha filtering systems *use*
etalons (internal ones) (I don't know of too many rear-mounted filters which
don't use etalons, except in professional circles, where Lyot-style filters
may be used). The DayStar line of filters does require f/ratios longer than
f/30 for the angles of light hitting the etalon to be within the correct
range. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

Mark Rosengareten wrote:

Great review, David! By the way, what small tabletop mount are you using? It
looks like an Orion slo-mo head, but I don't recognize the tripod.

I was thinking about getting a Bogen 410 geared head and a tabletop tripod as
well as using it on my Slik 400DX tripod.

I don't know who made it (probably Chinese), but it was purchased at the
Nebraska Star Party a number of years ago from Eagle Optics. It is similar to
the Bushnell "Shooter Stand" table-top tripod except that the head has 2-axis
slow motion. In fact, the head is indeed very similar to the micro one
currently being sold by Orion. It works pretty well, although eventually, I
will probably try something a little different. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

Bill posted:

Your review brings a question to mind regarding the "white light"
view. How does that WL view compare to a Baader solar filter view
(assuming you've looked through one of 40mm aperture)?

Its about the same except that faculae patches don't show up quite as well as
they do in the slightly bluer Baader filter. I don't often de-tune the PST
that far, as it is vastly more interesting to see what the Chromosphere is
doing. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

David Knisely wrote in message ...
Well, its finally finished and up in the CloudyNights Reports section (you
will need the Adobe Acrobat reader to read it). Check it out at:
http://www.cloudynights.com
--
David W. Knisely

David,

I had a look at your review a couple of days ago. You did a fine job
as always.

I've used my new PST every day since Monday and have had some great
views. On Friday afternoon I saw a loop prominence. Today I took the
PST to the annual Astronomical Society of Harrisburg picnic and
everyone was suitably impressed.

Dave Mitsky