A request was made for a review of the MaxScope 40 - actually, I have the
SolarMax 40 on an Orion ED80, but it's basically the same technology.
I'd been wanting to have my own H-alpha scope for a while now. I'd seen my
first real H-alpha views through a Coronado MaxScope 70 that my school's
astronomy department purchased, and I'd looked through Michael Swartz's
SolarMax 90 / Tak Sky 90 / Hi-Res Module setup on a number of occasions.
I'd been bitten by the bug, and wanted one of my own. I'd resigned myself
to waiting some number of years before I could get the money together.
The thing that tipped me towards buying a used SolarMax 40 setup was a
chance to look through some other 40mm H-alpha rigs. I was at the Peak a
few weeks back, setting up before sunset, and an SFAA member (possibly Mike
Portuesi, but I'm not sure) had a MaxScope 40. The view through that
instrument was quite nice. Later that same afternoon, an FPOA member set up
the club's 40mm Daystar H-alpha scope. That was quite a nice view, too.
As luck would have it, a Solar Max 40 went on Astromart a day or two later.
After some backing and forthing on email with the seller, we sealed the
deal.
For anyone who doesn't know, the Coronado H-alpha filter rigs actually have
two main parts: The "Narrowband Element" and the "Blocking Filter". The NE
is the gold-anodized thing that goes in front of the objective, and the BF
is usually manufactured as a 1.25" diagonal, although they do make some
other designs. You have to get the right BF for the focal length of your
scope. Refractors are usually recommended for their simplicity, although
other scopes do work.
After trying a few different designs for a homemade adapter to hold the
filter in front of the objective, I settled on a design that works
reasonably well. Let's not focus too much on the fact that it's made of an
ABS plastic pipe cap, a Sony adapter that I found at Fry's, some superglue,
and gaffer's tape. The less Coronado knows about that, the better. It
doesn't fall off, and it does a pretty good job of holding the filter
parallel to the objective. This is pretty important, as a non-square filter
may result in less visible detail. (Some deliberate tilting is okay,
though, because that can reveal fast-moving plasma whose light is slightly
doppler-shifted away from the usual H-alpha wavelength of 656.3 nm. The
T-Max tuner accomplishes this.)
Okay, so I've got the thing set up - how well does it work? Pretty well.
Enough that I'm quite glad I got it. No buyer's remorse here. I see the sun
in the deep red of H-alpha, which I find strangely compelling. (There's
something about saturated colors that I find oddly mesmerizing, don't know
why...) I see prominences coming off the limb, and I've been quite pleased
at how much small-scale detail I can see. I see some surface detail,
including sunspots, mottling, dark 'filaments' (which seem to be just
prominences seen against the disc), and bright 'plage'. Also bright flares.
Not all H-alpha rigs are created equal. More important than aperture is the
bandpass width. The SolarMax 40 says "<0.8 angstrom". For me this works,
although I have to say that is does help to be a reasonably experienced
observer. In order to maximize my surface detail, I use hands, eyepatch,
eyecup, etc... to keep all stray light out of my eyes. I look around the
disc a lot, I move the sun around in the field of view, and sometimes I
jiggle the scope a bit. It's a lot like deep-sky observing. Using these
tricks, I am surprised at how much surface detail I can tease out. It has
really taught me a lot about maximizing my perception of contrast.
My setup is basically an 'entry-level' rig, but I'm quite pleased with it.
Of course, there are setups out there that deliver noticeably spectacular
views. Michael's setup, for example, achieves a significantly narrower
bandpass (around 05.-0.6 angstrom, I think) by having an entire second NE.
This is called 'double stacking', and it yields much more surface detail. I
was really blown away by some of the surface detail I was seeing in his
scope yesterday. You can achieve this with a variety of configurations.
I haven't look through Coronado's new PST (Personal Solar Telescope), but I
have heard good things about them.
It's probably a lot quicker to get a used H-alpha rig on Astromart than to
order a new one, or at least so I've heard.
The neat thing about the Sun is that stuff actually changes! Not only does
the sun rotate, carrying a given feature across its face in several days'
time, but some of the features (proms, flares) can actually change within
minutes or an hour! The best solar viewing seems to occur when a very large
sunspot group is visible on the face of the sun, or is on the limb.
Otherwise, the sun is quiet, but still worth a quick look. Here's some good
news: Thanks to the science of helioseismology, astronomers can actually
'see' large sunspots on the FAR side of the sun. Amazing. So, you know when
something big is goingn to come around. Check spaceweather.com.
I think that the best philosophy on how to observe the sun comes from a
program I saw about a New York chef visiting the Basque country of Spain.
About food and drink the Basques said: "A little bit, often." So it is with
H-alpha.
Marek Cichanski
Received on Sat Jul 31 12:38:55 2004