Posts Made By: Larry Stedman

The rough rule of thumb is True FOV = Apparent FOV/ Mag

Take a 22mm Epic with 55 degree stated field of view. In your scope, it would yield 55x as the magnification. 55 degree/55x = 1 degree field of view on the sky. Or, let's do a 15mm standard Plossl, with 50 degree fov. It yields 80x magnification, or, with 50/80, .63 degree fov at the scope.

The purists and technical gurus will inform you that this is only an approximation and that the real field of view involves field stops, etc. but this should give you a ball park figure. Note: it can be off 5%, 10%, or 15%, partly because of the technical stuff, but also because, sometimes, manufacturers' stated fields of view are wrong, often too high! (In some rare cases, they've understated them!)

I have astigmatism, too, and means that I must observe with eyeglasses on for low power views to look good. Eyepieces with 20mm eye relief are recommended for eyeglass wearers (such as the Epics, Radians), but one can tolerate more or less e.r. depending on the thickness of one's glasses and how close they are to their eyes. 25mm+ Plossls or Ultimas (excellent line) have sufficient eye relief. One can barlow those to achieve higher powers, or get a mid-range Epic or X-Cel, and then at high power, one can remove their glasses and use most any eyepiece, or go for something more $$, say a Radian.

I particularly like an 8-24mm zoom as the eye relief is fine, it covers a wide range of magnifications, and the contrast, views match those of good Plossls.

I use Ultimas and Ultrascopics (24, 25, 30, and 35mm) with Orion and Celestron filters without any problem. Some combination of eyepieces/filters I own requires more delicate initial threading, but right now I don't recall which ones! I think there may be unit to unit variation rather than a line of eyepiece problem.

The great thing about Orion is that their 30 day money back pledge is for real. So, just buy the ones you need and if they don't work out, EITHER send them back--or better yet--because they will fit your other eyepieces--KEEP them and get another eyepiece! Chances are, though, that they will work fine.

But I'll let others who own the 10mm Ultima chime in.

Don't overlook Tscopes, either! Get a 13 or 14" scope for lots less than your $5000 limit... and pick your mirror maker, e.g., Swayze, Royce, Discovery... and have a well-designed, lighter-weight scope to boot. Check them out.

If you have particular weight or eyepiece height concerns, Tscopes could be your best bet. There's lots of customization options, too.

You've got some great eyepieces there--and good spacing. It matches my sequence for a 10" Discovery dob. Is yours an f/4.7?

OTOH, there's no reason to avoid a barlow--and it does offer incredible versatility and even better views. I would get a 2x barlow, say an inexpensive Orion shorty barlow. That would let you double up the power on your Radians (and maybe the 7mm Nagler, but I don't know that eyepiece). You might find that the planetary views are better through the barlowed Radian than the Epic/X-cel, but others who have done that should chime in. If the views are better, you simply sell out the redundant eyepieces.

Do you have a 2" focuser? If so, then I'd recommend a wide field low power 2" eyepiece for star hopping, framing larger DSOs, and sweeping the Milky Way.

Otherwise, you'll be the best judge of whether there are gaps... when you're out observing do you often wish for a little more or a little less power? If so, you've got a gap. If not, forget about it!

David, I just got one. Like you, I was concerned about spending that much $--and on a scope dedicated to only one object. If at all possible, I would definitely advise finding someone with a PST in your area and seeing what you think *before* buying one.

Although I had been wowed by views through *higher-end* set ups, I had never seen a PST in person. But various posts here and on Cloudy Nights persauded me that it was worth getting one.

Here are a few observations after two first-light sessions yesterday:

1) The prominences on the Sun's edge are quite small. (That's true even at the oft-recommended 8mm.) (Now, that could have been due to a quieter day of solar activity, but still...) Do not be fooled by movies you may have seen of large solar prominences--remove from your mind's eye any professional pictures you've seen.

2) Also, do not be misled by the many wonderful amateur photos you see of the Sun--many were taken through larger scopes, stacked filters, etc. and not the PST alone. Even the ones through the PST are often the result of using higher-end digital cameras, astro specialized cameras, or much image processing (stacking, contrast enhancements, etc.) Many do NOT really look like what you'll see.

3) Plus, the pictures through the PST are often of the most dramatic prominences... hence, not what you would normally expect to see. Many are using high levels of magnification and some are on tracked mounts.

4) The images will NOT necessarily knock the socks off of non-amateurs, at least not the way the views through the higher-end scopes/filters/stacking can. (This again may have been due to yesterday's Sun.)

5) NOW, having lowered your expectations, and if your budget can afford it, go out and buy one!

6) To get a sense of what you can expect, take one of the shots by Sean Walker on the Coronado web site and display it about 1/4 the size. Change or imagine the orange shade as more of a dull red. That will give you a sense of what things look like through the eye piece. Here are the links

http://www.coronadofilters.com/cgi/display_gallery.cgi?gallery=pst&title=Sun41305.jpg or

http://www.coronadofilters.com/cgi/display_gallery.cgi?gallery=pst&title=Prombestcolor.jpg

Alternatively, a shot that captures the redness better try this by Ivar Marthinusen, but again reduce its size

http://www.coronadofilters.com/cgi/display_gallery.cgi?gallery=pst&title=1.jpg

Good luck with your decision. I know I'm happy I got one.

This is a great idea for a thread... I hope others will chime in with favorite, unheralded galaxies that look good in smaller scopes.

I checked some old cryptic notes of mine and 2683 and 2403 provided interesting viewing.

I've only been out one day, two sessions, and heard no clicks (I think I would have noticed).

I would contact both Coronado and whichever dealer you bought it from to ask their opinions. I've found Coronado and Astronomics (where I bought mine) to be incredibly fast at responding.

Impressively LONG list! Probably would work wonderfully well for blitzkrieg astro tourism using Go-To or DSCs. :-)

Care to select the top 20 or 25? Say for scopes in the 8-10" range...

Or pare it down in some other way into something a bit more manageable (like your older lists!)? Perhaps 3 or 4 tiers of quality?

Thanks!

Nicely written description of the PST views. It captures well what one sees and the magical feeling it can induce.

Just read it, too. The filter pics in the table of contents at first seemed biased in that they were all Lumicon! Fortunately, the actual article had photos of others.

What struck me was that he found the Orion UltraBlock better than the Lumicon UHC! (Or at least the table showed that.) And how well the Meade O-III equivalent did.

I wish his table had used a different system... not about its visibility per se but about its improvement filter vs. no filter! Just check out the column for M37 to see what I mean.

I did appreciate, though, that he reached definite conclusions and was willing to rank products as to quality. Much better than the pablum, general descriptions often seen in the so-called "reviews".