Posts Made By: Mike Swaim

While I'm waiting for an 8" f/6 Dob to show up, I'm thinking about how I'm going to accessorize it. I've got a pretty good collection, (by my meager standards), of 1.25" eyepieces. But, I don't have any 2" e.p.s at all. I'm thinking that I'll probably get the BW Optik 2" 30mm 80*. That'll give me a nice 40x, 2* portal to cruise around in. I'm also thinking that I'll probably order an Orion Ultrablock narrow band filter, since that one seems to be well regarded by just about everybody.

So here's my question: Should I get the 2" Ultrablock to use with the one 2" e.p. , or should I get the 1.25" filter to use with everything else? I'd be a lot easier if I knew for sure that you could simply put a 2" filter in under the 2" to 1.25" adaptor. Alternatively, I guess I could just hold the 2" filter in front of the 1.25" e.p.s.

Got any thoughts on this?

Thanks,
Mike Swaim

I've noticed over a 5 year period that my interest in backyard astronomy typically cycles in regular annual intervals. Typically, I start getting interested in July and build to a near feverish interest by Oct, and then start losing significant interest in late Dec. From Jan. to June, I seldom observe more than one night per month, and not always even that. So, I'm just curious if anybody else will admit to being cyclical (not just cynical ;-) about am. astro.

Mike Swaim

Central NC, 680ft. above sea level:

Days without rain in July =10
Nights with completely overcast skies=20
Nights in which NO stars were visible as of 10:30pm =18 of 25 actually attempted
Number of mornings got up between 12am and 4:30am to see Mars= 12
Number of times late for work, or groggy at work due to astro attempts = 15
Number of times Mars was actually visible over the treeline and through the cloud cover or haze = 3
Number of times the seeing conditions permitted brief views over 100x = 2 (one spectacular!)
Number of times viewing led to an extended session = (1) 4.5hr session

Amount of funds spent on astronomy in July 2003 = $1262.50 ($630 to be refunded)

Rough guesstimate of amount of time spent on Astromart and other web resources pursuit to astronomy in July = 125-140hrs.
Amount of time spent at work earning a living and procurring astro toy money = 172hrs

And where am I on Aug. 2, 2003? Right back here looking for more. Dunno, what that sez about me.

Mike Swaim

Tony Flanders has put together a website on Messier Objects that is worth a view. Even better than the Messier catalog that he's got, are some essays on Surface Brightness, Telescope Limiting Mag and Aperature vs. Sky Glow. Throughout, he compares how a TV Ranger stacks up against a 178mm newt on some common objects in urban, suburban and rural sites of varying light pollution. At the bottom of the article on Aperature vs. Sky Glow there are some artists renditions of aproximately what M31, M38, and M42 look like through these scopes. These articles and their accompanying pictures and charts are worth reading. I especially recomend them to folks who are undecided about what aperature scope to get for their viewing conditions. Tony's focus is on faint fuzzies, not planets, but there is plenty of info there to start lively debates on a whole range of topics.

http://mysite.verizon.net/vze55p46/index.html

Just click on the topics to the left, and click on various hyperlinks throughout.

Mike Swaim

Does anybody know if this book is still available? I tried emailing the author, but the email link listed is no longer in service. Any info appreciated.

http://www.seds.org/pub/info/newsletters/sacnews/html/sac.110.best.ngc.html

Thanks,
Mike Swaim

I honestly hope that this doesn't start some sort of holy war, or any form of spat. I've been thinking about this for a year, though, and finally thought it worthy of tossing out here.

Todd Gross reviewed 70+ scopes, including many really high end refractors. Yet, when he chose to pick what he considered "The Best Planetary Scopes", nothing under 6" even made the first 9 picks, and mid-sized DOBs got the first several slots. Here's his list, directly from his famous site:

"BEST PLANETARY SCOPES SO FAR..

1. 14.5"
2. 16" & 18" Starmaster w. Zambuto and Pegasus optics 2. 12.5" Portaball from Mag1
3. 10" Teleport w. Zambuto optics
4. 8" Portaball with Zambuto optics
5. Takahashi FS-152mm & Currently Testing FCT150mm
5b. 6.1" D155 f/7 Astrophysics EDF
(Two above are close, TAK seemed better, Ed Ting is testing them against ea. other, and has come up
with the opposite conclusion)
(Takahashi TSC225 seems to fall approx. here.. as for the CN212, planets were not available)
6. C-14 SCT (not 100% positive, needed better seeing to confirm, brief test only, use this with skepticism)
7. C9.25" SCT Celestron SCT
8. 7" Starmaster with Zambuto optics, and 7" Teleport with Zambuto optics
9. Ultima 2000 8" SCT
10. 5" Takahashi refractor FS128 & 5.1" Astrophysics EDF (planets not avail. when FC125 was used)
11. Intes MN56 Mak-Newt (5" f/6)"
*********************************
Granted, I know that's just one guy's opinion, but he's certainly one of the most experienced folks out there. But when I look at that list, I really wonder why some folks are so eager to part with mega-bucks for 3-4" refractors. (I'm not knocking them, at all. I just really don't understand.)

It's also very, very interesting to me that the only scope on the whole list that I have any real experience with is the lowly Intes MN56 5" Mak-Newt. That scope seems to me like the real sleeper planetary scope. The fact that it even made such a distinguished list fascinates me. It may be last on the list, but it's commonly available for not much $$$, and it beat out many high end scopes just to make that list. I actually would've thought that several of the 4-5" APOs would easily beat it on planets.

What's anybody else make of all that?
Mike Swaim

Since I know a lot of folks are curious about this scope, I'm going to give some initial impressions before I've even had a chance to really see what it can do. I got the scope in on Monday, spent about 35 minutes putting it together, and have been waiting for a clear night to try it. Tonight wasn't clear, but I did get to use it for about 20 minutes before the clouds rolled in. More on that in part 2.

The base is very cheap, very dry, fairly heavy particle board. That much is to be expected. However, it looks suitable for it's task, and probably durable enough for a few years, though I expect repeated dewings will eventually cause the particle board to swell and chip. Replacing it with plywood would be very easy. Apparently this one shipped with the "new" round bottom baseplate instead of the older, tippier triangular one.

The teflon "bearing" surfaces are the smallest amount of teflon that will do the job, and they are single stapled in 3 places on each side of the rocker box. It's crude, but surprisingly effective. The scope turns easily on both axii.

The focuser is a pretty decent seeming rack and pinon with cast metal housing. It's got less slop in it than I've seen on some Crayfords. The 2" to 1.25" adapter fits well with little play, and 1.25" e.ps fit snuggly into it.

The 4 spider vanes are about the thickness of hacksaw blades, and are surprisingly sturdy. These seem much preferable to some of the wider, difraction spike causing vanes that I've seen on competing DOBs.

The silver painted thin steel tube is so short (45") that it's very easy to carry. On it's rocker box base the total height is just 50". At zenith, the eyepiece is centered just 44.5" from the ground. So viewing from a chair isn't just possible, it's *mandatory* if you don't wish to blow out your knees trying to kneel. Oddly, the interior of the tube is finished in a grayish paint that really isn't flat enough or black enough for my tastes. Eventually, I may flock it or texture and repaint the inside.

The whole assembly takes up less than 2 sq. ft. in a corner.
part 2 to follow
Mike Swaim

Here's a little calculator for figuring limiting magnitude under different conditions with different size telescopes. Put in refractor for binoculars and convert objective size to inches by dividing by 2.5
http://www.go.ednet.ns.ca/~larry/astro/maglimit.html

It's fun to play around with that calculator, but I'm not sure that I really trust it's output entirely. For instance, I wanted to see how things would deteriorate as I aged, so I entered values for 20x80 binoculars, mag 5.5 skies, refractor, intermediate skill level etc. and then only changed the age variable by adding 5 years over the course of several decades. It actually had the limiting magnitude *increasing* with increased age. In fact, it had a 15yr old intermediate skill level seeing less than a 55yr old intermediate skill level. I repeated that with 20x100, 25x100 and 40x100 optics and watched what it computed. It claims 11.83 for 25x100 & 12.45 for 40x100 at mag. 5.5 skies, 35* from zenith. I think that's optimistic, at best.

As far as figuring out what seeing condition limiting magnitude to enter, here are a couple sites. Neither is particularly great.
North American Meteor Network:
http://www.namnmeteors.org/lm_calc.html

SEDS:
http://www.seds.org/billa/lm/rjm.html

Those can sugest areas of the sky to look at to see what you can see. I don't really like the fact that the SEDS one has areas defined by triangles. It's kind of tough to visualize the triangles artificially drawn beside a constellation to count stars held within. If you type "limiting magnitude" or "telescope limiting magnitude" into Google or Dogpile it's kind of amusing seeing what all comes back. Of course, the fact that I find it amusing may have more to do with the fact that it's 4:30am and I have NO sky to look at,(again), so I'm stuck with computer constructs.

Mike Swaim

I'm looking for recommendations for a 2", wide FOV, 24-32mm, inexpensive eyepiece for use in a 6" f/5 (750mm) DOB.
Max budget is $175-$200, but of course, less is better if it's comparable.

I read with great interest the thread on the BW 30mm vs the GTO Proxima 31mm. The BW sounds like it's out for an f/5 reflector. I'm definitely willing to give up a little FOV for better edge performance, (up to a point!) Good contrast is very important to me.

GTO?
Siebert?
UO?
Ultima?
other?

Thanks,
Mike Swaim

Here's an article by the former chairman of the Commission on the Future of the US Aerospace Industry that puts the Chinese on the Moon within a decade (or less):

http://www.washtimes.com/op-ed/20030528-092308-4284r.htm

Is another space race possible or even probable? Would there even be a point to it all?

Mike Swaim