Posts Made By: Mike Swaim

When a friend asked if I wanted to look through his AstroPhysics 6" refractor, of course I jumped at the chance. Just for kicks, I brought along my Hardin Deep Space Hunter 8" Guan Sheng DOB. Due to a variety of circumstances, (such as 3 Deputy Sherriff's showing up to investigate "the mysterious people in the field", and the number of neighbors that showed up wanting to view Mars, and persistant fog and cloud cover), I didn't get to do a really detailed comparison. However, over the course of 2 hrs. I did get in enough views to at least have an initial series of observations.

There is no doubt whatsoever that the AP 155 was considerably more contrasty and showed better definition at all magnifications tried. It showed the background sky as being closer to black, whereas the Hardin DOB tends to show the nightsky as a dark grey. Similarly, the DOB puts nasty diffraction spikes on targets as bright as current Mars, whereas the AP shows the planet as a crisply defined disc. All that was to be expected.

The odd thing was that the AP 155 showed just as much detail on Mars with a 10mm Radian (108.5x) as it did with a 5mm Nagler (217x). Gerald North mentions this phenomena in his excellent book "Advanced Amatuer Astronomy" where he talks about using the minimum power necessary to see the finest detail.

To achieve a similar level of detail in the 8" DOB, I had to use a 6.7mm plossl for 179x, and views were improved again with a 15mm Super Plossl barlowed 2.8x for 224x. The biggest help for the DOB was the addition of a Baader Contrast booster, which did a lot for limiting the diffraction spiking and enhanced surface contrast. The images were no where near as pleasing as in the AP Starfire, BUT THE LEVEL OF ACTUAL DETAIL SEEN on the surface, was roughly comparable. In other words, a sketch from both scopes would've appeared similar, even though the view through the high end refractor was MUCH easier on the eye.

The fact that the AP 6" could show as much, if not more, detail at 109x than the 8" DOB was capable of at twice that power, is perhaps more testament to it's exceedingly high quality than is pushing it to it's magnification limit.

Mike Swaim

What's the smallest scope, and the least amount of magnification that folks can consistantly see defined dark areas of Mars with?

Previously, based on experiments with a variety of small scopes, and with comments I've seen on several forums, I had thought that there wasn't much point in going below about 100x100mm, with 120x120mm being far preferable. With good filtration, I find that I can regularly see the ice cap at just about anything above 48x70mm, but don't tend to see dark shading until moving up to *at least* a 100mm scope. So far, I've not been able to see much with the 70mm Ranger at any magnification or filter. However, I've seen some sketches on the web that show a good amount of dark detail with a 118x60mm when Mars wasn't even as close or as bright!!!!

Obviously, this has a lot to do with the skill of the observer and the seeing conditions. But, I'm curious if there's any group concensus as to a lower limit for being able to really discern consistant detail, (not just imaginative speculation).

Mike Swaim

In the book "Advanced Amateur Astronomy" by Gerald North, he brings up a concept that I never see mentioned. That is the idea of the human eye being the limiting factor in deciding telescope magnification. He cites 100 arcseconds as being an average for the finest detail resolved by the unaided eye, based on his testing of "a large number of teenage students". There's a note about that figure deteriorating with age. So, based on that as a starting point, he concludes that 100x would theorectically show all the detail that a perfect 5 incher could show, if it was diffraction limited to 1 arcsecond. So the idea is that is the MINIMUM magnification level needed to show the finest detail, (in a really good scope), but higher mags can be used, and in fact he mentions his personal preference for approximately 2x minimum.

Some things I might wonder about from that are: After that minimum point, would higher mags might be desirable to overcome atmospheric conditions? (The opposite of what might be 1st thought, but it makes sense in a limited way up to a point.) Also, I would wonder if, *up to a point*, higher mags. might actually help out lesser quality scopes by increasing contrast and image scale? Obviously there will be some definite points beyond which adding magnification won't help any scope. But, my q's center more around whether folks with really good scopes tend to find that they're getting nearly as much detail with relatively low mags, as with much higher.

Personally, I've never yet seen an example of powers over 250x (or thereabouts) actually improving an image, in any scope up to 18", but my sampling data is admittedly very, very limited. I've always attributed that to seeing conditions, but am starting to really wonder if that's correct. What's been your experience and with what scopes, what targets, and under what conditions?

Thanks,
Mike Swaim

In the Planet Killer thread, Russell Hopkins provided some interesting food for thought when he proposed: "What we need around here are razor sharp optics and high contrast to make the best of bad conditions. When seeing is bad (essentially all the time) a lot of size does not help. In fact, scopes under eight inches seem to have the edge during scintillation."

This is very interesting to me, as it ties in with several things that I've been wondering about. For instance, do really 1st rate optics make better use of crappy seeing conditions by being able to deliver more detail at lesser magnifications?

I've always thought that there was little use buying top of the line optics if one's primary observing location never provided anything beyond mediocre or terrible skies. But, some recent experiences have me questioning whether that's not exactly backwards. How does all this fit in if one's primary interest is in faint fuzzies, not planets?

Thanks,
Mike Swaim

Back in Nov. somebody was asking about one of these. Have any on this forum recieved one, or have any input beyond what's on the Hardin website? I've been very pleased with my Hardin DSH-8, and the 12 inch looks like it could put large apperature within ecconomic reach of a lot of folks. Comments?

Thanks,
Mike Swaim

Has anybody else noticed the recent spate of Burgess 1278's that are being offered for sale on Astromart almost as soon as the potential owners lay hands on them? In the last week alone, there have been 3 or 4 offered for sale after what can only be hours of actual use. One ad even states lens scratches as being considered by Bill B. as "normal" for polishing.

I've got no ponies in this race. But what intrigues me about this whole phenomena is that these folks have waited 'months' and are selling at what should be below market rate, rather than the more typical resale at a slight premium that long-awaited optics often fetch.

Are these scopes not living up to the hype, or have the owners simply "moved on" since ordering?

Thanks,
Mike Swaim

I gotta say that I've been sorely tempted by various Burgess scopes ever since I met Bill a couple years ago. With the latest crop of 1278s appearing here on Amart in the $300 range, it's a tempting proposition. QC issues not withstanding, it looks to be a heck of a deal. However, when I think about the fact that I don't have a suitable mount, and think about the reality of a 13lb, meter long scope, I have to wonder if it would really do anything that some of my other scopes won't already do.

For instance, I'd dearly love to see a detailed comparitive review of the Burgess 1278 vs a lowly Orion XT4.5 . I might expect the Burgess 1278 to beat the "kid's scope" at high power, but I wonder what it'd really come down to? It'd also be interesting to compare it to a 6" or 8" garden variety Asian DOB. Perhaps no diffraction spikes, in exchange for a tinge of chromatic abberation? Hmmmm....

Mike Swaim

Just a general question for folks; how many inexpensive and downright cheap scopes did you have to buy before moving up in quality?

I'm kind of unusal in that I started out with good scopes, (Intes Micro M603 and MN56), and have been moving backwards on the quality scale ever since. (Celestron 90mm Mak, Astro Rubinar 100mm Mak, TV Ranger, Orion XT4.5, JMI Next Gen 6", Discovery 6", Hardin DSH-8; just to name a few.)

I know what I really need to do: buy a Mag1 12.5" Portaball or 14.5" Starmaster. But, I seem to be psychologically incapable of spending that much, even though I know I'd enjoy them. Even though I know that's what I really *should* do, I still find myself shopping in the cheap market more often than not. It's kind of ironic.

So how long, on average does it take for folks to come to the "quality is best" way of thinking and quit hoping for too much out of too little?

Mike Swaim

It'll be interesting to see how many of us that pay our phone companies extra money each month for an unlisted phone number get booted out by this silly software. The way I see it, if I _don't_ get booted out, then my phone company is violating the contract not to share my info. and if I do get booted out, then it's just proof how ridiculous the whole thing is. Let's face it, I listed on my Astromart account, information that I'm *paying* to suppress from exactly the same kind of spambot software that Herb is now using. Either way it'll point to various problems with the way that people assume honest business to be conducted.

Have fun; stay honest to your principles,
Mike Swaim

Steve, you don't mention how important price is in your considerations. That could have a major impact on what you wind up with.

The absolute BEST nebula views I've ever seen in any instrument of any size (telescope or binocular) came from a highly modified ex-Naval binocular with 110mm objectives. The machinist owner had modified them to take interchangeable eyepieces and thus they could be used with nebula (and other) filters. You won't need the filters on M31, but for viewing the Veil and NA nebs and even for popping out the best of the Orion neb. (M42) and many others, the difference between a filter and none becomes quite apparent.

That point is key. Go for binos that feature 45* prims (for ease of use with minimum neck craning) and eyepieces that can take screw in filters. There are a variety of options these days that have those features in the $1K-$2K range.

Mike Swaim