Posts Made By: Mike Swaim

Daryl, I'm in total agreement, and for the same reasons. Recently, I've been trying to get aquainted with some DOBs I just got. It's been both fun and frustrating, considering that the NC skies just haven't been cooperating at all.

Last night I was out trying to make the best of the "sucker holes" in the clouds. I set up a 6" DOB and a chair, but it seemed like everytime I got the scope aimed at whatever portion of the sky was momentarily clear, and set up the chair for best head position, the temporary cloud openings would close soon after I'd selected an eyepiece and focused. In an hour, I had little to show for my efforts but mosquito bites. So, I put the DOB away and brought out the 12x50s and just sat back for a few minutes.

In about 10 minutes I saw more with the binoculars than I'd seen in an hour with the scope. Sure, the scope will go deeper, but there's a lot to be said for being able to instantly aim the binocs at "sucker holes" without any hassle or strange alt-az vs. tube rotation and chair configuration issues to worry about. The wide FOVs also helped get my bearings lots faster. Similarly, on nights of heavy dew, after the scopes are all dewed up, the binos just keep on going well into the night, with just occasional handwarmups to the objective end.

At the moment, I've got 4 scopes, but the real spot in my heart is for the simplicity and joy of binocular viewing.
Power to the Binos indeed !!!

Mike Swaim

I've been thinking a lot about that very issue, but take the exact opposite opinion. Does any scope really come complete with all the eyepieces, filters, finders, controls, dew management, collimators, mounts, encoders, doohickies and dinguses that everybody will want to hang on it for the rest of the time they own it? Of course not, because not everybody has the same ideas for what would make it perform at it's best.

What I've been pondering is why so many low to medium end scopes give the *illusion* that they come more or less complete. For instance, why even bother to include low-end plossls and junk finderscopes when those items are most likely to wind up basically unused after a few initial attempts? Personally, I'd much rather have the cost of those items deducted from the initial sales price.

I wonder how many folks get frustrated with their scopes based mostly on the low quality of the orig. accessories?
I note that most high end scopes don't come with accessories, but must be pieced together by the end user. I'm not so sure that's a bad thing.

I do wish that more retailers were more upfront with their ad copy in terms of really letting the public be aware of what that $300 scope would cost to get up and running. Just a thought, but I tend to think in terms of at least doubling the cost of the scope by the time I add the necessary add-ons. And that's before we even get started talking about necessary star charts, correct height chair, etc. ad naseum.

Mike Swaim

I've almost gotten out of astronomy a couple of times because of the cost of equipment and the hassle of setting it up for short sessions, compared to the actual amount of observing time I get. So, this time around, I decided to do something completely different. I knew I wanted portability and ease of setup as primary requirements. I also knew that I wanted a scope that could be used while sitting down. So, I picked up 2 inexpensive DOBs, just to see if I really liked the idea well enough to eventually get a really nice semi-custom DOB. Along the way, a 3rd opportunity presented itself, and so I now have 3 DOBs, ranging from 4.5" to 6" to 8". The most expensive one was the Hardin DSH 8" @$343 delivered. The other 2 were used Astromart specials. All 3 together cost less than a new Pronto OTA or Ranger package deal.

The comparison to the Pronto/Ranger is interesting, because even the least expensive Orion XT4.5" readily takes at least as much power and shows as much, if not more detail than my Ranger. Both the Discovery 6" & DSH 8" show consideraly more. Last night, I had the "toy" DOB outside looking at Mars for 2 hours. Despite the fact that it has a spherical mirror and throws up pretty ugly diffraction spikes on bright objects, it still easily showed me the Martian polar cap. And by using a photo filter in front of the eyepiece, it showed a good bit of dark shading on the planet. That's not bad for a $110 scope in poor seeing conditions.

My idea of eyepieces, is that I keep them simple, and pretty much use ones I bought here on Astromart for around $45-$55 each. Current favs are Meade 32mm Super Plossl, Meade 26mm Super Plossl, and UO 16mm Konig. When I want more power, I just use a 2.8x Klee barlow. I find that works as well or better than any of several smaller f/l plossls including more short Meade super plossls.

I haven't had any of these scopes long enough to really tell, but already I think I like them better than the small refractors and mid-grade Maks I've had. One thing I didn't count on, was how often one has to move the chair to use a DOB. But, these are a LOT of bang for the buck. They make me happy, anyway.

Mike Swaim

They mean resistance to internal fogging, not external. Internal fogging is what you get when you get condensation seeping into the internals of the optic.

Mike Swaim

Unfortunately, I did not get a chance to try the better eyepieces in the cheap DOB. I'd really wanted to see if they would help at all, or if their extra quality would simply be wasted on the cheap Taiwanese optics. Still, I came away impressed that the $300 DOB, using ~$50 Meade plossls, could even come anywhere close to showing what the ~$11K goto refractor could show with a suitcase full of Televue's best eyepieces.

I was extremely impressed with the amount of detail on Mars that the fine Astro Physics refractor could show at low magnification. It was a very impressive view. However, I feel somewhat better about this cheap DOB purchase just knowing that even at the AP level the amount of detail to be seen really isn't shockingly more than with much lesser instruments. There's no doubt that the view through the AP was more pleasing on all counts. But it wasn't MAGNITUDES more detailed.

The best improvement for the cheap DOB seems to be to really carefully pick the 1 or 2 best eyepieces, mag. levels for each viewing situation and mate them with appropriate filtration. For instance, the view using a UO 16mm Konig, barlowed 2.8x for 210x, was deemed unacceptable on Mars with or without any of the dozen filters at my disposal. Whereas the seemingly similar Meade Super Plossl 15mm barlowed 2.8x for 224x was really pretty good with a Baader Contrast Booster.

Folks wishing to squeeze that last bit of performance out of these cheap DOBs may bennefit greatly from considerable eyepiece/filter experimentation. Whereas, the optics of something as fine as the AstroPhysics seem to handle a variety of eyepieces a good bit better.

Mike Swaim

Tom, with a name like Koenigsfield, you might also want to consider the UO Konigs. The 16mm UO Konig has an advertised FOV of 65*. The field stop on mine measures exactly .75" or approx. 18.75mm. Compare that to the 15mm Meade Series 4000 super plossl which has a dinky little .52" or approx. 12.5mm field stop. (Somebody should check my caliper to metric conversions.)

I've never checked either one of these by star drift, but my overall impression in several scopes has been that the amount of useable field in the 16mm Konig makes it a worthwhile choice when a wider FOV is worth sacrificing some contrast to achieve. I don't know about others in the Konig line. Not all have such a wide FOV.

I like the 16mm Konig II a lot, but it doesn't take barlowing as well as the 15mm S.P.

In terms of overall performance for the buck, I like the orig. Japanese Meade Super Plossls a lot. They are the backbone of my e.p. collection. The 32mm will give the widest FOV possible in the 1.25" format. It's a good alternative to some of the "wide field" e.p.s The 26mm is a very consistant performer in all scopes that I've tried it in, and doesn't suffer from the quality issues that plague so many of the Chinese plossls. Barlowing the 15mm & 12.4mm S.P.s works out to be a very good alternative to using short eye relief orthos with very little performance lost. I like that solution so much that I just ordered the 9.7mm S.P.

Mike Swaim

The field stop on my 32mm Meade Series 4000 Super Plossl measures roughly 25mm. There are various 32mm 1.25" eyepieces that boast larger. Some don't even have a proper field stop and just use the barrel. I've only sampled a couple of those and they were generally unsatisfying. But, I've yet to see one that was as clear across the FOV as the Japanese made Meade Series 4000 Super Plossl 32mm. I sold a TV 40mm plossl to get this Meade SP and consider my viewing enjoyment & my eyepiece collection to have greatly improved by doing so. If you see one of these older Japanese made Meade Super Plossl 32mm coming available in the $65-$80 range, grab it! I like the standard Japanese made Meade Series 4000 26mm Super Plossl even better, and it winds up forsale a lot more often. The FOV isn't as large, but the contrast is generally better, and this focal length tends to work better in more scopes. The 26mm was recently rated well above many other competing eyepieces in a light transmission test posted to Cloudy Nights. Either or both of these should factor into your considerations.

Mike Swaim

In looking at several university astronomy lecture texts, it seems that one immediate problem with North's assumption is that there's little agreement about what the actual minimum visual resolution of the human eye is. This surprises me greatly. But the "standards" given as fact by various sources are all over the place.

Caltech: .5 arcminutes (30arcseconds)
Duke: 1 arcminute (60arcseconds)
Geo. Mason U.: .5arcminutes (30arcseconds)
Nasa 50arcseconds: (.833arcminutes)

Hmmm, .....
Mike Swaim

"I also discovered that you can do a nice job of aligning the focuser by inserting the laser in the focuser and turning the secondary over to face the ceiling. "

Would you explain what you mean by "turning the 2ndary over to face ceiling"?

I've got 2 of my small Dobs nice and tight with a Helix hologram laser collimator. But, I'm having fits trying to get the blasted 2ndary just right on a 6" f5. On the others, I just stuck the laser into the focuser and pointed the primary up to the ceiling and tweaked it. The secondaries on those were already centered. But, on the fast 6, the secondary is noticeably out of kilter with regards to both the focuser and the primary.

Everytime I loosen the screws and stick my fingers down there to adjust it, it seems like it gets a tad worse. It also seems like it moves as I tighten the lockdown screws. Any help appreciated. I'm actually wondering if I got a deal on this scope because the previous owner had trouble getting good collimation. It was so far out when I picked it up, that I'm not surprised the guy didn't like it. I've got it close, but it's not close enough for my eyes. I know it can be done, but it seems pretty touchy. I imagine it's just a matter of continuing to tweak it in increments, but if you've got a better way, I'm definitely in need of suggestions.

Also, if you've got any specific tips on flocking, I'd appreciate those as well. I'm definitely going to flock two of these. What do you do about all the screws that poke inside? I blacked them with a marker, but do you have to cut the f paper to fit around them, or just poke them thru?
Flocking the 4.5 doesn't look like it's going to be easy. I need somebody with kid-sized hands.

Thanks,
Mike Swaim

Michael Sutherland wrote:"It seems the longer I stay at this hobby, the more I find "rules of thumb" have exceptions. "

Ain't that the truth. The more I learn, the less certain I am that I "know" anything.

I also agree about the sky having very different conditions all at once. That's one reason that I've pulled back from rating seeing conditions by any of the "standard" methods. For instance, last night there was opaque cloud cover over much of my SE horizon. Yet, portions of the zenith were roughly mag 4.5, but the Milky Way wasn't really visible. There were patches to the NW that were downright good. That's typical for this location at this time of year, though the clear patches change all night. But, I have yet to find a rating system that would accurately convey a single swath of sky that ranges from Ant. I to Ant. IV. Are seeing conditions bad? Well, depends where you look.

Mike Swaim