Posts Made By: Greg Nowell

I'd rather have a bottle in front of me,
than have a frontal lobotomy.

regards
Greg N

My sense is that if you pay $2500 for a scope like that you shouldn't need to ASK if it's a good deal. You should already know: because you recognize the seller, the brand, or something else like it. Because you've owned them before and have been around people who have. There are a few items I have bid for on ebay for which I have a strong sense of the value; I bid low and if I win it I get it and if others also see it I don't win it and that's that. If you're going to pay "going rate" for some of these things, you can get them most any time--even a lot of scarce AP stuff.

For $2500 you can get a used NP101 which would be superior to that "rare" instrument in every respect.

Incidentally, it is not out of the question that he hit the zero twice. The ad is poorly edited.

regards
Greg N

I think that, all told, I would pick an FS128 as a general purpose instrument over a c8, or an equivalent or better triplet apo such as the TOA 130.

The approximate cost is 3x more. I don't think I would pick a four inch apo over a c8, but a four inch apo is a nice thing to have.

But the mechanical advantage of the SCT will be evident if you keep the same mount. A five inch refractor is much more demanding of the mount than an 8" SCT. For a good optical trade off--the aperture of the C8 for the wider field of view of the refractor, I consider that a reasonable trade if the refractor is a 5" and f/8 or faster. So optically 5" apo is >or=a good c8 (for general purposes where wide field is viewed as compensation for less light gathering).

Mechanically a 4" apo = a c8. You'll have to step down to 4" or less if you want the mount to be as steady as you are used to, an important consideration if imaging. This is also true of portability. The FS128 is much more hassle to transport than a c8. To get C8ish portability, the refractor has to be about a 4" f/6.

A four inch apo (from China) will come in a tad more than an XLT c8, by $100 or $150. The real good triplets will run 3x the price.

regards Greg N

Yeah you're going to get hammered $10 to $15 on shipping with Edmund. A fair used price for an RKE is around $45 shipped.

regards
Greg N

I'm not a fan of star tests because there is so much that can be done wrong with them. At least, speaking for myself. I'm more comfortable with "that's a good view of Jupiter or it isn't." Certainly you can have ten scopes that seem to star test well and half of them prove to be defective under other kinds of testing (such as quality of image).

But I don't think a 20% defect rate is anything to brag about. You are right, however, that even top names often mess up. Speakng from my experience, I've had not-so-good-luck with mainland China products (which incidentally is getting a lot of press on other issues: lead paint, defective heparin, contaminated food exports, etc.) in astronomy and have gotten more satisfaction by paying more and getting equipment that is all-around better built.

I freely recommend the mainland Chinese Newts to beginners, not because I think they have a better qc/qa than the refractors, but because I do think they are the best deal out there for newbies who might otherwise suffer from sticker shock. I guess I avoid recommending the refractors because you're paying more (as with any refractor design for qc/qa that appears to be no better than what you can get with the Newts.

I'm somewhat sorry to see some of the inexpensive Japanese achromats having lost out to the mainland Chinese. The Omcron (maybe similar to Antares) was a pretty good achro in its day.

regards
Greg N

I'm not partial to small apertures but here's my thought. One night I had the c14 out with the 102mm mounted on it. We were looking at M53 and NGC 5053. You can't do them in the same field of view with the c14 but you can with the refractor. We gradually reduced the magnification on 5053 on both instruments, till we were down to 98x (the minimum) in the c14 and 17x in the 102 mm. Then we went over to my buddy Pete's Dob on which he had one of these Stellarvue 50mm finders that use an eyepiece. By going from the C14, to the 102mm, to the 50mm, you got quite a lesson on magnification and field of view.

But the amazing thing was, you could see NGC 5053 (globular, not known as very bright)!! Now, if you had been star hopping using the 50mm I don't think you would have said, "Oh there it is, I see it in my finder." But by moving from larger aperture to smaller you could unmistakably follow the glob's progress from a glob to a barely visible dot in a huge field of view.

So my thought is, that you can get more out of a small aperture when it is paired with a larger aperture, and that your 60mm may surprise you the most when it is used in conjunction with a larger instrument.

regards
Greg N

As a matter of practicality I don't think the 5" scope would do too well in the rings with delrin tipped screws that you have put them in. I'm only "marginally OK" with their performance on my four inch. They get to be hard to adjust as the weight of the refractor increases. I think I'd want my FS128 (not shown in pic, that's the four inch) on solid rings where the adjustment takes place with some kind of cradle or better support.

I didn't *draw* this setup afraid I had to put it together the old fashioned (and expensive) way....

regards
Greg N

On a refractor group, ED means "warning! Extensive Discussion ahead!"

or "Extra Discourse"!

or "Everyone Disgruntled"!

or "Evangelical Discussions" ahead!

regards
Greg N

Well looking at the design again there does seem to be room for a dew shield; not for the entire OTA, but maybe enough. In days of yore I used to wrap my entire OTA.

The other thought is whether the design allows for the whole affair to be moved far enough "up". With a refractor and XW40 my C14 rides "very high" in the AP saddle. Mounting photographic equipment might push it higher still. Have you done a calculation to make sure that your design allows for the weight to be moved up far enough? Otherwise a counterweight would be needed as an accessory, possibly design a clamp on for the lip of the OTA.

BTW I like the Tak colors on the C14 and the dark colors used by the company are definitely sub optimal.

One interesting design consideration is whether you could have some kind of crank or ratchet system for balancing so one doesn't have to "slip and slide" with all that expensive crap on the mount. I'm not sure it would be worth the manufacturing complexity, but it's an idea.

regards
Greg N

I would go with something that's been on the market for a few years and where there are people who have a track record of taking pictures that you think are awesome. For example, there's a new astro-graf reviewed in S&T which gets the usual high praise but if you read carefully they haven't figured out their secondary support yet, and it seems kinda silly to be marketing a system without having jumped that basic hurdle.

A more economical option is to outfit the c14 with hyperstar and do that. But if you have the funds and are ready for a jump, there's no pretending that there are not higher quality options out there.

I would also suggest that for a U.S. buyer there is at this point a huge penalty for buying European and for a European there is a big discount for buying U.S., even with TVA.

regards
greg n