Posts Made By: Mike Hosea

Hard to say. You could try inserting a cardboard field stop into the old eyepiece to make its true field the same as the proposed new one. It won't have the higher mag, but it should tell you what the smaller true field will be like in a panning search.
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Mike

I personally think that in this price range and looking for wider fields your best bets are with some smaller manufacturers.

I would contact Gary Russell (Russell Optics and Machine--see the link on the Astromart homepage). The 19mm superwide (available in both 2" and 1.25" versions) is a solid performer. He also has had new 16.8mm and 15.5mm superwides available recently. The price on all these I've mentioned are $65 (less for the 1.25" 19mm superwide). I can only vouch for the 19mm superwide at this point. It's not the best 19mm available by a longshot, but the bang-for-the-buck is arguably unmatched. I'm currently awaiting a 15.5mm. Should have it tomorrow or the next day.

Another choice is Siebert Optics. Harry Siebert has a few different choices in the focal length and price range. I haven't tried any of them in this range, so I'm not making any claims, but most people seem pretty happy with his stuff.
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Mike

Mine was okay, but the mirror diagonal was crap. What kind of diagonal does yours have? It's possible the tube lengths are different for the correct-image and regular RA models, which could lead to the reticle eyepiece focusing problem that you noted if they were mismatched. I'm assuming you are already using the diopter adjustment of the eyepiece to focus and are just running out of travel. The reticles per se are probably focused by nudging the crosshair insert inside the barrel to move them. If the crosshairs AND the view are focused, then the parallax is a mystery. Just needing to pull the eyepiece back a little wouldn't explain it.
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Mike

Well, you don't buy a 7" Teleport because you're even thinking about CPIA. The 7" Teleport has a rather specific appeal due to its portability and convenience. It's particularly appealing for traveling when most of the competition is 4" or smaller with even higher CPIA.

Personally, I think CPIA will take you down the wrong path in telescope buying unless, perhaps, you are one of the lucky ones who can leave a large scope set up and ready to use, in place, in a private observatory or maybe get it out easily in some kind of roll-it-out arrangement. Otherwise, it's not unusual to hear of large scope owners who use them a few times a YEAR. I typically have my 10" Teleport out a few times a WEEK.

I think the cost of a scope should be measured in cost per hour of enjoyment--CPHE. Actuaries and bankers may want to set a discount rate and compute a present value, but these are mere details that apply to all the contestants. Thinking in terms of CPHE may mix things up a bit, and the benefits of more aperture make the Teleports some of the best scopes available at any price in terms of CPHE, despite a high CPIA for Newts--IMHO, of course, and YMMV. ;-)

Unfortunately, the term "available" is being used loosely in regard to Teleports.
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Mike

You can delete the message. Just log in, bring it up, and look for a [Delete My Message] option above the message.

Currently, Type 4 and 5 Naglers and Radians are made in Taiwan. Type 6 Naglers, Barlows, and Plossls are made in Japan. Not sure where the 4.8mm and 7mm Type 1's still being sold are made. Production did shift in part from Japan to Taiwan some years ago, so, for example, you might find a used 9mm Nagler made in Japan or Taiwan, depending on the vintage.
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Mike

I pretty much agree with what others have already said. I can't offer you advice based on specific experience with the C9.25, but I've had an 8" f/10 SCT and now use a 10" Newt, so this is in the ballpark aperture range that I use. In general I think how high you can go is less interesting than how high you SHOULD go, i.e. what is going to be the best choice most of the time. In time you can fill out your eyepiece set as seems appropriate to you, but to get started I would think of something like a 10mm Radian, 10.5mm Pentax XL, 9mm UO ortho, or 9mm Nagler Type 6. It's true you don't need the extra field of the Nagler or Pentax, but the Pentax and Nagler are superb eyepieces, and the extra field can be fun with lunar observing. A good Barlow can be an economical way to experiment with higher magnifications before making a significant investment. You could try 7mm on for size if you had a 14mm eyepiece and a 2x Barlow--that sort of thing. Quite generally, if your 9.25" scope is well-collimated I would think that your high magnification "cruising speed" would usually be higher than 200x and lower than 300x for atmospheric reasons.
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Mike

I can't comment on the Siebert Ultra. The 14mm Pentax XL does has some field curvature and so isn't sharp to the edge at f/5 if you focus the center of the field properly. The 14mm Radian is fine but with a narrower field, of course.

Maybe the 13mm Ultra will outperform the Radian and Pentax--I wouldn't know until I tried. It's possible. But Siebert's been saying stuff like that for a long time now. I tried the 7mm Standard Siebert out of curiosity because of similar hype, and while good for the money it was nowhere near as good as an 8mm Radian or 7mm Pentax XL. My apologies to antiestablishmentarians, but it just wasn't close. If all you want is performance in the center of field at f/5, though, your possibilities are almost limitless. It's wanting full-field sharpness (or close to it) at f/5 that will pare down your options dramatically.

I have a 14mm Radian now for my 10" f/5, but I hear good things about the 13mm Nagler T6. If you really are curious about the Siebert and you can't get the kind of direct comparison you're looking for here, then maybe you should try it and tell us how it works out for you. Be a trailblazer. :-)
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Mike

Be sure to use a fresh tube, otherwise it may not cure properly. I use GE Silicone II, the clear kind, and for secondaries I just buy a new, small tube each time. A couple of times I've removed a secondary that was attached that way, and it was basically necessary to cut through the silicone.

I don't worry, but if you're nervous about it long-term and don't have a mirror box cover, you can store your scope with a drawstring bag made of soft material, pulled up over the secondary and pulled tight around the top of the secondary holder. That, along with not storing the scope vertically, should make the risk of damage very slight.
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Mike

I haven't tried the Meade 13.8mm SWA, but from all I've read it should be "good" in an f/10 SCT. The price is good, but it is an older design that may show some edge degradation even at f/10 and definitely will show edge problems in faster scopes. When people sell these it is often because they have upgraded to an ultrawide with better performance.

The 14mm Meade UWA, on the other hand, is simply one of the best deep sky eyepieces ever made. It's also too big and heavy to be used safely in cheap 1.25" diagonals. I haven't tried the 13mm Nagler Type 6, but it gets good reviews and would probably be a better choice if smaller size and weight are important considerations.

The 14mm Pentax XL is another good choice, especially for an f/10 or slower scope. I love the 10.5mm and shorter Pentax XLs, but at 14mm I prefer the 14mm Radian, which I recommend to you if you can snag one in excellent condition off astromart for a good price.

The 13mm Vixen LVW is yet another choice. However, I've seen people take beatings when re-selling LVWs. Seems to be a matter of timing, though, so YMMV. I used to have the 22mm, 17mm, and 3.5mm Vixen LVWs and they were all pretty much the same except for focal length. If that similarity holds up for the 13mm, it has the worst lateral color you are likely to ever see but otherwise is sharp all across the field at f/10. I would rank the 14mm Pentax XL and Radian well above it, though, unless it doesn't have the egregious lateral color that its brothers have shown me.

So, to summarize, for deep pockets the 14mm Meade UWA or 13mm Nagler Type 6 would be great. Otherwise, my suggestion is to try to snag a used 14mm Radian off astromart.
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Mike