Posts Made By: Ron Bee

A very point Dan. But let me see if I understand your point clearly. Are you saying that there exist a minimum magnification in which below this the double-double will not split? If so, I'm with you here. However, if we take this a little further, are you also saying that this so called "minimum magnification" varies from individual to individual because of the eye? If so, I'm with you here as well ;-).

If not, I beg you a thousand pardons but would like to get a clarification in this case.

Thanks,
Ron B[ee]

Well, a difficult question to be sure, Larry. I myself upgraded from my old C102-HD to my TV-102 and have no regrets whatsoever. To me, the TV-102 helped me enjoy the 4-inch aperture even more ;-). The TV-102 wiped out that annoying purple halo from the C102-HD (interestingly, it didn't bother me at first). It seems to snap into focus more so than the C102-HD (hard to describe until you see it). Daytime view of the varmints is crisper. The space between Saturn's ring and the planet's disc is black at high magnification instead of "haze looking" through the C102-HD. Finally, the blue festoon really looked well, blue ;-). The lowest contrast features become more clearly discerned (as well as those very tiny craterlets). Even M13 looked more sparkled and more resolved at 293x than I ever saw in my old C102-HD. The details I've been seening of Mars this year was very satisfying.
http://members.cox.net/ronby/Solar-System/index.htm

So first of all, I'd keep the 12.5" as that will be your "light bucket" ;-). However, as you know, the 12.5" f/6(!) is no small scope which is perhaps why you have the C102-HD for quick setup time or when you don't have time to setup the 12.5" and wait for it to cooldown.

Thus the question really boils down to: would you like to get closer to apochromatic properties, the better mechanics and the better optics of the TV-102/FS102 over your current achromat? If so, then you have a tough choice ahead ;-). If not, well do nothing maybe a good choice.

How high of a magnification can you achieve with either the TV-102 or Tak FS102 will be entirely dependent upon the seeing (and of course the aperture). Have a look at the link above to see how the TV-102 can do on the planets.

As to which one: the TV-102 or FS102, I don't think you would be sorry with either. There are some minor differences however. The fire-sale price of the FS102 is a better $$$$ deal, but the TV-102 OTA only comes with a hard case (I've been using it a lot lately ;-), it's lighter and shorter (after the dewshield is retracted) than the FS102, and you can get serviced here and can talk to Al/David Nagler about any problems. I'd say both focusers are buttery smooth but I somehow prefer the feel of the Tele Vue (maybe it's the rubberize knob thingy); also the Tele Vue focusing knobs have holes that you can get the Focus Lever for which worked like a charm in reducing vibration from touching the focuser at high magnification and also act as fine focuser. As you can see, it boils down to a personal preference ;-). BTW, to get the best from these APOs, you should feed it the best diagonals and eyepieces.

Good luck on your quest and let us know what decide.

Ron the 4-inch Tall Evangelist B[ee]

Hello there Anders,

When shopping for a fine APO, I don't think there's a best brand IMO. The way to look at it is how much do you want to spend versus the level of optical excellence you want to achieve versus the level of mechanical excellence you want to reach versus the subjective look-and-feel appeal. Then, there's the focal length difference to take into consideration also (eg. for widest field viewing).

But given the two choices you mention and if "spending is not an issue", my vote given the metrics I outlined above would have to go the NP-101. However, given the "money no object" metric, there are other excellent highest level of 4-inch APO you can get namely the AP Traveller and the TMB 105 and 100.

Once the metric for "money no object" is removed, you'll need to start looking at compromises, not to say that you'll give up much either. As such, the Vixen is a fine choice (and the f/9 version which will give you a better color correction than f/6.5) as well as other doublet APOs such as the Tele Vue TV-102, Takahashi FS102, etc.

There are other non-refractor solutions to achieve a good view of the DSOs and the planets you stated.

Ron the 4-inch Tall Evangelist B[ee]
PS - To get an idea of what a 4-inch APO can do on the DSOs and planets (and the Moon), I invite you to visit this site.
http://members.cox.net/ronby/Palatable_4-inch.htm

Hello there Ken,

You have purchased much wisely ;-).

A premium eyepiece for the planets? First a couple of questions:

1) is your TV-102 on a driven mount?
2) how's your typical seeing? How does the view from your
9.7mm Plossl looks like on the Moon and planets? With 2X barlow (181x)?

If the answer to question (1) is yes, you have quite a few choices.

If (2) looks pretty good with the barlow on some nights, I'd say somthing in the area of 6mm would be very usable on many nights.

I find I use my 6mm TV Radian very often on the planets and the Moon. It is the first eyepiece I grab for the session. However, with Mars I can often use my 5mm Radian (176x) which give the smallest apparent size I prefer on the Red Planet currently. Recently, my default planetary eyepiece is now the new TMB SuperMonocentric. But this is a specialized eyepiece because of its small 30 degree AFOV. Also, I still prefer to "cruise" over the Moon with my Radian ;-).

Lastly, consider not only this instance which you're looking for an eyepiece. Do plan what you'll want to or think you'll want to get over the long term. I recently posted the eyepiece set I used for my TV-102 Light Cup.
http://www.astromart.com/messages.asp?message_id=124266&page=8

Ron the 4-inch Tall Evangelist B[ee]

I think one of the problems is most of us here (all of us?) don't have a good insight or experience into how APOs are made from design conception, to grinding/polish the glasses to alignment to delivery onto the UPS truck ;-). If anyone is interested, perhaps this link might just let us peek at the complexity of the operation ;-).
http://www.astro-physics.com/about_us/about_us.htm

To get an idea of finished lens prices, this might also give us a peek-a-boo ;-).
http://www.tmboptical.com/itemsGrid.asp?cat_id=27
From what I hear, Thomas Back works 7 days a week and can't afford to hire any help. So I don't think he's getting rich from selling APOs and lenses either but have certainly enriched his customers with savoring experience.

Ron B[ee]

That was a superb sketch, Sol! Were you able to make out the Encke Division?

Thanks,
Ron B[ee]
PS - My Light Cup and I would like to pass on a hearty congratulation for your superb Saturn sketch published in the Dec. issue of the S&T!

Another wonderful sketch and report, Carlos. Your observation has been sorely missed and I'm glad you get some more eyepiece time ;-).

One question: do you think your seeing condition now seems worse to you than at the times starting from within a couple of months before opposition (i.e. early morning hours observation)?

Thanks,
Ron B[ee]

Wow Jim, I wish you can't sleep more often ;-) so that we can feast our eyes with more of your images. Please keep up the good work. By Saturian, the Cassini Division is so wide(!) and could that be the illusive Encke Division at the ansae?

Ron B[ee]

Hello there Ted,

I had the fortune of observing through a finese 10" Meade LX200 from an SDAA club member during my private ;-) star party around opposition timeframe, which was a heck of a lot brighter than it's now. Boy, that sweet SCT seemed to have plenty of contrast with the Mountain of Mitchell *clearly* seen (which was also easily seen with my 8-inch Dob nearby as well but not so easily seen through my 4-inch APO)! We tamed the brightness by using my #23 and #25 filter as well as my Baader Moon and Skyglow filter and keep the magnification at around 250x (max. that night). BTW, I can tell that the owner takes a very good care of his LX200 ;-)! BTW, he told me that he replaced the standard diagonal with the 2" TV Everbrite and his LX200 worked much better afterward (he said it not me ;-). Though I silently confessed I hardly touched my own 4" APO sitting nearby that night, I still prefered to view with the 4-incher for some reason night after night ;-).

So do employ some filtering and of course check your collimation and let it cooled down, Ted.

Ron B[ee]
PS - Alas if the 10" SCT weren't so weighty ... ;-).

Hello there Paul,

Congratulation on your new TV-85. I don't know about the Axiom but I like the Celestron Ultima eyepiece.

If you can swing it, Tele Vue eyepieces (Panoptics, Radians and of course the Naglers) are good matches for the TV-85. I also find many of SCT owners at the star party likes the Naglers and Radians.

Ron B[ee]