Posts Made By: Ron Bee

I'm in a very similar position, Rob. Actually, if you use the 4" APO with patience and practice, you'll begin to see much more on Mars. I had a very decent view last opposition
with my 4" TV-102. But I'm searching for a larger scope (a reflector) to hedge my bets this year.

Since you've already got the 12.5" Dobs, I don't see that you need another scope. But then, it's really a personal decision.

Perhaps something in-between then like a 6" MN61/MN66 Maksutov Newtonian, reputed to have the most refractor like view? Many observers seem to consider 6" aperture as the sweet spot for planetary viewing.

Best of luck on your quest.

Ron B[ee]

Very nicely done, Yu!

Ron B[ee]

Hello there Srinivas,

It depends on the quality of optics and if it's cooled
down sufficiently enough. But I've seen the shadow transit
looking like a black pin pricked microscopic point at 72x (12mm Radian) through my 4" TV-102 APO.

Ron B[ee]
PS - Perhaps, a small, quick cooling, at-a-moment deploying
refractor is in your kharma ;-)? I've found my 4" refractor suiting my on-a-whim, busy, body-disbuilding :-( lifestyle perfectly. I'm also getting a larger aperture for when those great nights arrive.

Hello there Tony,

You heard lots of good things right about the Tele Vue-102!

Actually there are thousands of baffles, according to Steve
White. Inside tube material is not paint, but some rough
material I don't know what. When looking through the tube
at night at the moon, it's quite black. Tele Vue has been
using this design successfully for a very long time. BTW,
the "perfect" mark given by S&T review of the NP-101 also
uses the same design. For this reason, the Tele Vue OTA
is smaller in diameter and lighter than comparable OTA with
knife edged baffles.

The focuser is butterly smooth and IMO comparable to the
Takahashi which also has a butterly smooth feel to it
(though I prefer the Tele Vue larger knob with rubber
ring).

To find out more about the TV-102 in addition to the
reviews scattered through out the web, please join us at
the Tele Vue eGroup.
http://groups.yahoo.com/group/TeleVue/
And if you're really interested in finding out what a TV-102
can do, I invite you to visit this site (recently upgraded
to include planets and the Moon.)
http://members.cox.net/ronby/Palatable_4-inch.htm

Ron the Happy TV-102 Owner B[ee]

Though I've not used mine under a highly light polluted area, I've found the UHC to be best balance in that it worked on many objects and yet with enough brightness coming
through my 4" TV-102 APO. However, the O-III works better
on some objects but gave a dimmer view. I've never tried the LPR (i.e. milder than UHC) filter.

Ron B[ee]

TheSky will do it and perhaps others such as SkyTool, etc. However, beware that the data from these stars mostly come from the GSC catalog which is notorious for their inaccuracy (+/- 1 magnitude I've been told). The best source of accurate data is still via photometric data I'm afraid. Still it is better than nothing ;-).

Ron B[ee]

60x will not be sufficient for Mars, Jupiter and Saturn, Robert. Personally, I find ~150x the minimum satisfying
magnification with Mars needing at least ~175x.

The 100mm Astroview is an achromat with very fast f/6
focal ratio and you may get a good amount of chromatic aberrations for which you may or may not mind. One good achromat around 4" you're talking about for planet is the chinese made Celestron C102-HD (or its Synta equivalent). But be sure you can get one from a reputable dealer and can exchange it if you get a lemon. At a higher cost, the Japanese made Vixen 102 achromat (same f/9.8) has a very good reputation.

Ron B[ee]

One variable in buying your first scope no one has yet mentioned Robert is: life style. How busy are you? Most of us still have to work for a living. I guess some of us even have hectic and stressful life-style :-(. Something to think about.

Ron B[ee]

>A good experiment is to place a quality 4-inch refractor (assuming acceptable suppresion of chromatic abberation) next to an 8-inch reflector and point both instruments at a planet (e.g. Jupiter). While the 4-inch refractor will provide a sharp and high contrast image of the planet the larger reflector will show the colors visible much more readily. This is not an attack against smaller apertures but only a scientific fact.

That's a very good post Carlos. I hope to be in the position to do a comparison soon as I'm planning to acquire an 8" Discovery PDHQ Dobs (with small secondary - 19% obstruction). I sure hope the 8" will beat my 4" TV-102 APO to a pulp; otherwise, I'd be extremely disappointed. Regarding colors, I do see various different colors on Jupiter and Mars (last opposition) and Saturn (though Saturn doesn't have a great deal of color variation).

Ron B[ee]

Well Allison, is there such thing as "minimum aperture" I wonder? When I look at some of these DSO (and planetary) sketches from this guy who uses a 60mm refractor, I truly marvel and wonder indeed!
http://skytour.homestead.com/sketch.html

Personally, I need a 4" refractor minimum ;-). BTW, mine
is setup on the SP EQ mount with tripod legs all spread out ready to go in seconds. The diagonal and 30mm Ultima are
all there setup as well.

Ron B[ee]