Posts Made By: William Paolini

October 7, 2006 02:35 PM Forum: Eyepieces

Harry Siebert Ultra Series

Posted By William Paolini

Larry,

I have the 7mm, 11mm, and 15mm Ultras. These are great. I also had the 22.5mm and the 30mm but these latter two did not handle a fast mirror well at all.

But 15mm and smaller are wonderful in a fast scope. The afov is very generous and although I never measured it looks to be a real 70 deg as it is much larger than a Radian. In a fast scope (I have an f4.7) about the central 66-75% is corrected very well. After that some coma and astigmatism starts. Of course the 15mm shows more, the 11mm much less, and the 7mm almost none so it's entire field is really good.

All have very little CA. Some on the edge but you have to hunt for it. They also put up a quite small star point size. Much smaller than others I have tested against (UO HD, Radian, etc.).

They seem to be quite color neutral. On-axis very very sharp too. Wonderful for lunar viewing. On planets, Jupiter in particular, the 11mm brings out the best banding details of most all my EPs, perhaps tied with Radian which does very well in this department.

Contrast wise they are not as contrasty as a Radian or UO HD. Perhaps a tad behind the UO HD. Even so, they do a great job on opens and globs. Very nice added context with the wide field.

All in all they are quite a great eyepiece in the 15mm and shorter focal lengths. Harry does not advertise a 5mm but says he can make one up. Actually I feel they do a bit of a better job than his Star Splitters. Even though I have BO/TMB Planetaries (which for me are a better choice than a Radian, especially given price) and UO HDs, and I don't need a 5mm Ultra, I am still debating getting one made up to add to my stall. At 70deg afov these hold a nice niche in the marketplace, especially for the price and performance level. So would be nice to round out my series so I had a 5mm, 7mm, 11mm, and 15mm. Add to that my 24mm TV Wide Field (to be replaced hopefully by a 24mm TMB Paragon when it comes out for a pincushionless fov) and this group of 5 EPs gets me everywhere very well all at 65-70deg afov. Hard to beat that.


October 10, 2006 07:01 PM Forum: Eyepieces

Nagler Typr 6 vs. Pentax XW

Posted By William Paolini

Charles,

Thanks for the comparison! How did you find the focus snap for each EP? Either one easier to reach optimum focus than the other?

Also, would be interesting to also hear a quick compare (if you have time) on a glob for light grasp and contrast and point size comparison. M15 is up and about and a good test target.

Thx.
-Bill

October 10, 2006 09:39 PM Forum: Eyepieces

New UO Wide Field Eyepieces?

Posted By William Paolini

A bunch of places market these. I have not tried one myself, but understand from UO that they are NOT as sharp for planetary/lunar work as their Orthos.

October 13, 2006 01:10 PM Forum: Eyepieces

A little star testing

Posted By William Paolini

Floyd Blue said:
I also found that when I switched to the Radian EP, the diffraction rings were more sharp and easier to read, which was an interesting find. The difference was fairly large, with much better definition. I did not have a Plossl or Ortho of 5mm to try so these were the only EP used.

Floyd,
This is quite interesting. One day when you get a chance (and the weather cooperates) could you do a side-by-side with both your 127ED and you Dob to see if this find is consistent for both types of scopes?
Thx,
-Bill

October 13, 2006 02:24 PM Forum: Eyepieces

More Power, Scotty, in my 102 FL!

Posted By William Paolini

Any telecentric style barlow is supposed to maintain the AFOV and ER chanracteristics of an eyepiece (e.g., TV Powermates, Siebert Telecentric Barlows, etc.). Conventional barlows alter the afov and ER charateristics to a degree.

I use barlowing extensively, Ultima 2x and Klee 2.8x. I find the Ultima narrows the afov a bit more than the Klee, but ER I have not found altered obviously - although I never paid attention either.

Also, I have yet to find any EP + barlow combination that performs worse than the equivalent FL EP without barlow. Often actually better in terms of resolution. For instance, a few evenings ago I put the Nagler 12mmT4 on the Ultima barlow for an effective 6mm view. I then compared that to my 6mm OU HD and 7mm TMB/BO Planetary on the Perseus Double Cluster. No real difference! Yes, if I really really looked and examined very hard, the Nagler under barlow was ever so slightly dimmer, but not easy to notice at all. So for practical purposes, the same...which was amazing especially compared to the UO HD with its simple optical design.

So I'd suggest you get both a 3x and 5x barlow and start using the longer FL comfortable EPs for high power work. 12mm, 9mm, and 7mm EPs combined with 3x and 5x barlows will get you a nice range of effect FLs all the way down to 1.4mm!

October 19, 2006 01:56 PM Forum: Eyepieces

Zoom eyepieces for high power - TeleVue?

Posted By William Paolini

Inge,

I do not have the 3-6 zoom, but it's on my list. I've been doing a lot of investigating into it and talking to many people who own it. Not one of anyone I have talked with, both online and in phone conversations, has had anything negative to say about this EP. In fact, for those who have other premium EPs, they put the Nagler 3-6 Zoom on par with the Tak LEs in terms of sharpness and contrast, so good reviews and everyone says it's worth the money. And, in addition to the obvious 1 Ep replaces 4, it evidently has the added benefit of an unusual observing experience since I'm told it maintains focus while zooming -- so this is supposed to be dramatic for Lunar viewing and zooming into details (Globs also). For that reason alone I am considering it. And it is a bit pricey for a 50deg afov EP (IMO), but I think that will get balanced by the potential of the in-focus zooming for observing and of course by any multiple EPs it may replace.

Although I never asked (perhaps someone here can chime in), I assume it barlows well also? While there has always been (and continues to be somewhat) this stigma associated with barlows, I have found they introduce no issues. For instance, last evening I barlowed up my 12mmT4 to 6mm using an Ultima 2x. So that combination has 9 glass elelments. I compared that to my 6mm UO HD Ortho on NGC 869. Both EPs brought in the same faint stars and the same adverted ones. So whether 9 elements or 4, transmission basically unaffected for visual observation. So if the 3-6 barlows well then you also get a 1.5-3.0 with your 2x. That should cover all the high power bases!

-Bill

October 19, 2006 02:14 PM Forum: Eyepieces

Question on a Nag. 7mm. EP

Posted By William Paolini

John,

The original smooth body also had 2 versions, one with a circle-N optical house mark, and then later models without. Many users attest that there is a performance difference between these two in terms of light transmission (the circle-N being better).

btw - please update that picture of your eyepiece case and erase the Pentax O-7 as it now safely sits in my case instead! Thanks...it arrived yesterday in perfect condition smile

Appreciated,
-Bill

October 20, 2006 08:11 PM Forum: Beginning Astronomy?

Eyepiece Question?

Posted By William Paolini

Chris,

I have the Orion XT10i (f/4.7). Here are the EPs I find that work very well:

BO/TMB Planetaries - 5,7,9mm 60deg AFOV. Nice and sharp and contrasty to the edge, barlow wonderfully. A bit more contrast for DSO than the Nagler but sacrifice AFOV. But even at 3.5mm BO easy to track DSO in my Dob.

Nagler - 12mmT4 82deg AFOV. Sharp for central 75%, then coma in outer 25%, not too bad though. Barlowed up to 6mm or 4mm all coma is gone and maintains light thruput - so no need for extra Naglers! Basically the 12mmT4+2xUltima equals light transmission of 6mm UO HD. So a 2x and 3x barlow together are cheaper than even one more Nagler. I'm thrifty.

In the 32mm-15mm realm not a lot in 1.25" that is great inexpensive unless you can find the discontinued UO Super Erfles in 16, 20, 25 which all do great in central 75%. All the Plossls work great of course but for those long FLs I want more than 50deg AFOV! If you have the money go for a 24 Panoptic, otherwise wait until early 2007 when the 16, 20, 24 TMB Paragon's in 1.25" are due out with 69deg AFOV. I'm waiting.

28mm RKE - 55+deg AFOV (it seems, they say 45 but clearly not). Actually is excellent for finding things and at only $54 can't argue. Stays nice and sharp over most AFOV and bright!

30-40mm - 40mm TMB Paragon 2". Again, sharp over 3/4 central AFOV like 12mmT4. Very bright and flat flat field. Yes it's a big exit pupil and you lose light, but you get all that extra TFOV which is what you want from a scanning EP. The amount of light you lose from the larger Exit Pupil equates to bringing your 10" down to an 8" I believe if I recall my calculations a while ago. No big deal since I get 2.3deg TFOV from it smile

So if you don't mind barlowing, get a 2x and 3x 2" barlow, then a 12mmT4 and a 40mm Paragon and from that small combo you get:

40, 20, 13, 12, 6, 4mm a nice spread and it saves bucks and it works wonderfully. Or skip the 12mmT4 and get a 13mmT6 and a 9mmT6 with only a single 2X barlow for a little more flexibility:
40, 20, 13, 9, 6.5, 4.5

-Bill


October 20, 2006 08:54 PM Forum: Deep Sky Observing

Clear Sky Clock Wind Prediction Accuracy

Posted By William Paolini

You'll get a much more accurate prediction if you go to the local aviation weather site. If you contact any local small airfield in the area they usually have a phone number for automated info which gives the winds aloft at varying altitudes. If you can get aceess to an online system, local PIREPS (Pilot Reports) get you real time assessments.

I used to be a pilot and the aviation weather facilities run through FAA are much more accurate than local weather channels, etc., especially for within 12 hour predictions very accurate. Anything past 24 hours is really a crap shoot.

-Bill

October 22, 2006 02:21 PM Forum: Eyepieces

Best Current Production High Power EP

Posted By William Paolini

James Fusco said:
I have a few zeiss orthos, UO HD's & planetary, Pentax ortho,Vixen orthos,Tak LE, even a old GOTO, old TV's and New. I'm a apo guy and always end up grabbing the TV 2.5 T6 Nagler.I think Al did a great job removing the warm color that comes with using ed glass. I find the zeiss to be the whitest on vega, next the pentex, strangely the old GOTO H was dam good too. But the TV T6 are very white, sharp, and have a WF. Stressing the EPs yes I did that too.I attached a 2.5, 4 and a 5x powermate to the end of the 2.5mm and was able to view the moon. What is nice to, I was able to take pictures through that system. So when you ask for best, you need to ask yourself will I use it. Like a car, is it fast, just in a straight line or curves too. I use all my eps hoping to see something better than the other, but then to gravitate to the nagler's T6.

Jim,

That's interesting...1st time I heard anyone mention that the T6's removed the warm tones. I've never had a T6 so can't compare.

In many respects I think you are quite correct. Under normal, or even good+ sky conditions, most eyepieces perform the same (resolution), with the exception of contrast and afov of course. That being said, the very large afov of the Nagler is seductive. So I can see why you always reach for it. I think it is only when the sky is excellent and we push our scopes to their limits that we can begin to really see the differences between what are considered the best (Zeiss) and others. That being said, then 9 times out of 10 I agree and the Nagler would probably get picked most often.

As anotehr poster here suggested to me, this quest for the best is really for those rare times when everything falls together and the best optics will really shine smile

Thanks for your post...good insights smile

-Bill