Posts Made By: William Paolini

I started with I believe a 600 refractor back in 1965. Couldn't "find" a thing with it so used mostly for terrestrial. Then moved up to a 4.5" Reflector which was wonderful. Again, not sure who's brand. After that got some astro fever and ground my own mirror to make a scope plus got an 8" mirror from someplace and me and my dad build a Newtonian around that and used an Edmunds equatorial to hold it. We built the tube out of stainless steel! I recall all the drill bits we went thru poking the various holes in that tough metal. It was a tank for sure, but it sure performed and I'd routinely go 100x per inch with that thing on the Moon. Was out looking at the Apollo landing sites each time they landed or took off from those adventures. Up to this time I had the typical 1.25" eyepieces from Edmunds or Celestron. Then this new thing came out on the market called a Nagler or something so I ventured into my 1st premium EP and spent all my money on 2 eyepieces, a 4.8mm Nagler and a 24mm Wide Field. These things were like a quantum leap over everything else (and I still have them).

After the 8" home made Newt, I downsized back to my 4.25" Newt and that served me forever. Then I went to college and dropped the hobby. Finally, when I graduated and began to earn some money I got back into it and got myself a present of a C-8 Delux. That was one great scope and I used my 2 premium EPs in it, but also had the Celestron Orthos and Erfles which also worked quite well. In transit as I moved from the East coast to Chicago, the C-8 was stolen by the moving company and in the light polluted Chicagoland area I just picked up a Meade 2045 102mm SCT to hold me over. I kept and used that for 10 years before I finally (now back on the East coast) picked up my Orion XT10i and it has been the greatest thing since apple pie. I think a 10" is a great compromise between size and performance. It's "big" but still a very "personal" instrument. With the 10" and it's great performance I have gone EP crazy and have run thru just about everything short of Zeiss Orthos and Meades. So aside from those just about everything else has been in my stall that was worth being in there.

So after all this time, where has the EP journey taken me? To a very mixed spot, not of the one line or perfect EP that everyone is searching for, mut of overlapping EPs since no one EP is strong in everything that I may end up needing while observing. So on the high power end I at times need wide fields so I can get more context. For this, the T6s are used and their primary usage is for Lunar and Globs since they excel there (note the Hyperions or XWs would have done as well or even better in the case of the XWs, but a personal preference of mine is for high power EPs to be a smallish form factor, so this gave the T6s the edge as wide-fields). For sharpest on-axis work for planets and doubles and DSO, I've settled on Tak LEs as being the best in my tests for these objects. Sure the SMC Orthos are a tad better, but the Taks do almost as good plus have the larger afov and the nice 10mm eye relief so better than typical orthos or plossls. But so far, except for the SMC Orthos, nothing (yes nothing!) has been sharper on-axis, nor as contrasty.

On the low power end the search for something I really like in a fast Dob, with it's fast optics issues off-axis, has been really hard - especially since I do not like adding a Parracor into the mix since I have tried it and I don't like the extra magnification and I can detect the light loss from the extra glass quite easily. Add to my problem that I really don't enjoy 2" EPs all too much because I don't like fussing with switching between 1.25" format and 2" and the search is even more difficult. So again, I've had a host of Plossls and Erfles in the longer focal lengths and nothing really stellar IMO. The best view to date has been thru the Panoptics and older TV Wide Fields when I get longer than 15mm. But another personal preference for me has been the discovery that I don't like rectilinear distortion in my low power EPs since I have gotten used to things being orthogonally correct with the Erfles and Plossls I have been using over the years. So when I pop my TV Wide Field for instance in the focuser and look at a familiar subject, the star positions being somewhat off from true just looks "wrong" to me. Same with Panoptics and Naglers in the longer FLs. So my search has not yielded much luck until the 40mm Paragon came along. Now that is nice - every star in the place it should be across the field. But what to do about the 15-25mm range since no Paragon's yet? Well, since I can't wait, I went for the 14mm and 21mm Denks. Beautiful looking, small form factor, big eye lens, good edge correction in the fast dob, and almost zero rectilinear issues! Finally I'm happy

So there you have it, after Celstron Orthos-Erfles and Meade Plossls-MAs and RKEs, and UO Erfles-Orthos-Konigs and Sieberts Ultras-StarSplitters-Observatories and TeleVue Plossls-Panoptics-Naglers-Radians and Pentax XW-SMC Orthos-XFs and BO/TMB Planteries-WAs-Monocentrics and Orion/Baader Stratus-Hyperions and Takahashi Les what I have ended up with are:
**Hi Power Resolution - Tak LEs
**Hi Power Context - Nagler T6
**Mid Power - Pentax XF
**Lo Power - Denks and Paragon

So now that I've found my stall am I finished? Nope Because I've discovered that if I can get my scopes focal ratio at f/15 or above, then the Pentax XFs and Denks smoke all the high power EPs when the hi power EPs are in the scope at f/5!! I mean smoke them! So if I throw a good 3x Barlow under the XFs or Denks, then the T6s, LEs, and even the SMC Orthos aren't as sharp. So I guess that brings us back to the olden days of scopes for us high power junkies - focal ratio RULES!

It's just never ending - guess that's why it's so much fun

14mm to locate, 7mm and 5mm to view is what I usually use in my Orion XT10. If it's really tight then I throw a 2.5x barlow under those EPs. So 160x - 400x are the powers I use.

As far as EPs...

14mm Denk
5mm and 7mm T6
7.5mm LE

As far as high powers under barlow, I find the 7.5LE gives me a touch darker background and a little better star rendition under barlow than the T6. I usually start the viewing with the T6s, then finish it up using the LE.

Were you using a diagonal? Happened to me one and turned out to be the less than premium (and dusty) diagonal. Try viewing thru the scope with and without the diagonal to see if that impacts the halo/scatter. Make sure the eyepiece you are using also does not show the same issue thru another scope to eliminate the EP being the cause.

Dmitri,

What was the exact location you were at? Either Lat/Long or close cross roads so I can Mapquest it. And this was April 13th last month correct? I want to see if I can check out some of the winds aloft and other things that were happening at 2am if the aviation weather resources still have that back data. Sounds like there was a moment of very rare clarity.

-Bill

How about 2.8mm and 4mm instead?

I've opted for the Pentax XF 8.5mm and 12mm on top of a TV 3x Barlow. Quite frankly the performance of these combo's has blown me away. Sharpness/Transmission/Contrast are jaw dropping in my 10" Dob. Have never experienced EPs that barlow and perform like these.

[COLOR="Blue"]Do you feel that the wider FOV and longer eye relief is a necessity or a luxury that you can do without?[/COLOR]

I feel the longer eye relief is something that should be considered a necessity. If we keep the eye relief short for high power EPs (aka - ala ABBE Orthos), then it is just too difficult to linger long. As far as the afov is concerned, I feel the wider ones are definitely luxury items. By wider I mean anything wider than 50-60 deg. Sure it's "nice" but if everything can be well corrected in the 50 deg fov, then that is golden IMO. I use a dob and do not have automated tracking, but have no problem hand tracking even at highest powers and 50 deg afov. 60 makes it comfortable for me. 82 deg is no necessary and a luxury.

[COLOR="Blue"]If the FOV is wider, must it be all usable or is it ok for a percentage of the field to be soft or astigmatic?[/COLOR]

I feel that 85% must be usable and sharp for me to feel the wider afov is worth it.

[COLOR="Blue"]Is it acceptable to have any color at the very edge of the FOV?[/COLOR]

Again, like the previous question...but a little more forgiving. As far as CA, if it starts showing around 25% from edge, that's fine with me.

[COLOR="Blue"]What are your feelings on Rectilinear Distortion since this is a necessary evil for very wide afov EPs? (Sorry...this is my add - haha)[/COLOR]

The affect RD has on me differs by target, plus I feel one gets used to. The problem occurs when you pop and EP in without much RD and you now have a comparison point. Last evening was very clear and I was out enjoying the Lunar terminator with my 5T6 in my 10" Dob. After using the 5T6 I moved to a 3x barlowed 14mm Denk. It was strange...it just looked so much "cleaner" and "real"! As I switched back and forth I then noticed why. 2 reasons....first it was as sharp at the edge as it was in the center in the Denk with barlow whereas the T6 was soft in the outer 15-20%. But as the terminator moved across my afov it became apparent why the Denk appeared so much "cleaner" ... the terminator showed only about 1/3 as much RD as it moved as the T6. This bowing of the terminator line gave me the impression of an unnatural view. Something I was not bothered by previously, but in the comparison, the Denk then stayed in the focuser for the rest of the evening. Like I said...the impact of RD for me is target dependent. Hi powers usually not ever a bother, but on the Lunar terminator now that I've seen a straighter one, it makes a difference.

Great questions Floyd!

Bill,

Considering just the 2 scopes you mentioned, with no considerations for costs, I would think it is an easy choice (regardless of urban or rural, but more so for urban).

While the 4.5" does have more light gathering power, let's remember that it's not really gobs more, but just 1.47x more than the 90mm after you figure in the loss due to the CO. Given your location you're not going to get any satisfying views of DSO even if you had a 10" scope quite frankly. That being the case we are talking a very limited number of DSO, a few more Globs, many more star clusters, then a lot of time on doubles the Moon and planets.

While I don't have a 4.5" scope I do have a 6" SCT and an 80mm refractor. Of these 2, I grab the 80mm about 95% of the time, and the 6" the other 5% just because it feels neglected. Yes I can see deeper with the 6", but given the difference in star images that the refractor puts up, I prefer to go less deep. Yes I get more resolution with the 6" on planets and the Moon, but the refractor snaps better and actually pumps higher powers better. Interestingly, both scope show their sharpest high power image around 150x in my area (lim mag 3-3.5 and Pickering 3 is the normal). However, on the same evening the 80mm can be pumped much higher with much much less fall off in image degredation. So on Moon and Planets, the 80 is actually more enjoyable.

On brightest DSO, I also prefer the 80 over the 6". Yes I get lots less light on M42 in the 80, but up at 150x I still see lots of moltiness in the nebula and the trap is gorgeous since star points are rendered so much better. For things like doubles, it's no contest that the refractor is taken out...although true that the colors are less pronounced. However, again, the difference in colors you will see given you only have 1.47x as much light from the Starblast, I'm not sure it will be significant, especially from an urban site. My 10" sure shows the colors better, but not 3x better, and it's a 10" compared to a 3 inch!!

Finally we get to the mechanicals. Night and day difference for the APO...plus I am supposing you get a 2" focuser as well. So the Starblast can get a 24 Pan in the tube showing 3.39 deg TFOV whereas the 90mm can get a 40mm Paragon showing you 4.88 deg TFOV of perfectly formed refractor star points.

Anyway, given the plus on the Starblast is 1.47x the light gathering, while the plusses on the 90mm APO are more contrasty image, better star so much images for clusters and doubles, will push more power, can get wider TFOV with 2" EPs, better mechanicals, and something you'll probably want to keep forever or hand down....I just think it's an easy choice.

-Bill

Bill,

If you seriously want to get it down to just one scope, then what you can do as an experiment is to determine if a 5" is really going to do it for you. You 6" must put up a good image with its chromacor, mask it down to 5" and see if you still feel satisfied with the images you are getting with the objects you normally view.

If stepping down to 5" loses you too much from what you are used to with your 6, then you have discovered that a 5" of any type will not satisfy you and that a premium Dob, or perhaps a good 8" Mak-Newt may be where you should be headed for your one scope quest. This of course makes the assumption that a 6" APO is out of the question due to the obvious funding issues one of these would cause.

Good luck on the quest. Personally I think 3 is a good number...a nice light bucket...a pleasingly sized refractor...and some kind of grab&go.

Good luck!
-Bill

If you want to keep it in the family, you could get a 14mm extension ring for your 13mm Hyperion and that would get you square in the middle at 10.5mm FL. Or you could by both another 13mm Hyperion and 14mm ring so you don't have to do the swapping.

Alternatively you could get the 11mm T6. However now you are introducing a different design, and hence perception, in the mix as you move from longer to shorter FLs. I am finding that the T6s perform a notch better than the Hyperions. The wider afov, better edge correction, smaller form factor, less sensitive eye placement, and warmer coatings are consistently making my perception of the T6 in use as more comfortable to use and better performing overall. Even with the tighter eye relief I am finding the T6 more comfortable but that's because I rarely put my eye close enough to get all the 82 deg so I tend to stay backed off a bit so only getting about 70 deg which is just fine given the added comfort. Anyway, at 2.2x the street price for the T6 new, I guess this should be expected that overall it would perform better.

Here's one...

Eta Carinae - Mag 6.21 - Dist 7,500 LY

...although I've seen some say as little as 6,000 and others as much as 10,000, most though put it in the 7-7.5 kLY range.

...and not a very friendly neighbor at that it seems:
http://www.astronomy.com/asy/default.aspx?c=a&id=5717