Louis D

1 minute ago, Karan05 said:

Im viewing Jupiter and Saturn which is at gr8 position for me Living in India...

Yep, you're even further south than I am here in Texas.  You can relate to air you can wear. 💦

I would avoid Kellners in favor of Plossls.  There were a few Japanese made (Nikon and Pentax) long Kellners that are highly sought after, but beyond that, they're generally not that great.

If you get a custom Dob with a hand figured mirror, it will show planetary detail better than any Mak or SCT of equal aperture as well as showing DSOs very well in my experience.  Take the money to buy one really good scope with excellent resale value rather than two mediocre commercial scopes.  Not knowing where you live, I can't really make any recommendations, new or used, to look for.

Here's an interesting read including a direct comparison between the 95mm Baader Travel Companion and the 92mm AP Stowaway.

1 hour ago, buzz said:

My book, The Astrophotography Manual, is intentionally not a beginner's book. It is aimed at existing practitioners who want to progress. Astro books go out of date very quickly and some of these are already showing their age. I have just published a new book, aimed at beginners, called "Capturing the Universe" which is bang up to date.

Sounds good.  Are the rest of the books on that list also aimed at more advanced photographers and are not usually recommended on here for that reason?

I know what you mean about books going out of date.  I have Michael Covington's Astrophotography for the Amateur from the late 90s.  It focuses on film photography since digital photography was in its infancy when published.

16 hours ago, Sunshine said:

I guess when it comes to finding any flaws in eyepieces, regarding field curvature on the 14XW, ignorance is bliss.  It hasn't struck me yet but, now that you mention it, i'll be looking for it next clear night. 

If you're under about age 45, you probably won't notice any field curvature because you still have visual accommodation.  In other words, you don't have presbyopia yet (needing to wear bifocals).  My 14mm Pentax XL also has field curvature.  I never noticed it until I got presbyopia.  I then replaced it with the 14mm Morpheus, which also has some, but it is less severe and further out.  That, and being over 10 degrees wider is quite noticeable.

Any idea what focal length(s) you're leaning toward?

The 22mm Omegon Redline and its other-branded bretheren are flat of field, unlike the 20mm XW, and sharp out to about the last 10% at f/6, and even then, the astigmatism is only minor.  I finally retired mine only after doing multiple comparisons to the 22mm NT4 (which I finally found used for under $280).  The Nagler is sharper beyond the 30 degrees off-axis point, but it's more difficult to take in the entire 82 degree field with eyeglasses.

The discontinued 22mm Vixen LVW might be worth looking into on the used market as well if you want to stick to 1.25" eyepieces.

5 hours ago, markse68 said:

Despite not really understanding what I was looking at (what do those ray trace patterns (splodges) mean- worst aberrations?

The spot diagrams show a star image at best focus (I think it ignores curved focal planes) in an f/5 system.  The black is simply a green wavelength since it's in the middle and our eyes are most sensitive to green.  The red/blue plots show chromatic effects on the image.  Horizontally, you are moving from center (axis) to edge.  The degree increments vary by actual field width. The ExP numbers refer to exit pupil separation at midfield and edge.  The greater the difference, the greater the SAEP (kidney beaning).  Normally a circle of known size is drawn around each plot for scale so you can judge whether or not the aberrations would be visible to the eye.  However, they are missing from those plots and is only shown at the top.  Here's another set of plots from the webpage previous to the linked image with more discs shown:

In these, the center color is explicitly shown as green instead of black.  The plots are also shown for f/10 and f/5 systems so you can compare the performance as the scope places more stress on the design.

Yes, I have 2.0 diopters of astigmatism in my observing eye, so eyeglasses are a must down to about 1mm exit pupil.  It's also helpful in that I don't need to clean my eye lenses very often nor do they fog up very easily thanks to having the eyeglasses as a barrier.

Both are fine with eyeglasses.  No crowding or exit pupil issues.  The APM UFF 24mm is also decent with eyeglasses as are the 22mm 70 degree eyepieces like the Omegon Redline SW.  The 40mm Meade 5000 SWA is excellent as well if you can locate one.  There's also the ES-92s, Delos, Delite, and XWs.  The Vixen LVWs were a little tight on eye relief with eyeglasses, so I went with the XLs.  The NT4s are also tight on eye relief with eyeglasses.

16 hours ago, LDW1 said:

If it has the chrome barrel it is the older model, the newer has the black barrel, it isn’t near as good as the older model. The views through my older model are excellent. I also just ordered the new Orion E Series 21.5 - 7.2mm  model,  $90 C +$20 ship. with a lot of good reviews over here, so far.  PS:  Every one should have one as a compliment to your other fixed, for the quick zoom nites when time is short.

Holy !#$@.  There are three versions of this eyepiece at least:

Original Japanese version:

Original Chinese version:

Current Chinese version:

2 hours ago, Don Pensack said:

Also the ETX scopes and LXD mounts.

I had always thought the ETX scopes were originally made in the US.  I didn't realize they were getting them from JOC all along.

21 hours ago, Don Pensack said:

APM XWAs and UFFs are made in China by KunMing United Optics (KUO)

KUO has made eyepieces for Meade, Celestron, William Optics, Stellarvue, APM, Telescope Service, and many others

And by all accounts, they are very well made and fairly innovative.  It's a bit of a shame Chinese manufacturers haven't branded their own optics and sold them as such.  As a result, there's a lot of confusion in the marketplace about house brands versus clones versus competitive designs.  When you put your company brand on something, there's a much higher sense of pride and desire to avoid selling sub-par goods.

It kind of reminds me of Japanese optical houses in the post-WWII period when many of them sold their goods in the US under various house brands such as Sears, Wards, Penney, Vivitar, Soligor, Spiratone, Kalimar, Cambron, Quantaray, Phoenix, etc.  No one in the US really knew who was making what, and it was a total quality crap-shoot.

I think I have a 2" M&SG filter kicking around somewhere that I picked up for cheap on closeout.  I'll have to try putting it on the front of my 50mm RACI to see if it works sometime.

29 minutes ago, skybadger said:

I got the top end of the eyepiece to unscrew but I am suspecting that the bottom end also unscrews, due to the lack of the zoom barrel shifting or exposing any screws.

I suspect that the silver bit unscrews from the base  but i just might break it trying.

It's probably just got a bit of thread-lock on it to keep it from unscrewing during zooming.

More interestingly, where was the optical design done?  Germany?  China?  Other?

5 hours ago, DeathWarpedUp said:

However theres a part of me that wonders maybe I shoud tie my UHC to my finder scope with a rubber band at this point

A 2" filter would fit just about perfectly on the front of a 50mm finder scope.

5 hours ago, matthasboldlygone said:

Can someone just tell me what to buy 😂

Well, you just changed the subject from your initial question.  If you're looking to buy, what is your budget, usage intention of visual vs. astrophotography, distance to carry or wheel-out scope to observing location, your personal weight lifting ability, portability requirements, desired objects to view/photograph, storage room available, manual vs. push-to vs. goto vs. tracking, etc.

1 hour ago, jetstream said:

Yes I can see 2 close stars get a bit closer near the edge of the Docter but I like this much better than having the moon "egg out" in my Ethos at the edge.

Doesn't the moon get tangentially flattened in the Docter at the edge (like it's squished up against the field stop)?  I see that in the Meade MWA 26mm.  Both forms of distortion are unfortunate but unavoidable in UWAs.  Perhaps the "egg" distortion is worse on the moon aesthetically.

Mono mostly because it's a hassle to setup the binoviewer and to keep readjusting the angle as I move around the sky.  Binoviewing is excellent for full moon viewing because there's no eye fatigue since both eyes see the same brightness.

How about baking it in the sun to kill off the mold via intense UV?  I know our Texas sun works wonders on such things.

6 hours ago, Stu said:

Let’s not forget petzvals! There are quadruplet and quintuplet designs with doublet or triplet objectives and reducer/flattener doublets at the rear to flattener the field and reduce the focal length.

Oh, I remembered them, but I didn't know exactly how to classify them among the latest crop of ED/APO scopes coming out of China. 🤔

And yes, @merlin100, they're delicious. 😉

5 hours ago, andrew s said:

There are of course different reflectors. In addition to the Newtonian/Dobsonian we have the various Cassigrain flavours which include classical, Dall-Kirkham and Richey-Chretien as the  most common.

The also have a variety of correctors to remove various aberrations. 

Recently a range of small affordable CC and RC scopes have become available.

Regards Andrew 

And the various reflector designs to eliminate the central obstruction: Off-axis Newtonian, Yolo, Schiefspiegler, Stevick-Paul, Herschelian, etc.  Of course, these are mostly ATM builds.

53 minutes ago, John said:

The most basic type that you can buy is an achromatic doublet - 2 lens elements. This would be your "standard refractor"

Nobody makes or sells a single element (non-achromatic) refractor.

The next step is an ED doublet refractor which uses a low dispersion glass element to reduce markedly the amount of chromatic aberration visible.

The next step is a triplet which if well executed can reduce chromatic aberration to virtually zero. 

Within each of the above types there are a range of qualities available and a wide range of pricing. The more expensive ED doublets can be somewhat more than a low to mid cost triplet for example.

The major advantage that the reflector has is that the cost per cm of aperture is a lot, lot lower because there are less optical surfaces to figure, polish and coat.

There are plenty of threads on the forum discussing the merits of the various scope designs. In my view they all have their strengths and weaknesses. Thats probably why many of us end up with a variety of them !

And I would go further to subdivide ED and APO into four general categories:

1. ED Doublet of FPL-51/FCD-1 glass.

2. ED/APO Doublet of FPL-53/FCD-100 glass.

3. ED/APO Triplet of FPL-51/FCD-1 glass.

4. APO Triplet of FPL-53/FCD-100 glass.

As you progress into more elements and more expensive glasses that have lower dispersion, you get better chromatic correction.  Design points 2 and 3 above can flip flop depending on the level of design execution.  As discussed in another recent thread, the actual design choices for the objective and it's mating element(s) (curves, spacing, etc.) also make a difference in its ED/APO characteristics.

Then there's flourite "glass" which has properties slightly better than FPL-53 and is even more expensive.  It used to be the only game in town for ultra-low dispersion objectives.