Louis D

41 minutes ago, Marvin Jenkins said:

We all assume that newer is better but in some areas of life this is not always so. Just a question, to get a grip on how much we have improved or not. I take it that TV Nagler are the best. (generally right now) 

Has this always been the case, or are there times when different EP’s were the choice with scopes of the day? I understand that sometime ago scopes for amateurs were not what they are now (no reference to quality) but the choice now is amazing.

Anti-reflection coating has advanced a lot, even in the last 20 years.  SAEP (kidney beaning) in UWAs is under much better control today as well.  That, and stray light control has improved in many premium eyepieces.  That 14mm Meade 4000 UWA has very well corrected field flatness and astigmatism across the field, but it does a terrible job of controlling stray light and kidneybeaning.  The 14mm Morpheus is better on both counts, and yet has a bit more field curvature and edge astigmatism.

The 14mm Pentax XL has excellent stray light control, no edge astigmatism, and no SAEP, but it does suffer from field curvature.  The Pentax XWs have slightly better coatings leading to slightly darker background sky.

The 5.2mm Pentax XL has very few flaws to this day.  Perhaps it could use those slightly improved XW coatings.

The Nagler T1s had loads of SAEP at longer focal lengths and tight eye relief at 4.8mm and 7mm.  I'm sure their coatings could also be improved upon.

The Vixen LV line view a bit dark for unknown reasons.  My 9mm from 1997 shown below gives excellent views otherwise (great stray light control, no SAEP, excellent coatings, flat field, and sharp to the edge).  They also exude quality when you pick one up and look it over.

4 hours ago, Ags said:

When were Speer WALER eyepieces introduced? My only ocular that could possibly qualify for this thread is an SW 10.

It depends on the series and vintage within it.  If it has orange lettering, it is definitely pre-2000 like my V1 S-W 5-8mm zoom from 1999 (pictured with my 1998 vintage 5.2mm Pentax XL):

Probably my oldest eyepiece is my 14mm Meade 4000 UWA smoothie (mid to late 1980s, I believe), shown here with my also vintage 14mm Pentax XL that I've owned since new in 1998:

9 minutes ago, RobH2020 said:

If I do get hold of the 200mm I'd be intending to sell the 150mm, but I don't think I'd bother offering postage (collection only), too much hassle and risk of breakage!

Most Dobs and tripods are typically pickup only in the US simply due to the bulk.  However, people are shipping SCTs, Maks, APOs/EDs, and mount heads, and even those get expensive.  It comes down to supply and demand.  While no one might want to shell out $1000 to $5000 on a particular item locally, someone in the US more than likely will (we're like the whole EU as a market).  When they're in it for that kind of money, tossing in another $50 to $200 for shipping is peanuts.

As far as the really big and expensive items (20"+ Obsession Dobs, etc.) that you really can't safely ship at any price, people tend to agree to meet up at some intermediate point for exchange and make a short vacation out of it.  They used to meet up at big star parties or NEAF for these exchanges, but they've all been cancelled.

You could also try putting anti-vibration pads under each foot of the baseboard.  They can help dampen vibrations to under a second.  You can cheap out and get great performance with Sorbothane pads such as these.  Just don't forget they're under each foot at the end of the night.  If you're on dirt or grass, there isn't much of a reason to use pads.

6 minutes ago, RobH2020 said:

Interestingly the second-hand market is pretty robust at the moment, I've seen a Skyliner 150 dob currently on £300 and rising on ebay, and that's retail priced at around £220 usually.

So a good time if you want to get rid of kit!

I've seen this in the US as well.  Ads on CN have been running double to triple the typical volume, and asking prices are at near new prices on desirable items.  When you figure in actual shipping and online payment charges, they're often well above new prices that typically don't charge for these two conveniences.

13 hours ago, Dantooine said:

HCA’s most important, it all folds without them. 

Stupid American question.  What's an HCA?  I gather it is a healthcare related acronym that we don't use here.

I'd probably go with a 30mm APM UFF, a 17.5mm Morpheus, a 12.5mm Morpheus or APM 84° High Eye Relief Flat-Wide, a 9mm Morpheus, a 6.5mm Morpheus, and a 4.5mm Delos.  That totals somewhere between $1298 and $1354 before tax, which is about £1,000.  You didn't specify if we needed to include tax.  Americans rarely price things after taxes because they're not hidden with the exception of gas (petrol) taxes, and they vary from state to state.

1 hour ago, HollyHound said:

No, in all seriousness I am very happy with the 70(ish) degree FoV, as I find it very relaxing to view for long periods, and the eyepieces I have for that work well now in both the dob and refractor... so I am more than content 😃

I enjoy the 92 degree field of view of the ES-92s, but also quite enjoy 65 to 75 degree fields of view as well.  There's room for all fields of view depending on the mood of the observer.

It would be nice if Bresser also offered a low profile focuser option with a minimal secondary obstruction of around 20%.  The current setup has a 28% obstruction which is quite large for a visual Newtonian.

8 hours ago, Ricochet said:

Out of interest, how do you connect the flattener for use visually? Is it screwed to the nose of a 2" diagonal with extensions to get the correct distance? Do you have to have any form of adjustment on it to change that distance for eyepieces that have their focal planes at different heights?

I use a GSO dielectric 2" diagonal that happens to have an SCT nose thread.  I replace the original nose barrel with a 15mm SCT to M48 thread adapter.  I then screw the TSFLAT2 into it.  The original nose barrel is about 15mm too long and over corrects field curvature as a result.  I discovered this method with my AT72ED (430mm FL).  I thought I would need to shorten it up on my new to me 90mm TS triplet APO (600mm FL), but it surprisingly works fine at this spacing as well.  Shortening it up didn't seem to improve matters, so I left it long to have more barrel in the focuser.  I may play with it more in the future.  I'm not taking photographs, after all.  I'm just trying to get rid of most of the annoying field curvature.  If 90%+ of it is gone, I'm happy.

I've found this spacing works well for pretty much all of my eyepieces despite the fluctuation in focusing distance.  Again, this isn't photography, being in the ball park to eliminate 90%+ of the curvature is enough to move it from annoying to barely perceivable.  It's the same for my GSO CC, if 90%+ of the coma is gone, I'm good with it and don't feel a need to fine tune the distance for each eyepiece.  Only my 12mm TV NT4 focuses way off and had to be parfocalized (20mm below the shoulder) for both CC and FF.

6 hours ago, HollyHound said:

Based on what I discovered last night, I have to say that I feel any reports of edge behaviour for eyepieces in a (faster) Newtonian without a coma corrector, are likely going to be limited by visible coma!

And by corollary, eyepiece reports in non-flat field refractors should not critique eyepiece field curvature since it is very difficult to separate it from that of the scope.  I use a TSFLAT2 in each of my refractors to come close to a flattened field.  Unless you spend all of your time observing objects on axis such as planets using a tracking mount, I can't understand how so many people can stand the strongly curved field of short ED and APO refractors.

According to @Don Pensack, Newtonian coma grows linearly from center to edge, so the wider the apparent field of view at a given magnification, the more obvious coma becomes.  Doubling the magnification results in the same amount of coma because it is half as large, but magnified twice as much, so you're back where you started.

This is in contrast to field curvature where low powers and wide fields really do show more field curvature than higher powers with the same apparent field since it's not a linear relationship across the image circle.

I took some images through my 8" Dob with my DSLR tonight and composited the best Jupiter image with the best Saturn image and then stretched the background to pick up the Galilean moons.  No stacking here.

On 18/12/2020 at 09:01, vlaiv said:

Just had this come in after two month wait for stock to refill:

 

Do you make a habit of dangling new astro toys above a considerable drop?  Are you demonstrating how confident you are of your equipment handling skills?  Perhaps you're demonstrating to the new guys in the astro toolbox who's in charge?

Given my sometimes shaky hands, I found those images terrifying and should have been prefaced with the warning "Some viewers may find the following images disturbing."

Good point about the secondary centering.  Do you have a sight tube?  If so, insert it so far into the focuser that the end of it looks to be the same size as the secondary when viewed from the peephole.  It will be obvious if the secondary isn't dead centered in the sight tube view.  There are generally nuts or screws/bolts at the ends of the spider vanes to adjust the X/Y position of the secondary over the primary.  There is also generally a single bolt with nuts at the center of the secondary spider to adjust the Z position (toward/away) of the secondary relative to the primary.  After loosening and adjusting this one, you may have to make sure the secondary is still square with the focuser again by rotating it before tightening everything down again.

On 13/12/2020 at 15:15, TomBee said:

This market is really strange and this time it seems to be the end of Meade
 

Meade as a brand will continue, though attached to what products, I don't know.  Brands are typically the most valuable items in bankruptcies.  The question is, who will own the rights to the Meade brand when all is said and done.

Meade SCTs will continue to be manufactured in China by Ningbo Sunny and their suppliers/subsidiaries.  What brand name will be slapped on them remains to be seen.  Ningbo Sunny is not in bankruptcy, only its US subsidiary Meade is.  Because of incorporation laws, Ningbo Sunny is completely isolated from these bankruptcy proceedings in the US.  At this point, the most they stand to lose is the Meade brand, but I have my doubts about that as well.

I think the #2 screw is a safety screw to keep the dovetail from sliding all the way out of the clamp should it loosen.

I use a 1.25" visual back and diagonal when using my binoviewer natively with the Mak to minimize the increase in focal length.  I still come out way ahead with them instead using my effectively 3x Barlow OCS/GPC in the Mak magnification-wise.

Yes, you're pretty well covered for eyepieces.  The f/12 focal ratio of the scope, along with it's narrow rear baffle, really limit the range of usable eyepieces and exit pupils.

I went ahead and added an SCT thread adapter and a 2" visual back so I could use my 2" diagonal and 2" eyepieces with my Orion 127 Mak.  Skywatcher is selling their 127 Maks this way on this side of the pond now.  It does vignette a bit, but the view is massively wider.  Here's a comparison image I took through my 127 Mak showing the difference in true field of view and vignetting with widest true field 1.25" and 2" eyepieces:

It's really nice to be able to use my large stable of 2" eyepieces with it now.

This is what the setup looks like:

6 hours ago, DeanCJ said:

we only have one BST Starguider and that is the 8mm, for a comparison we bought a Vixen 8mm NPL and to my eyes the NPL is much better, the view is much sharper and somehow seems cleaner if that makes sense. 
Overall, I would say, in the 8se the improvements with the SLV’s are, for us good not massive but subtle, and worth the money. 
As a bit of a side note, we also have a Star Travel 102 for wide-field viewing which I believe has a focal ratio of f5 and is generally considered as fast. With this scope the SLV’s work really well, a big improvement, I guess better corrected may be the term.

The NPL line are considered very well executed Plossl/symmetrical class eyepieces.  At f/10, it doesn't surprise me that they excel.  However, they have limited eye relief and a 50 degree-ish field of view.

Try the NPL in your achromat and see how it does at f/5.  It may still perform well in the center, but it may tend to go blurry toward the edges.  I don't know how well corrected they are in faster scopes.

The BST Starguider will hopefully continue to work well at f/5 thanks to its negative positive design that effectively slows down the light cone internally to the eyepiece, allowing it to perform better.  The SLVs employ a similar design, just better executed and at a higher price with a narrower field of view.

Pulling it all together, the Delos and Pentax XW lines are executed to levels as good or better than the SLVs while yielding wider fields of view with just as much eye relief and excellent performance in fast scopes.  The Morpheus are close to them, but come up short in a few focal lengths.

1 minute ago, banjaxed said:

I must remember NOT to go to a star party 😀

The corollary to this is that you must not look through premium telescopes with apertures significantly larger than your own scope(s) at star parties, or you will get aperture fever in short order, and that tends to drain ones wallet of all available funds.

16 minutes ago, John said:

You could probably just get to that 1st step on the red line, stay there, and enjoy the hobby just as much !

Up until you go to a star party and look through a premium eyepiece and get hooked on the view.

If you're hunting for planetary nebula with a low power, 2" eyepiece, having a well corrected field can help immensely in distinguishing tiny, fuzzy PNs at low power from merely bloated stars due to poor field correction.  Same goes for Uranus and Neptune.

My Mak is left side mounted on my alt-az, so the 3-way dovetail adapter allows the RACI to be pushed further left and lower by mounting it in the leftmost position, improving balance in altitude.  I can't remember in which order I have the QF and laser sight, but I really only need one or the other in general, so I generally mount one or the other, but not both.