Louis D

41 minutes ago, DaveL59 said:

A sound suggestion, thanks 🙂

I will eventually locate my old ones, can't recall the brand that was now but was fair at the time, tho the Nikon with ED glass would likely outclass it. If the experiment with the one I have works then I'd consider getting an 'upgrade'. I'm figuring some adhesive velcro tape on the back of the moving assembly would allow a small weight to be attached when needed to aid with balance.

Some gaffer's tape would probably work to affix the tele adapter in place since the imager housing is push-fit.

Given the long focal length of the taking lens, finding a wide angle adapter that might work will be difficult.  It would require what was referred to as a "zoom through" adapter that didn't lose much image quality as the lens was zoomed toward the telephoto end.  Even then, most fall apart at around 6x which would be about 260mm FL in 35mm equivalent.  The problem is that you're only using the central part of the adapter when zoomed in, and that is not the intended use case.  Generally, things get blurry with lots of chromatic aberrations.

4 hours ago, DaveL59 said:

Agree re lobbing a wide/tele, weight may be a factor, will have to locate the one I had and see if its even worth a try.

I have a bunch of fisheye, wide, and tele adapters from my videoing days.  A ~50mm rear threaded adapter is going to be a bit on the heavy side to cover such a large objective.  As such, a counterweight attached to the opposite side of the device would be necessary to avoid tracking issues.

As a suggestion, the old Nikon TC-E15ED has 50mm rear threads, quality ED glass (no added violet fringing that I've seen in high-res test images), and weighs 275g (9.6 oz).  It might be a good candidate to try.  They go for about $20 to $35 plus tax on ebay stateside, a bit more in the UK.  It's my goto telephoto lens for my Canon VIXIA HF M41 with the appropriate step ring.  I get better image quality with it by backing off the 10x zoom a bit to 6x or 8x and letting it bring me to ~10x without as much violet fringing as the native 10x.

I believe most of the rebranded refractors from China/Taiwan are all made by Long Perng, SharpStar, KUO, Synta, JOC, and maybe one or two others.  I say find the one with the features you like best at the price you like best and just enjoy your scope.

On 13/09/2023 at 15:11, RT65CB-SWL said:

Bear in mind @Nugs Meade was brought by Bresser. Instead of ‘spot the ball’ it’s going to be ‘spot the likeness’… https://www.bresser.de/en/Astronomy/Telescopes/BRESSER-Messier-MCX-127-GoTo-Telescope-EQ-AZ.html

Meade was bought by Ningbo-Sunny and then awarded to Orion USA as a result of an anti-trust lawsuit filed in US courts by Orion USA.  Synta (Celestron), another defendant, wisely settled with Orion for a mere $500,000 early on and kept control of the Celestron brand.  Sometimes it pays to settle for a nominal sum and admit no wrongdoing.

On 14/09/2023 at 11:30, sojourneyer said:

Meade is now owned by Orion and Explore Scientific is the exclusive distributor of Bresser products in the United States

Technically correct about Meade, but I just wanted to clarify that Orion never actually bought Meade, it simply owns it.

Luckily, with so few elements, the number of combinations to try to find the best correction isn't too vast.  Some combinations probably won't even allow the lenses to fit back into the holder with retaining rings.

On 13/09/2023 at 11:50, Mandy D said:

LEDs are monochromatic light sources. They do not produce broad band spectra, which is why we see the big spike at around 430 nm ( blue). To get white light from LEDs there are two common methods, one is tri-colour, with red, green and blue emitters which, when the light is mixed in the correct ratio, produces an approximation to white light. The second method, is the most common and certainly being used in street lights and most other "white" light sources. The blue photons carry high energy (remember E = hν, h is Planck's constant and ν is the frequency associated with the photon), which exceed the level needed to excite fluorescent materials which then release visible photons in a broader band which can be seen rising to the right of the main spike and then tails off at longer wavelengths. The fact that 430 nm LEDs are used, explains the high blue content in the spectrum of "white LEDs".

Thanks for pointing that out.  I was curious why there weren't spikes in the red and green parts of the spectrum if they were using three LEDs to get some semblance of white.  I knew the blue-violet spike was due to an LED, but could not understand the rest of the diagram.

A company named Seoul Semiconductor has an updated, broad spectrum white LED light for more natural (hopefully) indoor lighting.  It, in their words, "combines a purple (sic) emitter with a red, green, and blue (RGB) phosphor mix, as opposed to the conventional white LED that relies on a blue emitter and yellow phosphor."  I think they meant a violet emitter, not purple which would be a combination of red and blue light.  It probably got corrupted in the Korean to English translation.  Here's their comparison image.  Their new LED is in the upper right corner:

Used outdoors, this white LED would be even worse for the HB, OIII, and Swan emission bands than the typical B+YR white LED in the lower left corner.

On 14/09/2023 at 06:46, maw lod qan said:

These are now the trend with new installs over here. I'm also seeing a lot of parking lots retrofitted with them.

Anything that cuts down on the light shining outward has to help some,  but reflected light is still the problem.

What I see at 4am when I go to work is businesses with exterior lighting on the building itself around entrances and on the corners that are still terrible. The sky glow back West from where I live is mostly due to exterior lights on businesses that are closed at night.

Exactly.  I've got a car dealership, tollway interchange, and multiple shopping strip-malls that didn't exist 30 years ago when I moved out here.  They are lit up bright as day all night, reflecting light off of everything back into the sky.  Luckily, I'm within a few years of retiring.  I'll be moving to some truly dark skies when I do.

In my neck of the woods, my dull orange skies have turn bright gray as if there is a gibbous moon somewhere in the sky.  In fact, in the middle of the night, it almost seems like twilight.  I'm blaming much of that on overly bright LED lights reflecting off pavement.  It's so bright, some drivers forget to turn on their headlights at night.

Low pressure sodium (LPS) lamps are quite easy to filter out with just about any light pollution filter.  Not so with an LED lamp.  Just look at the spectrograph below to understand why:

That's why traditional light pollution filters will be rendered nearly obsolete in the very near future, if not today in many locales:

On 10/09/2023 at 04:08, Elp said:

It has been stated in Cuivs latest video that it doesn't operate in EQ mode and never will be updated to. Their reference was to using a bigger tripod.

Would it be possible to EQ mount it and then tell it you're at the north pole (for northern hemisphere users) to fool it into EQ mode?

16 hours ago, JeremyS said:

It is. Viewing, touching and smelling. Total sensory immersion 😊

16 hours ago, IB20 said:

I’ve often thought I’d like to collect a best of each range eyepiece set at each FL, if we are talking availability in the current eyepiece market.

Since the OP doesn't explicitly say new eyepiece market, I'll include readily available eyepieces in the used eyepiece market, since I have experience with several lines that are recently discontinued or partially discontinued.

For the Meade HD-60, I'd give the nod to the 6.5mm with the 9mm a close second best.  Both are very close in performance to premium eyepieces in my collection at similar focal lengths.

For the Starguider Dual ED (Paradigm), I liked the 12mm best despite not being great.  The 5mm and 8mm are technically better, but the ability to get sharp focus is a pain.  None rise to near premium levels, however.  Tight eye relief for eyeglass wearers is also a minus for the entire line except for the 25mm.

For the Nagler T4, the 22mm is easily the best of the three due to having the best behaved exit pupil (least SAEP) and longest eye relief.  Sharpness wise, the 17mm is very close, but the 22mm wins out.  The 12mm has severe EOFB sometimes extending almost to the center depending on conditions.  Other 12mm eyepieces didn't show this in side-by-side swaps.

For the ES-92, the 17mm is slightly sharper at edge than the 12mm and slightly contrastier across the field.  The exit pupil is also easier to hold in the 17mm due to have less SAEP than the 12mm.

For the 70 degree eyepieces known as Astro-Tech AF70, Omegon Redline SW, Celestron Ultima LX, etc., the 22mm is far and away the best, closely rivaling the 22mm NT4.  The 13mm and 17mm suffer from lateral chromatic aberration making them unusable for me.  I've also read that the 13mm has severe EOFB, but I haven't noticed it.  I haven't tried the 3.5mm, 5mm, and 8mm because I've read nothing but poor reports about them.

For the Morpheus, I can only compare the 9mm and 14mm.  Of those two, the 9mm is basically perfect center to edge while the 14mm has subtle field curvature and edge astigmatism.

For the Pentax XWs, I can only compare the 3.5mm, 7mm, and 40mm.  Of these three, the 3.5mm is basically perfect center to edge while I have issues with lateral chromatic aberration in the 7mm and field curvature and edge astigmatism in the 40mm.  If there was a 7mm Delos, I'd swap out the XW for it in a heartbeat.  I've considered the 6.5mm Morpheus, but I've read it is tight on usable eye relief relative to the 9mm and 14mm I have.

For the Pentax XLs, I can only compare the 5.2mm and 14mm.  Of those two, the 5.2mm is basically perfect center to edge while the 14mm has distinct field curvature, but is sharp to the edge once refocused.

Among the Aero/Lacerta ED, I can only compare the 35mm and 40mm.  Of those two, the 40mm is significantly better corrected center to edge.  It's almost the same correction-wise as the 40mm Pentax XW while being significantly lighter.  The 35mm ED is wider in AFOV, but has less usable eye relief, so these two ED eyepieces differ in more respects than just center to edge sharpness and contrast.

For the APM Hi-FW, the 12.5mm is the automatic winner because there is only one focal length in the line.  I really like it despite reports of EOFB that I have yet to notice.  It is what the 12mm NT4 should have been.

For the Delos, I only have the 10mm, but I have a hard time imagining any other focal length could improve on its sharpness and contrastiness.  Stars are pinpoint center to edge even without a coma corrector in my f/6 Dob.  I've swapped the CC in and out to confirm this.  Other eyepieces easily show the primary's coma without a CC while the Delos somehow does not.  I can't explain it.

For the Baader Scopos Extreme (Orion Stratus), I only have the 35mm, but it is very nearly perfectly corrected center to edge with exceptionally tight stars in the central 50%.  I've not been tempted to get the 30mm having read multiple reports putting it well behind the 35mm.  That, and I now have the 30mm APM UFF.

For the APM UFF, I can only compare the 24mm and 30mm.  Of those two, the 30mm is better corrected center to edge, but the 24mm is really the only game in town for long eye relief and maximum TFOV in a 1.25" 24mm eyepiece.  The 30mm is the sharpest 30mm eyepiece across the field that I've used, so I'd consider it best in class across eyepiece lines.

9 hours ago, M40 said:

Scatter - not sure what that is as it's the first solar image I have taken and it was a simple screen grab and crop from the phone with no stacking or processing.

Stray light lightening what should be a more or less black background.  It's that orange glow around the sun in your image.

9 hours ago, M40 said:

Certainly cloudy when I took the picture.

Aha!  It was clouds scattering sunlight.  That would explain it.

Here's an image I snapped of the sun through my RACI finderscope with a front solar filter on a partly cloudy day.  Sunlight scatter is pretty obvious throughout the frame.

3 hours ago, JeremyS said:

C’mon Louis. You’re not even trying 

🤣

I'm really slacking off at 10mm and especially 11mm (none). 😊

57 minutes ago, MalcolmM said:

I wish I knew! It just sorta happened! I realise it's both daft and decadent! And now I have them I'm really reluctant to get rid of any of them as I've read so many posts from people selling eyepieces and then immediately regretting it! I do like the option of using different eyepieces as they give very different viewing experiences and some suit some scopes better than others. The Masuyamas are mostly used in the Mewlon for example. 

I'm trying desperately hard not to buy any more but the new TLPs and the Masuyama orthos are proving hard to resist 🙂

Malcolm 

If you don't need the money from the sale of eyepieces, have the space to store them, and enjoy comparing them once in a while; then by all means keep them all with a clear conscience.  Do what's right for you.

Here's my 9mm to 10mm collection.  Curiously, I only have one 10mm eyepiece. 

Just above that at 12mm to 12.5mm is where the pile-up occurs in my eyepiece collection:

Clearly, some are very specialized eyepieces at this focal length.

A couple of quick questions:

• What is the pixel resolution on each axis of the imaging chip?
• Any idea what's going on with all of the scatter in the solar image?
  • Do you think it is due to the solar filter, objective, or lack of internal stray light control?

2 hours ago, Don Pensack said:

I used to use those, too, until I left one in my car on a hot day and the plastic melted against my filters and ruined a dozen filters.

The lesson to be learned is to not leave them in a hot car, I guess.

Sounds like what happened to my boxes of crayons left in the car on summer family road-trips when I was still into coloring books.

Thankfully, since I observe from around my house, melting filter wallets hasn't been an issue for me, but I see your point.

2 hours ago, John said:

That is why I no longer own SCT's, MCT's or Mak-Newtonians.

To do my comparison I would need to borrow one 🙂

If you were nearby here in Texas, I'd definitely let you borrow my 127 Mak for as long as you wanted.  I can't remember exactly when the last time was that I used it.  It was probably when I took some recent SAEP/CAEP images through some new to me eyepieces.  Its slow f-ratio really brings out the worst in eyepieces relative to SAEP/CAEP.

Yep, there even appears to be a cross-section of the optical section labelled Barlow Element that might help with the original question:

I use photographic filter wallets to hold my filters.  Typically I can fit two to four 1.25" filters or two 2" filters into a single pocket, depending on how big the filters were it was originally intended to hold.

14 hours ago, John said:

I'd love to put a Skywatcher mak 127mm alongside my ED120 refractor and (carefully) compare the views.

I think the result would be very close on deep sky objects. On double stars, the moon and planets, I suspect things might swing in favour of the refractor but only very slightly.

If I did the same comparison using my ED102 refractor I think the mak 127 would show a clearer advantage on DSO's and would possibly beat the 102 refractor on the higher resolution targets as well.

If you're just popping out for 10 or 15 minutes to grab a quick peek at a planet, the 127 Mak is a terrible choice.  It shows all sorts of chromatic aberrations at high power on bright objects while trying to cool down.  By comparison, I see no such issues with a similarly sized Newtonian.  My 90mm triplet shows spikes around bright objects while trying to cool down, so also not a good quick peek choice.  My 72ED doublet is pretty much ready to go immediately, though.

It really depends on your intended use case which telescope will provide the best images.

On 05/09/2023 at 16:45, DaveL59 said:

I'm sure the grandkids would be bored after 10 mins on the same target too lol.

That's kind of what I observed at a recent public star party where the unwashed masses stood around for a few minutes watching a nebula's image grow brighter and more detailed on a large monitor in a similar setup, but with a 10" reflector.  However, well before 10 minutes had passed, they had moved on to see what other scopes were aimed at.  Perhaps if it were the only scope available, they'd have stuck around.

Also, the shorter the Barlow tube (shorter focal length) or the longer the diagonal's optical path length (2" diagonal is longer than 1.25" diagonal), the larger the multiplier effect of putting the Barlow before the diagonal will be.  Looking at the above equation, it should be obvious why these two points are true.

Here's the only diagram I know of for a 3 element Barlow:

As far as dust and dirt, random specs of dust have practically no effect, so leave them be.  A deposited film of atmospheric grime can lead to decreased contrast.  Scratches near the center can be very detrimental, but there's really nothing you can do about them.  Simply moving a bright object like a star around the field until the spiking disappears or is minimized can mitigate the effects.  Microscratches across an entire lens from overzealous cleaning can also decrease contrast by scattering light.  Again, nothing can be done about them.

How about a view showing how you attached it?  I'm curious.