Louis D

If you're not short of cash or storage space, go ahead and hold onto that ED80 and FF/R for a bit. I'm a bit of a hoarder myself (don't ask). However, it saved me this weekend. My upgraded receiver for my stereo system suddenly died (went into protection mode), so I swapped in my old one that I was getting ready to sell. It turns out, it works well enough to hold me over until I can figure out my next step to replace or repair the upgrade one. I'm not saying your new triplet APO is going to "die" at some point, but something else could happen to it (dropped, stolen, fungus, etc.).

My two OIIIs are both narrow enough to not cover both sets of lines, thus I found myself having to swap between them based on the object. Stacked, they pass barely any light and view darkly on all objects. At least I finally found a good use for my decade old Zhumell OIII filter. It was never very good for its intended purpose. It was only once I saw where its passband fell in my spectrograph imagery that I had my aha moment it might make for a good C2 line filter. Last night I confirmed it. I don't know if I'd pay $100+ for a Lumicon Comet filter just to get the views I was getting last night of Comet C/2022 E3 (ZTF), but if Svbony would market one for under $40, I'd probably recommend it. They could add it to their UHC, CLS, and M&SG filter package. I have no idea if their OIII filter is any good. Hopefully it is on-band like my Lumicon and not off-band like my Zhumell. Basically, any OIII rejects that have a too far right passband could find a new home this way.

I bought a 127 Mak for my grown daughter to use on camping trips with her family. It's rugged and compact. I have one myself, but for home use I tend to use my 8" Dob for planetary viewing. Another option not mentioned so far would be a GSO/StellaLyra/TS Optics Classical Cassegrain, either 6" or 8". The late, great @johninderby really liked his 6" and 8" CCs and talked about them often on SGL.

Tonight, I was viewing Comet C/2022 E3 (ZTF) with the Svbony 3-8mm zoom getting good views in my GSO 6" f/5 Newt under Bortle 6/7 skies before the full moon overwhelmed my skies. My Speers-Waler 5-8mm zoom was also showing it well. However, when I swung the scope over to nearby Capella, I noticed that the Svbony seems to show more scatter around this bright star than the S-W zoom. I'll have to investigate this further on other nights with other objects. I don't recall scatter being a big issue with Jupiter in my earlier testing. If anyone else has seen increased scatter in the Svbony compared to other eyepieces (zoom or not) on bright objects, please post your observations on here. I was alerted in a PM that there is also the possibility of it viewing slightly darker than other same focal length eyepieces, like the Vixen LV eyepieces of the 90s. I think I may have seen this effect, but it is subtle if it exists. I definitely think the Orion Nebula showed up better in the Svbony than in the S-W zoom possibly because of this background sky darkening effect. Again, post on here if you're seeing the Svbony zoom viewing darker than other eyepieces at the same focal length(s).

I verified tonight that my old Zhumell OIII does indeed work quite well as comet filter when viewing Comet C/2022 E3 (ZTF) tonight in my GSO 6" f/5 Newt under Bortle 6/7 skies. I was able to see the greatest extend of its coma with this filter in place. The Lumicon OIII just made things worse by blocking the comet's light, so it's definitely the right shifted nature of the Zhumell bassband working to let through the C lines. Too bad they aren't sold anymore. I wonder if any currently available cheap OIII filters have this same off-OIII band performance. I'm glad I kept it around. The Svbony UHC was second best, helping to increase the amount of coma visible by blocking light pollution. The Zhumell Urban Sky (Moon & Skyglow) filter helped a tiny bit, but not enough to want to go back to it a second or third time. On the Orion Nebula, the Lumicon OIII was best with the Svbony UHC very close behind by also passing the H-Beta line. The UHC provided a more pleasing view by showing stars better. The Zhumell OIII made it somewhat more difficult to see the nebula because I think it is passing only one of the two OIII lines, and then just barely. All of this was done early before the full moon completely washed out my skies.

I tried out several filters on the Orion Nebula (M42) tonight in my 6" f/5 GSO Newt under my Bortle 6/7 skies before the full moon overwhelmed everything, and the Svbony UHC struck the best balance between seeing stars and nebula and seeing only nebula. The Lumicon OIII did a slightly better job at improving contrast by making the sky background even darker without attenuating the nebula significantly (by blocking H-beta). My Zhumell Urban Sky (Moon & Sky Glow) filter didn't do much to block light pollution. Maybe a bit, but not enough to want to continue to use it. Based on that, I would recommend the Svbony UHC for certain as a light pollution filter when viewing nebula. The Svbony CLS is going to pass a bit more blue and red while still blocking all green/yellow/orange (where the majority of light pollution resides), so it should perform similarly. For galaxies, which emit broadband light similar to LED lighting, dark skies are the only real answer. You can try a UHC/CLS filter on them, but don't expect miracles.

Are your local streetlights low pressure sodium (yellow-orange) or LED (broadband white)? The former can be effectively filtered while the latter cannot.

As for which to choose, I went twice with the Synta 127 Maks because I used to be able to pick them up used for $200 shipped off of CN classifieds here in the US. Now, they tend to fetch $300 to $350 which is still quite a bit cheaper than new, if you can find one in stock. The ES/Bresser 127 Maks never come up used here in the states, and I'm not about to start buying new now at today's inflated prices and 25% special tariff.

In the case of a Mak, objective diameter refers to the front corrector plate, not the primary mirror diameter, so FLO got it right.

Thanks for the effort. It is appreciated.

Here's the Datyson Moon & Skyglow from ebay for under 3 GBP. How wrong can you go for that money?

Howdy from Texas.

I've always meant to ask, how long do you spend each year updating it?

Option one would be a generic Moon & Sky Glow (Urban Sky) filter which are pretty close to the same as the BN at a fraction of the price. This will cut yellow and orange completely and dim some green. Option two would be a Svbony CLS filter. It completely cuts all light from green to orange leaving only blue and red. It's like using a hammer to drive a tack, though. Option three would be a Svbony UHC filter. It's a bit narrower in the blue and red parts of the spectrum increasing contrast on nebula even further than the CLS. Take a look at this post of mine about LP filters from a couple of months ago. Here's some various filter spectral images from Star Hunter and myself to see what gets cut and what remains.

The Baader Scopos Extreme 35mm is quite sharp at f/6 edge to edge, and sublimely sharp in the inner 50%. It has tighter stars there than many of my premium wide fields. The downside to it is how big and heavy it is. Weight wise, it slots between my 12mm and 17mm ES92s. As such, I don't need to rebalance my scope when switching among these three eyepieces.

Here is Jon Isaacs's mini-review of it on CN. He is an incredibly experienced observer, so I trust his take on it. I have the 35mm Aero ED, and it is sharp at f/6 out to 75% of the field. At f/8, either eyepiece would probably perform quite well.

Adding the CLS filter all the time could be very detrimental for planetary viewing where light pollution doesn't matter much at all, but the cut out wavelengths (green through orange) could have conveyed a lot of detail.

For starters, try reading this CN thread on Kitakaru eyepieces from other retailers in the past. That's about all I know of them.

The problem with these budget scopes isn't so much the objectives, which can be quite good, it's the rest of the system. They may have plastic focusers, plastic body diagonals, internal aperture stops, and wobbly mounts. I would contact and work with Tejraj & Co. which is sort of the FLO of India. They are a long standing, legitimate Indian astronomy retailer who should be able to answer your questions and find something within your budget. If you need help post-sale, they'll be there to help. Look at their house brand Star Tracker telescopes. There are several sub-15,000INR options available. It's best to support these dedicated astronomy retailers because they have been disappearing around the globe over the last 20 years with few replacements.

No stacking is possible unless you pair it in front of a thicker filter with front female threads. Don't remove the retaining ring unless you do it indoors over a cushioned surface in case the filter material drops out. There's no guarantee that the revealed female threads are even 1.25" filter compatible. If they are, and the stacked filter has long enough male threads to securely hold the filter material in place, you might get away with a fixed stack that night. I would be hesitant to swap the stacked filter in the field in the dark for fear of losing the back filter material. As a workaround, try attaching one to the filter threads of the eyepiece and hold the other between your eye and the eyepiece to quickly try different stacks to see which might be worth pursuing via other brands for one of the two filters. Another option would be to put one filter on the front of the diagonal and one on the eyepiece if not using a Newtonian telescope. On the plus side, they're lower profile, so they may fit in some filter wheels better. They are also cheap relative to GSO made filters which do have front and rear threads. These Svbony filters are also way cheaper than Baader, Lumicon, and Brandon color filters.

Give them a try. What's the harm? Worst case you confirm your impression of them.

Lightweight zooms are very handy I've found to avoid swapping two eyepieces while making sure neither is tipped in the holders. It makes for a more relaxing viewing experience.

How about a beauty shot of all of them out of their boxes. For all we know, you bought a bunch of empty boxes. 😄

Ask yourself where do you find yourself lacking in focal length options? Also ask yourself where you'd like a wider apparent (and true) field of view at a particular focal length. You're already pretty well covered for monoviewing. I'm not sure what eyepiece pairs and GPC/OCA/Barlow elements you're using with your binoviewer.

I've had my ST80 since about 2000. Since it was such a poor performer relative to my Dobs, I was very dismissive of it and relegated it to travel use as a spotting scope or white light solar scope (as during the 2017 eclipse). I tried that Minus Violet filter shown in my post above and found it did so little to cut stray violet light that I abandoned experimenting with filters to improve the image in the ST80. Now I've circled back to see if the right filters with just the right cutoff characteristics could make these achromats more palatable to reflector folks like myself. @RatletI predict that someday in the next 5 years you'll pop for a 70mm to 100m ED or APO scope of some sort. The difference in performance as compared to a similar f-ratio achromat is astounding. My FPL-51 doublet AT72ED started me down this road around 2013. In 2019, I upped my game and got a TS-Optics 90mm FPL-53 triplet APO after realizing what features mattered most to me. Both are a lot of fun to use and hold their own against larger reflectors or compound scopes. The best part? No filtering is needed for clean, sharp images.