Meade Infinity 102

[Ray of LIght]

18 hours ago, Mak the Night said:

You're welcome Ray. I hope you have some good weather for tonight. It's been raining all day here. You must be near some pretty tall trees to obscure Polaris lol!

Got first light last night! Jupiter and moon, moon was great using Omni 9mm eyepiece. I was a able to align the Rigel Quickfinder using both objects and Arcturas. Seems to work really good. My only disappointment was the view of jupiter which was showing false color and hard to focus. I understand that the 600mm refractor is not the best for planertary viewing so I am considering a 5mm TMB II clone or an X-Cel 5mm (i believe). In other words an Orion Expanse or Edge On type wide field planrtary eyepiece. Do you think these types of eyepieces might help my situation? Btw, the waxing moon was so bright it washed out a lot of other objects I could have tried to find. Plus, as a rank beginner using a new telescope for the first time I guess I did ok ?. The TeleVue 25mm was a pleasure to use and works great. There is a lot of light pollution in the front side if my house so I need to work on trying to alleviate that. The cheapo LPR didnt help much under the conditions. May need to invest in a better filter. Any advice would be welcome!✨

[Ray of LIght]

Almost forgot to mention that I bought an Omni 4mm plossl, but in hindsight, because of the minimal eye relief, that was probably a mistake. At least it wasnt an expensive mistake! I will try it out but not holding out too much hope it will help with planets. 

[Mak the Night]

2 hours ago, Ray1103 said:

Got first light last night! Jupiter and moon, moon was great using Omni 9mm eyepiece. I was a able to align the Rigel Quickfinder using both objects and Arcturas. Seems to work really good. My only disappointment was the view of jupiter which was showing false color and hard to focus. I understand that the 600mm refractor is not the best for planertary viewing so I am considering a 5mm TMB II clone or an X-Cel 5mm (i believe). In other words an Orion Expanse or Edge On type wide field planrtary eyepiece. Do you think these types of eyepieces might help my situation? Btw, the waxing moon was so bright it washed out a lot of other objects I could have tried to find. Plus, as a rank beginner using a new telescope for the first time I guess I did ok ?. The TeleVue 25mm was a pleasure to use and works great. There is a lot of light pollution in the front side if my house so I need to work on trying to alleviate that. The cheapo LPR didnt help much under the conditions. May need to invest in a better filter. Any advice would be welcome!✨

I'm glad you got a good session in! Too bloody cloudy here lol. The Moon can look really good at magnifications between 50x & 100x. I can get 66.6x on my 90mm Mak with a 15mm EP. In fact, I got first light on my Antares 15mm (Masuyama clone) not so long ago with the Moon. You should have got some good Terminator shadows on a descending waxing gibbous Moon (shown below in the Virtual Moon Atlas at Transit 20:40 BST, 50.2° in Cancer). Especially around the Montes Appenninus and around the Sinus Medii regions.

I'm not surprised the Moon washed out other objects.

Jupiter is notoriously difficult to observe and is often best viewed in twilight conditions. My guess is that its high albedo (intrinsic reflectivity) combined with atmospheric turbulence is a strong factor in why it can often get 'woolly' or fuzzy sometimes. I often use a neodymium filter, a binoviewer and orthoscopic eyepieces to observe Jupiter. It can demand patience and long observation periods to tease out detail.

It's been a long time since I've used an achromatic refractor. You might consider something like the Baader Fringe Killer or Semi Apo Filter for blue/cyan fringing.

https://www.firstlightoptics.com/achromat-semi-apo-filters/baader-fringe-killer-filter.html

https://www.firstlightoptics.com/achromat-semi-apo-filters/baader-semi-apo-filter.html

Oddly, I was discussing 4mm EP's not so long ago. The smallest I've ever used are 6mm Celestron Plossls and this Hutech 6mm ortho'. I only really use the Hutech on my 90mm scope and it gives me 166.6x! I think you would be better off investing in a good quality 3x or 5x Barlow for high power lunar/planetary magnifications. I'd aim for about a minimum planetary magnification of around 130x - 150x, bearing in mind, on some nights I struggle with 100x with Jupiter and I live in a small village in the greenbelt at a fairly high altitude above sea level (so light pollution isn't a huge issue for me). I nearly bought a bino pair of the TS Optics equivalent of the Orion Expanse. I'm pretty convinced they're rebadged Barsta EP's. Instead I went for a pair of 9mm WO SWAN's. Which turned out to be a bit of a disappointment. I think a wide angle EP would help with keeping an object on axis at high magnification. I find anything wide angle is easier to manually track planetary objects at high magnifications. I'm not sure what to recommend though. 

[Ray of LIght]

I bought the TMB II 4mm planetary eyepiece out of hope that it will help. Your advice is sound and wise as usual. Hopefully my views will be clearer (no such word I guess), and I can Barlow an Omni plossl with a decent eye relief if I have to. Im really hoping the planetary eyepiece works. A couple of questions: when you say "on axis"' what are you referring to? The other is that I would really like to send you some pictures but I am not sure how that is accomplished via the forum. Stupid questions but trying to learn ?! Thanks again for all you have done for me!

[Mak the Night]

3 hours ago, Ray1103 said:

I bought the TMB II 4mm planetary eyepiece out of hope that it will help. Your advice is sound and wise as usual. Hopefully my views will be clearer (no such word I guess), and I can Barlow an Omni plossl with a decent eye relief if I have to. Im really hoping the planetary eyepiece works. A couple of questions: when you say "on axis"' what are you referring to? The other is that I would really like to send you some pictures but I am not sure how that is accomplished via the forum. Stupid questions but trying to learn ?! Thanks again for all you have done for me!

The TMB looks pretty capable, although I've never used one. It could be that 150x was pushing it a bit for Jupiter on the night you were observing it. I rarely get a decent image of Jupiter at 150x with a 4" scope. It was sometimes difficult enough with a 130mm scope. Oddly, surface detail on Jupiter can often be more easily seen when it's in the vicinity of the Moon.

http://www.scopesnskies.com/prod/TMB/4mm-planetary.html

I always thought 'on axis' referred to the procession of stars and/or objects as they pass across the eyepiece field of view. On an undriven scope RA will make objects appear to move across the field of view in the eyepiece (both sidereal and plane of the ecliptic). A motorised scope should track the object's apparent motion, traditionally this was achieved with one clockdrive and utilising Equatorial mounts (aka German mount). In the first, undriven instance, an object on-axis will move into the field of view and through the centre of the eyepiece field stop circular view and eventually move out of sight. In the second instance the viewed object should stay in the centre of the eyepiece view and anything away from the exact centre of what can be seen is considered 'off-axis'. Due to the peculiarities of particular eyepieces, and depending on their design and intrinsic quality, they can sometimes show less defined or distorted views (pin cushioning or colour distortion) as you view off-axis. This is more noticeable observing  objects such as some asterisms or globular clusters (like M44 & M45) that can more or less fill the field of view.

https://en.wikipedia.org/wiki/Distortion_(optics)

You should be able to upload pictures in the forum from file and drag and dropping them or clicking the Choose Files link. Which should open your file manager directly to folder and then you just double click on the selected picture to upload the file.

[Ray of LIght]

1 hour ago, Mak the Night said:

The TMB looks pretty capable, although I've never used one. It could be that 150x was pushing it a bit for Jupiter on the night you were observing it. I rarely get a decent image of Jupiter at 150x with a 4" scope. It was sometimes difficult enough with a 130mm scope. Oddly, surface detail on Jupiter can often be more easily seen when it's in the vicinity of the Moon.

http://www.scopesnskies.com/prod/TMB/4mm-planetary.html

I always thought 'on axis' referred to the procession of stars and/or objects as they pass across the eyepiece field of view. On an undriven scope RA will make objects appear to move across the field of view in the eyepiece (both sidereal and plane of the ecliptic). A motorised scope should track the object's apparent motion, traditionally this was achieved with one clockdrive and utilising Equatorial mounts (aka German mount). In the first, undriven instance, an object on-axis will move into the field of view and through the centre of the eyepiece field stop circular view and eventually move out of sight. In the second instance the viewed object should stay in the centre of the eyepiece view and anything away from the exact centre of what can be seen is considered 'off-axis'. Due to the peculiarities of particular eyepieces, and depending on their design and intrinsic quality, they can sometimes show less defined or distorted views (pin cushioning or colour distortion) as you view off-axis. This is more noticeable observing  objects such as some asterisms or globular clusters (like M44 & M45) that can more or less fill the field of view.

https://en.wikipedia.org/wiki/Distortion_(optics)

You should be able to upload pictures in the forum from file and drag and dropping them or clicking the Choose Files link. Which should open your file manager directly to folder and then you just double click on the selected picture to upload the file.

Oh man, looks like I'll be eating meow mix with you Mak ?! The Baader Fringe Killer looks like just what the doctor ordered. It might just work well with the planetary eyepiece too. Btw, thanks for all the info, I never heard of that filter before and it's great that it is geared toward fast achromats like mine. As far as the pictures, I usually use my iphone when I go on the forum but if I want to send pictures I will have to use my PC. I read that some people thread the fringe killer to the diagonal and keep it there. Would be more convenient that way. Will keep you posted on my progress with obtaining the filter. I'm assuming that other filters could be threaded onto the eyepieces as needed. I am going to be shopping around for prices; so far I have seen them for 78.00 US. Let me know what you think and thanks so much Mak! 

[Mak the Night]

52 minutes ago, Ray1103 said:

Oh man, looks like I'll be eating meow mix with you Mak ?! The Baader Fringe Killer looks like just what the doctor ordered. It might just work well with the planetary eyepiece too. Btw, thanks for all the info, I never heard of that filter before and it's great that it is geared toward fast achromats like mine. As far as the pictures, I usually use my iphone when I go on the forum but if I want to send pictures I will have to use my PC. I read that some people thread the fringe killer to the diagonal and keep it there. Would be more convenient that way. Will keep you posted on my progress with obtaining the filter. I'm assuming that other filters could be threaded onto the eyepieces as needed. I am going to be shopping around for prices; so far I have seen them for 78.00 US. Let me know what you think and thanks so much Mak! 

Yeah, cat food's not so bad after a while lol. I have an Antares Amici prism (90°) diagonal with a comparatively short nosepiece that I often use with my binoviewer. I can actually stack a couple of filters onto it without them poking too far into the OTA and colliding with the primary.

It's solidly built even though the body is a dense resin rather than metal, the bottom base plate is actually metal though, as are the nosepiece and EP holder. It's surprisingly good for 35 quid. I don't trust heavier diagonals plus the weight of the bino yet.

I got first light with the 30mm Vixen NPL on the Moon earlier, although I bumped up the magnification later on my 90mm Mak. The Moon looked quite stunning from 33.3x right to 166.6x! Can't say the same for Jupiter though. I went out again later to get a butcher's hook at Saturn and Mars. Both are around 16-17° at Transit (higher than Antares). There couldn't have been 5° between them. I got some nice views of Saturn last year with my 102mm Mak and 130mm Newtonian in late May through June before it seemed to deteriorate slightly. The real shock was how good that Vixen is, even at 33.3x I could quite plainly see Saturn's rings. It seems to have bright, clear and sharp optics. Highest I really went on Saturn was 66.6x. I think I'll have to wait a few weeks before it gets better. Mars is looking bright and very red.

[Ray of LIght]

More good info Mak, thanks! I guess will be a good idea to park the fringe killer in my diagonal. Just cant wait to get it! I think my best time to observe Mars and Saturn will be in May, as you said. Hopefully will be able to get the fringe killer soon, read some great things about it. Will keep you updated on my progress. Thanks again for all the pictures, diagrams and links, I look/use them all ?!

[Mak the Night]

I think Saturn will be a couple of degrees lower at Transit than last year, Mars won't be much better. At a low angle you are looking through a lot of atmosphere, luckily after a couple of streets it's mostly farmland to my south and west so at least it limits light pollution. I can often see M4 (about two and a half Full Moons distance to the west of Antares) with the naked eye in the summer. It's a nice globular and easily seen with a smallish aperture scope. If M4 is readily apparent to the naked eye for me, I know the transparency and general seeing will be good for Saturn (and Mars of course).

I think if you keep the diagonal parked in the scope with the filter threaded into it, it should be relatively fine. In my experience though, filters seem to be dust and debris magnets and I tend to keep my filters in boxes or sealed containers when not in use. It's not like many decent filters are cheap these days either, my two Baader filters together cost more than my first scope and my TV Planetary Bandmate cost more than most of my individual eyepieces did.

Baader make a cleaning fluid for eyepieces which can also be used on some filters. Baader claim that many of their filters are virtually indestructible, but I don't believe them. I don't think you can be too fastidious about cleaning expensive kit. Or maybe it's just me lol.

A rocket blower works really well for shifting dust etc.

 

[Ray of LIght]

I don't have a blower, I will order it now. I do have a lens pen, but I may have read to not use them on filters, except for the brush? I will google the cleaning solution and check it out. Whats your opinion of the lens pen? I suppose if I leave the fringe killer on my diagonal I can always inspect it before I do an observing session to see if it needs a cleaning. Or I can just put it on every time. Still more convenent than putting it on when swapping eyepieces i guess. I was also checking out the semi apo filter but my gut is that the fringe killer may be the better fit for my set up. Hope to talk soon! Questions, questions ?

[Mak the Night]

A blower is very useful I find, as brushes can leave tiny hairs behind, although the brushes are still useful in themselves. I don't recall reading that Lenspens shouldn't be used on filters, but I personally don't use a Lenspen on filters usually. I think Lenspens are alright if used carefully as they can remove smudge marks left after cleaning and drying with cleaning fluid and a microfibre cloth. I have a couple of the Celestron Lenspens, which are licence made from the original distributor/manufacturer.

It does the job.

One caveat though, not all 'lenspens' are equal and the first one I used was from this (now discontinued) TS Optics kit.

The fluid, the cloth and the blower are all perfectly fine. The knock-off TS Optics lens pen isn't so fine and the felt pad soon came off the reversible cleaning end. I have three of the Baader cloths as they are kept in my eyepiece cases. I occasionally soak them in warm water and then dry them out. I don't use any cleaning agent so as to not introduce anything that could potentially damage optical glass.

At the stage this jpeg was taken the pad was still attached to the triangular end.

I didn't even use it a lot, and luckily it didn't detach while I was cleaning anything expensive. I believe it was this one: http://www.teleskop-express.de/shop/product_info.php/info/p81_TS-CleanPen---Reinigungsstift-und-Pinsel---3-Reinigungsmoeglichkeite.html

If the diagonal is left in the OTA you might get away with leaving it threaded on. It's just that in my experience, filters seem to attract dust, grease and fingerprints with an inexplicable rapidity lol.

[Mak the Night]

Got a decent view of the Moon and Jupiter a bit earlier (90mm Mak), both past Transit. I got up to 100x on Jupiter (Baader 10mm Eudiascopic) and the EZ, NEB and SEB were pretty easily discernible. I could also make out Io and Europa. Jupiter was at azimuth 7.6° and 45° altitude in Leo. Mare Imbrium was bright and clear, Plato very distinct, nice Terminator shadows to the west of Clavius.

[Ray of LIght]

More great info Mak. I believe I have the original lenspen so should be ok, I will just use it carefully. I ordered the blower, tried to get one as close as possible to the one in your picture. Would like to order the Baader Fringe Killer this week or next so in the meantime I am still researching similar MV and skyglow filters. Right now still feel the fringe killer is the one. It's kind of expensive so i really don't want to buy two or three redundant or almost redundant filters. Will definitely have it for Saturn and Mars, hopefully will help me get somewhat better views. Speaking of diagonals, awhile ago I bought an Astromania 90 degree diagonal for my 70mm and it is pretty nice but is left/right reversed. The stock Amici type diagonal on my Meade 102 is more comfortable to use for me right now. Whats your take? Maybe I should give it a try once my experience level goes up a bit. So, the TMB II planetary 4mm eyepiece should be coming in a few days so trying to acquire some decent eyepieces and filters (no more cheapos!), which may or may not help my fringing and CA problems with bright objects but since there is no way I can afford an APO refractor, I have to do the best with what I have ?. Hopefully talk soon! Thanks for all!

 

 

[Mak the Night]

Oddly, I've just ordered an original Lenspen and rocket blower lol. I don't know much about the Burgess/TMB eyepieces and their clones, apart from the controversy of course. As I've never used one it's difficult for me to be objective. I've attached an old PDF from the Cloudy Nights forum with some information you may find interesting. I have a variety of diagonals, virtually all of them are prisms, some are Amici prisms. I tend to use Amici prism diagonals for lunar/planetary viewing and I have good quality Williams Optics and Omegon ones. With Mak/SCT's it's rare to see any reflections from the roof of the prism, but I believe that they are more perceptible in refractors. I know the die hards and purists intensely dislike Amici prisms, and I think this is a throwback to when there were not really any decent astronomical Amici prisms readily available. I certainly have no qualms about using them myself. I have an Orion Amici prism diagonal (I'm pretty convinced it is a rebadged Guan Shen Optical) and it has a decent sized prism, yet is quite light compared to my other diagonals and I use it almost exclusively with my 90mm Mak because of this. I find it works perfectly well. At the end of the day, much of it boils down to personal preference. I've directly compared some of my Amici prism diagonals with normal prism diagonals (including a Celestron diagonal) and I actually can't see any difference. If anything the Omegon Amici prism actually seemed to give a brighter image, although it did feature a bigger prism.

This may be of interest: http://www.telescope.com/Articles/Equipment/The-Advantages-of-Observing-with-Correct-Image-Diagonal/c/9/sc/192/p/106656.uts

Burgesstmb.pdf

[Ray of LIght]

I agree, even my stock Amici prism seems ok. May upgrade one day. The Baader Fringe Killer is arriving Thursday. I am not expecting miracles but i should see some improvement, I hope ?! The TMB 4mm is arriving Saturday. I will let you know if my planet observations get any better. Hoping to get the scope out tonight or tomorrow night. Of course won't have new equipment yet ?. Got the blower already so I should be ok for light cleaning. I will check out the links you sent. After doing some research it looks like the TMB eyepiece I bought, while not the Thomas Back original, may be the closest I am going to get to it. Will let you know how it performs. At 150x I shouldn't really be overdriving my telescope. Shouldn't 200x be about max? I guess if you go by 50x per inch of aperture, which I will probably never attain where I live! So, again, I am learning a lot from you and I look forward to our conversations!

[Mak the Night]

I see different figures for maximum magnifications with a 102mm aperture. TeleVue claim 60x per inch with good optics (under 6"). If you transliterate (lol) the Imperial measurement of 4" directly into its Metric equivalent and use this rule it can give 241x as an absolute resolution limit. However, even if you assume perfect seeing conditions you have to take the exit pupil on any specific scope into account. Which means my f/12.7 102mm Mak can only realistically reach 208x for an exit pupil of around 0.5mm. I can reach this with an eyepiece of 6.25mm focal length (usually a 2x Barlow combined with a 12.5mm bino pair of AH orthoscopics seen bottom left below). Although, in most normal conditions with a 102mm, I would aim for around 130x - 170x as a general high planetary magnification.

If my calculations are correct a 4mm eyepiece should give you 150x for a 0.68mm exit pupil. So anything between 208x - 216x could be possible as an absolute maximum I suppose. To be honest though, apart from the Moon, 130x-170x is more realistic. I've had Saturn up to 260x with my 102mm Mak, although it was a much darker and grainy image. I also regularly use my 16mm T5 Nagler and 2.5x Powermate to get 203x with my 102mm Mak on the Moon.

[Ray of LIght]

More magnification for my scope than I thought, but I would be happy with 150x right about now! Thats a nice case in the picture you sent, they are pretty pricey I think. My son bought me an Op-Tech soft case, its good for now since I dont go too far with my kit. I have two sizes, the small one is real small but good to just grab. I suppose I have collected a lot of stuff in a short time, some of it not great but some, as you know, is pretty good. I suppose we learn from our mistakes. I consider them spares, lol ?! Anyway, still waiting for stuff and will keep you updated. Too bad I cant see Mercury from where I live, will you be able to view? Thanks again for all!

[Mak the Night]

A lot of it comes down to conditions. I got to observe Jupiter and the Moon last night before and after Transit. Both seemed to improve after the lunar Transit (23:37). The Moon was Waxing Gibbous at 35.8° in Leo at a distance of 405, 326 km.  The transparency just wasn't good enough to get above 100x, although I did get that on Jupiter for a while. Mostly I was around 55.5x - 66.6x. I even went down to 33.3x and 40x at times. Europa and Io were close together on Jupiter's east and Ganymede was also visible further off the west. Aristarchus was very bright on the Moon, although Herodotus was still visible and the whole Schroter's Valley region was very well defined up to around 66.6x. Admittedly I was using the 90mm Mak but I doubt the 102mm would have made a huge difference because of the overall conditions.

The bino case in the picture is a Geoptik and cost me about 50 quid I think. It has no provision for a carrying strap so I loop a Geoptik strap around the handle to carry it. It's a necessity for me as my right arm is partially paralysed and I have to carry things outside piecemeal so to speak.

http://www.geoptik.com/index.php?route=product/product&filter_name=valigia&product_id=898

The Speers-Waler didn't pan out so I've obtained an 18.2mm TV DeLite (on the extreme left of the case below) which I can Barlow to 9.1mm, instead. My initial daylight testing of the DeLite was very impressive and it has orthoscopic - like qualities. I can't wait to point it at Mars (or anything) in a big SCT.

http://www.televue.com/engine/TV3b_page.asp?id=238&Tab=EP_EDE-18.2

I should be able to see the Mercury Transit, although I don't usually solar view. Mercury Transits aren't that exciting IMO lol.

[Ray of LIght]

Glad to hear that about Mercury, lol! I want to run something by you: I have a couple of not so good Barlows, I have been looking at the High Point Scientific 2.5x Barlow. I doubt I can afford the TV Barlow and I probably don't really need it. I would rather put the money into another TV eyepiece. Anyway, the HPS Barlow is getting great reviews and looks finely made. Seems to be a re-badged GSO product, as you would say. Even with all my eyepieces I feel I should also have a decent Barlow. My other choice is the Orion Correct Image Diagonal that you have and seem to be happy with. Both the diagonal and the Barlow are the same price. I want to treat myself, again, but I'm not sure which is the higher priority. I will not even consider another filter until I see how the Fringe Killer either works or not. Will have to give the filter some time, I did read about a yellow cast it imparts to objects but it might not be so bad if it addresses some of my CA issues. So, can I ask your take on the diagonal or Barlow question? Its not that my stock correct image diagonal is so bad it's just that the Orion may be better but the Barlow would replace the cheap ones I have. Of course I can get both eventually, but after this I need to lay low for awhile ?!

[Mak the Night]

2 hours ago, Ray1103 said:

Glad to hear that about Mercury, lol! I want to run something by you: I have a couple of not so good Barlows, I have been looking at the High Point Scientific 2.5x Barlow. I doubt I can afford the TV Barlow and I probably don't really need it. I would rather put the money into another TV eyepiece. Anyway, the HPS Barlow is getting great reviews and looks finely made. Seems to be a re-badged GSO product, as you would say. Even with all my eyepieces I feel I should also have a decent Barlow. My other choice is the Orion Correct Image Diagonal that you have and seem to be happy with. Both the diagonal and the Barlow are the same price. I want to treat myself, again, but I'm not sure which is the higher priority. I will not even consider another filter until I see how the Fringe Killer either works or not. Will have to give the filter some time, I did read about a yellow cast it imparts to objects but it might not be so bad if it addresses some of my CA issues. So, can I ask your take on the diagonal or Barlow question? Its not that my stock correct image diagonal is so bad it's just that the Orion may be better but the Barlow would replace the cheap ones I have. Of course I can get both eventually, but after this I need to lay low for awhile ?!

I'm guessing you're talking about this Barlow: http://www.highpointscientific.com/2-5x-barlow-lens-by-high-point

It's rebadged and sold by many companies in Europe and the USA. It actually is made by Guan Sheng Optical.

I recently acquired the TS Optics version.

You'll notice mine doesn't have a barrel safety undercut as in the photo above from the GSO site itself. That's because someone at TS Optics informed me that GSO have actually decided to cease putting undercuts on the draw tubes of their eyepieces. Much to the relief of most of us with diagonals with compression rings.

As to your dilemma; I'm not sure what to tell you as I haven't used the stock Meade diagonal. From what I've read though it's pretty competent. The light train is only as good as its weakest link of course. If I had to prioritise, with a scope of 600mm focal length, the Barlow seems like the option to go with. Overall it's pretty decent and appears well made for the money. I've only used it on my 90mm scope and I can't really find any faults in it. The thumb screw is decently made, although I doubt it's captive, I haven't screwed mine totally out to see lol! It has a brass compression ring though. Although my Antares 15mm UPL, with its shallow undercut, is pretty easy to extract from it. TeleVue tapered undercuts are no problem.

The Orion diagonal is good, but no better than the Antares I also have. You may find the Sky-Watcher or TS Optics Amici prism diagonals are only the same. Orion often seem to be a bit more expensive. The quality control is generally good though. A 15mm EP combined with the 2.5x Barlow would give you 100x and a 10mm would give 150x. It would certainly be a great help with planetary/lunar viewing I would imagine. My Newtonian has a 900mm f/l and I regularly (almost always) used a 3x (TeleVue) Barlow with it. Often combined with fairly inexpensive eyepieces and it still looked great lol. Bear in mind, eyepieces with safety undercuts can snag on compression rings as you extract them. This isn't always problematical, but I once spent over half an hour trying to remove a 17mm Celestron (GSO) Plossl from that TV 3x Barlow. After that, I changed all my Plossls for TeleVues and only used the Barlow with smoothies or tapered barrels. It's OK if the draw tube equipped with an undercut is being inserted into a diagonal or adaptor without a brass compression ring as there is nothing for the undercut to snag with on extraction.

These three 15mm EP's show, from left to right, a tapered undercut, a smooth barrel with no undercut and a standard GSO - style undercut.

This Japanese made Antares (Masuyama clone) eyepiece displays a typical Japanese - style shallow undercut. These are easier to extract from compression rings.

This Vixen also has a long shallow undercut.

Brass compression ring on a 2.5x TeleVue Powermate.

So, I'd go for the Barlow first!

[Ray of LIght]

Mak, I didnt see a thumbscrew on the HPS Barlow. Am I missing something? Will my eyepieces get caught in the compression ring? Sorry Mak, a little confused. My beginner self is showing its ugly head ?. Maybe I am buying the wrong Barlow. Hope we talk later.

[Mak the Night]

4 hours ago, Ray1103 said:

Mak, I didnt see a thumbscrew on the HPS Barlow. Am I missing something? Will my eyepieces get caught in the compression ring? Sorry Mak, a little confused. My beginner self is showing its ugly head ?. Maybe I am buying the wrong Barlow. Hope we talk later.

I think you'll probably be fine with the Barlow. The thumb screw just secures the eyepiece into it. Undercuts are a highly debated issue in astronomy. They were designed to stop eyepieces falling out of adapters/diagonals if the thumbscrew became loose. Compression rings were designed to not mark draw tubes as thumbscrews on their own can do this. The problem is using eyepieces with undercuts with diagonals with compression rings. Most of the time an eyepiece with an undercut will extract from a compression ring. Sometimes they can be problematical though. That's all. Sorry for the confusion.

This is the top of my TS Optics (GSO) 2.5x 'shorty'. The thumbscrew which enables the eyepiece to be held in place pushes against a brass compression ring. When tightened the brass ring distorts to clamp the eyepiece draw tube. Some thumbscrews are 'captive' (like on TeleVues) so the screw can't accidentally fall out if loosened too much. Without the compression ring the screw itself would hold the eyepiece fast. If the screw loosened the eyepiece could be in danger of falling out. So the undercut was developed to help prevent this. The thumbscrew would loosen but still be caught in the undercut groove on the draw tube thus preventing the eyepiece dropping straight out, like it possibly would if it did not have a safety undercut.

Unfortunately, thumbscrews can mark smooth draw tubes and this may affect any resale possibilities if the owner wished to sell the used eyepiece. As the marks can often look unsightly. So, the compression ring was designed to clamp eyepieces without marking and possibly in a safer way preventing them becoming loose and dropping out.

The problem was when eyepieces with undercuts were placed into diagonals/adaptors/Barlows with compression rings. Insertion was usually not a problem but when extraction was attempted the bottom lip of the undercut would sometimes snag the compression ring, often causing hang-ups and preventing a smooth removal whilst in the field.

Furthermore, there is controversy on how the eyepiece sits in the adaptor and whether the undercut could cause it to cant or shift angle as it sits in the diagonal or other appliance, thus affecting the light transmission.

Flared or tapered lower undercuts (as seen on TeleVue EP's) address the extraction hang-up problem in the main, but I have been reliably informed that Guan Sheng Optical have actually decided to abandon safety undercuts altogether, as can be seen on my Barlow.

 

 

[Ray of LIght]

Thanks for the clarifications Mak. I think the pictures of the HPS Barlow just don't show the thumbscrew. I ordered the Barlow and the Fringe Killer came yesterday as well as the TMB 4mm. The TMB eyepiece looks nicely made, it's as large as my 32mm Omni Plossl! Hoping for decent skies tomorrow night, going to rain today ((Friday). I need a few good sessions just to field test half the equipment I have collected, but I assme there is no rush. I'm going to install the Fringe Killer on the diagonal and keep it there for now. For that kind of money I am going go use it, like it or not?! I will let you know how things work out and keep the info coming, I truly appreciate everything! If you have any other ideas how I can control and/or diminish the CA on my 102 my ears will be open! I have some hope for the Baader Fringe Killer though, fingers crossed!

[Mak the Night]

3 hours ago, Ray1103 said:

Thanks for the clarifications Mak. I think the pictures of the HPS Barlow just don't show the thumbscrew. I ordered the Barlow and the Fringe Killer came yesterday as well as the TMB 4mm. The TMB eyepiece looks nicely made, it's as large as my 32mm Omni Plossl! Hoping for decent skies tomorrow night, going to rain today ((Friday). I need a few good sessions just to field test half the equipment I have collected, but I assme there is no rush. I'm going to install the Fringe Killer on the diagonal and keep it there for now. For that kind of money I am going go use it, like it or not?! I will let you know how things work out and keep the info coming, I truly appreciate everything! If you have any other ideas how I can control and/or diminish the CA on my 102 my ears will be open! I have some hope for the Baader Fringe Killer though, fingers crossed!

The whole undercut controversy has been raging for a while as far as I can tell. I've attached Ray Taylor's Compatibility Study that he first published on this forum as he had to wait a while for it to be published on Cloudy Nights for some reason. I actually contributed a tiny bit to Ray's research when he asked people to report their personal experiences with certain combinations of equipment in relation to the issue. His analysis of the situation is highly accurate in my opinion and his report is very detailed. He very accurately explained why I had experienced some of the difficulties I had encountered, and even explained why certain combinations of eyepiece/Barlows worked with no problems. I had suspected a lot of what Ray explicates in his report for a long time. But his analysis depicts exactly what the problems with certain undercut designs and combinations of adaptors are. I just had a vague unformed notion.

I think you'll need a good high powered eyepiece like the TMB as I don't believe relatively fast refractors are very forgiving with less expensive eyepieces generally. Apart from filters to compensate for any chromatic aberration and quality eyepieces I can't think of much else to improve with an achromatic refractor. I think observing when the target object is at a higher altitude or at planetary Transit may improve observing quality as you are looking ostensibly through less atmosphere. If you have a decent view south it would help. Optics are essentially all about compromise. It's a matter of 'swings and roundabouts' as we say in the UK. With my 102mm Mak I can get good high magnifications with relatively modest quality eyepieces. I have little in the way of chromatic or other aberration. The scope is small and highly portable. But there is a limited FOV and the lowest magnification I can get is 32.5x for a 3.1mm exit pupil. I once tried to find Saturn with it without a reflex sight. I could see Saturn, you couldn't miss it, trying to find it with a 4" Mak without a finder was like something out of the Krypton Factor lol!

I added the 25mm Vixen to my grab'n'go 90mm bag as lunar viewing with the transparency we're getting here at the moment isn't too good. The Vixens have huge eye lenses and being simple Plossls give me bright, sharp images at 33.3x and 40x. Which is the sharpest focus I could get the other night. On a good night I should easily see the Milky Way with the naked eye where I am at this time of the year. The weather has got to get better!

This is the Antares Speers-Waler 9.4mm. It has a generous 3cm eye lens as you can see. It's quite well made but when I received it there was a flaw in one of the lenses that could be perceived when viewed through. At first I thought it was just some debris on the eye or field lens, but it wasn't. I have a feeling it was old stock. I returned it and will be refunded. Caveat emptor!

It's a shame as it looks quite nice and I got to daylight test it. I think it has an integral Smyth lens as there are extension tubes that can be threaded into it that change its focal length. I was a bit disappointed as I wanted it for the Mars Opposition, but I have a TeleVue DeLite now. So I'm OK.

I just hope we both get some decent weather to test any new gear soon. I'm kinda optimistic about observing the Moon at Transit tonight, they've predicted clear skies. Which is hard to believe.

E-A Compatibility Study PDF-S.pdf

[Ray of LIght]

A lot of food for thought there Mak. We seem to be on a coincidence kick! U mentioned my new TMB eyepiece and I just finished a long string about the aforementioned clone controversy. I found some of it quite hysterical and some very thoughtful. Obviously I have myself a clone since it quacks like a duck and I purchesed it from neither High Point or Astronomics. Of course the proof is in the pudding and the jury is still out. I hope it performs well no matter who made it because I do need it to perform, as you mention. If not, what TV eyepiece would you reccomend to replace it? Just in case. I'm an italian from brooklyn (not where I live now), and I hate getting ripped off. I could probably afford one other TV eyepiece for inder 150 US. I figure I would pick your brain if you are not too busy. Those comments and reviews on the TMB clones kind of got me feeling queasy. You have made yourself indespensible and I apprdciate it!