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Recommend new stuff to go with my 12" LX90


Paul-F
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Hi - I have a 12" LX90 (bought in 2007) with a small selection of eyepieces. Since I bought the Ethos 18 months ago that ep has probably had 80% of my viewing time and I can spend a whole evening with that alone! I am thinking that I want to cater for excellent high mag planetry views as I am happy with DSO so what ep (s) to get, I want to cover normal seeing conditions and then have kit for those really good occasions. I have a 2x & a 3x barlow that came with my previous scope that are quite frankly rubbish so maybe a quality Barlow should be considered?

My current eyepieces are as follows:

38mm 70 afov 2"

32mm Celestron Plossl 1.25"

25mm Meade Plossl 1.25"

21mm Baader Hyperion 1.25"

17mm Ethos

17mm Baader Hyperion 1.25"

13mm Baader Hyperion 1.25"

I am getting rid of the 'barely used' 21mm & 17mm Hyperions as the Ethos has them well and truely covered ... !

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One option for high power would be a Tele Vue 2" 2x Powermate. Used with the 17mm Ethos this would give you in effect an 8.5mm Ethos. I've been using one with my 13mm, 8mm and 6mm Ethos and it works superbly. Not cheap but a heck of a lot less expensive than buying another Ethos :smiley:

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Having a scope with the same mirror set-up as you, at least that is what we are told. I would not go above a 10mm eyepiece and my recommendation would be a 10mm Delos, though sometimes I think even that is too high a power and you are better off around 12mm -13mm. I do find the Televue range work very well on the LX scopes though many would say they are wasted on F10 focal ratios. Across this range I have only Televue eyepieces any of the Delos would be a superb addition to your collection be it 10mm 12mm or even 14mm, the latter is my favourite Juptier/Saturn focal length, though Mars needs a little more somewhere near the higher end of these.

Though I value Johns advice highly, I have only once used 8mm and that was the hunt for the star in the middle of M57, the Ring Nebular which I bagged. I do observe from a very dark site with very low polution of any kind, the area being rural in every sense of the word.

However to really throw a spanner in the works and I am sure John would not disagree the 13mm Ethos is a very fine eyepiece indeed but for the price it has every right to be.

Alan.

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I dont think a delos is wasted anywhere personally. Obviously your point is that an F10 can stomach much lower quality but mine is that a Delos is a widescreen orthoscopic which should be great in whatever you plug it in. 10mm is a native 305x eyepiece in a 12" F10, right?

A TV barlow 2x to give you 8.5mm Ethos (widescreen Delos) and 352x. This is giving you a lowish exit pupil of 0.86mm (i think, not sure how to calculate exit pupil with SCTs as the central obstruction eat into clear aperture a bit.) and will be limited to favorable seeing conditions

Personally I think a 17mm Ethos in a 12" F10 is already a planetary eyepiece giving 180x. If that works for you as DSO I think it probably does as a planetary as well.. at best i'd say get a 14mm Delos for 220x. You dont go beyond that often. There's a 12mm for 254x but I think you'll get more use out of a 220x. An Ethos' 100 degrees at this magnificatoin might feel wasted. Especially in a tracking mount, its a personal preference though I guess.

I'd honestly say get something lower like a Nagler 31T5 and then barlow that up for planetary. gives you two more options of 98x and 196x. Or maybe a 26mm Nagler and barlow/powermate giving 117x and 234x

If it's too much money you could always go ES. These are great eyepieces in a F10 id imagine as they are good in my fast F4.7. A 24mm ES with a 2" ES telextender would run you less than a new Ethos i'd imagne and give 127x and 254x over 82 degrees

Edited by Stargazer_00
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Some good points there made by Stargazer00. You don't reallly need to be going above X250 ish, on the Moon yes but the seeing in England will limit what you can use in any case at or below this. SG00 rightly said the 17mm Ethos is already a planenry eyepiece giving a Mag of around 180, you get a very clean image at this most nights. Just as an aside it is of paramount importance that you allow enough cooling time with these scopes. In my case in summer it's warming time.

I have no ExSc eyepieces but I have used many Meade eyepiece ( UWA, SWA SP all from the 5000 range ) which were made at the same factory to the same focal lengths in many cases, now as to whether they are the same, worse or better I have no idea, but I would not think there is much between them myself. They work very well at F 10 and can be got cheap enough secondhand, less than half there new price in some cases as prices have been driven down by the buying of EX Sc from the States.

I would also be careful with large lump eyepieces like the Nagler 31mm, Ethos 21mm and 30mm UWA Meade, there are others, these are very heavy on the back of a scope like ours and realy need to balanced with a special system from ADM which is not cheap. You can use it without but I feel this is causing wear to the motors.

Alan.

Edited by alan potts
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Thanks for the responses, and some good comment there I feel which gives me some ideas.

I have gone well over 300x cleanly on the odd occasion but recognise also that 200x is a step too far on others so yes, the Ethos 17 is a great ep, is a great match for my scope @ 180x and is nice on the planets/DSOs and thats why it gets the most use ... the 13mm Hyperion is solid too at times so want to push a bit more with a good quality ep. I am thinking that barlowing/powermating to about 250x with a 125x base will do me but possibly be a bit on the heavy side or maybe a simple quality ep or 2 below 17 mm for planets .... dont need wide fov for max mag I feel.

Well, at least I have my Options A (medium fl wide fov + 2x) & B (simple ep or 2 for high mag) to contemplate as I don't fancy purchasing a single expensive small fl ep that will not get lots of use as conditions rarely allow it ! Maybe get rid of the hyperions altogether and get a couple of these ... http://www.firstlightoptics.com/japanese-made-eyepieces/hutech-orthoscopic-eyepiece.html

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Paul,

Expensive but the 12mm & 14mm Delos's would work rather well on the LX 12 inch, the old 14mm Meade UWA is also very good on these scopes, there was also 12mm & 14mm Radians, 60 degree FOV that would make a nice planetry eyepiece .

If it helps and I know we are in different countries but 13-15mm is an area that can get regular use on an LX, above this you are trusting to luck of the weather conditions.

Alan.

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One option for high power would be a Tele Vue 2" 2x Powermate. Used with the 17mm Ethos this would give you in effect an 8.5mm Ethos. I've been using one with my 13mm, 8mm and 6mm Ethos and it works superbly. Not cheap but a heck of a lot less expensive than buying another Ethos :smiley:

..those Powermates...fantastic
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Had the scope out on Saturday and spent time startest collimating as best I could on Polaris with a 2x barlowed 8mm reticule ep so I was pretty sure I had given it a good shot. I then attached the crayford focuser and aligned on Saturn & the Moon for a couple of hours. Conditions seemed good, the 13mm (234x) Hyperion was sharp so I upped the mag by adding a 28mm ring for a 9.2mm fl to give 331x ... this was just in and out of focus about 50/50 on best focus with usual detail present so I was happy with that, maybe that night about 270x was a decent goal which is about 17 with a 1.5x barlow ... with this in mind I have ordered a 1.5x/2x ED Rigel 2" barlow for those occasions when I want to go beyond 17mm with the Ethos. I know it may not deliver and I will report on how it works for what I want .... On DSO I 'll stick with the 17mm Ethos as my regular upper limit!

A Powermate pushing to 2x on the 17mm Ethos was a bit to far IMHO ... however a 21 mm Ethos with a powermate might well be on my list but I'd like to actually try before I invest into that so will see if the local club members can help out there .. Actually, I realised the other night that I havent used the Hyperions much tbh and I'll keep the 21/13mm for now as they are OK and do have a role to play in my ep collection methinks ...

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