7.5mm plossl impatience!

[Jimtheslim]

I am currently in the process of updating my eyepieces that I got with my Skywatcher 90mm (f/10) refractor. Last night I had a chance, between the clouds, to try out my new (although bought second hand) Meade Plossls on Jupiter. These are 12.4mm and 26mm. First thing I would say is that I definitely noticed the difference over my stock 10mm and 25mm that came with the scope, especially the 12.4mm and I'm pretty sure the stock eyepieces will remain on the shelf from now on. So for anyone who was in the same boat as me and thinking about updating one at a time by buying second hand Plossls it seems to be a good way to go about things

After reading a good article on eyepieces here I now want a 7.5mm Plossl. Trouble is it seems hard to find second handers. I note that Orion make a 7.5mm but to buy new they are twice the price of the Skywatcher 7.5mm. Is there really that much difference? Should I be patient and try and hope to win a bid for something like an Orion one day or just buy a new Skywatcher for the same price? Or would it be worth going even lower to something like a 4mm or 6mm or would these be not much different to the 12.4mm used with the 2x Barlow?

Thanks

[nightfisher]

First, what scope are you using these in?

have to say you may struggle with eye relief on a 7.5mm plossl and the shorter focal length plossl`s are even harder to deal with, i have a lovely 6.3 plossl and i really struggle to use it, though i can use a 4mm orthoscopic!

[Jimtheslim]

90mm f/10 refractor

[ronin]

A 7.5 plossl will deliver about 5mm of eye relief so you will need to have your eye very close to the top lens, a 4mm is I think a waste of time, and not sure about a 6mm plossl, as that will also mean getting close to the eyepiece.

The scope at f/10 should be OK with plossl's but it is the nature of a plossl that is the question.

I would suspect that the Orion is the same as the Skywatcher under the outer skin.

I would have thought an 8mm and 10mm eyepiece would be reasonable, and plossl's may deliver the comfort in use at these.

Depending on the cost you may find it more sense to get something like the BST starguider, but it depends on the plossl cost.

[Jimtheslim]

Thanks, I was guessing that with most Plossls being seemingly made in China that they were likely made in the same factories and may not be a great deal of difference in the actual otpics, perhaps the more expensive ones are a tad more refined in the finishing? I will keep looking for a second hand 7.5 or 10.

[Jimtheslim]

I also see a lot of new unbranded Plossls on ebay that look too good to be true for the price, any experience with these?

[ghostdance]

'Too good to be true' has to tussle with 'Suck it and see'....

Depends on price and information.

Usually, for me, 'too good' wins the bout.

Heck of a lot of sheep in wolf costumes out there....

[Charic]

My  view / response is similar to those of ronin on this issue for your present scope.

I  borrowed an 8mm TeleVue from ghostdance, I did not like it? it was the shortness of the eye relief that affected me, compared to my BSTs? The shortness of eye-relief on a 7.5mm will be short too.

That said, look at my signature and you will see four Plossl EPs,  Revelation Astro [GSO] from Astroboot,  wickedly cheap and they actually work and give very good results (my eyes) but reduced AFOV compared to the 60° AFOV I'm accustomed too!, The 9mm feels so comfortable yet has the same 6mm ER as the 8mm EP? that 1mm of extra focal length must make the difference to my comfort level?

But I've been reading some more about the TeleVue Plossl's, and despite the short 6mm ER on the 8mm EP, the actual design of the TV  Plossl may be of better use to me  ( for my eyes ) over what I presently  use,  don't get me wrong, the EPs in my collection are very good, but I like to keep testing and trialling to validate my responses?

Here goes  I may even re-invest in some Televue Plossl EPs starting with the 11mm? 

[ghostdance]

My  view / response is similar to those of ronin on this issue for your present scope.

I  borrowed an 8mm TeleVue from ghostdance.....

Here goes  I may even re-invest in some Televue Plossl EPs starting with the 11mm?

Wanna borrow my 11 or 15? Happy to oblige and you may as well make sure before splashing out

[Charic]

Thanks S,  your always generous to help,  and should the need arise I'll PM as always.

There is mention of 'Etho's image quality for Plossl prices, and  text on the web  about astigmatism / coma correction due to their ( now expired ? ) Tele Vue patent for the Plossl range, compared to other branded Plossl EPs.

I'm still very happy with the results I achieve from my present  Eps  when  time  and weather permits to have a peek at the skies above, but I'm now  more dismayed with the the amount of light pollution here, even though  I shield my eyes from the light from within my Dob observatory/tent? Views are so much better away from this site, its the time and effort required. 

Should I ever go faster than f/6,  then the TVPs may prove to be  practically more beneficial  for that scope. Another 10° field of view with the TVP and a little more eye-relief,  it would be a no brainer! I'm often reminded by folk who are users of the TV  Plossl range that there will be notable differences between the TVs and other Branded EPs, ie cheaper variants? 

[ghostdance]

Anytime C

Always happy to help in having some fun in trying out stuff...

S

ps I can't really help on the 'notable differences' front - it's just that I've never met a Tele Vue I didn't like! And I've only scratched the surface... can't wait to try a Nagler f'rexample, or indeed another Radian.

[Roy Challen]

Second the Tele Vue 11mm plossl - best eyepiece I own or indeed looked through

[Charic]

Second the Tele Vue 11mm plossl - best eyepiece I own or indeed looked through

....noted. I seem to be fixated on two focal lengths at present (for my tests)  6mm and 12mm. I'll even consider Barlowing  a 12mm. Your not the first to say how good the 11mm TVP  is, but its still not a 12mm!

At the end of the day, despite what's written in specifications, If my (old) eyes prefer the Revelation, William Optics or Tele Vue or other  branded Plossl on this present telescope then that eyepiece will remain!

I wont know until I try them myself, but  I still  have to contend with the shorter eye relief of the Plossl range, as were suggesting to the original post, with their intended  7.5mm Plossl. But if you have never tried anything else, a 7.5mm Plossl could be as good as it gets until you try something else? I started out with 60° fields of view, anything less feels inferior now, the reason I so quickly discounted the 8mm TV, yet in  reality , do I really  need 60° views when trying to view the GRS on Jupiter with this scope? 

[Charic]

...........I've been reading / studying some more  about the Televue Plossl's and came across this article again ( http://www.brayebrookobservatory.org/BrayObsWebSite/HOMEPAGE/PageMill_Resources/Comparison%20test%20of%20TVPlossl%20vs%20Brandon.pdf ) the reason I wanted to try the  GSO Revelation!

Remembering my  first trial with the TeleVue 8mm Plossl, and in comparison to my present  9mm Revelation, it seems a hard issue to spend  the extra, for peace of mind, when the Revelations are so cheap,  and  work just fine.

I still don't have the weather for observing, further testing (I think I have been out twice this Year, its that bad ? ) but the 52°afov  the Revelations afford,  and their extreme value ( sure I paid £9 for one of them, New ? ) is the reason I might just settle for the Revelation GSO  set.  ( for now? )

[John]

I don't think I've ever read a positive comment from Chrs Lord on a Tele Vue product.

[bingevader]

If you want the higher mags, but not the poorer eye relief, then yes, a barlow is the way to go.

I like my TV plossls, even the 8mm.

And yep, second hand, they're a bargain.