Eyepieces section for SCT owners?

[Ruud]

  
Im not sure if I have this correct but on the FOV calculators the TV55 gives me the same view as the 40mm Pentax?
  

  
That's about correct. I used to have a TV55 but sold it. If I were you I'd go for the Pentax XW 40: smaller exit pupil, darker sky background, same true field of view. A nice eyepiece for a total lunar eclipse.

I rely on short focus refactors, btw, for wider views. These days my longest focal length is 34mm @ 68°. In the WO73 that gives a 5.14° view. Perfect for a lunar eclipse: plenty of stars around the eclipsed Moon makes it look extra good.

[Bigzmey]

Good quality 20mm EP is must have for SCTs since it delivers 2mm exit pupil. For majority of DSOs it is the optimal exit pupil.

Now, stepping down 40mm is too close to 30mm. From my experience I would suggest EP in 50-55mm range instead. A good quality 2" Plossl like TV 55mm.

Hi Bgzmey

Im thinking the 17.5 Morpheus will provide for the 20mm range with 2MM Exit?


Im not sure if I have this correct but on the FOV calculators the TV55 gives me the same view as the 40mm Pentax?

I will attach an image from the FOV calculator with my 9mm & a 17.5mm

From that it looks like equal steps out to the Pentax 30 & 40...Im not buying 2 EPs though!

The ES82 30mm looks somewhere in between.

The dark Blue is the 55mm Plossl


download.png


Cheers buddsy

Yes Morpheus 17.5mm is close enough to be 20mm EP. If you add 27mm Panoptics and 40mm Pentax XW you will get a nice spacing of 1.5x magnification factor between EPs.

In my experience if spacing between EPs are too short you will end up ignoring some of your EPs during observing.

While building your EP collection you want to cover broad range of exit pupils from 1 to 5-6mm in 1.3x to 1.5x steps, and space EPs evenly.

Even though 56mm TV Plossl has the same AFV as 40mm XW, or 30mm Nagler, it is still useful to have since it provides lower power and wider exit pupil. To use nebulae filters for example.

[buddsy]

Many thanks Bigzmey!

That info makes sense.

Im giving this some thought!

I like the idea of the Pentax EPs due to their comfort and build quality. However I have read they have issues off center.

The ES82 30mm by many accounts is sharp across the view.

I think this is the case in a slow F10 SCT but am not sure if this is just in the faster scopes?

Thanks again and sorry for so many questions!

Oh meant to add I have a 0.63 Celestron Focal reducer. I bought this so I can video the moon full frame with my DSLR. Ive read a few things that its not helpful for visual? Is that correct?

buddsy

[Bigzmey]

Many thanks Bigzmey!

That info makes sense.

Im giving this some thought!

I like the idea of the Pentax EPs due to their comfort and build quality. However I have read they have issues off center.

The ES82 30mm by many accounts is sharp across the view.

I think this is the case in a slow F10 SCT but am not sure if this is just in the faster scopes?

Thanks again and sorry for so many questions!

buddsy

You can't go wrong with ES EPs, they are solid performers. I used to have a set of ES 82 and had many good nights with them. The only issue for me was short eye relief (I observe with glasses). Then I tried 10mm XW, and realized that it is not just better eye relief and ergonomics, but the coatings and finishes are better. I was able to resolve fainter DSOs and fainter stars with XW than with ES.

True, field of curvature is an issue for XWs in fast reflectors. If you plan to get a DOB in future ES would be a more universal choice. But if you stick to CATs and refractors I would take XWs over ES82s anytime. On faint DSOs I would take XWs over Televue EPs as well, just because modern TV EPs have darker coatings. Otherwise they are great.

[Bigzmey]

As for the reducer, it is a matter of preference, like barlows.

Since you need to remove diagonal to put reducer on, it is not practical to take it off and put back on during the session.

If you decided to keep it on you need to build your EP set around that. Your 2mm exit pupil EP becomes 12.6mm instead of 20mm and 5mm exit pupil will be achieved with 30mm EP. There is an advantage to that - you gain wider FOV, but you also introduce vignetting and loss of light. Since, I like to push my scopes to the limits, I prefer to get all the light I can. Also, for high power observing I prefer F10 vs F6.3 (with reducer) for variety of reasons.

[buddsy]

Thanks for your detailed replies its much appreciated.

I think I would prefer to build my set around not using the reducer.

Now I just need to save a bit before I choose the next one. :-)

buddsy

[Bigzmey]

Thanks for your detailed replies its much appreciated.

I think I would prefer to build my set around not using the reducer.

Now I just need to save a bit before I choose the next one. :-)

buddsy

I tried reducer, but realized I prefer native F10. One of considerations is that EPs bellow 10mm often include built-in barlow. Basically, you add 4 element reducer to the optical train, and then barlow (built in or stand alone) to get to high powers: lots of extra glass for no good reason.

[Bigzmey]

And you are always welcome! A few years ago I was asking the same questions.

[buddsy]

I tried reducer, but realized I prefer native F10. One of considerations is that EPs bellow 10mm often include built-in barlow. Basically, you add 4 element reducer to the optical train, and then barlow (built in or stand alone) to get to high powers: lots of extra glass for no good reason.

I did read that some where.

I guess thats evident in the Hyperions. As you can undo and add the spacer between the top element and the bottom (Barlow?) element even leaving the last out completely.

Fascinating the physics behind the theories of making lenses. So much R&D must go in to creating even before the manufacture...then we come along and say "I dont like it"

buddsy

[buddsy]

Got my Morpheus 17.5 today and just had my first go with it tonight.

Very bright night (not fully dark either) moon was very full and very low in the sky.

Still the feel and comfort of the EP is very nice. I like the FOV

With the eye cup down its like looking into a window into another world.

The eye cup up is good to cancel out light from other sources.

Needless to say Im very happy with this one.

Regards

buddsy

[Bigzmey]

Congrats! How it compares to Luminos 19mm?

[buddsy]

Congrats! How it compares to Luminos 19mm?

For me and my eyes although the Morpheus has slightly less FOV it feels more usable. With the 82 deg Luminos I could not see the edges unless I tried to look around to the edge moving my head. I guess this is where personal taste comes in?

With the Morpheus I can just about see the edge of the FOV when looking in the EP. I like this as I feel I can see the whole of the view. With the 82 I wasn't sure if I was missing something at the edge as I couldn't see it.

In comparison and an example which might make it more understandable I have the standard 40mm Celestron plossl which I think has a 43 deg field of view. Looking into this EP is like looking down a long thin tube. Which I find horrible.

The Luminos I still think is quite nice to be honest.

I feel the Morpheus has easier eye positioning than the Luminos and I think i could see the very feint stars due to the background being a bit darker in the Morphues too.

buddsy :-)

[notFritzArgelander]

The Luminos are nice for price for 82s but 82s are not to my taste either. I’m sticking to my Pans I guess.

[FerrariMX5]

I'm wondering if a separate area for eyepieces by type of scope would be helpful.

I'm looking for a high power to view planets and I'm fairly settled on the Morpheus 9mm

As I said previously as a SCT owner I am finding it hard to get clear information that suits my scope.

Be interested in your thoughts

buddsy

I totally agree and I am seriously considering the Morpheus 9mm now that you mention it.
225 times Magnification (On my 8" SCT) would seem to be a good balancing point for Jupiter, Saturn and Mars.

A separate section would be most helpful.

Tony

[buddsy]

I totally agree and I am seriously considering the Morpheus 9mm now that you mention it.
225 times Magnification (On my 8" SCT) would seem to be a good balancing point for Jupiter, Saturn and Mars.

A separate section would be most helpful.

Tony

Hi Tony

I wonder if the Mods would allow an eyepiece thread in the Catadioptric telescopes section?

Anyway the 9mm is pretty good. I had hummed and hard for ages about this or the 6.5mm.

Most consensus is the 6.5 for you and I would be too much...apart from people with 8" & 9.25"who seem to use it on Jupiter and the moon to good effect.

Im going to save up for the 6.5 after using the 9 to view the moon with.

buddsy

[notFritzArgelander]

I totally agree and I am seriously considering the Morpheus 9mm now that you mention it.
225 times Magnification (On my 8" SCT) would seem to be a good balancing point for Jupiter, Saturn and Mars.

A separate section would be most helpful.

Tony

......
I wonder if the Mods would allow an eyepiece thread in the Catadioptric telescopes section?

''''''

Thankfully, I'm not a mod. I don't have the temperament or long suffering patience for it.

I really hope that they don't. The design of the site is well thought out and pretty clean. It is easy to find the information and discussion you seek. I think that this suggestion would break the well thought out design of the site and would render it less attractive. So that's how my mileage varies form yours.

[Bigzmey]

I totally agree and I am seriously considering the Morpheus 9mm now that you mention it.
225 times Magnification (On my 8" SCT) would seem to be a good balancing point for Jupiter, Saturn and Mars.

A separate section would be most helpful.

Tony

Hi Tony

I wonder if the Mods would allow an eyepiece thread in the Catadioptric telescopes section?

Anyway the 9mm is pretty good. I had hummed and hard for ages about this or the 6.5mm.

Most consensus is the 6.5 for you and I would be too much...apart from people with 8" & 9.25"who seem to use it on Jupiter and the moon to good effect.

Im going to save up for the 6.5 after using the 9 to view the moon with.

buddsy

6.5mm is definitely too much in SCTs for most targets except splitting tight doubles. You will get more use from 14mm, which would fill the gap between 17.5mm and 9mm

[OzEclipse]

Hi Peacemaker and Buddsy,

Peace Maker - your didn't tell us what telescope you have. Buddsy, these comments are directed more towards some of your specific comments.

Like many others, if you only want to use this on f10 telescopes, then your choices widen considerably. If your budget extends to Pentax XW's you won't be disappointed. I have used Pentax XW's belonging to a friend of mine on his and my scopes. They are all very good. I have used the XW5, XW10, XW14, & XW20. Of the examples I have used the XW5,14,& 20 were outstanding. The 10 was excellent but just a touch less sharp than the 5 or 14. I compared a Pentax XW5 with a Baader Hyperion 5mm. The Baader is noticeably and annoyingly darker than the Pentax and the Pentax much sharper. It is on my future acquisitions list. On one night when the atmosphere was very stable, I was using it with two similar telescopes - a Takahashi TOA150 6"f8 and a Newtonian 6"f7. Using the Baader, both scopes gave average views, using the XW5, we were resolving better than the Rayleigh limit.

I am not trying to push you toward a 5mm eyepiece. I agree with prior advice that an eyepiece in the 12-14mm range will be much more useful than a very short one. So the XW14 is highly recommended.

Wide angle
I have the 'hand grenade' the Televue Nagler 31mm. Beautiful eyepiece works on any f ratio. HEAVY!! about 1kg or 2 lbs.

You can mount a Vixen rail on your CPC tube and mount a small counterweight on a Vixen Dovetail adapter to offset the imbalance. Alternatively, I think you can buy Velcro strap on weight belts to add weight evenly around the front of the tube.

Before the Nagler, I used and still own a 20 yr old version of the Moonfish 30mm UW 80 deg eyepiece-
http://moonfishgroup.com/catalog/produc ... anguage=en
I don't know if these eyepieces are still available.

It works well in my 8"f9 Cassegrain and my ED80 f7.5. Not so well on my f5.6 newtonian as they state clearly on their website. I also bumped into a guy in outback Australia during the 2012 transit of Venus. He had limited knowledge and had bought an AUD$8000 package from a local retailer. Meade 12"f10 SCT, fork mount, web cam for streaming etc etc.In the package were the worst eyepieces I'd ever seen. He was quite stressed that he bought a lemon. I looked at his eyepieces. One of them had a big air bubble in the eyepiece field lens almost in the centre of field. Others were just no name rubbish. We put my Moonfish 30mm in and it gave very nice views.

I don't own the 15mm 80deg Moonfish but I have read numerous bad reviews of it.

I own a GSO Superview 42mm. Don't like it at all in any telescope. It's sold as 60 deg apparent field but it has an out of focus field stop which is quite distracting and limits the field to about 54 deg and then the soft edges limit the useable field further.

Joe

[buddsy]

Hi Joe

Thanks for your insight.

The Morpheus seems to be a step up from the Hyperion range.

I have read very good things about the Pentax and I considered buying either the 30 or 40mm

At the moment for wide view im looking at the APM 30mm UFF. Seems to hold its own against the Pentax and Televue...all for £180.00

I did consider the Moonfish and heard good things about it. That and the Williams Optics SWAN.

The APM seems to have very good reviews in direct comparisons and is often described as being Morphues like in it use.

The weight rail I was looking into. I found a great thread on cloudy nights with peoples pictures of their CPCrigs and many had the weight rigs to balance the heavy EPs.

Cheers again.

buddsy

[Peacemakeresq]

Don’t know how I missed this thread. (Yes I do.) I thought I noted that I have a Celestron Nextstar SCT 8se. I bought a kit with 3 EPs, a 2x Barlowe and 2” Diagonal. 40 mm, 32mm & 26mm. It also came with 5 colored filters. Since then I bought a 2 1/2 x Celestron Barlowe. And 2 Meade MWA EPS, a 15mm & 21mm. I also bought a Baader Scientific Mark IV Zoom. The 2 Meades and the Baader are my work horses after I have done my alignments? Does anyone have an opinion of those Meade MWAs? What about the Zoom IV? I am viewing Saturn, Jupiter & the moon this summer. Was viewing The Orion Nebula before it set. A little Mars in the late Winter early Spring. We have not had particularly good viewing weather this Summer, and most nights my neighbors have the porch light on in the backyard. It is supposed to be clear tonight, so I may go out.