Low Power Wide Angle Inexpensive Eyepiece for my Mak? Ha! I should be so lucky!

[Splodger]

Hi all, As the title suggests I would like to get my hands on a low power wide angle/field eyepiece for my Mac. It's a Meade LX85 150mm - 1800mm FL f/12. I knew when I bought the scope that it would have a narrow FOV, but I would like to at least get The Seven Sisters and Andromeda in the FOV. Also, I don't want to spend a great deal of money. 1.25" would be ideal, but I could keep a 1.25" to 2" adaptor attached to the eyepiece. I've never used an adaptor before and am also wondering if it would affect the FOV. Any suggestions? 

The images attached show the FOV of my scope with my 40mm 52° Meade Super Plossl and a Celestron Omni 56mm which has a FOV of 47°. I don't own the Omni, it's just the best option I could track down.

[John]

These are big targets - Messier 31 (Andromeda Galaxy) is around 3 degrees across in full - 6x the apparent diameter of the full moon. The widest true field you can give with a 1.25 inch eyepiece in your scope will be just under 1 degree. If you can use a 2 inch eyepiece that can be 1.5 degrees.

That is wide enough for many other DSO's though.

 

Edited January 3, 2022 by John

[Franklin]

William Optics 2" 40mm Swan has a 70deg aFov. Will give you about 1.75deg at 45x in your mak, they come up used for about £70. Not the best corrected but should be fine at F/12. I had one and used it at F/11 and it was good across most of the field. Not much else really unless you shell out on a super expensive ultra wide?

[John]

1 minute ago, Franklin said:

William Optics 2" 40mm Swan has a 70deg aFov. Will give you about 1.75deg at 45x in your mak,..

1.55 deg at 45x ?

 

[Franklin]

7 minutes ago, John said:

1.55 deg at 45x ?

Yes, my bad, I can't count. 1.55deg is correct now I've got the calculator out. Still, 3 full moons worth.😀

[cajen2]

Best I can think of for cheap is a Svbony 20mm UW - 68°, about £40. Anything with a substantially wider FOV is around the £1-200 mark: OVL PanaView 2" EPs are 70°, Baader Morpheus 76°, etc.

[cajen2]

Good value low-power EPs are the Vixen NPL (Plossl) - I have the 30mm and it's great for the money (£48) but only a 50° FOV.

[John]

5 minutes ago, cajen2 said:

Good value low-power EPs are the Vixen NPL (Plossl) - I have the 30mm and it's great for the money (£48) but only a 50° FOV.

Yes, that's one that I like too

An F/12 scope is never going to be able to excel at wide field observing though. That's why lots of folks end up owning more than one scope.

Edited January 3, 2022 by John

[Splodger]

1 hour ago, Franklin said:

William Optics 2" 40mm Swan has a 70deg aFov. Will give you about 1.75deg at 45x in your mak, they come up used for about £70. Not the best corrected but should be fine at F/12. I had one and used it at F/11 and it was good across most of the field. Not much else really unless you shell out on a super expensive ultra wide?

Thank you. Seems just about perfect. 

[John]

So you will need to get a 2 inch diagonal as well, unless you are already using one.

 

[Splodger]

2 hours ago, John said:

So you will need to get a 2 inch diagonal as well, unless you are already using one.

 

I thought I could use a 2” to 1.25” adapter 

[Mr Spock]

4 hours ago, Splodger said:

I thought I could use a 2” to 1.25” adapter

No - a 2" eyepiece needs a 2" diagonal. Does your scope accept 2" fittings?

You may be limited to 1.25" eyepieces. In which case a 32mm 50° or 24mm 68° eyepiece might suit better.

[John]

7 hours ago, Splodger said:

I thought I could use a 2” to 1.25” adapter 

If you do that you will not get the benefit of the 2 inch size eyepiece format because the adapter will squeeze the field of view down to what can be accommodated by the 1.25 inch end of the adapter. 

Also the arrangement of having a bulky and heavy 2 inch eyepiece hanging off an adapter inserted into a 1.25 inch diagonal will look clumsy and could be insecure.

As @Mr Spock says, you will need to get a 2 inch fitting diagonal for your scope. These come with an adapter so that you can still use your 1.25 inch eyepieces as well.

[Franklin]

14 hours ago, John said:

Yes, that's one that I like too

I just picked up a few NPLs for my travel scope and I'm impressed. Particularly the 30mm which has a wider fov than my Baader 32mm plossl.

[Pixies]

20 minutes ago, Franklin said:

I just picked up a few NPLs for my travel scope and I'm impressed. Particularly the 30mm which has a wider fov than my Baader 32mm plossl.

It's nice, isn't it. It's so light, too.

[John]

23 minutes ago, Franklin said:

.... Particularly the 30mm which has a wider fov than my Baader 32mm plossl.

I compared the two a few years ago:

Where on earth have those 9 years gone

 

[Franklin]

42 minutes ago, John said:

Where on earth have those 9 years gone

9 times round the Sun!

Yes it was your excellent review that prompted me to try the NPL. I really like the BCOs but the 32mm BCP, even though it produces lovely crisp views, has a smaller aFov and the field edge is not well defined. I've kept the Baader with the intention of pairing it because when used with a parfocal ring (about halfway on the nose) I've found that i can use it in my Maxbright binos without vignetting. I know in doing this I am limiting the aFov further but it means I can get a really low power in the binos with a nice well defined field edge. But I have to say that the NPL30 is probably the best I've seen in this 1.25" 32mm plossl range. Haven't tried a TV32mm plossl though.

[Louis D]

Not just a 2" diagonal but also a 2" visual back as well.

I checked the US description of your scope, and it was supposedly packaged with both a 2" diagonal and visual back when new.

All sorts of widest field 2" eyepieces in the 35mm to 42mm range should work quite well in your scope.  f/12 is not very demanding as others have pointed out.  You could even go with a 48mm to 56mm eyepiece for widest field without exceeding a 7mm exit pupil.  At f/12, there are lots of lower cost options available.

[JAC51]

https://www.cloudynights.com/topic/498028-meade-lx70-150mm-f12-maksutov/

Has a thread on this telescope which would seem to confirm that, although a good telescope, it is limited to using 1.25” eyepieces only.

[Mr Spock]

4 minutes ago, JAC51 said:

Has a thread on this telescope which would seem to confirm that, although a good telescope, it is limited to using 1.25” eyepieces only.

That's an LX70 not an LX85 

Looking at this image suggests the 1.25" unscrews so you can fit a 2" visual back. I would take it off first just to be sure though.

 

[Don Pensack]

I believe the instrument comes with a 1.25" star diagonal and visual back, but has a standard SCT thread which will accept a 2" visual back and 2" star diagonal.

I don't think the scope comes with those, however.  They would have to be added.

[JAC51]

https://www.cloudynights.com/topic/498028-meade-lx70-150mm-f12-maksutov/

Has a thread on this telescope which would seem to confirm that, although a good telescope, it is limited to using 1.25” eyepieces only.

I stand corrected thank you gentleman.

[Louis D]

16 minutes ago, Don Pensack said:

I believe the instrument comes with a 1.25" star diagonal and visual back, but has a standard SCT thread which will accept a 2" visual back and 2" star diagonal.

I don't think the scope comes with those, however.  They would have to be added.

I was just going by the specifications on Meade's webpage for the LX85 which states the following:

Diagonal	2" 90-Degree Mirror with 1.25" Adapter

[Louis D]

9 minutes ago, JAC51 said:

https://www.cloudynights.com/topic/498028-meade-lx70-150mm-f12-maksutov/

Has a thread on this telescope which would seem to confirm that, although a good telescope, it is limited to using 1.25” eyepieces only.

I stand corrected thank you gentleman.

Admittedly, if your 150mm Mak has a 25mm rear baffle, it's going to be a bit tighter than the 27mm rear baffle in my 127mm Synta Maks.  However, I'm able to use 2" eyepieces in my 127mm Synta Maks with about 40% light loss (vignetting) at around 90% to the edge as shown below.  You would just experience a bit more vignetting in your 150 Mak.  Both images taken from the same distance with the same diagonal, so the focal length is a bit longer than if I were using a 1.25" diagonal.

In real world use, I find the expanded true field of view with 2" eyepieces to greatly outweigh the outer field vignetting.

[Splodger]

11 hours ago, Mr Spock said:

No - a 2" eyepiece needs a 2" diagonal. Does your scope accept 2" fittings?

You may be limited to 1.25" eyepieces. In which case a 32mm 50° or 24mm 68° eyepiece might suit better.

I've had a quick look and the VB and the aperture for the diagonal are both 1.25" as far as i can tell. I think I would be getting to the point of diminishing returns if I were to go down the route of converting it. Someday soonish I may have a larger scope and I think I'd be better off spending money on that. It's very good to understand all this though. It will definitely my purchasing decisions going forward.