Maxvision 24mm UWA

[alan potts]

Just an interesing report I thought I would share with you all.

I am at the moment trying to sell my 24mm Meade S5000 UWA, this is supposed to be the same as the topic title. I have had a contact from a buyer in Sofia who has a few very good eyepieces, 7mm XW, 11mm Nagler, 18mm Meade UWA and a Maxvision 24mm UWA

A couple of days ago he wrote to me telling me about bad ghosting on planets and stars when he is using it in his 12 inch Sky-Watcher Newt and expressed an interest in my Meade.

Now I would have thought ghosting was a problem that is harder to see with higher magnifications on longer focal length scopes and more obvious on shorter ones. I tried it out last night in my APO which was giving me a power of X34, in other words fairly low, I used bright objects in a dark sky before the Moon gate crashed the party.

There was a very slight ghost on Jupiter that I could see that I didnot find distracting at all, in fact I had to really look for it, there was nothing what so ever on stars like Sirius, I didn't split the double by the way.

Judging by the way the gentleman in Sofia told the story I wonder if Maxvision and Meades really are the same dancer with a different tutu.

It may be nice if I could get the two together.

Any comment will only help.

Alan

[michael.h.f.wilkinson]

Side by side comparison is probably the only way to find out. A really fast scope would probably tell them apart most readily

[alan potts]

Michael,

So the speed of the scope plays a part? My fastest is F5.26, maybe not enough, is there anything in what I said about the magnifcation?

Alan

[michael.h.f.wilkinson]

Michael,

So the speed of the scope plays a part? My fastest is F5.26, maybe not enough, is there anything in what I said about the magnifcation?

Alan

All aberrations show up more in fast scopes, and ghosting is most prominent in objects of high surface brightness. A large exit pupil (and therefore fast focal ratio) will show the effect up most, I would guess.

[rowan46]

admittedly I only have an f6 so not hugely fast but no ghosting on  jupiter with my scope and a maxvision not that I use it that much on planetary it's not what I bought it for

[alan potts]

Rowan,

I tend to agree with you I reckon the 24mm could be a planetary eyepiece in my LX with its 3048mm of focal length but even there we are only at X126 or thereabouts. I will ask the guy what the focal ratio of the scope is he is using, I thought most 12 inch Newts were about F 4.9 so not mind blowingly fast.

I would like to test these two over a few nights.

Alan.

[bingevader]

We're still waiting for the star party! I'll bring mine with me! 

I've only (  ) an f6 'scope too, but I've not noticed any ghosting, it's slightly soft around the edges, but I agree with Rowan46 in that I don't consider it a planetary EP. I'll have another look tonight.

Cheers

[jetstream]

My Luminos ghosts in my 10" dob f4.8,but not in my 90mm f7 frac.I think it may be relaled to the greater volume of light gathered entering the EP at 10" ap,the Luminos will also show a relfection of my eyeball that can look like a ghost...the coatings on these EPS are not as good as say ES etc-they may bounce a false image back in there to see.As far as magnification goes my 23,10,7mm Luminos ghost in the dob.

[alan potts]

Just an up-date, I tried two scopes last night at the very ends of my collection, the M/N F5.26 and the Mak at F15. My 24mm UWA did show a very slight ghost on Jupiter using the 190mm but nothing on stars, however the Mak 180mm was more obvious as the ghost was no brighter but larger, there was also a slight ghost on Sirius which I can't say I have seen before. I like to think I am fairly observant, not long ago I did an extentsive review with this eyepiece and the 26mm Nagler and can't recall seeing a thing, it just goes to show I need a kick somewhere, sorry for missing this.

I think a great deal of it ( excuse time ) is covered up by the placing of an object in the centre of a driven scope and as such is not really visible and in honesty don't really bother me too much. However on a Dobsonian the ball is in the other court and I could see some people not liking the result.

Both scopes were checked with 20mm and 26mm Nagler which I had handy and there were no such ghosts, another reason why they are expensive.

Bingevader, do you ever give up?

Alan.

[great_bear]

Put it in a 2.5x Powermate and take a look - then the ghosts really come out to play...

[bingevader]

I had a look the night before last with the Maxvision 24mm UWA. It's quite picky about eye placement. I could cause plenty of ghosting and flaring if I tried hard enough. But when looking normally through the EP at Jupiter, the ghosting was slight, but minimal and does not appear on anything else. This is however through the lowly f6 8" dob, I can't comment on how it would fare through a bigger faster 'scope.

Cheers

[alan potts]

Ben,

I am wondering if the quality varies a bit in these Maxvisions but your findings sound much in line with my own Meade 24mm. Thanks for trying it for me.

Alan.

[bingevader]

Yep, I wonder if the quality control is a good as it might have been with Meade, but mine makes me smile when I put it in the focuser, so no complaints here. And, as I've said in a previous thread, FOV aside, I prefer the more subtle contrasts I get through it on, say M42, rather than the mega light transmission of the TV plossl. 

If you did want to compare the 2 side by side.... 

[wolfpaw]

If you have a Maxvision that you bought from Explore Scientific then you can send it back and they'll test it. If it's faulty then you'll get a replacement. The problem with this is that the EPs are so heavy it would cost a fortune to post it back to Germany.

[alan potts]

Wolfpaw,

One reason I only buy Televue now, they test all their eyepieces before they send them to customers though having smashed one I think they need to do a bit more work on the kissing concrete test.

Alan.

[bingevader]

Ouch!

Nice soft grass here!

[alan potts]

Ben,

I reported on site at the time of the mishap the 6mm Delos was in the 115mm APO which cost a lot more than the full range of Delos eyepieces. The only damage to the scope was a dent to the dew sheild and I almost had a heart attack. I liked the 6mm so much I got another one, this time secondhand, just in case.

alan.

[michael.h.f.wilkinson]

Put it in a 2.5x Powermate and take a look - then the ghosts really come out to play...

The 2.5 powermate is 1.25", the 24mm MV 82 deg (UWA) is 2". I think you are referring to the 24mm 68 deg (SWA). I have two of the latter (for future binoviewing), and I will check out any ghosting this evening on one of them (the other is on loan to the Blaauw Observatory of the university for their public outreach evenings).

[alan potts]

Michael,

Should a Powermate make it worse? I am of the opinion that longer focal lengths made it easier to see, even Sirius put on a bit of a showing though not Rigel near by.

I never noticed the ghosting before and I though I was looking really hard for faults, maybe paying too much attention to sharpness and the like and not seeing the full picture.

Alan.

[michael.h.f.wilkinson]

Michael,

Should a Powermate make it worse? I am of the opinion that longer focal lengths made it easier to see, even Sirius put on a bit of a showing though not Rigel near by.

I never noticed the ghosting before and I though I was looking really hard for faults, maybe paying too much attention to sharpness and the like and not seeing the full picture.

Alan.

I wondered about that too, but a powermate is telecentric, which means that the rays do pass through the optics in a slightly different way. This change could alter internal reflection, in principle

[alan potts]

Michael,

I guess as we are talking about a Powermate which is of course Televue I wonder if the prblem exists with a full TV set-up. While I was doing this test in 4 of my scope I used a spread of Televue eyepieces just to see if any of them had the same problem. I did not use all my eyepieces but of those I did employ not one had a ghost, so I imagine the advise is buy Televue if these spirits bother you.

Myself I would not use the 24mm UWA as a higher power eyepiece, for me it is a finder, even in my LX it is not really high power. I must say as a finder I could not see ghosting on stars, Jupiter, yes but why look at Jupiter at X30. You would need a 16 inch LX 200 with it's 4 meter F/L to be getting up to planetary powers and I don't think many people have one of them.

Alan

[bingevader]

Ben, I reported on site at the time of the mishap the 6mm Delos was in the 115mm APO which cost a lot more than the full range of Delos eyepieces. The only damage to the scope was a dent to the dew sheild and I almost had a heart attack. I liked the 6mm so much I got another one, this time secondhand, just in case. alan.

Ah, yes, I remember now. 

The 24mm is great on DSOs for me with the 8" 'scope, I'd never have thought of looking at Jupiter through it had I not seen this thread.