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7mm Celestron Luminos

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#1 starbase25

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Posted 13 September 2017 - 11:38 AM

How good is this eyepiece? would it be ok to use for deep sky viewing?

 

thanks



#2 Augustus

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Posted 13 September 2017 - 11:52 AM

The 7mm is a bit high power for deep-sky viewing, except on maybe globulars and planetary nebulae. I really liked my 15mm but it was too heavy.



#3 starbase25

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Posted 13 September 2017 - 12:20 PM

My apologies. I should have mentioned for high power / deep sky like globulars and planetary nebulae. A 7mm isn't really high power for me. I would get 218x with a 7mm.



#4 JHollJr

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Posted 13 September 2017 - 12:26 PM

I have it and I like it. I only use it for planets and the moon.

#5 Augustus

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Posted 13 September 2017 - 12:30 PM

My apologies. I should have mentioned for high power / deep sky like globulars and planetary nebulae. A 7mm isn't really high power for me. I would get 218x with a 7mm.

The eyecup is weird and the cap on top doesn't fit with the eyecup extended, but other than that it should be fine. A Meade 8.8mm UWA is a bit lower mag, but it's waterproof and you can leave the eyecup in the position you like. I like my 5.5mm UWA.


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#6 starbase25

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Posted 13 September 2017 - 12:45 PM

 

My apologies. I should have mentioned for high power / deep sky like globulars and planetary nebulae. A 7mm isn't really high power for me. I would get 218x with a 7mm.

The eyecup is weird and the cap on top doesn't fit with the eyecup extended, but other than that it should be fine. A Meade 8.8mm UWA is a bit lower mag, but it's waterproof and you can leave the eyecup in the position you like. I like my 5.5mm UWA.

 

I've seen one of the 7mm Luminos with the cover completely off. I wonder how much better that would be?

 

https://stargazerslo...bcd6fdd6dbc.jpg



#7 NiteGuy

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Posted 13 September 2017 - 12:48 PM

For what those cost used ($70 or less) it's a great bang-for-the-buck eyepiece for anyone on a budget. While the twist up eye cup is nice, the innards can "rattle" when shaken on many of Luminos eyepieces (but, hey, you're not shaking the eyepiece while observing are you?). It's main shortcoming is Edge-Of-Field Brightening that can be somewhat annoying for deep sky observing.

 

For not much more $$ a better choice might be an Explore Scientific 6.7mm 82-degree. It's much better in the EOFB department with a bit better edge sharpness and a couple more mm of eye relief. The 6.7mm would give you 228x and that might be okay or it might be too much (you didn't mention the brand, type, size or focal ratio of your scope).



#8 starbase25

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Posted 13 September 2017 - 12:50 PM

For what those cost used ($70 or less) it's a great bang-for-the-buck eyepiece for anyone on a budget. While the twist up eye cup is nice, the innards can "rattle" when shaken on many of Luminos eyepieces (but, hey, you're not shaking the eyepiece while observing are you?). It's main shortcoming is Edge-Of-Field Brightening that can be somewhat annoying for deep sky observing.

 

For not much more $$ a better choice might be an Explore Scientific 6.7mm 82-degree. It's much better in the EOFB department with a bit better edge sharpness and a couple more mm of eye relief. The 6.7mm would give you 228x and that might be okay or it might be too much (you didn't mention the brand, type, size or focal ratio of your scope).

Does the 7mm have edge of field brightening?  A 6.7mm will give me 228x. To me high power is more like 450x, which I use for small planetary nebulas, Uranus + Neptune or close double stars. But if the 7mm Luminos is ok, I might try it out.


Edited by starbase25, 13 September 2017 - 01:06 PM.


#9 NiteGuy

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Posted 13 September 2017 - 01:47 PM

 

 

Does the 7mm have edge of field brightening?  A 6.7mm will give me 228x. To me high power is more like 450x, which I use for small planetary nebulas, Uranus + Neptune or close double stars. But if the 7mm Luminos is ok, I might try it out.

 

It does have EOFB but the high magnification mitigates it to a large extent. If you buy used, you can basically "buy and try" for almost free.


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#10 CrazyPanda

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Posted 13 September 2017 - 03:06 PM

How good is this eyepiece? would it be ok to use for deep sky viewing?

 

thanks

How good it would be for deep sky viewing depends on what telescope you have. The magnification you've mentioned it would give you isn't a problem, but if you end up with a 0.3mm exit pupil trying to get it, it might be.


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#11 russell23

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Posted 13 September 2017 - 03:43 PM

 

For what those cost used ($70 or less) it's a great bang-for-the-buck eyepiece for anyone on a budget. While the twist up eye cup is nice, the innards can "rattle" when shaken on many of Luminos eyepieces (but, hey, you're not shaking the eyepiece while observing are you?). It's main shortcoming is Edge-Of-Field Brightening that can be somewhat annoying for deep sky observing.

 

For not much more $$ a better choice might be an Explore Scientific 6.7mm 82-degree. It's much better in the EOFB department with a bit better edge sharpness and a couple more mm of eye relief. The 6.7mm would give you 228x and that might be okay or it might be too much (you didn't mention the brand, type, size or focal ratio of your scope).

Does the 7mm have edge of field brightening?  A 6.7mm will give me 228x. To me high power is more like 450x, which I use for small planetary nebulas, Uranus + Neptune or close double stars. But if the 7mm Luminos is ok, I might try it out.

 

The 19mm Luminos had some of the worst EOFB I have seen.  But EOFB can vary across a line - there seem to be less reports of EOFB with the shorter FL Luminos.   If it is in your budget I would recommend the 6.5mm Morpheus. 


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#12 NiteGuy

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Posted 13 September 2017 - 07:37 PM

I guess that you really have to ask whether or not your particular scope is "worthy" of the investment that comes with a high quality, more expensive eyepiece. For a great many years, I was "the king of bargain-basement club" when it came to scopes and eyepieces. What that really meant was that I continually bought and sold one crap eyepiece or accessory for another, always trying to find that one magic bullet that cost almost nothing (and doesn't exist in the real world!).

 

These days I'm settled in at what you might call mid-level. At mid-level, I build all my own Dobsonians (but no mirror making) and I've purchased a very enjoyable mid-level 80mm refractor (FPL-53, semi-APO) along with a nice Russian 6-inch Mak. My equatorial mounting (Meade LXD-75) is definitely "low-end" but it tracks well, slews well, and fits all my small scopes and DSLR, so it does everything I need.

 

The coolest thing about mid-level is that it finally enables me to buy top-level gear in the used market with my very thin wallet (thankfully, I've never had a thing for Ethos eyepieces!). So my eyepiece quiver is primarily various TeleVue Naglers with a Morpheus, Explore Scientific and a few oddballs thrown in (the last "new" eyepiece I bought was in 1983). I'm very happy with things at this point in time. When I buy an eyepiece today, it usually "sticks around" for a very long time and I know that my eyepieces are extracting all the performance possible out of my scopes. Here's hoping a few of these insights will save some of you a lot of time and money in the long run.


Edited by NiteGuy, 13 September 2017 - 07:42 PM.

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#13 starbase25

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Posted 13 September 2017 - 08:52 PM

 

How good is this eyepiece? would it be ok to use for deep sky viewing?

 

thanks

How good it would be for deep sky viewing depends on what telescope you have. The magnification you've mentioned it would give you isn't a problem, but if you end up with a 0.3mm exit pupil trying to get it, it might be.

 

It would actually give me a 1.4mm exit pupil. (12 inch Lightbridge).



#14 CrazyPanda

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Posted 14 September 2017 - 06:56 AM

 

 

How good is this eyepiece? would it be ok to use for deep sky viewing?

 

thanks

How good it would be for deep sky viewing depends on what telescope you have. The magnification you've mentioned it would give you isn't a problem, but if you end up with a 0.3mm exit pupil trying to get it, it might be.

 

It would actually give me a 1.4mm exit pupil. (12 inch Lightbridge).

 

Well, aside from potential EOFB issues others had mentioned, I would say this is a pretty good value DSO eyepiece that would be good for most of the smaller Messier objects. I like viewing DSOs like M57, M27, M13 and many others at high magnifications and about a 0.5 degree TFOV. Seems to frame them well while giving me good magnification to view them at.

 

My go to DSO eyepiece in my 8" SCT is a 12mm Nagler. 170x, 1.2mm exit pupil, and 0.54 degree TFOV. The 7mm Luminos will give you a slightly narrower field of view, but brighter exit pupil and higher magnification, so objects should look quite good in it. 


Edited by CrazyPanda, 14 September 2017 - 06:58 AM.

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#15 starbase25

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Posted 14 September 2017 - 12:43 PM

 

 

 

How good is this eyepiece? would it be ok to use for deep sky viewing?

 

thanks

How good it would be for deep sky viewing depends on what telescope you have. The magnification you've mentioned it would give you isn't a problem, but if you end up with a 0.3mm exit pupil trying to get it, it might be.

 

It would actually give me a 1.4mm exit pupil. (12 inch Lightbridge).

 

Well, aside from potential EOFB issues others had mentioned, I would say this is a pretty good value DSO eyepiece that would be good for most of the smaller Messier objects. I like viewing DSOs like M57, M27, M13 and many others at high magnifications and about a 0.5 degree TFOV. Seems to frame them well while giving me good magnification to view them at.

 

My go to DSO eyepiece in my 8" SCT is a 12mm Nagler. 170x, 1.2mm exit pupil, and 0.54 degree TFOV. The 7mm Luminos will give you a slightly narrower field of view, but brighter exit pupil and higher magnification, so objects should look quite good in it. 

 

Thanks CrazyPanda!  Best of skies to you! cool.gif




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