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What eyepiece would you recommend?

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#1 backinsac

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Posted 13 July 2012 - 11:38 PM

Hi, I was just given (by a coworker) a Bushnell Northstar Model 788840. It is a 1300 mm x 100 mm Maksutov-Cassegrain telescope which came with a 4 mm eyepiece. I haven't had an opportunity to use it yet and since I'm new to astronomy, I've tried to read as much as I can before taking it out. I am interested in observing the moon and the solar system planets. My research has indicated that I should invest in some quality eyepieces, but I don't know which ones I need. I am looking to get a Meade 4000 series 26 mm plossl and maybe a Barlow 2x. Are these right for this scope, or am I completely lost. All input is welcome. Thanks.

#2 panhard

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Posted 13 July 2012 - 11:44 PM

Welcome to our corner of cyberspace. :band: :band: :grouphug: :whee: :dob: I would say that would be a fair place to start.

#3 KWB

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Posted 13 July 2012 - 11:52 PM

Hi, I was just given (by a coworker) a Bushnell Northstar Model 788840. It is a 1300 mm x 100 mm Maksutov-Cassegrain telescope which came with a 4 mm eyepiece. I haven't had an opportunity to use it yet and since I'm new to astronomy, I've tried to read as much as I can before taking it out. I am interested in observing the moon and the solar system planets. My research has indicated that I should invest in some quality eyepieces, but I don't know which ones I need. I am looking to get a Meade 4000 series 26 mm plossl and maybe a Barlow 2x. Are these right for this scope, or am I completely lost. All input is welcome. Thanks.


Hello and welcome to CN :grin:

Your telescope has a long focal length and when used with a 4mm eyepiece,would provide 325X. Even where I live with transperent skies,that is simply too much magnification to provide a clearly seen image about 98% of the time.

The 26mm eyepiece is a good economical choice,providing 50x which is a very useable magnification any night and will show a much larger portion of the sky. A 2X barlow is a perfect compliment to that eyepiece,giving 100X,a magnification I can use any night when there isn't cloud cover and provide you will planetary detail.

It's a very good,economical start. :waytogo:

#4 beatlejuice

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Posted 14 July 2012 - 12:04 AM

I would recommend a 17mm and 25mm Sterling Plossl Sterling Plossls and a 2x barlow. They won't break the bank and they are pretty decent and well reviewed eyepieces. That will give you the equivalant, with the use of the barlow, of 25mm,17mm,12.5mm and 8.5mm. I really like the 25mm that I have.
I almost forgot, welcome to CN.

Eric

#5 howard929

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Posted 14 July 2012 - 12:13 AM

Hi, I was just given (by a coworker) a Bushnell Northstar Model 788840. It is a 1300 mm x 100 mm Maksutov-Cassegrain telescope which came with a 4 mm eyepiece. I haven't had an opportunity to use it yet and since I'm new to astronomy, I've tried to read as much as I can before taking it out. I am interested in observing the moon and the solar system planets. My research has indicated that I should invest in some quality eyepieces, but I don't know which ones I need. I am looking to get a Meade 4000 series 26 mm plossl and maybe a Barlow 2x. Are these right for this scope, or am I completely lost. All input is welcome. Thanks.


Hello and welcome to CN :grin:

Your telescope has a long focal length and when used with a 4mm eyepiece,would provide 325X. Even where I live with transperent skies,that is simply too much magnification to provide a clearly seen image about 98% of the time.

The 26mm eyepiece is a good economical choice,providing 50x which is a very useable magnification any night and will show a much larger portion of the sky. A 2X barlow is a perfect compliment to that eyepiece,giving 100X,a magnification I can use any night when there isn't cloud cover and provide you will planetary detail.

It's a very good,economical start. :waytogo:


Kenny,

Broken brained as I am I came to the same magnification and opinion about the 4mm EP that scope comes with. Curious as to why it's included since the high average for my area is right around 35x per inch and "usually" 50x is stated in most telescope specs as the highest useful magnification.

Worse then that is if I'm working the numbers correctly, that's a f/13 scope and the 4mm EP has a exit pupal of .3??

OTH, possibly a inexpensive 8-24 zoom wouldn't be too bad for the OP to get started with.

Howard

#6 backinsac

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Posted 14 July 2012 - 12:26 AM

Howard, if I get a 8-24 zoom, then I would not need the 17mm, 25mm, and 2x barlow that Eric recommended, correct? Also, how sensitive is the zoom control on one of these eyepieces? And finally, what would be a good, inexpensive model to look into? What are the disadvantages of the zoom compared to the Plossl? Sorry for all the questions, and thanks everyone.

#7 KWB

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Posted 14 July 2012 - 12:33 AM

Hi Howard

You are quite correct in your calculations, Sir. As they say, figures don't lie and liars don't figure. :grin:

I have no idea how the OP ended up with this combination but it would surely turn away most new users with this eyepiece/scope combination. In this instance I feel it better to encourage our new member rather than to recommend any particular eyepieces to him. IMO and IME with these small Maks,his idea of an upgrade makes sense from a viewing standpoint as well as an economic one. For a little over $40.00 new,he can accomplish what he seeks.

BTW,you are a bit of a nightowl. It's good to see someone from 2 time zones ahead of me still logged on. :waytogo:

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#8 howard929

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Posted 14 July 2012 - 01:12 AM

Ahhh, I see that good things come to he who waits. Nice scope you have there.

As for me, the restrictions on bedtime for us retired folk do require that I.. basically do as I please. Packing it in now so Good Night to you who has to stay up and keep things in order 'round here. :bow:

To the OP>

Hello and Welcome to Cloudy Nights.

You've gotten some already and the rest of the pros will follow in the morning with way better reccos then my foggy brain can offer you.

Howard

#9 Ratchet

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Posted 14 July 2012 - 01:13 AM

Wow, 4mm in that scope is pretty crazy indeed.

#10 howard929

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Posted 14 July 2012 - 01:18 AM

Howard, if I get a 8-24 zoom, then I would not need the 17mm, 25mm, and 2x barlow that Eric recommended, correct? Also, how sensitive is the zoom control on one of these eyepieces? And finally, what would be a good, inexpensive model to look into? What are the disadvantages of the zoom compared to the Plossl? Sorry for all the questions, and thanks everyone.


OK. Just saw this.

Nope. A 8-24 zoom like the Zhumell model that I have is all you'd need, which if nothing else is a lot of fun to use, has a wider field of view compared to Plossls, is not real bad at what it does nor is really great either. With your f/13 scope it would perform for you better then it does with the f/6 scope that I have.

HTH

Howard

#11 KWB

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Posted 14 July 2012 - 01:20 AM

Thank you,Howard. :)

May I say you have come a long way very fast as to your education in this hobby. I value your opinion and IMHO you are one very fine asset to this forum.

I wish we had a few thousand more just like you! :bow:

#12 400years

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Posted 14 July 2012 - 07:15 AM

My scope came with an SR 4mm eyepiece plus two others. I use the others, but the 4mm doesn't seem useful at all. When you guys say 98% of the time it's useless to you, when would the 2% be? In addition I was wondering what the SR meant.

#13 star drop

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Posted 14 July 2012 - 09:14 AM

My scope came with an SR 4mm eyepiece plus two others. I use the others, but the 4mm doesn't seem useful at all. When you guys say 98% of the time it's useless to you, when would the 2% be? In addition I was wondering what the SR meant.

Here is a good link to an eyepiece primer.
For most of us living in the northeast United States the 2% of the time would be when a certain hot place freezes over.

#14 craytab

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Posted 14 July 2012 - 10:37 AM

My scope came with an SR 4mm eyepiece plus two others. I use the others, but the 4mm doesn't seem useful at all. When you guys say 98% of the time it's useless to you, when would the 2% be? In addition I was wondering what the SR meant.

Here is a good link to an eyepiece primer.
For most of us living in the northeast United States the 2% of the time would be when a certain hot place freezes over.


Yes, and when that certain hot place freezes over it means the atmosphere is super steady and very transparent which would allow super high magnification and excellent light through put to look at those faint, faint fuzzies!

#15 artweiss

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Posted 14 July 2012 - 12:39 PM

Go to a telescope store and look through all eyepieces.
See what matches your eye. eye-relief, size,etc.
Then consider magnification.(view)

#16 Achernar

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Posted 14 July 2012 - 12:54 PM

You'll need a set of eyepieces to use the telescope to best advantage, and an eyepiece with a focal length around 25mm, another around 15mm and a third eyepiece from 10 to 8mm will cover most objects nicely. You will get magnifications around 50X, 85X and 140X respectively. A barlow will also be handy for the times when more magnification is needed. If you are on a budget, you can get three good Plossls for less than $150.00 new, or pick them up on the used market for a lot less. Of course, if the optics are good, you can use any eyepiece you like and get pleasing views, as long as they fit the diagonal.

Taras

#17 Pharquart

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Posted 14 July 2012 - 07:13 PM

In addition I was wondering what the SR meant.


SR stands for "symmetric Ramsden." A Ramsden eyepiece has a design that dates back to the late 1700s. It contains only two lenses, making it less expensive to produce, and typically has a very narrow apparent field of view. Many super budget telescopes contain a SR4 (4mm Ramsden) eyepiece solely so the box can claim some excessive magnification, usually well above what that particular telescope (and atmospheric seeing) will support.

Brian

#18 Dave Hederich

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Posted 14 July 2012 - 07:56 PM

Looks like they added the 4mm EP to be able to claim a fantastic 325 power. The only other EP included is supposed to be a 25mm for a much more usable 52X. This is similar to my old Tasco 102mm Mak. Hopefully you lucked out and got one with decent optics as I did. If so, it will respond well to higher quality EPs, as long as you don't try to exceed the maximum that the scope's optics and atmospheric conditions will allow. The manual that came with my Mak cites a maximum USEFUL magnificaction of 240X (6mm EP). But this would only work on nights when atmospheric conditions are crystal clear, i.e. almost never.

http://www.opticspla...-telescope.html

#19 backinsac

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Posted 14 July 2012 - 08:08 PM

Thanks guys, I learned alot. The link to the eyepiece primer page was very helpful.

I think I might take Howard's advice and get a Zhumell zoom for now. That way I can get the telescope outside for some viewing. The best price I seem to find for this eyepiece is about $60 or so, does that seem reasonable? In the meantime, I'll also keep my eyes open in the classifieds for some better quality eyepieces at an affordable price.

It might sound crazy, but I haven't tried the telescope out yet because I don't want to be disappointed with the trouble that the 4mm eyepiece might bring.

#20 Jerry-rigged

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Posted 15 July 2012 - 12:28 PM

That scope sounds close to my ETX90 - 90mm x 1250mm. I have good luck with a 28mm edmunds RKE ans a 12mm Celestron X-cel.

#21 Benson

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Posted 16 July 2012 - 04:48 AM

4mm is too strong. A decent zoom would be a great choice. I have a hyperion MK3 - its very nice and reasonably priced. A widefield ep [30mm+] ep would also be good.






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