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TahoeNoob
sage
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Reged: 10/31/12

Loc: Sierra Nevada
Best EPs for a XT10i?
      #5538022 - 11/24/12 11:06 PM

Hello friendly experts!

Next week I'll be receiving a used XT10i. It's going to be delivered by a friend who lives out of the area. I bought the scope on Craigslist, my friend is just the delivery man. Along with the scope, I'll get two eyepieces; the ones that originally came with the scope:

1) 25mm/1.25" Sirius Plossl
2) 10mm/1.25" Sirius Plosel

I will not be receiving a barlow.

So, my question is... should I sit tight and see how things go, or should I buy a couple eyepieces along with a barlow? If I buy something, I don't want to buy rock bottom stuff, but I can't afford high end stuff. What are some good mid-range eyepieces and barlows that're compatible with a XT10i? Do I need any 2 inch EPs, and how much can I expect to pay for what I need?

I saw one person recommending Explore Scientific 82* EPs. Bang for the buck wise, are they a good deal?

I hope to use this scope mostly for viewing DSOs, and my skies are pretty darn dark! There's some light spill-over from a nearby town, but not too much. (I think most people would be very happy to be in my situation.) Do I need any filters?


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TahoeNoob
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Reged: 10/31/12

Loc: Sierra Nevada
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538036 - 11/24/12 11:21 PM

I should add that I'm a little bit concerned, because I read that XT10s are "hard on EPs."

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GOLGO13
Carpal Tunnel


Reged: 11/05/05

Loc: St. Louis area
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538076 - 11/25/12 12:00 AM

The ES eyepieces would be your best choice. Especially if you don't want to spend too much money. I really like the 6.7mm 82 degree myself (mine isn't ES, but it's pretty much the same eyepiece...the 6.7mm Meade UWA 5000 appear to be made by the same folks or copies).

Since those are on sale right now you may want to get one or two. The best part is the wide field of view allows you to observe longer before nudging the scope. But if you go too cheap on wide field eyepieces, their flaws can be exposed by the fast scope.

2 inch eyepieces are not required. I use a 24mm 68 degree as my low power which is still 1.25. But 2 inch low powers can be nice. Just don't go too cheap on those with that scope.


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GOLGO13
Carpal Tunnel


Reged: 11/05/05

Loc: St. Louis area
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538083 - 11/25/12 12:04 AM

For filters you may want to get an Oxygen III for objects like the Veil Nebula. Use it with lower power. But if you are in dark skies like that you should probably try a bit without. Check out Globular clusters...and for certain the Wild Duck Cluster ...The Orion Nebula goes without saying.

The Intelliscope has a monthly tour which is worth using. Just do a month or two plus or minus from the current month.

ENJOY


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timfiskwa
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Reged: 12/22/07

Loc: Richardson, TX
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538084 - 11/25/12 12:06 AM

Hello TahoeNoob and welcome to cloudynights. I highly recommend a 2x Barlow like the Orion shorty to get good planetary closeups. I also would get a 7.5 or 6.3 mm to power up in good seeing, useful for close double stars, lunar, and planets. The 25mm is a good low power eyepiece. Great for star hopping. Maybe a 17mm or 12.5 mm for midrange, all Plossls. I am thinking of a 2" for myself, perhaps in the 25-32mm range. Premium eyepieces really are nice and the views are great if you can get them like the panoptics or ES 32mm, but they are beyond my budget.

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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: Best EPs for a XT10i? new [Re: timfiskwa]
      #5538210 - 11/25/12 02:19 AM

Quote:

Hello TahoeNoob and welcome to cloudynights. I highly recommend a 2x Barlow like the Orion shorty to get good planetary closeups. I also would get a 7.5 or 6.3 mm to power up in good seeing, useful for close double stars, lunar, and planets. The 25mm is a good low power eyepiece. Great for star hopping. Maybe a 17mm or 12.5 mm for midrange, all Plossls. I am thinking of a 2" for myself, perhaps in the 25-32mm range. Premium eyepieces really are nice and the views are great if you can get them like the panoptics or ES 32mm, but they are beyond my budget.




I agree. fancy wide fields are great to have but are not a necessity. i personally bought the 5 pc orion plossl set to get myself started and give me options. it helps that they purposefully forgo an EP around 25mm because thats the one they put with the majority of their new scopes. the set comes with a 6.3, 7.5, 10, 17, and a 42mm (42 deg on the 42) along with the shorty 2x barlow and your basic run of the mill color filters and a .9 neutral density filter in a decent case that has some room to stick some more things in. at 150-170 bucks its hard to beat to get one started with some decent eyepieces.

i will say that out of the various eyepieces i use the 6.3, 10, 17 and 42 the most. having all those high power options at hand is very nice for viewing planets because if the seeing isn't quite good enough you can just swap to a slightly lower power and get more detail.

the 42mm sounds like it would be a great low power and it is but because its 1-1/4" and only has a 42 deg AFOV its true field is only a little bit better than the 25mm that comes with the scope but none the less is easier to use and because the top lens is recessed quite a bit in the housing its a good general view EP that is very resistant to dewing up. it made my 25mm obsolete until i picked up an O-III filter and i found that for whatever reason the 42 seems to cause some crazy reflections in the upper housing when using that filter so my 25mm gets dedicated O-III use when i'm viewing those types of nebula now so its regained some of its usefulness again.

before buying more expensive EP's i'd go out to star party's at a local club if you can and use/borrow other folk's units. i've viewed through quite a few high end wide field EP's and a number of lower end ones as well. the time i got to view through some Televue's it was in an 18" obsession so its kind of hard to tell how much was the EP and how much was the scope but the views were breathtaking for sure. just yesterday i got to use someones Orion Q70 38mm in both his XT10 as well as my XT8 and i have decided that is my next and first 2" EP. i spent more time with it in my 8 as thats what i'm going to use it on but the views were very good in both scopes in my opinion and thats good enough for me. i'm personally going to save my cash to get a bigger scope next because from what i've seen that makes the biggest difference in what you can and do see along with viewing conditions (light pollution, transparency, seeing etc.)

another thing thats much cheaper than opting for expensive wide fields on these dobs that will help tremendously with viewing planets and double stars at high power is upgrading the alt and az bearing surfaces. 2 days ago i bought a sheet of Fiber Reinforced Plastic (FRP) and cut a diameter for the base bearings to ride on and 2 strips that i tied up to the alt bearings like another member on here Jason did on his scope and it made the alt so smooth i had to make and strap a counter weight to the back of my scope. i've got more end weight than you right now though as i added a Rigel and a 8x50 RACI finder to my XT8 without the RACI it does not need the counter weight even with a pretty heavy EP. the advantage in doing this though is that when tracking planets before at high power i'd be constantly messing with the position to get say jupiter at the top of the field so i can then let the scope settle then view it for 5 seconds or whatever then do it all over again. with the FRP bearing mod i no longer overshoot moving the scope at high power and it takes much much less time for it to settle down after moving it. this is much less of an issue at low power but its still somewhat of an issue.


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kfiscus
Carpal Tunnel
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Reged: 07/09/12

Loc: Albert Lea, MN, USA
Re: Best EPs for a XT10i? new [Re: frito]
      #5538227 - 11/25/12 02:58 AM

Lots of people rave about ES eps. I've not tried any. I opted for buying used Televues from highly-rated Amarters and CNers. I haven't regretted it for a minute. 35 Pan, 24 Pan, 13 T6, 7 T6.

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CosmoSat
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Reged: 07/24/09

Loc: India
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538265 - 11/25/12 04:43 AM

For planetary I would suggest this 5mm 1.25" Paradigm Dual ED eyepiecefor ur f/5 scope.

The 2X apochromatic ED Barlow.. Done know if it can be converted to work as a 1.5x too tho.

Or u can consider this GSO 1.25" 2x Achromatic Barlow Lens if u want the 1.5x option.

A 15mm or so wide angle eyepiece for Deep sky observing.. like the 14mm ES 82° eyepiece(getting mixed reviews this one).

Clear Skies!


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rick-SeMI
sage


Reged: 01/08/11

Loc: Michigan - USA
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538377 - 11/25/12 08:22 AM

When I bought my Orion 90mm Mak-Cass I also purchased the Orion eyepiece case with 5 eyepieces, 5 color filters, a neutral density filter and a shorty 2x barlow.

Well I used the eyepieces (plossls) a little over a year and used one or two of the filters a couple of times.

My next purchase was the Orion Q70 26mm 2".
Then the ES68° 24mm, ES82° 14mm and ES82° 6.7mm 1.25" EP's.
In close succession an Orion Ultrablock filter, DGM NPB filter and a Lumicon OIII filter.

These are the eyepieces I use the most with the XT10i:
ES 82° 14mm and ES 82° 6.7mm.
I also use the Ultrablock, NPB, OIII and Orion Neutral Density (from the case) and the 2x barlow on occassion.

Edited by rick-SeMI (11/25/12 08:26 AM)


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Happy Birthday Achernar
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Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538415 - 11/25/12 09:28 AM

With F/5 and faster telescopes, you really cannot get good views with many low end eyepieces. A good Plossl will work, but they have a narrow field of view compared to more modern eyepieces. Inexpensive wide field eyepieces often do not fare well at F/5 or below. They are just not corrected well enough for astigmatism and other aberrations for short focal ratio telescope. The Explore Scientific eyepieces are moderately priced and they do work very well at F/4.5. I have all of them except the 30mm model, they are very sharp and very contrasty. Field flatness is good and lateral color around the edge is there but not enough to be a concern. There is some distortion, which is common in many ultra-wide angle eyepieces, but unless you are looking at the sun or moon, it's not going to be apparent. They do have a little flaring issue when there is a very bright object just outside the field of view, mainly with the 8.8mm but that is maninly with the moon. Fit and finish are excellent They come pretty darn close from what I can see to Naglers but at a much lower price. There is one caveat however, if you wear glasses, you will have to take them off to look through these eyepieces, or wear contacts. I wear glasses and consider taking them off an acceptable tradeoff for all the advantages the ES 82 degree eyepieces offer. You may or may not be able to look through them without eyeglasses on. Where these eyepieces excell are deep sky objects, and the huge 82 degree apprent field of view makes finding, and tracking objects a lot easier. In general, they are a good choice for a F/4.5 or F/4.7 Dob of any aperture. They are all very good, but from what I can see, the 24mm, 11mm and 6.7mm are a little better than the others. You do not need 2-inch eyepieces unless you are looking for a low-power, wide or ultrawide angle eyepiece. In any case, the telescope is already able to accomodate them since a 10-inch Dob usually has a 2-inch focuser. ES also has a line of really good 68 degree eyepieces as well that deserve consideration. There are other 68 degree eyepieces that have good performance with long eye-relief, which will allow you to see the whole FOV with your glasses on.

Taras


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City Kid
Carpal Tunnel
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Reged: 05/06/09

Loc: Northern Indiana
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538495 - 11/25/12 10:35 AM

I've had an XT10 for 10 years or so and I can tell you what focal length eyepieces I've found to be the most useful with that scope. For me, the mid-range eyepieces get the most use. Something in the 17mm - 13mm range. For my taste the eyepieces in that range provide the most pleasing views on most DSOs. In the higher power range, eyepieces from 6mm to 8mm have been the most useful. Again this is for my tastes and my situation.

I think you can do just fine using the eyepieces that come with the scope for awhile. The 25mm will allow you to find objects and will frame most of the larger objects quite well. The 10mm will give you good upper mid-range magnification. Time spent using those will give you an idea of where you want to go from there.


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TahoeNoob
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Reged: 10/31/12

Loc: Sierra Nevada
Re: Best EPs for a XT10i? new [Re: City Kid]
      #5538565 - 11/25/12 11:27 AM

How would it be if I went with something like this:

1) BUY- 28mm/2" ES 68*
2) HAVE 25mm/1.25" Sirius Plossl
3) SKIP 18mm/2" ES 82*
4) HAVE 10mm/1.25" Sirius Plosel
5) BUY- 6.7mm/1.25" ES 82*

6) BUY- 2X apochromatic ED Barlow for 2" eyepieces, with 1.25" adapter This is the barlow that CosmoSat recommended. (Another barlow option would be to buy the other barlow that CosmoSat recommended, the 2x/1.5x one. That option would fill the 18mm void. Would that be a better option????)

If the 18mm eyepiece was 1.25 I'd probably buy that too. It's 2" though.

BTW, the focuser on this XT10i, that I'm getting, is going to be a 2" Crayford 2 speed focuser from Scope Stuff (with 1.25 adapter)... it was upgraded. I'm not sure if that matters, or not.

Edited by TahoeNoob (11/25/12 11:30 AM)


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City Kid
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Reged: 05/06/09

Loc: Northern Indiana
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538594 - 11/25/12 11:50 AM

I think that would give you a good range of magnifications.

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csrlice12
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Reged: 05/22/12

Loc: Denver, CO
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538606 - 11/25/12 11:59 AM

While heavy, The ES82, 24mm (2") is a heavy beast, the 10XTi can more then handle it. Next I'd get the ES82 11mm as it is the best of the bunch. Next is a tossup between getting the 8.8mm or a barlow for the 11mm. Me personally, my barlows exist to take up space in my bag; but they were useful until I no longer needed them, and do work well (get the shorty barlows, any of the GSO clones will do.

The ES82 24mm will give you 50X with right at 5mm exit pupil, which is considered near perfect. I'm attaching a chart showing how the different f/l ES82* (and some ES68*) would work in the 10XTi. If the weight of the 82* 24mm, consider the ES68* 24mm as it is much lighter and a little cheaper, but also works well in the 10XTi.

Another item to invest in is a collimation system, the cap that comes with the scope is only used to check the primary alignment. You will need a good cheshire/collimating eyepiece. You can get good results with these tools, however a laser collimating system will be more accurate, but also more expensive. The Howie Glatter laser/Tublug for reflectors is considered the best on the market as it is the only laser I kow of on the market that WON'T lose it's own collimation (do you really want to collimate your collimater?). You'll also want to find something comfortable to set on. I've used an old milk crate for a long time; am considering that drummers chair from Harbour Freight at $20.

I have to say, the 10mm is my alignment eyepiece to line up the finderscope and do the 2-Star alignment. If it's in view of the eyepiece then (anywhere in the field), it'll be in the FOV of the wide-fields. Other then that, the 10mm is a paperweight. The 25mm Plossel is a very good plossel, but has a limited FOV.

Also, there are a lot of free apps for your computer/phone/tablet like Stellarium to help you learn the skies.

You're gonna love that scope. Clear Skies.


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TahoeNoob
sage
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Reged: 10/31/12

Loc: Sierra Nevada
Re: Best EPs for a XT10i? new [Re: csrlice12]
      #5538706 - 11/25/12 12:58 PM

Thanks! This is the type of thread I was hoping for!

>> I'm attaching a chart showing how the different f/l ES82* (and some ES68*) would work in the 10XTi.

There's an attachment? I'm not seeing one.


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panhard
It's All Good
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Reged: 01/20/08

Loc: Markham Ontario Canada
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538711 - 11/25/12 01:04 PM

Me neither.

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csrlice12
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Reged: 05/22/12

Loc: Denver, CO
Re: Best EPs for a XT10i? new [Re: panhard]
      #5538721 - 11/25/12 01:23 PM Attachment (38 downloads)

ooops, here tis.

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TahoeNoob
sage
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Reged: 10/31/12

Loc: Sierra Nevada
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538727 - 11/25/12 01:26 PM

Ok, now I'm completely confused!

The Tublug, itself, doesn't seem to be a self contained laser emitting device, as the Orion Deluxe Collimator is. Do you have to buy a separate laser unit that fits inside the Tublug?

I think this line, here, is what's confusing me: "Use with a regular laser collimator in single beam mode to perform barlowed laser Newtonian primary mirror alignment on closed tube reflectors."

Use with a regular laser collimator? Huh? You're supposed to stick an Orion Deluxe Collimator into the Tublug? Is that what they're saying? I think I'm missing something.

The quote is from this site:
http://www.greatredspot.com/collimator.htm


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csrlice12
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Reged: 05/22/12

Loc: Denver, CO
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538735 - 11/25/12 01:34 PM

Yes, the laser is separate from the Tublug. This is a complete collimating system for both the primary and secondary mirrors. You'll never need another. A 2" Glatter laser and Tublug runs about $265. Like I said, you could go the Cheshire/collimation eyepiece route and get pretty good results for cheaper.

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TahoeNoob
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Reged: 10/31/12

Loc: Sierra Nevada
Re: Best EPs for a XT10i? new [Re: csrlice12]
      #5538773 - 11/25/12 01:56 PM

Oy! LOL

Is this the "Barlowed Laser Collimation" method that I've read about:

http://www.cameraconcepts.com/barlowed%20laser%20collimation.pdf

Why not just use a regular Barlow Lens and an Orion Deluxe Collimator?

I don't mean to be dense... but still am. I'm sorry; I'm 100 percent sure that I'm missing something.


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WAVT
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Reged: 08/22/10

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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538786 - 11/25/12 02:04 PM

You have chosen a great scope! The 10" push-to Dob is a favorite for lots of folks. Good luck with it.

The 11mm ES 82° eyepiece is a great one, and priced well. It will blow the socks off the 10mm plossl that comes with those scopes. It also barlows very well. I like the the GSO 2X 1.25" barlow as you can unscrew the lens and make it a 1.5X barlow as well. The 11mm ES 82° and a barlow will really give you some very good moderately high power viewing options.

Depending on your budget, I would also recommend a low power wide field eyepiece. In a 1-1/4" size, you can't do any better than a 32mm Plossl (for the money) Sterling, GSO 32mm Plossls are decent. The TV 32mm Plossl is excellent.

Moving up and out to a 2" low power, wide field eyepiece will enable you to take in some wonderful large patches of sky and really put objects in context with their surroundings. The 10" dob has good wide field capabilities that you should take advantage of.

The TV 31mm Nagler coupled with a Paracorr is the gold standard for gorgeous wide field views in your scope, but... the cost is astronomical.

There is an aboration called coma that is inherant in your scope. Cheap low power eyepieces do a *BLEEP* job of correcting for it and you will see seagulls instead of stars, especially around the perifery of view. TV Naglers and some of the ES eyepieces do a better job correcting for coma, and the paracorr all but eliminates it. Most people are so stunned by the wide field views that they don't notice or object to the coma they see when looking thru a good quality low power eyepiece, and for them a paracorr is not a necessity.

The 30mm ES° eyepiece strikes a good balance between price and quality. For around $250 you will get huge enjoyment cruizing the milky way and it will take in Pleiades nicely.

I bought a 38mm Orion Q70 clone(an Agena 38mm SWA) and use it in my 10 dob and really like it. Of this inexpensive line of 70° eyepieces, the 38mm is the best of the lot. Yes, the exit pupil is wasteful, and the stars have tails in the outer 1/3 of view but I still keep going back to it every time I have my 10" dob out. I bought it used on CN classifieds for $60. I would suggest you keep yours eyes open for a similar deal. You just might get hooked on big wide fields and end up investing in premium optics. You will always be able to sell it if it doesn't float your boat.

Good luck with your new scope.


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JohnMurphyRN
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Reged: 09/09/12

Loc: Near St Louis
Re: Best EPs for a XT10i? new [Re: WAVT]
      #5538828 - 11/25/12 02:18 PM

Quote:


Depending on your budget, I would also recommend a low power wide field eyepiece.

Moving up and out to a 2" low power, wide field eyepiece will enable you to take in some wonderful large patches of sky and really put objects in context with their surroundings. The 10" dob has good wide field capabilities that you should take advantage of.

The TV 31mm Nagler coupled with a Paracorr is the gold standard for gorgeous wide field views in your scope, but...


The 30mm ES° eyepiece strikes a good balance between price and quality. For around $250 you will get huge enjoyment ...






I concur...

There's an ES 82* 30mm in the EP classifieds for $200 (not mine).


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TahoeNoob
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Reged: 10/31/12

Loc: Sierra Nevada
Re: Best EPs for a XT10i? new [Re: JohnMurphyRN]
      #5538852 - 11/25/12 02:31 PM

I think I'm starting to get a handle on this. Tremendously useful information here!

Thank you everybody!


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Warren914
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Reged: 03/21/12

Loc: Nova Scotia, Canada
Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538882 - 11/25/12 02:50 PM

The Baader Hyperion 8-24mm zoom with 2x ED Barlow would give you a wide range of focal lengths down to 4mm, in either 1-1/4 or 2-inch format.

I use mine in 2-inch format with a GSO ED barlow. I find it is easier to turn the knob to find optimum magnification rather than fumble through multiple eyepieces.


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panhard
It's All Good
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Loc: Markham Ontario Canada
Re: Best EPs for a XT10i? new [Re: Warren914]
      #5538902 - 11/25/12 03:00 PM

I use my 8mm & 13mm Hyperions the most. I must also mention that I also have the fine tuning rings.

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csrlice12
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5538960 - 11/25/12 03:25 PM

Because with the Orion, You'll spend as much time collimating your laser so that you can collimate your scope. Most lasers are that you breathe near them, they'll lose collimation. The glatter is factory tested by beating them on hard surfaces before they go out the door (true story). They don't lose collimation unless you drop them while skydiving.... Kind of like the difference between a Porshe and a Yugo......both are cars, but the Porshe is a fine tuned automobile.

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panhard
It's All Good
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Re: Best EPs for a XT10i? new [Re: csrlice12]
      #5539039 - 11/25/12 04:19 PM

Glatter is good. Not at all like the cheap ones.

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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: panhard]
      #5539068 - 11/25/12 04:36 PM

I doubt doubt that, but I can't even figure out what needs to be bought for a complete setup. Oh, and expensive!

If I go this route, it'll have to be in a 1.25" model... and it can't cost 265 dollars.


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csrlice12
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5539094 - 11/25/12 04:45 PM

That's why I also earlier recommended the Cheshire/collimation eyepiece, which will give very good collimation results for visual use. Most people use these very, very effectively and have used them for years...and they are a LOT cheaper then the laser systems.

Edited by csrlice12 (11/25/12 04:48 PM)


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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5539109 - 11/25/12 04:51 PM

... also, from what I understand, you're centering a shadow that bounces back from the primary mirror, not the actual laser light that bounces back. As a result, they say it doesn't matter if the collimator "wobbles" a little bit in the focusing tube.

I saw a YouTube video where Howie even demonstrates this. Starting at about 9:10:
http://www.youtube.com/watch?v=sd3stObWI_I

If that's the case, does it really matter what type of collimator you use?



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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: csrlice12]
      #5539111 - 11/25/12 05:00 PM

Thank you csrlise12! I meant to say "I don't doubt that" in the post above... not that I do doubt it. I'm certainly not doubting your expertise. You clearly know way more than I do and probably ever will!

Even so, I think I'm going to go with an Orion Deluxe Collimator. I can't justify spending that kind of money on a collimator. Maybe later, when I find out that my system doesn't work, I'll see things differently.


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City Kid
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5539112 - 11/25/12 05:02 PM

Quote:

... also, from what I understand, you're centering a shadow that bounces back from the primary mirror, not the actual laser light that bounces back. As a result, they say it doesn't matter if the collimator "wobbles" a little bit in the focusing tube.

I saw a YouTube video where Howie even demonstrates this. Starting at about 9:10:
http://www.youtube.com/watch?v=sd3stObWI_I

If that's the case, does it really matter what type of collimator you use?






Yes it matters. When you are using the TuBlug and centering the shadow of the center spot you are adjusting the tilt of the primary mirror. However, you don't use the TuBlug when adjusting the tilt of the secondary mirror. In that case you are centering the laser to the center dot on the primary. If the laser itself isn't collimated then the tilt of the secondary mirror won't be correct.


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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: City Kid]
      #5539119 - 11/25/12 05:11 PM

That makes sense to me.

It's different parts of the whole process. I think I'm focusing too much on just one step of the process.

I need to take a break and think this over... is this a concept that all noobs struggle with?


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City Kid
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5539140 - 11/25/12 05:35 PM

I agree with csrlice12 that you can get by with a cheshire eyepiece for now. It would be a lot cheaper than the Glatter tools. What I wouldn't do is buy a cheap laser collimator. You can be more accurate with a cheshire than a miscollimated laser. Eventually you will see the need for better tools and you can spend the money then. Until then, learn to collimate with the cheshire. I would also suggest that you take a look at the Catseye collimation tools. They are every bit the quality of the Glatter tools. I have both the Catseye and the Glatter and I like them both. In fact the cheshire that Catseye sells would be great if it's not out of your budget.

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Re: Best EPs for a XT10i? new [Re: City Kid]
      #5539200 - 11/25/12 06:25 PM

You can use a Orion laser collimator and get the exact results as a TuBlug, I do it all the time, all you need is a barlow. See link http://www.smartavtweaks.com/RVBL.html
Tim


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Re: Best EPs for a XT10i? new [Re: Tim D]
      #5539454 - 11/25/12 09:36 PM

Quote:

You can use a Orion laser collimator and get the exact results as a TuBlug, I do it all the time, all you need is a barlow. See link http://www.smartavtweaks.com/RVBL.html
Tim




Thank you! I finally understand! I can't wait to try this. Thank you!!!


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CosmoSat
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5539635 - 11/25/12 11:34 PM

Quote:

Even so, I think I'm going to go with an Orion Deluxe Collimator. I can't justify spending that kind of money on a collimator. Maybe later, when I find out that my system doesn't work, I'll see things differently.




Here are a few collimators to choose from..Collimation & Focusing Tools. Over the Orion collimator..I would rather suggest u the Agena 1.25" Side View Newtonian Laser Collimator with 2" Adapter which I believe is manufactured by GSO or this one...GSO 1.25" Newtonian Deluxe Laser Collimator III.

The 25mm plossl u hve giving a 5mm exit pupil and around 50x magnification shud take care of the low power views for now..u can consider one later if u are not happy with the views or if u find urself using those low powers most of the time.

Rather try finding an eyepiece of around 15mm fl for dso's.

For planetary I would suggest u the ES 4.7mm Eyepiece giving an 1mm exit pupil and about 250x magnification. with the 1.25" barlow..u would get 375x and 500x mag.

Clear Skies!


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Re: Best EPs for a XT10i? new [Re: CosmoSat]
      #5539761 - 11/26/12 02:41 AM

I bought an Orion Deluxe Laser Collimator and ended up giving it away with the warning that it was only useful as a cat toy. If I touched it while it was in the focuser, the red dot jiggled all over the place. If I turned it in a circle in the focuser, the red dot made a circle on the primary.

I replaced it with a much cheaper Cheshire/sighttube combo that works just fine, doesn't need adustment and has no moving parts to break or wear out.

Maybe if the scope were f/4 or less, and cost a fortune, I could see the need for laser precise collimation to squeeze out every ounce of possible performance. For a 10" f/4.7, just center the crosshairs in a cheap Cheshire and be done with it.


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csrlice12
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Re: Best EPs for a XT10i? new [Re: TexasRed]
      #5539977 - 11/26/12 09:24 AM

TexasRed is right. For now, use the Cheshire/sighttube combo. More accurate collimation would only really be needed for AP.

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howard929
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Re: Best EPs for a XT10i? new [Re: csrlice12]
      #5539997 - 11/26/12 09:46 AM

Quote:

TexasRed is right. For now, use the Cheshire/sighttube combo. More accurate collimation would only really be needed for AP.




As you know, a mis-collimated secondary results in a loss of light while a mis-collimated primary results in a loss of clarity. I found that getting collimation as close to spot on as I can before ventureing out is an important step for successful viewing. Couple that with changing collimation during a long viewing session due to tube flexure , it's handy to be able to collimate in the dark and IME that's where a barlowed laser set-up for tweaking the primary mirror really pays off.


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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: howard929]
      #5540172 - 11/26/12 11:43 AM

I don't mean to start a fist fight, but are the HoTech collimators (they're available on eBay) worthwhile?

BTW, there's also a 2" Glatter collimator available on eBay for a Buy It Now price of 220. (If those things were half the price, I'd probably bite the bullet and buy one.)


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csrlice12
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5540184 - 11/26/12 11:53 AM

The Glatters are nice to have, but like anything, your budget is going to come into play. It took me many years before I started earning the money to allow me to afford some of the better equipment. You can get along fine with the manual barlow/laser method or the Cheshire collimation equipment for a much lower price. The difference for viewing will be negligible....

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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5540255 - 11/26/12 12:43 PM

Quote:

I don't mean to start a fist fight, but are the HoTech collimators (they're available on eBay) worthwhile?






I have one and like it. There's a used one in CNC reasonably priced (not mine).

I was using a cat-toy mounted with set screws in a piece of PVC for collimation before I got the hotech. With the use of a barlow, my primary was spot-on using that cobbled together makeshift(you don't center the return laser; you center the centerdot's shadow)....


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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5540354 - 11/26/12 01:52 PM

In case they haven't been mentioned already, the Baader Planetarium Hyperions are very good buys. The Celestron X-Cel LX eyepieces are quite good for planetary work.

The Explore Scientific 68 and 82 degree eyepieces are well worth considering, as has already been mentioned.

Dave Mitsky


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csrlice12
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Re: Best EPs for a XT10i? new [Re: Dave Mitsky]
      #5540362 - 11/26/12 01:59 PM

I know we have been discussing eyepieces and collimater, etc...but let's not lose sight that the best thing you can do for your scope is to get it to dark skies. A collimated scope in dark skies will perform better with ANY eyepiece....

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howard929
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5540472 - 11/26/12 03:03 PM

Quote:

I don't mean to start a fist fight, but are the HoTech collimators (they're available on eBay) worthwhile?

BTW, there's also a 2" Glatter collimator available on eBay for a Buy It Now price of 220. (If those things were half the price, I'd probably bite the bullet and buy one.)




The rub with a laser like that one (GSO, Orion, Hotech) is they don't fit snugly in the focuser and don't set themselves in the focuser the same way with each insertion. That's not a problem for adjusting the primary mirror if a barlow is used but it's a disaster for adjusting the secondary mirror. I use a sight tube for that which is a once in a blue moon adjustment and a barlowed laser for the primary which I tweak quite often. So, yes, that HoTech should be fine for the all important primary mirror adjustments as long as you use a barlow with it.

Edited by howard929 (11/26/12 03:06 PM)


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JohnMurphyRN
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Re: Best EPs for a XT10i? new [Re: howard929]
      #5540541 - 11/26/12 03:38 PM

Quote:

Quote:

I don't mean to start a fist fight, but are the HoTech collimators (they're available on eBay) worthwhile?

BTW, there's also a 2" Glatter collimator available on eBay for a Buy It Now price of 220. (If those things were half the price, I'd probably bite the bullet and buy one.)




The rub with a laser like that one (GSO, Orion, Hotech) is they don't fit snugly in the focuser and don't set themselves in the focuser the same way with each insertion. That's not a problem for adjusting the primary mirror if a barlow is used but it's a disaster for adjusting the secondary mirror.




I considered that, so after collimation was complete I removed and reinserted the hotech and it still showed centered. It's a tight fit in the focuser and returns to same orientation. FWIW, lately I just collimate with the hotech without barlow and call it done.


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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: JohnMurphyRN]
      #5540666 - 11/26/12 04:58 PM

Is a "sight tube" the same as a Cheshire? I think I'll be getting one of those with my scope. It'll do, for now, until I have a better idea what I need/want.

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Dave Mitsky
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5540884 - 11/26/12 07:38 PM

No, although a sight tube and a Cheshire "eyepiece" can be combined in one unit.

http://www.garyseronik.com/?q=node/165

http://www.tomhole.com/Barlowed%20Laser.htm

http://www.amateurastronomy.com/collimate.html

Dave Mitsky


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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: Dave Mitsky]
      #5542422 - 11/27/12 04:26 PM

Thank you. I bought one of those sight tube/Cheshire combo units last night.

Meanwhile, is a 3X barlow a bad idea? (I know they make them up to 5X, but are they worthwhile?)


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csrlice12
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5542429 - 11/27/12 04:29 PM

To be truthful, my Orion Trimag (3X barlow) has been in my scope once-when I bought it; and has been in the case since then. It would have to be a very rare night of seeing for me to consider using it....

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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: csrlice12]
      #5542474 - 11/27/12 04:57 PM

I bought 24mm and 11mm ES 82* eyepieces. I'd like to get an 18mm, and maybe a 4.7 at a later point in time. For now, I feel like I've spent enough money though!

I'm wondering... last night I was reading Backyard Astronomy Guide and I read that the longest eyepiece I should get for my XT10i is something like 31/32mm. It has to do with the exit pupil diameter being 7mm... so anything longer than that would be a waste of glass/money. Is that true?

I'm mostly interested in DSOs, not the planetary stuff, so I think it makes sense to focus more on the longer eyepieces. That's correct, right?


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GOLGO13
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5542494 - 11/27/12 05:11 PM

Tahoe...you can try out the numbers with your eyepieces, but a 3x barlow wouldn't be bad per se. Gives 150x with a 24mm eyepiece. On a really good night it would give 400x with a 9mm eyepiece.

I have 2x and 3x barlows...I admit I got the 3x for my refractors so I could get higher magnifications, but it works find in the reflectors also. If you have nice 2x and 3x barlows, you don't need a lot of eyepieces to get a wide range of magnifications.


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CosmoSat
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5542500 - 11/27/12 05:14 PM

For most DSO's.. a 15mm or so eyepiece giving a 3mm exit pupil would be more useful. A 5mm-7mm exit pupil for a handful of objects like the pleadies or the Andromeda galaxy or for scanning the rich milky way region.

Clear Skies!


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GOLGO13
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5542505 - 11/27/12 05:17 PM

Low power is good...but you will want one eyepiece with an exit pupil of 2 as well.

Yes, with your scope 31 or 32mm eyepieces would pretty much max out exit pupil. As you get higher numbers you may start getting blackouts (I think it's the central obstruction which causes that phenomenon). I use a 24mm as my low power...since you got one I'd say your OK for low power.

Your 11mm is a good DSO and medium power eyepiece.

Then you'd want one higher power one for smaller DSOs like Globular clusters and planetary nebulas.

That's actually all you'd really need in my opinion.


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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5542527 - 11/27/12 05:30 PM

CosmoSat, you're saying I should skip the 18 and get the 14 instead?

I bought that 2x barlow you suggested. (The one that doubles as a 2x or a 1.5x.) My 24 will become a 16mm or 12mm.


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Dave Mitsky
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5542539 - 11/27/12 05:45 PM

Quote:

I'm wondering... last night I was reading Backyard Astronomy Guide and I read that the longest eyepiece I should get for my XT10i is something like 31/32mm. It has to do with the exit pupil diameter being 7mm... so anything longer than that would be a waste of glass/money. Is that true?

I'm mostly interested in DSOs, not the planetary stuff, so I think it makes sense to focus more on the longer eyepieces. That's correct, right?




An eyepiece producing an exit pupil greater than 7mm (for those whose pupils can still dilate that much) effectively reduces, or stops down, the aperture of the telescope, thus trading a greater field of view for decreased brightness. This works up to the point when the shadow of the secondary mirror (the central obstruction in an obstructed design) starts to be very noticeable.

Dave Mitsky


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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: Dave Mitsky]
      #5542568 - 11/27/12 06:07 PM

Ok, that's actually good news. The 30mm eyepiece is pretty expensive. If I don't need it, that's a good thing! The 24mm ES 82* will be my longest eyepiece. It's a 2" eyepiece. Big and heavy!

So, being more interested in DSOs than the planetary stuff, does it make more sense for me to fill the gap between 24mm and 11mm with an actual eyepiece, and then fill the high power gap (below 11mm) with my 2x and maybe a 3x barlow? (That would give me some extra eye relief on the high power stuff too, I think. That would be good.)

I feel like I'm getting close to understanding what I need. The way I'm looking at it is this: "focus on eyepieces between 24mm and 11mm, and "cheat" a little bit below 11mm." Is that a bad idea, or is it reasonable... for somebody that's interested mostly in DSOs? (I can't even see the ecliptic from my house, unless I break out the chain saw. Getting into the car wouldn't be the end of the world.)

Sorry for all the thinking out loud, but I'm also looking for confirmation. Which, I guess, means I'm asking. Am I totally out to lunch here?


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Dave Mitsky
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5542577 - 11/27/12 06:14 PM

I would skip the 3x Barlow lens and get a 7 or 8mm eyepiece with good eye relief.

Dave Mitsky


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BDS316
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5542723 - 11/27/12 07:54 PM

Low power finder eyepiece: a 2 incher. You only need one 2-inch eyepiece with a scope of 1200mm focal length.
30mm Sterling Plossl or 28mm ES 68deg or used Meade 28mm SWA

Medium power: 11mm ES 82deg

High power: 1.8-2x Barlow used with the 11mm.

Hi quality minimalist set.


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GOLGO13
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5542813 - 11/27/12 09:02 PM

I would focus on your high magnification eyepiece vice finding something between 24mm and 11mm. You could barlow your 11mm or get the 6.7mm 82 (a personal favorite of mine).

low, medium, high = happy observer


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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: GOLGO13]
      #5543229 - 11/28/12 02:22 AM

6.7mm gives me 179X, which I could barlow to just below 400x.

What is the most powerful magnification that I'm ever likely to want to use? Under absolutely perfect seeing conditions. 400?


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CosmoSat
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5543255 - 11/28/12 03:02 AM

The highest useful magnification that the 10" f/4.7 scope can be used at under perfect conditions will be around 500x and a 0.5mm exit pupil(that is 50x per inch of aperture). The 4.7mm eyepiece will give u a 1mm exit pupil and 255x magnification, and with the 2x/1.5x barlow u get 0.5 and 0.75mm exit pupils with about 380x and 510x..thats a good range for planetary whenever u get the opportunity to use it.

As for the mid power...u rather hold back until u get the telescope...try using the ones u hve and see how they fare.. The 24 along with the barlow will work very well too.

Clear Skies!


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TahoeNoob
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Re: Best EPs for a XT10i? new [Re: CosmoSat]
      #5543262 - 11/28/12 03:19 AM

Perfect! Thank you very much!

That's the exact information that I was looking for. And yes, that's what I'm going to do. Hold back, and see what happens. (BUT, I'll write down what I've learned... so I'll have it in the future.)

I think that 2x/1.5x barlow is going to come in very handy.


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WAVT
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Re: Best EPs for a XT10i? new [Re: CosmoSat]
      #5543268 - 11/28/12 04:10 AM

It is theoretically possible to achieve a view thru a 10" manually driven dob at 500X but I haven't done it. The hand eye coordination and concentration required are astronomical, not to mention that the seeing conditions must be absolutely perfect. It took many hours of eyepiece time for me to achieve satisfactory views above 200X. At 300X I don't find observing very much fun (in an undriven scope)

Put 6 or 11 dozzen hours with your eye up to the 6.7mm ES82° in your 1200mm scope (179.1X) then decide if you need more power. This is a great high power eyepiece for someone starting out on a XT10i.

It's all about practice. Your eye needs to learn and discern detail at the eyepiece. Only after many many hours of manually guiding a Dobsonian mounted Newtonian Reflector will you become one with the scope. Even some of the most acomplished veteran observers will push or pull the wrong way.

To find and observe cool stuff with a dob is easy. Point and look. It's that easy. Get some practice and go up over 100X. Now you've got to pay attention. Go to 200X and you will be amazed at how fast the target appears to move. (actually, it appears to move 200 times faster than you would see movement with the naked eye)

Fast Newtonian reflector telescopes can show several degrees ° of sky with a low power wide field eyepiece. It is easy to keep a target within your field of view, and the plethora of targets means you can casually spend a lifetime looking at really cool stuff. Don't be too quick to crank up the power. That is a real newby mistake. Enjoy that 25mm, and get to know your scope. Learn the sky ( a little at a time) only then will you be able to push the limits of the scopes capabilities. Astronomical viewing is a lesson in patience. Relax and enjoy the ride.


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GOLGO13
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Re: Best EPs for a XT10i? new [Re: TahoeNoob]
      #5543382 - 11/28/12 08:03 AM

500x (I've done it a few times in my 10 inch) is possible. But that would need to be an exceptional night. In general 300x is more reasonable as a max for most observing conditions. I tend to stay closer to 240x as my max.

I agree a barlow is useful for those nights where everything is perfect. It's nice to be able to push the scope to its limits.


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csrlice12
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Re: Best EPs for a XT10i? new [Re: BDS316]
      #5543388 - 11/28/12 08:12 AM

I have both the 30mm and 24mm in the ES 82* series and I use the 24mm a LOT more then the 30mm. The 24mm frames the lagoon nebula beautifully. With the 30mm I can't take in the whole FOV, I have to move my head around to see it all..but then, I'm nearing 60, so someone younger might fit the FOV of the 30.

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