Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

General Astronomy >> Beginners Forum

Pages: 1 | 2 | 3 | 4 | (show all)
kfiscus
Carpal Tunnel
*****

Reged: 07/09/12

Loc: Albert Lea, MN, USA
Re: Orion XT8 questions...and more... new [Re: stargazer424]
      #5565038 - 12/10/12 10:40 PM

I have always given the advice to people starting to buy gear to start with 2 EPs, then a barlow, then a high-power EP if they still want to. If the OP is torn between brands of barlow, I'd say to wait, research, borrow and try, then buy. The nice thing is, barlows are cheaper than EPs.

Post Extras: Print Post   Remind Me!   Notify Moderator  
stargazer424
sage


Reged: 10/03/05

Loc: Central NJ
Re: Orion XT8 questions...and more... new [Re: kfiscus]
      #5565093 - 12/10/12 11:15 PM

Order Placed! Went without the Barlow, but I do think I will be getting one. Just need to find the right one at the right place...

Post Extras: Print Post   Remind Me!   Notify Moderator  
Shawn Garbett
member


Reged: 10/02/12

Loc: Nashville, TN
Re: Orion XT8 questions...and more... new [Re: stargazer424]
      #5565131 - 12/10/12 11:35 PM

I recently got the Orion XT10g for my wife. She loves it. I can answer a few of these.

Quote:


Question 1: Orion XT8, is it easy to transport? I live in an apartment and would need move the telescope to a different location to use it.





You'll probably be alright in that regard. For the 10" we're talking about a bigger car, probably a mini-van already. Moving it around is easy. It's the room it takes up in car that can be a problem (got to put kids somewhere). The 8 is probably more manageable.

Quote:


Question 2: Could someone run down eyepiece/lenses in layman's terms. I am versed in cameras/photography so is it the same where the higher the mm the more "zoom" you get? Are there "must have" and "don't ever buy" eyepieces. And what is a Barlow? I wear glasses, does that affect eyepiece selection at all?





Pay attention to the maximum and minimum effective magnification on the website. The range is 29-300X for the XT8. It has a 1200mm focal length. So eyepieces should never be outside of 41mm to 4mm in size. You want a wide field and a higher magnification. I would recommend something around 25-30mm for the wide field. Preferences for the higher mag run between 8-15mm for this size scope. We have the 25mm deep sky Orion and the 9mm ES 100. A 2X barlow would give you a 12.5mm and a 4.5mm equivalent with these two, a good range. Asking about barlows is a loaded question, opinions run the to all extremes about them. I think you have to try one for a year, and use several eyepieces before you make up your mind. If you wear glasses, eye relief is important. 17mm or larger is great. 15mm or less and the field of view will be reduced (I.e., if you get a 100 degree, can you live with only realizing 82 degrees?). Unless you have astigmatism, you can probably focus without the glasses. The package I got also had a 14.5 with illuminated cross hairs for alignment. It's irritating for anything but alignment on the goto, but I don't know how I'd live without it. If you don't get the goto, you won't need anything like it.

300X is for the rare day the weather is perfect, don't go for this to start.

Once you advance to seeing the limitations of your equipment in few years, consider a paracorr. At present, I've learned what the coma is, but haven't been bothered by it enough to drop the $$$. I've heard getting a paracorr, is like a scope upgrade for the dobsonians. So you can enjoy a better scope in years to come.

Quote:


Question 3: How high up is the eyepiece on average when viewing. I'm 5'10", would I need to be sitting or bending over to view? I have a camping chair, but I don't know if it will be tall enough to use.





You'll probably be fine standing. However, some folks like a right-angle finder upgrade to save their neck. Personally, I couldn't do without it--I'm physically fit, but had a back injury years ago that doesn't allow certain positions.

Quote:


Question 4: Any thoughts on Orion's "Build a scope" to customize accessories VS getting the scope and accessories/upgrades separate? What about the Beginner Barlow Kit or the LE Bundles?





Decide and try different configurations. Buy the minimum possible to get started--this is the best advice I got a few months back. To balance it if you get a bigger finder and heavy eyepieces, get a couple 1lb magnets and wrap them in duck tape.

Quote:


Question 5: Everyone talks about how easy a dob is to push around to find something. Can you tighten/loosen the mechanics? I think I am more worried about finding something and then accidentally moving the scope and losing it than not being able to move it at all.





After a few nights with it and a copy of "Turn Left at Orion". I can find things quite rapidly. Never tried to tighten or loosen. If you bump it, you find it again. It's part of the experience, and I find it relaxing. Each to his own.

Quote:


Question 6: What will I actually see when looking at, say, a nebula? I know it won't look like Hubble images, but will it just look like a cloud, or will it be interesting. Anyone have photos that more closely represent visual experience.





A nebula will look like a wisp of grey cotton in an odd shape, unless it's Orion. They are more difficult to see, and nebula filters help. They are still fascinating. I did a public telescope party recently. Setup the dumbbell nebula with a filter. When you tell a 6 year old that's an exploded star, their jaws drop. I personally, having a background in finding resonances in 3-d spaces, found the shape fascinating. Orion, is the only one you can really see the color, and it's jaw-dropping.

Read up on dew. Get a hair dryer. I've been looking into 12V ones to run off a marine battery.

Jupiter is incredible right now, if it weren't for the d*** clouds.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Allan...
sage


Reged: 10/24/12

Loc: Penticton B.C. Canada
Re: Orion XT8 questions...and more... new [Re: stargazer424]
      #5565224 - 12/11/12 12:32 AM

I have an XT8 and was wondering if I should buy an ES11 or not. I already have a good Agena 20mm (70 deg) which I like very much; barlow it down with a 2x to 10mm. Will I see much benefit in getting the 11mm (other than wider view)? Or should I go for something like an 8.8mm ES? I dont have anything in that range as yet, though I do have a 14mm that I sometimes try to barlow down to 7mm but often its too much, with my seeing conditions. thanks, Clare

Post Extras: Print Post   Remind Me!   Notify Moderator  
CosmoSat
Pooh-Bah


Reged: 07/24/09

Loc: India
Re: Orion XT8 questions...and more... new [Re: Allan...]
      #5565371 - 12/11/12 03:25 AM

with ur f/6 scope for highpower planetary viewing I would recommend atleast one eyepiece giving u something around an 1mm exit pupil like this Agena 1.25" Enhanced Wide Angle Eyepiece - 6mm to be used whenever the conditions allow.

Clear Skies!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Billytk
scholastic sledgehammer


Reged: 04/22/12

Loc: Lake Mary, Fl.
Re: Orion XT8 questions...and more... new [Re: CosmoSat]
      #5565464 - 12/11/12 07:14 AM

I have a Baader zoom eyepiece and a 2x barlow. The zoom ranges from 24mm to 8mm. It's like having a case of eyepieces in one package. I love it!

Post Extras: Print Post   Remind Me!   Notify Moderator  
nploop102
member


Reged: 12/06/12

Loc: Austin, TX
Re: Orion XT8 questions...and more... [Re: stargazer424]
      #5566861 - 12/12/12 12:40 AM

Quote:

Order Placed! Went without the Barlow, but I do think I will be getting one. Just need to find the right one at the right place...




Sweet!


Post Extras: Print Post   Remind Me!   Notify Moderator  
stargazer424
sage


Reged: 10/03/05

Loc: Central NJ
Re: Orion XT8 questions...and more... new [Re: nploop102]
      #5567756 - 12/12/12 02:42 PM

Quote:

with ur f/6 scope for highpower planetary viewing I would recommend atleast one eyepiece giving u something around an 1mm exit pupil



Ok so I understand Focal Length, Field of View and Eye Relief. What is the exit pupil?


Post Extras: Print Post   Remind Me!   Notify Moderator  
pogobbler
sage


Reged: 09/30/08

Loc: Central Indiana, USA
Re: Orion XT8 questions...and more... new [Re: stargazer424]
      #5567832 - 12/12/12 03:29 PM

Quote:

Quote:

with ur f/6 scope for highpower planetary viewing I would recommend atleast one eyepiece giving u something around an 1mm exit pupil



Ok so I understand Focal Length, Field of View and Eye Relief. What is the exit pupil?




The exit pupil is basically the diameter of the light exiting the eyepiece. You can calculate it by dividing the focal length of the eyepiece by the focal ratio of the telescope... for example, a 30mm eyepiece in an f/6 scope would give an exit pupil of 30/6 or 5mm. Lower powers have larger exit pupils and higher powers have smaller exit pupils. Since the pupil of the dark adapted eye is going to be around 7mm (the "entrance pupil") for most people, an exit pupil of greater than that is "wasting" light, reducing the effective aperture of the scope, so a power that gives a 7mm exit pupil is generally given as the lowest effective power for the particular scope. People's maximum pupil size will vary, and tends to decrease with age, but 7mm is a decent rule of thumb. At small exit pupils, the floaters in the eye become more prominent-- think of the sharp shadows produced by a concentrated light source, equivalent to a small exit pupil vs. diffuse shadows produced by an extended, diffuse light source. These floaters can be an issue with high powered planetary or lunar observing, bothering some observers more than others. Doing a little math, the 1mm exit pupil the poster recommended would be a 6mm eyepiece (6mm/6 = 1mm), or, of course, a 12mm eyepiece with a 2x Barlow. The magnification would be 200x, which is a good reasonably high power, though, with scopes about 6-8" and up, I like being able to hit around 300x, too, for those nights of very good seeing. I've used such powers on my own XT8 on Jupiter this fall and it was still a very useable power and I could track manually just fine.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Allan...
sage


Reged: 10/24/12

Loc: Penticton B.C. Canada
Re: Orion XT8 questions...and more... new [Re: pogobbler]
      #5568017 - 12/12/12 05:51 PM

Great (and easy to understand for a newbie) explanation of exit pupil, Tom. My eyes arent that young anymore and I think mine are likely less than 5. How do you find that out? From an Optomestrist/eye exam? I have witnessed the floaters, too; not a big problem though; I learn to ignore them. In the Summer, when I had just got my XT8, I thought that I was looking at insects flying across the scope but when Fall and Winter hit, and they were still there, THEN I knew what was happening...lol. As I said, its no biggy. thanks, Clare

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starhunter249
sage


Reged: 06/07/10

Re: Orion XT8 questions...and more... new [Re: Allan...]
      #5568280 - 12/12/12 09:06 PM

I have the xt8g and its very portable in two pieces. I seldom carry it all in one piece. Its heavier than the classic version. It should be pretty easy to move around. Stairs will be a two trip affair for just the telescope.

Eyepieces- I rarely use a 4 mm. Most of the time I can push 200x (6mm) on average. Good nights, 250x. Nights of extreme dry and steady air that permits the use of the 4mm, i can push the scope to 400x with a barlow.

I have the 38mm 2inch Q70. It is surprisingly really good for those massive wide field views of the pleades and double cluster for example. Good bang for your bucks.

The owl expanse pieces are cheap and better than the Orions. I think they are $30 dollars a piece. Atleast that is what I paid for them. The 9mm and 15mm are my favorite. The TMBs are not as good as I was expecting. Bright objects will scatter light around the edges. Its really annoying. I don't use them as much. Other eyepieces that I recommend are the sterling plossls. There are wicked sharp and cheap. My favorite is the 20mm. I have two of them for binoviewing.

You can get a lot of good cheap eyepieces that perform to about 90 percent of the top of line expensive eyepieces. I have a poor man budget so I got to shop for bang for the bucks. Wait til after xmas. Massive eyepiece sales and you can pick a lot on the cheap.


Post Extras: Print Post   Remind Me!   Notify Moderator  
stargazer424
sage


Reged: 10/03/05

Loc: Central NJ
Re: Orion XT8 questions...and more... new [Re: Starhunter249]
      #5568879 - 12/13/12 09:38 AM

Eyepiece sales AFTER Christmas? I would have thought they would be cheaper right before. Oh well, I will keep my eyes open. Just have to decide which pieces to get. I don't have a huge budget for EPs, and I can't really imagine spending $100+ on one at this time.

Since the telescope I ordered comes with a 2" 30mm Wide Field (40x) and a 1.25" 9mm Plossl (133x), I was thinking of the following to start:

- 2" 2x Barlow so I can use it for both the 30mm and the 9mm giving me a 15mm (80x) and 4.5mm (266x)
- Something in the 12mm range (100x/200x)

With that I would have 40x, 80x, 100x, 133x, 200x, 266x. That would probably give me a good, even starting setup, right?

Is there any need for a beginner to get something LARGER than 30mm or something between 30 and 12?


Post Extras: Print Post   Remind Me!   Notify Moderator  
Shawn Garbett
member


Reged: 10/02/12

Loc: Nashville, TN
Re: Orion XT8 questions...and more... new [Re: stargazer424]
      #5568922 - 12/13/12 10:13 AM

Quote:

With that I would have 40x, 80x, 100x, 133x, 200x, 266x. That would probably give me a good, even starting setup, right?




That's a lot of options. The 30mm and 9mm with barlow is enough to start.


Post Extras: Print Post   Remind Me!   Notify Moderator  
stargazer424
sage


Reged: 10/03/05

Loc: Central NJ
Re: Orion XT8 questions...and more... new [Re: Shawn Garbett]
      #5569217 - 12/13/12 01:00 PM

OK, so Barlow it is! I'll need a 2" Barlow. Been looking at this one:

Zhumell 2in. 2x ED Barlow

Or this one at the same price:
Apertura 2” 2X ED Barlow Lens


Then there is this one, which looks like the same one, and pretty much the same $$ with shipping:
Astro-Tech AT22XB

This one looks the same but its more $$:
GSO's 2" 2x ED Barlow

I am guessing they are ALL the same ones, but with different branding?

Any other websites/stores that would sell any of these for less? Amazon has them at 59.98 too.


Post Extras: Print Post   Remind Me!   Notify Moderator  
nploop102
member


Reged: 12/06/12

Loc: Austin, TX
Re: Orion XT8 questions...and more... new [Re: stargazer424]
      #5569236 - 12/13/12 01:07 PM

Let me know how that Barlow works out for you. I might get one as well sometime after Christmas.

Post Extras: Print Post   Remind Me!   Notify Moderator  
galexand
sage
*****

Reged: 07/10/12

Loc: Bloomington Indiana
Re: Orion XT8 questions...and more... new [Re: stargazer424]
      #5569386 - 12/13/12 02:34 PM

I figure you've got more than enough answers on most of these questions. So for most of them, I'm just going to say: Don't be afraid to under-spend on eyepieces. The "cheap garbage" coming out of China these days is comparable to a precious gem 20 years ago.

But question 6, what do you see. I recommend looking at sketches. Sometimes the artist can get a little carried away with nebulae, but a lot of the sketches here just exactly match how I see it through the eyepiece. For example I would call these drawings of globulars canonical:

http://www.cloudynights.com/ubbthreads/showflat.php?Cat=&Board=Sketching&...

Might want to check out the rest of the board:

http://www.cloudynights.com/ubbthreads/postlist.php/Cat/0/Board/Sketching


Post Extras: Print Post   Remind Me!   Notify Moderator  
Allan...
sage


Reged: 10/24/12

Loc: Penticton B.C. Canada
Re: Orion XT8 questions...and more... new [Re: galexand]
      #5570049 - 12/13/12 10:08 PM

Would like to hear people's opinions of using weights on the OTA of an XT8. I may order a RACI and heavy eyepieces soon and suspect it will be top heavy. Magnets? Where to get? How best to attach? thanks, Clare

Post Extras: Print Post   Remind Me!   Notify Moderator  
galexand
sage
*****

Reged: 07/10/12

Loc: Bloomington Indiana
Re: Orion XT8 questions...and more... new [Re: Allan...]
      #5570634 - 12/14/12 10:48 AM

Testing your pupil size...

This may not be accurate, but here's how I *think* I tested the size of my eye's pupil. This could probably stand to be a whole separate thread.

I put a 25mm eyepiece in my 6" F/5 reflector, so that yields an exit pupil of 5mm (mm of eyepiece / F-number of telescope). I found a bright star and slightly de-focused it, just so it was big enough that I could clearly see the secondary shadow. So I was looking at a little white circle with a black hole in the middle, and 4 black lines for the secondary spider supports. I think that white circle basically represents the primary mirror, or equivalently the aperture of the telescope. So if my eye's pupil is bigger than the exit pupil, I would expect to be able to see light from the entire mirror at once. On the other hand, if the exit pupil is larger than my eye's, then part of the mirror would not be visible, the light that hit that part of the mirror would be wasted.

In this case, I could not see the entire mirror. As I moved my eye around (getting different angles into the EP), I could clearly see different parts of the mirror, but never the whole thing at once. So I concluded my pupil was (slightly) less than 5mm. I switched to a 17mm EP (exit pupil 3.4mm), and could easily see the whole mirror at once, so I think the pupil was more than 3.4mm. I'm only 32, but there is a *lot* of localized light pollution on my front porch so I was probably not very dark-adapted so a pupil around 4-5mm seems plausible to me.

The only caveat I can think of is that the exit pupil of the EP might change slightly when it is out-of-focus like that, that's why I de-focus it only a little bit. But for all I know the technique itself is entirely bogus. I just like thinking of new ways to look through the telescope to try to visualize some of the optics concepts I read about..


Post Extras: Print Post   Remind Me!   Notify Moderator  
Billytk
scholastic sledgehammer


Reged: 04/22/12

Loc: Lake Mary, Fl.
Re: Orion XT8 questions...and more... new [Re: Allan...]
      #5570786 - 12/14/12 12:35 PM

Quote:

Would like to hear people's opinions of using weights on the OTA of an XT8. I may order a RACI and heavy eyepieces soon and suspect it will be top heavy. Magnets? Where to get? How best to attach? thanks, Clare




Try Scope stuff. I think that's the name? I belive they have them.


Post Extras: Print Post   Remind Me!   Notify Moderator  
CJK
professor emeritus


Reged: 12/05/12

Loc: Northeast TN
Re: Orion XT8 questions...and more... new [Re: Allan...]
      #5572077 - 12/15/12 07:06 AM

Quote:

Would like to hear people's opinions of using weights on the OTA of an XT8. I may order a RACI and heavy eyepieces soon and suspect it will be top heavy. Magnets? Where to get? How best to attach? thanks, Clare




ScopeStuff likely has what you need: Telescope Balancing Kit

-- Chris


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | (show all)


Extra information
2 registered and 21 anonymous users are browsing this forum.

Moderator:  zjc26138, WOBentley, kkokkolis 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 2940

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics