Beginner's Eyepiece Strategy
Posted 30 November 2013 - 10:31 AM
In the meantime get yourself a great 2"diagonal and a feathertouch 2x focuser. If you decide to go for an electronic focuser, also consider top end options. You will always be able to use most of these on any scope.
After you've saved some more money up, consider investing as much possible on a good mount (avx, ioptron, lx850, AP, etc, this will mainly depend on your budget). After that, upgrade your scope and keep going after eyepieces until you have a decent set of great ones.
Only then, should you consider astrophotography and a refractor. Otherwise you will end up spending thousands and end up with some frustration because you can't those amazing pictures.
If you want pictures go for a mount then a great refractor or astrograph.
An SCT Like you SE is a great starter scope. If you add the Wifi link and spend some money on sky safari, you will have lots of fun. If you have a Canon or Nixon digital camera, spend some more on DSLR remote and it will keep your astrophotography desires in check until you can afford a decent rig for that purpose.
Regarding Barlows, go for focal extenders instead of Barlows.
Posted 30 November 2013 - 12:04 PM
Seems like I should get the scope, a 16mm ortho to go along with the 25mm kit plossl, and a barlow so I can experiment at four different magnifications. After I get familiar with it, I will spend the real $$$$ on the focal lengths I really like
Posted 30 November 2013 - 06:35 PM
After several days of doing scattered research on the web, I am at the point where I think I could benefit from some direct advice. I've decided on a scope (Nexstar 8 SE), and now I am trying to figure out which eyepieces to start out with. I realize that my preferences will evolve over time, so I'm just looking to get started with something that makes practical sense. So here is my plan so far.
Scope Specs: 203mm, f10
1) 32mm plossl - 64x, 3.2 exit pupil. Something basic
2) 20mm wide - 100x, 2.0 exit pupil. Everything I read tells me that that is the "Sweet spot", and this is where I will likely be spending most of my time. Therefore, I'm willing to invest a little more here and get something with great contrast and a wide field of view
3)10mm ortho - 200x / 1.0 exit pupil - for when I want to look at planets. Don't need wide field of view here, and the ortho design seems to be the best bang for the buck.
OK, I've just browsed prior responses, but here goes...
I just actively returned to this pursuit after 35 years on the sidelines and probably the biggest change has been eyepieces, so I'm not far off where you are (I bought a C8).
The first thing I decided was to buy high quality basic eyepieces until I could decide what I really wanted. As a result I bought:
32mm TeleVue Plossl
25mm TeleVue Plossl
20mm TeleVue Plossl
15mm TeleVue Plossl
The 15, 20, 25 I bought as a set from someone on the classifieds. It helped me sort out the myriad possibilities of focal lengths. Plossls are nice solid basic performers, and the better the quality you can afford the better. I bought these because I knew I could resell them and recoup virtually all of my initial investment (I've bought all my eyepieces used). I added the 32 when a deal became available.
I bought a 2x extender from Explore Scientific. Highly regarded and not expensive (only thing in my eyepiece case bought new). I've since bought a 2.4x Dakin barlow, but I bought that purely because I knew Ralph Dakin before my hiatus from astronomy (I have other things from him as well). I also picked up a 0.63x reducer. More options...
I decided I wanted more magnification for the few times I could really enjoy it and bought a nice classic volcano top 6mm Ortho. Before I got to use it, I came across a killer deal on a TMB Planetary II 6mm. Here's where thing started changing....
I got a semi-decent night finally to compare the Ortho with the TMB II. That is where I learned to truly appreciate the wide view eyepieces. Total game changer.
After refiguring my desires I realized I could replace both the 32mm and the 25mm with a 24mm 68* eyepiece (I was planning on a Panoptic, but made an opportunistic purchase of an ES instead). With the 82* AFOV of the Naglers, I could consolidate further. I ended up with a 16mm T6, an 11mm T6, and a 7mm T6. All 1.25", so no need to upgrade my TV 99% diagonal or my ES 2x extender.
All this started with the huge appreciation of the extra FOV of the TMB 6mm vs the Ortho 6mm. And while some people would suggest the 7mm T6 is not necessarily a good planetary EP, it still beats either 6mm I have.
I'm not particularly saying you should follow my lead. But I'm hoping my recent experience will give you something to think about and lead to a plan. Whether you start basic like me and go fancy later, or just go for the end-game (whatever it is) from the start is up to you. In my case, I just didn't know what I really wanted and until I experienced the relative wide field of the TMB, I still had no idea what I really wanted.
I'm personally really happy with my selection. I chose TV because while they may not be the absolute best in all (or even any) cases, they are truly the gold standard in eyepieces (despite arguments by some) and will always hold their value. That said, my 24mm 68* ES is very impressive. I've had a few chances to upgrade to a 24mm Panoptic, but have been hard pressed to pull the trigger just yet. That 24 ES really impresses me. Currently, due to availability, you'll have a hard time finding deals on used ES eyepieces. You can get better deals on TV, but they are still much pricier than the ES. Beyond those two brands, I cannot help. Everything I read said buy the best EPs you could afford and I've not been disappointed in the least.
This was wordy, but I hope it helps. Good luck. Buying EPs can be really really confusing to a newbie, or even in my case, someone returning from a long layoff.
Posted 30 November 2013 - 06:46 PM
Posted 30 November 2013 - 07:21 PM
Posted 02 December 2013 - 02:02 PM
A 2x barlow would yield:
32mm (by itself)
20mm (by itself)
16mm (32mm with barlow)
10mm (20mm with barlow)
I thought the barlow increased magnification not reduced it.
Let me rephrase that:
A 2x barlow used with 32mm and 20mm eyepieces would effectively give you the following eyepieces:
32mm (32mm used by itself)
20mm (20mm by itself)
16mm (the 32mm eyepiece used with the barlow)
10mm (the 20mm eyepiece used with the barlow)
Posted 02 December 2013 - 04:59 PM
I thought the barlow increased magnification not reduced it.
What a barlow does is increase the effective focal length of the instrument, e.g., in your scope, your 2,000mm focal length becomes effectively 4,000mm.
The eyepiece does not change focal length, but it has become somewhat of a customary shorthand to halve the eyepiece focal length, because it gets you to the same magnification and it's easier to think of when deciding which eyepieces to purchase.
Remember, magnification is: Instrument focal length/eyepiece focal length.
Therefore (keeping the math ultra-simple), using your scope as an example:
2,000mm focal length instrument
yields 100x (2,000/20)
If you add a barlow:
2,000mm instrument fl with barlow is effectively 4,000mm fl
20mm eyepiece focal length
yields 200x (4,000/20)
Now the common shorthand:
2,000mm instrument fl
20mm eyepiece fl with barlow is equivalent to 10mm
yields 200x (2,000/10)
Once again for clarity, a barlow increases the instrument's focal length and does not halve the eyepiece focal length, but the numbers work to the same magnification and for deciding on eyepieces, the shorthand is easier to think of in your head.
Posted 02 December 2013 - 05:01 PM
The 16mm also replaced the 15mm and the 20mm for the same reasons.
I probably could have just skipped the 11mm, but what the heck, I was buying eyepieces...
Posted 03 December 2013 - 09:50 AM
In the same boat ordering the 11 inch edge hd cgem dx, it somes with a 23 mm. This threat really helped me out on what direction to go! still a little unsure thoe seems like i would want a higher mag for planets than 12mm
For my C11 (older carbon fiber tube, but basically the same scope) I use the following:
ES82 30mm for wide field views (with a 2" diagonal of course) Gives about 1.3deg
ES82 18mm for detailed views of DSOs (again with a 2" diagonal)
ES82 11mm for planetary views
I use the 30mm about 60% of the time, the 18mm about 35% of the time and the 11mm really just for looking at planets, so 5% of the time (at most).
Below 11mm is rarerly useful, but I have a 2x barlow and a 7-22mm zoom if I want to push it.
Before I had the ES line I only had an Orion Sirius 32mm and the Orion 7-22.5 zoom.