Eyepiece upgrade path?

[Lowepro]

I have a 12" Bintel Dob, and I've only really been using a couple of eyepieces from my el cheapo skywatcher with it.

Sooo, I was wondering in what direction should I go with aquiring new eyepieces? It sounds like they are very much worth the investment.

After searching around IIS, I was thinking a TV 13mm Nagler and maybe a barlow might be a good place to start. The cost of this would probably be my limit for a few months, and then perhaps get another two TV pieces later on.

Of course for the same money you can get a case of cheaper eyepieces, but it sounds like a couple of good eyepieces are better than having a bunch of cheapies. Yes?

Should I get a brand other than Tele Vue? Start with a different size/type? Get lots of cheaper eyepieces, or a few medium cost ones? I'm dreaming if I think one or three TV pieces will be enough for my amateur needs?

Just wanting to know where my money should go, and what the purchase path on pieces should be....

[Wavytone]

Well the first thing is to identify the shortest and longest useful focal lengths and work out a selection of say 3 or 4 focal lengths spanning that range, then look at what's available.

An f/5 that suggests you might have the occasion to use 4-5 mm, while at the long end around 25mm is likely to be the practical limit. If you're opting for say 3 eyepieces, this suggests 5, one around 10-12 and 25mm. For a set of 4 eyepieces: 5, 8, 13-15, 25.

Note you could also do something similar with 1 eyepiece and 2 Barlows, or 2 eyepieces and 1 barlow.

There is also the question of what you are using it for. For high power I would suggest image quality (sharpness edge to edge, colour correction especially near the edge, transparency, distortion) are higher priorities than extreme field of view, and in this respect you could consider thiongs other than TV Naglers/Ethos, such as the Zeiss Abbe Orthoscopics.

If you want the ultimate widefield experience above all else, then yes the Ethos/Naglers are for you, and you'll only need 2, possibly 3 to cover the entire range and FoV of your scope. The Explore Scientific 14mm widefield is an Ethos clone, and should cost a lot less than the Ethos.

Lastly you didn't say anything about your vision - I wear glasses - and I find it a lot more comfortable to use eyepieces withn a lot of eye relief. For this reason I have a set of Vixen LVW's and a set of Vixen LV's - the LVW's are "the good ones" and the LV's are for when I have other people around or star parties etc.

My scopes are f/7 and f/15 so I can go right up to 50mm (though this would be useless in yours):

LVW 5, 8, 13, 22, 30 and a TMB Paragon 40mm,
LV 4, 7, 10, 15, 25 and 50.

[Greenswale]

After looking through lots of stuff, I learnt pretty quickly that premium eyepieces make a significant difference to viewing. I also determined that I enjoyed long eye relief and a wide field of view, and that this would come at a price. Barlows were not something that I considered, preferring to simply use stand alone eyepieces to meet my prime needs.

Outcome - I started with a 10mm XW Pentax and 32mm Televue, understanding that the TV was an interim 'find stuff' eyepiece. (With this eyepiece, I have learned about 'seagulls' at the edge of the view, something not present in Pentax.) Over time, I added a 7mm XW Pentax, and have a 20mm XW coming to me by mail, due next week.

Am I happy? You bet. Views are splendid, the eyepieces are just superb (for me!). I just love looking around in the eyepieces, big views, gorgeous flat field, great contrast, don't have to nudge too often etc, etc.....!

The future? Maybe a 3.5mm XW for those really good seeing nights.

When you are casting about for eyepieces, be prepared to look around for the best price. I try to support Australian business, but have found significantly better prices overseas.

And the oft repeated words of advice - try before you buy. Clubs and groups are the best places to do this, most members will be delighted to assist you.

Good hunting!

Wren

[Lowepro]

Thanks for that.

I've got perfect vision.

I guess I would want to start with an eyepiece (if I can only get one), that is a good all rounder for viewing planets, nebulae, moon, etc.
So, the Explore Scientific 14mm widefield might be a good place to start? And then a barlow, a 25mm and then an 8mm?
I guess I could get a whole set of that brand/type fairly quickly, which would give me a whole variety of views.

Oh,is 2" much better than a 1.25"?

I think I would be happy spending $500~ every few months, if that gives you more of an idea of what would suite me.

[wavelandscott]

My thoughts are as follows...

Get the best gear you can afford...and use it often.

Read the material on the TeleVue website about eyepiece selection for a small dobsonian (your's is bigger than small but the concept is the same).

Select a good High, Medium and Low magnifiaction eyepiece.
You can use the eyepiece calculator on the TV website to do some calculations for your scope.

In my opinion TeleVue is hard to beat with their widefield (Nagler/Ethos) eyepieces 11 mm and above. Also in my opinion Pentax shines (XW) at 10 mm and below...depending on which ones you need for your scope to fit H,M,L you can then do further research accordingly. As part of that research you should try and use some of them before you buy them.

Good Luck!

[Lowepro]

Thanks for the advice!

I notice on another thread someone advises this for an eyepiece setup for a 12" dob, which would be in line with what you are suggesting:

Low power = 30mm Pentax XW or 27mm TV Panoptic
Med Power = 16mm Nagler T5 or 13mm Nagler T6
High Power = 10mm, 7mm and 5mm Pentax XW's and a 8.5mm Pentax XF


I'm wondering about getting something like the Orion Premium 7.5mm-22.5mm Zoom (1.25"), or Tele Vue CS Zoom 8mm-24mm Dioptrix (1.25") as a starter, and then building up the other pieces and selling this later on. I know you don't get a great FOV though, so not sure if it would be a bit of a waste of a first step. What do you think?

[Solanum]

One thing to consider (a point made above I think), is what will you be looking at? I find that in my 10" Dob I rarely use an eyepiece above 20 mm. So spending significant money on that range is not really worthwhile, particularly when money is limiting.

I also find that seeing is rarely good enough for anything less than my 8.5 mm Pentax. However, when seeing is good enough I think better quality at high magnification is important, so if I'm going to spend money on an eyepiece I won't use a lot, it will be on the high mag one, not the low mag one.

[norm]

Low Power 24mm Televue Panoptic
Medium 13mm Televue Ethos or 13mm T6 Nagler
High 10mm Pentax XW

17mm Ethos another possibility if you want to fill in the 2" gap as the others are 1 1/4".

Good luck with your decisions.

BTW: The 24mm is one of the more regularly used eyepieces - very vertatile imo:thumbsup:

[GrahamL]

I'm unfamiliar with the zoom eyepieces your thinking of, but do note they have a very small fov.

I have owned a few of those and used in my 12" dob for quite a while.

27 pano .. very comfortable low power eyepiece , lots of eye relief
and great views , heavyish but not overly so. I didn't have to mess
with couterweights to much when dropping to higher powers.

16t5.. eye relief is very tight with this one .. (why I sold it)
not loads of info about this one around.. I think its a great eyepiece
very sharp views , compact and that great widefield view.

13t6..lots of info out there on this one for good reason.. its got a lot going for it, compact , great wide views and a power that will live in your focuser more often than not.

I sold on the above two because comfortable eye relief has become an issue for me more recently.

14 xw .. lots of eye relief and excellant views, not as compact as the 13 t6 and of course it dosn't yield that ultra wide fov . I wanted top stay around this mag and this one fits the bill well.

8.5 xf.. I noticed when I finished my 12" that my 7 nagler just wasn't getting as much use anymore.. the xf does.. its one I can generally drop in the focuser and get some use of most of the time
great pentax views ,a little narrower fov ,very light and priced very nicely .

I am still hanging on to my three eyepiece policy and there are definately other options but for me in a 12" f5 these work out just fine

good luck with your choices ..its only money.. you'll forget how much these pricey bits of glass can take off you soon enough:thumbsup:

[Lowepro]

Great stuff. I'm learning heaps here. I guess spending your dosh is a good research incentive.

Where do people buy their pentax eyepieces? (and other ones mentioned here - TV, meade and generic are all I can find on oz websites)

[GrahamL]

http://118.127.11.230/catalog/index.php?cPath=33&sort=4a&page=3

I thought they used to sell the xf series to but it dosn't seem to be there anymore ?
not sure what gives with the xw 7 price listed above .. might be worth checking with the vendor to see if its a typo if you were considering as there is a little price differance there.

From Japan Barry is great to deal with my order took a few days.

http://www.kkohki.com/English/kkohkiparts.html

[wavelandscott]

I got my Pentax XW eyepieces at Star Optics in Queensland. I got my TeleVue eyepieces at Bintel (stores in Sydney and Melbourne).

Cheers,

[Lowepro]

So I'm thinking a 13mm Nagler first (to hold me over for a few months) , then 27mm Panoptic (not too sure if this would be better than the 24mm because it is 2"?), and then a Pentax XW 10mm.

It sounds like that would cover most the bases, from what you're all saying. Yes?

Would a TV 2x barlow with the 13mm be good for planet viewing in the mean time?

[Starkler]

A 7mm xw i think would be a great planetary ep in that scope giving 214x.

You need to find out whats important to you and what you dont mind sacrificing. Do you want generous eye relief or generous field? Is 70 degrees with comfort enough, or is it worth sacrificing a little comfort for some extra field? Nobody on a forum can answer that question for you.

I probably wouldnt suggest mixing short and long ER eyepieces like nagler type 5/6's and pentax xw's. I have a range of pentaxs and a 24mm panoptic and the shorter ER makes the pano the odd one out and it feels cramped to me.

I would choose either a 13mm or a 10, but not both as they perform a similar role as a dso workhorse. If working with three eyepieces I would choose one 20-30mm, one 10-13mm and a 7mm pentax xw/xl for planetary/lunar/high power.

Another good choice in a 13mm is a Vixen LVW