Low Mag recommendations

iceman (Mike) · #1 09-05-2006, 06:13 AM

Ok, i've pretty much decided on what my short focal length eyepieces are, or will be.

I've got the Vixen 22mm LVW coming in the next week or two. I've got a gap to fill between the 14mm Meade s4000 UWA and the Vixen 22mm LVW, and a gap (or two) to fill in the "above 22mm" focal length range.

My requirements:
- I'm using a 10" f/5 dob
- I'm quite critical of sharp across the field
- 82° FOV isn't super important, but I'd prefer a wider field (ie: plossls won't make the short list). So above 65° TFOV is preferred.

For the first gap, I'm thinking of something in the 17-18mm focal length. Any recommendations?

For the second gap, i'm thinking around the 25-27mm focal length. The 27mm Panoptic springs to mind immediately. I've used Louie's in my scope before and though it was very nice, but it was quite a while ago. I'd need to familiarise myself with it again before buying it, as I was disappointed with the 22mm Pano in my scope (but LOVE it in Rod's). What others would make my short list in that focal length?

For the last gap, i'm thinking something above 30mm+. The 31mm Nagler would be nice, but there's zero chance i'm spending $950+ on a single eyepiece. 35mm Pano? What else?

Thanks in advance for your suggestions.

Starkler (Geoff) · #2 09-05-2006, 08:10 AM

I have the same scope as you as you know Mike, and I dont see any need to fill any gaps between my 14mm pentax and the 24mm panoptic.

In your case the gap will be less considering that your 14mm is a UWA, and the 22mm is a SWA in terms of FOV.

I have a 31mm nagler, but find the exit pupil too big for use at home in light polluted skies, giving a grey sky background instead of black. Consequently it only ever comes out at dark sky locations.

I really like the 27mm panoptic

janoskiss (Steve H) · #3 09-05-2006, 11:28 AM

Quote:

Originally Posted by iceman

I've got a gap to fill between the 14mm Meade s4000 UWA and the Vixen 22mm LVW

There is a gap?? What gap?

I have a 17mm T4 I haven't made up my mind up about yet, 50/50 whether I sell/keep it.

How about the 28mm UWAN for the top end? Andrews is selling WO gear now too (along with Frontier Optics), and the Aussie dollar is doing well, so there might be a bit of room for haggling.

ving (David) · #4 09-05-2006, 12:59 PM

pretty sure you have been thru this before mike

you have tracking, why not just get a TV plossl and not worry about seagulls? say 32mm.... or go for a 35mm ultima?

with these you won't have to worry about the edge performance as the edge will be great!

astropolak (Joe) · #5 09-05-2006, 04:26 PM

I have both the 17mm T4 Nagler and the 28mm WO Uwan.
If we are having one more meet at Kulnura you can borrow them to see if they work in your scope - I am yet to see anything better....(in my LX90).

RGDS Joe

Merlin66 (Ken) · #6 09-05-2006, 06:10 PM

To achieve an exit pupil of say 8mm ( a fully dark adjusted eye pupil) ;any bigger doesn't really get any more light into the eye; on your telescope this would require a 250/8= 32mm eyepiece. So any eyepiece around 30/ 32mm will give you the lowest possible maginfication that you could use visually.
I use a 32mm TV plossl, OK for me.

janoskiss (Steve H) · #7 09-05-2006, 06:28 PM

Merlin, exit pupil = eyepiece focal length / telescope f-number = telescope aperture / magnification. The 10" dob is an f/5, so 32mm eyepiece will give an exit pupil of 32mm / 5 = 6.4mm.

But 8mm ex. p. is probably a bit optimistic anyway, even under dark skies.

ving (David) · #8 09-05-2006, 06:33 PM

between 6 and 7 is best

ausastronomer (John Bambury) · #9 09-05-2006, 10:09 PM

Mike,

I agree with a couple of the others. I see absolutely ZERO need for an eyepiece between the 22mm Vixen LVW and the 14mm S4000 Meade UWA, considering the scope you own. A complete waste of money IMO, particularly when you do the numbers on magnification and TFOV.

Like Geoff I own the same scope as you, for DSO work I could live forever with 2 eyepieces only, the 27mm TV Panoptic and the 10mm Pentax XW. I do use the 14mm Pentax XW from time to time, but its a luxury not a necessity.

CS-John B

wavelandscott (Scott) · #10 10-05-2006, 08:34 AM

While not as experienced as some of my more learned colleagues, I agree with their comments...what gap?

I have been and am of the opinion that 3 or 4 "high quality" eyepieces and a barlow (or two) are all you need...

High Power, Medium Power and Low Power...with the variation High, Medium High, Medium and Low acceptable as well...

Cheers...

ballaratdragons (Ken) · #11 14-05-2006, 11:13 PM

Also depends on what you want to look at! Do you want it to fill the FOV?

For my Galaxy hunts I only use 2 EP's. And it's a massive gap!!!

I 'find' a galaxy with my 2" 32mm Erfle (I used to use my 2" 30mm SuperView), and then 'study' it with my 9mm Plossl (hopefully soon to be replaced with a Takahashi 7.5mm ED).

That's a BIG gap, and all my other EP's sit gathering dust (not literally).

dhumpie · #12 16-05-2006, 05:28 PM

I do a lot of my observing from my suburban mag 5.3 to 5.6 skies and I find the ep I use most is my 20mm KK Widescan III. Perfect balance of magnification to increase contrast and nice wide FOV for scanning in the 10" GS. I also have a 24.5 Meade SWA but don't use it as much

Darren

square_peg114GT · #13 17-05-2006, 03:03 PM

I agree with the others that you have no gap between your 14mm and your 22mm. On the low power end I would consider the 27 Pan and the 28mm UWAN (William Optics). If you can wait about 2 months I would seriously consider a 30mm Orion Stratus, too!! They're scheduled to arrive in July. The 30mm Stratus will sell for $180 (US) and the 35mm will sell for $200 (US). I just reviewed what appears to be a prototype for the 35mm Stratus. The prototype is a very remarkable eyepiece and bodes well for the new low power Stratuses. That review is here:

http://www.cloudynights.com/item.php?item_id=1451

iceman (Mike) · #14 17-05-2006, 03:29 PM

Thanks for all the suggestions and input.

I won't get anything between 14 and 22 (saves me money!). My 22LVW is finally ready to pickup from astro-optical, yippee!

Pegster, thanks for input on the Stratus 30mm, sounds like a good budget low power.
How much do the 28mm UWAN's sell for? They're getting good reports aren't they?

janoskiss (Steve H) · #15 17-05-2006, 07:36 PM

They are going for $600, but with several dealers now selling them you might get it for close to US equivalent price, $US400.

Yes, great reports on CN. There is a fairly comprehensive review on CN too. I would buy one, but then what would I do with it? Look at it and ponder what the sky might look like if it wasn't for the clouds... I have enough eyepieces for doing that already.

astropolak (Joe) · #16 17-05-2006, 08:02 PM

Mike
Try Frontier Optics - much less than $600.00

(for the 28mm Uwan).
Try before you buy, I will lend you mine next time in Kulnura.

RGDS Joe

iceman (Mike) · #17 18-05-2006, 07:59 AM

Awesome, thanks Joe.

I plan to be at Kulnura on the 27th, weather permitting.

matt · #18 25-05-2006, 04:20 PM

Hey Mike.

You had your first light with that 22LVW yet?

Looking forward to reading your comments.

iceman (Mike) · #19 25-05-2006, 07:06 PM

Picked it up yesterday. Didn't use it last night, was busy battling the platform.

Keen to give it a good shootout this weekend at Kulnura if the weather is favourable!