I have a 12" Meade Dob (FL: 1524mm) and I'm pretty stoked at what it offers. Unfortunately I'm getting greedy (surely that's not a bad thing?! ) and I want higher power mag. for some closer peeks of planets, and a cleaner picture (less coma etc).
I don't mid spending the money, however, I hate wasting it. That being said, if anyone can offer some advise on what eye pieces to buy for this scope, which I would (most) benefit from, I would be deeply grateful.
Also (after reading some mags and books on eyepieces) I'm leaning toward a Tele Vue Paracorr and the Nagler style.
I don't suffer from any eye issues and fine movements on the scope is a breeze...is 4mm do-able?
My current eye pieces are
Meade QX Wide 26mm
Meade 5000 Plossl 14 & 9mm
Meade 5000 UWA 6.7mm
The Tuneable paracorr is a wonderful thing - it improves the image right across the field. Some people say they can't see a difference, but I have never found that to be the case when I pass them mine. If you are fussy about coma, then it's a must.
Other than that, a 2x barlow or 2.5x powermate should complete your collection for the moment. (thats not entirely true - you need a good 35mm).
I was loooking at the very same thing, thanks. I was considering taking the step to 2" for wider field, was looking at 2x and 4x Powermate. Still undecided about Barlow.
All barlows are not created equal. I have a 2" 2x Televue BigBarlow which is a fabulous thing. I replaced a 'value' brand, which was not up to the job for me.
You don't often hear anyone complain about powermates either...
Okay, so I get this right, I whack a Big Barlow (2x) into the 2" focuser, then the Parcorr with whatever eyepiece, and set it to a particular mark determined prior (I read the post on working out the positions and marking the Parcorr for each eyepiece).
I'm guessing the Parcorr is 2" in and out, with the removable 1.25" adapter. So it can handle the 36mm also. Correct?
That's a truck axle setup! I may need to bolt a 12volt car battery next to the fan.
You never need to use the barlow and the paracorr together - the barlow will make a coma free f10, so the paracorr will just be an expensive heavy thing in the way.
The paracorr does contain a 10% barlow in it too, but that is to push the focus out a bit so you shouldn't need to modify your scope to use it. (caveat you need about 10-15mm more in-travel to get focus. if your eyepiece is already racked in close to the tube, you may need to make some mods)
You are correct about the adaptor.
When you use a paracorr and a 35mm Panoptic, you will indeed need a truck battery to stop the whole thing toppling over and arms of Thor to pick up your eyepiece case
Jonathan, thanks for all your help. I think I have it clear now.
I'll get a Paracorr, a (Meade UWA) 4.7mm for the planetary viewing, and a Panoptic 35mm for my spacewalk...Would the Tele Vue Nagler Zoom 03-6mm with the Paracorr be too much power and too little field of view? 50deg as opposed to 82-100deg (UWA and Televue Nagler respectively).
The additional travel for the high power should be fine, as my 6.7mm is a long way out in its travel. I have to take a guess for low power travel with both the 35mm and Paracorr, however, as I want the coma correction for planetary viewing, it is my primary concern, so if the low power combo is out I won't be concerned.
Personally I'd be very careful about buying a 4mm e.p., even if you are thinking of a Nagler. 2 reasons:
1) the power. In your setup this equates to 381x magnification. You might find you are limited the number of times you find seeing adequate. I run a 9mm nagler in a 16" f/4, which is 200x and I find about 50% of the time I'm not happy with the images (of course when I am, wooo!)
2) Eye relief. I can't comment on the 4mm nagler, but I've seen some short f.l. eps which are not fun to use.
In my opinion if you find your 9mm meade 5000 very good (I love my 16mm), buy a powermate to get the power. Then get a paracorr if you are not happy with the images.
I think you would want to try a barlow first before buying one . They cause a lengthening of the eye releif which some people find hard to handle, and also can be ungainly. Also with low power eyepieces there can be some vignetting at the field stop. I don't think you would benefit much from a Paracor at F5 though you will see some small gains.
As far as high power goes you can't go past the Televue Radians as they have stunning contrast and a 20-mm eye releif. Some people swear by the Pentax eyepieces too. 5mm would be optimal for good seeing giving you a 1mm exit pupil.
The most glaring hole in your collection is the 14mm Plossl and 9mm Plossl. You would benefit from a better eyepiece like Nagler 13mm type 6 for deep Sky ( or even a 2" televue 17mm Nagler Type 4 ) . 9 mm Nagler would be good also or a 10 or 8mm Radian or Badder Hyperion.
Hi Glen, thanks for the advice, but I'm a little confused now; can you use a powermate and a Paracorr at the same time?
I would be much happier to just magnify images using the eyepieces I already have, but also want to clean up the image a bit too.
I thought my only option was to use a Paracorr with a higher power eyepiece.
Cheers
Mark
Hi Mark,
Although I've never used a paracorr, I have always thought this combination was possible. I went away and checked and found this reference on Bintel's site:
Note for Dobsonian/Newtonian Owners
When using Tele Vue’s Paracorr coma corrector, the 2.5x or 5x Powermate™ should be inserted into the Paracorr’s 1-1/4” adapter (i.e., between the Paracorr and the eyepiece). For 2x and 4x 2” Powermates, first insert the Powermate™ into the focuser, then the Paracorr into the Powermate.
Have a look at the 2.5x Powermate in the eyepiece section and click on all product knowledge and go to the bottom.
I would have thought going to a higher power, hence narrowing the field, would make coma less of an issue and eliminate the need for a Paracorr. I suppose it ultimately depends on your optics and what you consider is acceptable.
In my 12" asside low power .. around 100 x gets the most work
I couldn't imagine you getting a lot of use below a 5 mm eyepiece
I found my 7 mm nagler was pushing it often so let it go .
A 10 mm xw and a decent 2x barlow would give you a fine
combination .. An excellant medium power eyepiece with the option
to ramp up the magnification when seeing allows.
TBH i would be surprised if you needed something to counteract coma with a 4mm piece on a 12' dobsonian, coma would be more apparent on low power, wider field views, i would think from about 15-20mm and longer it might be more of an issue.
A generic appraisal for the Siebert Optics is this; I have the Ultra 17mm & 9mm + the Ultra 2x barlow.
I use the optics on my 12" F5 scope.
Star images are pinpoint and sharp to the edge, individually and combined.
Contrast is also excellent.
The other good feature is that the barrels are made of aluminium, making them a lot lighter than comparable e/p's.
If you're after a e/p that looks good from the outside, forget the Siebert they are rather plain looking.
But..........if external beauty doesn't worry you and you're after a very good performing(optically)e/p, then this is for you.
TBH i would be surprised if you needed something to counteract coma with a 4mm piece on a 12' dobsonian, coma would be more apparent on low power, wider field views, i would think from about 15-20mm and longer it might be more of an issue.
I agree. I would've thought that for planetary viewing with high magnification, the highly reduced field of view would have cut the coma out. When viewing planets, why would you want to use a wide field eyepiece, the object will be too small(unless you enjoy that view).
On the other hand, you would want coma correction for viewing wide field deep space objects of the open clusters and nebulae type of objects. Galaxies and globulars will require dark skies and higher mag in general also, so a coma corrector may not help here either.
I recently purchased the Baader MPCC(Multi Purpose Coma Corrector) which I use for imaging and chose it because it DIDN'T increase my magnification on wide field objects. The parracor is overpriced for what it does(my opinion only, based on hours of web searching, not open for discussion) and a Baader MPCC will serve you well for a lower cost.
I recently purchased the Baader MPCC(Multi Purpose Coma Corrector) which I use for imaging and chose it because it DIDN'T increase my magnification on wide field objects.
My 2 bobs worth.
Is it worth buying the Baader MPCC for visual observations in a low power eyepiece i.e. does it reduce outer perimeter coma noticeable?
) and I want higher power mag. for some closer peeks of planets, and a cleaner picture (less coma etc).
and fine movements on the scope is a breeze...is 4mm do-able?
better put disc brakes on my DOB
