Eyepieces for 12" Dob

[Starkler (Geoff)]

Regarding buying premium eyepieces.
For dso viewing the eyepiece that will get most use one is the one that will give a 2-2.5mm exit pupil. For an f5 scope this translates to a 10-12.5mm eyepiece

An eyepiece around this range is definately the first one to buy.

[janoskiss (Steve H)]

Do try out some eyepieces before shelling out the big bucks. Each design has its strengths and weaknesses and what is best for you depends to a large extent on your own personal preferences.

[Starkler (Geoff)]

Originally Posted by janoskiss

Do try out some eyepieces before shelling out the big bucks. Each design has its strengths and weaknesses and what is best for you depends to a large extent on your own personal preferences.

Couldn't agree more !

Some will recommend a nagler 13mm type 6, others will say Pentax XW 10mm.
The user experience with these two is very different and personal prefs will decide which one you want.

[mickoking]

Another thing

When viewing nebulae a good filter can make a HUGE difference. I keep a OIII filter almost permanantly attached to one of my 20mm eyepieces. The contrast/visual gain on some objects like the Eta Carinae Neb (NGC 3372) and the Tarantula Neb (NGC 2070) among others is phenomenal, particuly in a 300mm 'scope.

Highly recommended

[Tamtarn]

Hi Mick
We have a Astronomik UHC filter we find works well on our Meade ETX 125. ( 5" )
Do you think this will also be suitable on our 12" Dob ?
Barb & David

[mickoking]

Better

[janoskiss (Steve H)]

what's better Micko? The UHC better than the OIII? I've been considering buying an OIII filter but only if it does something visually different to a general purpose narrow band nebula filter.

[mickoking]

Originally Posted by janoskiss

what's better Micko? The UHC better than the OIII? I've been considering buying an OIII filter but only if it does something visually different to a general purpose narrow band nebula filter.

Sorry for that. What I ment to say is the UHC filter will work better on the larger 'scope.

With regards to the OIII filter It has higher contrast than the UHC filter, Borrow one and check it out if you can, I promise you it will be worth it

[Tamtarn]

Steve you will find info on the UHC at http://astronomik.com/english/eng_uhc.html Everone seems to have their own preferences on Nebula filters. It gets down to personal choice.

Barb

[Tamtarn]

Sorry forgot to add we chose the UHC to use with our 5" scope at the time

Barb

[ausastronomer (John Bambury)]

Hi all,

I am a bit late to this thread.

If you only plan to buy 1 filter for DSO work, the UHC is the best one to get. The OIII and UHC assist to a similar degree on a lot of targets, but there are some targets where one filter will work better than the other. The UHC offers "some" improvement on a larger number of targets than the OIII. In addition the UHC does not dim the background field stars quite as much as the OIII. Owning a 12" scope, if its within your budget you will get some benefit owning both a UHC and an OIII filter, but you will use the UHC more often. In smaller scopes (less than 8" aperture) the UHC will see a lot more use than the OIII. I own both the Astronomiks UHC and OIII as well as the DGM Optics Narrow Pass Band (NPB). The Astronomiks filters are the best available IMO. The DGM is the best value for money.

CS-John B

[square_peg114GT]

Ths is the most comprehensive comparison of nebula/light-pollution-reduction filters that I've seen.



Filter Performance Comparisons for Some Common Nebulae

Hey, you guys will have exactly what I have, I have an ETX90 with the full complment of 9 Meade Plossl EP. When I bought the GSO 12" (rebadged as Bintel) it came with some pretty ordinary EP, they dont focus well to the edges but OK as beginner EP, the Meade plossl's all focus perfectly in the 12" and I dont recommend changing them for anything less than expensive EP's like the Televue etc. you already have the best "mid" priced EP.s.

Save your money and buy yourself a green laser, remove that crappy old finderscope on the ETX and retro fit it with the laser, then the goto on the ETX combined with the green laser works a treat for finding objects with the DOB. Best money you could spend for the moment.

Cheers, Dennis.

[Tamtarn]

Hi John

Thanks for your input on filters.
We are looking forward to using the UHC on the Dob ( Dob pick up day tomorrow ) Maybe a OIII further down the track.

Our next buy will probably be a 10XW. and then possibly a Stratus 21mm or LVW 22mm if funds permit.
Also int in a green laser to be mounted on to our ETX125 so we can use it as a tracking scope for the Dob. The ETX already has a Red Dot finder.

Thanks Again
David

[Tamtarn]

Hi Dennis

We have had thoughts on a laser for the Dob and using the Red Dot finder on the ETX, But your suggestion would probably be better.
Can advise details of your green laser setup with bracket and what power of the laser you use.
Where did you buy it and what brand ?

Thanks
David

[ausastronomer (John Bambury)]

Originally Posted by Tamtarn

Hi John

Thanks for your input on filters.
We are looking forward to using the UHC on the Dob ( Dob pick up day tomorrow ) Maybe a OIII further down the track.

Our next buy will probably be a 10XW.

David/Barb

Sorry I missed this post. I have been really busy and haven't visited the forum much recently. I only picked it up when I was following up on your post about taking the plunge and buying a premium eyepiece.

I hope you decided to buy the 10mm Pentax XW? It is the best 1.25" eyepiece I have ever used !!!! and I have used a fair few. It is also perfectly suited for medium power DSO work in your 12"/F5 as it creates a 2mm exit pupil @ about 150X which is ideal for that purpose.

Originally Posted by Tamtarn

and then possibly a Stratus 21mm or LVW 22mm if funds permit.

David

At this focal length the 21mm Denkmeier is the best 1.25" eyepiece I have used. I own the 20mm Pentax XW and have also used the 22mm Vixen LVW, 21mm Orion Stratus, 19mm, 22mm and 24mm TV Panoptics. Of all these I like the 21mm Denkmeier, although they are all very good.

http://www.buytelescopes.com/product.asp?pid=10465

The Denkmeier eyepieces only come in 14mm and 21mm focal length and are designed for use in the Denkmeier Binoviewer but work very well in fast scopes and used singly. They are about $US 260 or $AUS 400 each.

CS-John B

[Tamtarn]

Thanks again for your info John. We will certainly consider the Denkmeier in the 21mm range when funds permit.

We appreciate your opinion on this subject.

Barb & David