Baader Hyperion chromatic aberration? Help!

[FINDTHESUN]

Hello!

I'm a happy owner of an 8-inch Skywatcher dobsonian.

Recently got a couple of Baader Hyperion eyepieces to compliment my SW PanaView 32mm.

Just had a session outside looking at the Moon, the stars.

Lunar views through Hyperions was fantastic! Some nice close-ups and sharp craters.

Here's a quick pic I made with my phone: http://i.imgur.com/Gg9gX3J.jpg

Then I wanted to see how Hyperions compare to my 32mm Panaview when looking at the stars.

Had a glimpse at Capella, Mirphak, Algol and a few doubles...

To my surprise! I couldn't really achieve a sharp focus to get a perfect pinpoint starlight! There always seemed to be some sort of chroma aberration.

The stars looked a tiny bit 'mushy' and were shining slightly with extra colours, whereas the PanaView gives a perfect, sharp view!

5mm was meh, probably viewing conditions were not as good. Expected big things from 8mm but no. Only 17mm gave a somewhat nicer view of the stars.

It was a bit frustrating experience as I expected Hyperions to be pinpoint sharp too.

I think when I tried removing the first group of lenses and making Baader a 2" eyepiece the view improved slightly.

So what might be the reason? Is this normal? Any thoughts?? Are Hyperions actually not as good as PanaView?

Thanks!

[John]

From what you say, the shorter focal length eyepieces produced less satisfactory views. This seems to me to indicate that the seeing conditions and possibly the state of the scope were playing a major part in the quality of the views.

The 5mm Hyperion was giving 240x with your scope - if the seeing conditions and /or the collimation or cooling of the scope were not in good order the star images would not be great.

Using less magnification would show tighter star images, which seems to be what you found.

[Moonshane]

What he said ; 0)

[Dave In Vermont]

Ditto. CA does make me think of the collimation as the first 'primary' suspect. Have you collimated your friend?

(finger on my "Astro Baby" trigger)

Dave

p.s. - Very nice Moon photo! Great contrast.

[Thales]

Interesting, as I have similar queries. What I thought were gping to be good seeing conditions last night did leave me disappointed.  The same EPs I've used recently under low lying intermittent cloud and gave me really good star fields, last night, under cloudless skies, gave me all kinds of stuff.  The sky itself seemed brighter and more light polluted from a nearby town than usual which I put down to more moisture saturation in the air, and hence more diffracted light   Stars were much better with 24/26mm than anything shorter, but even with them eventually mist halos formed that I couldn't quite get rid of.

[Moonshane]

Clear transparency sometimes = poor seeing and vice versa. Occasionally you get good for both. These are rare nights so make the most of them. In other nights pick your targets and magnification according to conditions.

[John]

It was very milky here last night. I found my smaller aperture refractors produced nicer star images than my big dobsonian could.

[FINDTHESUN]

Thanks for the replies, guys! I guess it's all down to viewing conditions. Probably was a bit hazy. I need to have a few more tests.

The scope is collimated well, as I didn't have any problem with PanaView. Really happy with this ep! The stars, clusters look fantastic, perfect pinpoint focus and contrast.

I want to keep one or two Hyperions and now wondering which would be the best.

I think 5mm is definitely a bit of an overkill, so 8mm seems to be a popular choice. But I really enjoyed the Moon views through 13mm, which I could also barlow or fine-tune with rings if needed. It also makes for some nice Lunar photoshoots. BTW, how much narrower does the field become when using FT rings?

17mm looks like a nice mid-power eyepiece too, but I was aiming more at a high-power for some Jupiter nights soon!

Have to choose now between 8, 10, 13 and 17mm! Don't think I need 21 or 24.

[FINDTHESUN]

BTW have you seen this already???

Amazing high res Project Apollo film scans!

https://www.reddit.com/r/space/comments/3n9ads/herere_some_of_the_high_resolution_film_scans/

[Lowjiber]

I assume you are aware that removing "the first group of lenses" changes the focal length of the eyepiece... thus reducing magnification, and perhaps accounts for your slight improvement.

You don't need to remove the lenses to use a Hyperion in a 2" focuser.  Just stick it in there.

Clear, Dark Skies

[davefrance]

You don't need to remove the lenses to use a Hyperion in a 2" focuser.  Just stick it in there.

Clear, Dark Skies

True, but watch it doesn't collide with the diagonal mirror. 

[FINDTHESUN]

I assume you are aware that removing "the first group of lenses" changes the focal length of the eyepiece... thus reducing magnification, and perhaps accounts for your slight improvement.

You don't need to remove the lenses to use a Hyperion in a 2" focuser.  Just stick it in there.

Clear, Dark Skies

Thanks. Actually I tried to just stick it in a 2" focuser without removing the lenses and it didn't focus for me.

[Dave In Vermont]

My current entertainment is seeing how my eyepiece collection responds to having a Barlow-lens cell screwed into the barrels. This should result in about a 50 to 60% increase in magnification - it's from a 2X Barlow. I'm using a cheap-ish Barlow from Orion-USA. It's called a 'Shorty.' I tried using a 2X TeleVue Barlow-lens cell. And found out TeleVue made these in an oddball size that won't mate with anything other than the original barrel - the stinkers. Anyone else run into this problem with other brands?

Next clear & calm night I'll be trying this trick on my Hyperions. See what that has to say.

Dave

[FINDTHESUN]

Is there a way to attach a 2.25x Baader Barlow (which comes with their zoom ep) to a 2" eyepiece? Are there any adaptors?

[mcolbert]

I suppose there's always oxy-acetylene?  

sorry, couldn't resist - and resistance is useless.

michael

[Dave In Vermont]

Is there a way to attach a 2.25x Baader Barlow (which comes with their zoom ep) to a 2" eyepiece? Are there any adaptors?

Which Baader Zoom does this come with? I ask as I recently bought the Baader Mark III Hyperion Zoom - 8 - 24mm, It came with everything under the Betelgeuse but a Barlow.

I did look at Baader 2.25X Barlow. It appears it accepts 2" eyepieces, which with an adapter also accepts a 1.25" EP. So to your question, FINDTHESUN - yes you can. This is from FLO:

http://www.firstlightoptics.com/baader-planetarium/baader-hyperion-zoom-barlow.html

And then there's this:

http://www.firstlightoptics.com/baader-planetarium/baader-classic-q-225x-barlow.html

Does this answer your question? It was a bit vague regarding what you wish to connect to what exactly.

Dave

[YKSE]

Is there a way to attach a 2.25x Baader Barlow (which comes with their zoom ep) to a 2" eyepiece? Are there any adaptors?

I think the dedicated 2.25x Baader Barlow comes with a T2 connector as shown here(B inthe picture):

http://www.teleskop-express.de/shop/product_info.php/info/p5059_Baader-Hyperion-2-25x-Barlow-lens-w--1-25--and-T2-connection.html

You should be able to use a T2 to M48(2" filter thread) adapter like this

http://www.teleskop-express.de/shop/product_info.php/info/p378_Baader-Adapter-T2-female-to-M48---2--filterthread.html

to connect the barlow to 2" filter thread.

You might get some vignetting to barlow the 2" eyepiece with 1.25" barlow though.