Return to the Cloudy Nights Telescope Reviews home page


Observing >> Solar Observing and Imaging

Pages: 1 | 2 | (show all)
George9
sage


Reged: 12/11/04

Re: 90mm APO + Herschel wedge vs C6 SCT + Baader film new [Re: brianb11213]
      #5999778 - 07/31/13 10:10 AM

I hope the wedge is at least a little better even for visual work because I just paid for it. So far I am seeing brianb11213's 10% or so (under average seeing). But I was just saying that it shouldn't be a 5- to 10-fold improvement for visual work, unless perhaps there is a problem with the film. A simple test would be to carefully put the C6's film in front of the 90mm apo and see if it works better. But make sure it is safe and secure (i.e., really mount it; don't just hold it).

Post Extras: Print Post   Remind Me!   Notify Moderator  
KJL
super member
*****

Reged: 06/07/12

Loc: Boston, MA
Re: 90mm APO + Herschel wedge vs C6 SCT + Baader film new [Re: George9]
      #6074828 - 09/11/13 10:52 AM

I wanted to update this thread with a second round of observations not long after my last post, but life intervened and I kept postponing it. Because the results were so contrary to my first session I thought I'd post my observations anyway in the hopes that it helps someone with their own WL purchasing decisions.

To summarize some of the earlier posts, there were those who experienced better results with Baader film on a larger aperture scope vs a Herschel wedge on a small refractor:

Quote:

frolinmod: The C6 with Baader film will beat the 90mm with Herschel wedge. I've personally seen this comparison done in real life. It isn't even close.




Quote:

George9: Along those lines, I saw a 6-inch f/15 refractor with a nice Herschel wedge (I think Baader) and continuum filter versus a 10-inch f/5 Newtonian with Baader solar film. They were both great, but the 10-inch did better even under just very good seeing. Under great seeing, I think the difference would be bigger. And the 10-inch was a portable scope.

Medium-sized mirror-based scopes paired with full-aperture Baader film can be really impressive for pure visual work, and I think they are undervalued.




Vs:

Quote:

brianb11213: OK. As it happens I own both a good quality 110mm apo (WO FLT 110) and a C6 tube. I have Baader solar film filters for both.

The smaller refractor almost always outperforms the SCT - despite considerable trouble being taken to insulate the SCT tube, the tube currents are a real issue. Just occasionally when the sun is low in the morning & the seeing is unusually stable the two are about equal for visual work.




Quote:

zippeee: I use full aperture film (CPC11) and a Herschel wedge for WL, both with solar continuum filters. Here's what I've noticed;

Contrast is way, way better through my raptor. The sky is darker and sunspots seem to pop out more (almost looking 3d). I can pick out penumbral detail better as well.

Aperture is the king of resolving detail though. I can typically resolve granularity better with my CPC, BUT (big but) the air has to be cooperating too. Otherwise, at any comparable magnification, they're fairly close.




And finally:

Quote:

Me: So my first impressions are that I will be dragging the C6 + Baader film out to do WL viewing of the sun rather than the SVR90T + Lunt wedge.




I had two more opportunities to do some WL viewing after my initial session above. The first was in the late afternoon where I wanted to double-check the Baader film vs Lunt 1.25" wedge on my 90mm APO. I am somewhat embarrassed to admit that the Astrozap Baader solar filter I bought for the refractor is barely used and is therefore in mint condition. There is nothing in its construction that betrays error in execution: it is not super-flat (has some "stretch wrinkles") and there is no dust that I can see. Really, it is mint. Moreover, there is no change in performance even when I hold up my brand new Kendrick Baader film for my C6 SCT over the 90mm's objectives, so I'm almost 100% certain I'm getting the full Baader film performance on my 90mm APO.

Nevertheless, my original conclusions still hold: the scatter is ridiculously lower on the wedge and the contrast difference is correspondingly sharper. In terms of scatter alone, looking through the Baader film is a bit like looking through a dew-covered lens, frankly. The overall improvement in detail is definitely 2x better, IMHO. Or put another way, I have to work at least twice as hard to see the same details in the Baader film that are blatantly clear in the wedge.

The next day, I had the opportunity to compare the 90mm APO with Herschel wedge with my C6 SCT with Kendrick Baader film filter, the combo this whole thread is about. I wasted no time with any other combination. This time, my conclusions are completely reversed from my initial impressions! The 90mm APO + wedge performed just as well as I had remembered: very contrasty with excellent detail even at an astonishing 252x. This was achieved with a Nagler 2-4mm zoom at 2.5mm, with a mere 0.36mm exit pupil. I was having to "shake" my eyeball periodically to move floaters away from the center FOV so that I could view penumbral detail better, but there was no question the SVR90T was taking the magnification magnificently.

OTOH, the C6 SCT + Baader began breaking up at a mere 170x or so, or the short end of my Leica ASPH zoom. Tube currents were a dramatic downer during this session: to be honest I was even having trouble maintaining an un-muddled view at 125x.

Given my requirements for quick grab-and-go viewing sessions, I have to admit that I am now favoring taking out the 90mm + wedge over the C6 + film unless I know conditions are going to be perfect for the SCT. In fact, I was in Palo Alto a few weeks later (red zone as opposed to my Boston white ) and am very happy I brought the Lunt 1.25" wedge to go with my 50mm APO doublet rather than the Baader film filter I also have. Not only is the diagonal much more durable and compact, but the view is just deliciously contrasty and detailed. I did forget my polarized filter (!) and I really could use one more eyepiece to tune the right magnification for the conditions, but overall I'm so happy with the Lunt 1.25" wedge.

Thanks again for everyone's advice and patience with me. It has been very educational, and I ended up happy with my decision to buy both the wedge and the film. I look forward to the wintertime when I leave my C6 outside to acclimatize and then its performance with the Baader film will consistently beat the 90mm with Herschel wedge. Until then I will favor the 90mm which as others have insisted (correctly) will perform more consistently in different seeing conditions.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Ain Soph Aur
professor emeritus
*****

Reged: 08/11/11

Loc: West Tennessee
Re: 90mm APO + Herschel wedge vs C6 SCT + Baader film new [Re: KJL]
      #6075301 - 09/11/13 02:49 PM

Hi KJ. I did alot of side by side comparison late winter/early spring between a fully cooled down (as possible) C8 + Kendrick/Baader filter vs a Carton 4" f/13 + Baader Herschel Wedge which I had just bought. The C8 never bested the 4" with wedge, or really even came close.

Of course, a C6 is a different beast and may equalize easier during solar observing than a C8 ever can.


Post Extras: Print Post   Remind Me!   Notify Moderator  
George9
sage


Reged: 12/11/04

Re: 90mm APO + Herschel wedge vs C6 SCT + Baader film new [Re: Ain Soph Aur]
      #6075512 - 09/11/13 04:45 PM

Interesting. I later did a lot more comparisons between my 2" wedge and my Baader film, both on my 5" AP apo. I really don't see a difference in contrast or resolution, not on the sun and not even scattered around the sun. (The brightness of the wedge is great for high power or a low sun.) Maybe the reason for the different experiences is variation in the wedges or films.

George


Post Extras: Print Post   Remind Me!   Notify Moderator  
KJL
super member
*****

Reged: 06/07/12

Loc: Boston, MA
Re: 90mm APO + Herschel wedge vs C6 SCT + Baader film new [Re: George9]
      #6075687 - 09/11/13 06:58 PM

Quote:

Interesting. I later did a lot more comparisons between my 2" wedge and my Baader film, both on my 5" AP apo. I really don't see a difference in contrast or resolution, not on the sun and not even scattered around the sun. (The brightness of the wedge is great for high power or a low sun.) Maybe the reason for the different experiences is variation in the wedges or films.




Perhaps. But I've been thinking about your post as well as those of brianb11213 above and wonder whether the view from a wedge and Baader film converge as apertures increase. I would say the contrast of solar limb is pretty much the same between the C6 + film as my 90mm APO + wedge. The "milkiness" of the Baader film vs wedge only appears on the 90mm and 50mm APO.

Unfortunately I don't own another larger scope (yet!) to test this theory, but if I'm right the point where Baader film begins to approach a wedge's performance is somewhere between my 90mm and brianb11213's FLT-110. And if that's true, then the existence of Lunt's 1.25" version of the Herschel wedge is especially great news for WL observers with smaller (<4") refractors.


Post Extras: Print Post   Remind Me!   Notify Moderator  
brianb11213
Postmaster
*****

Reged: 02/25/09

Loc: 55.215N 6.554W
Re: 90mm APO + Herschel wedge vs C6 SCT + Baader film [Re: KJL]
      #6076342 - 09/12/13 04:22 AM

Quote:

But I've been thinking about your post as well as those of brianb11213 above and wonder whether the view from a wedge and Baader film converge as apertures increase.



Not in my experience. Visually, the wedge has a slight edge over film irrespective of aperture (when used on the same tube). Maybe some batches of solar film are better than others ... or maybe some users of solar film have neglected to remove the translucent protective layer when making the filter up, this will definitely cause the poor contrast that some users report.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
4 registered and 12 anonymous users are browsing this forum.

Moderator:  Phillip Creed, nitegeezer 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1369

Jump to

CN Forums Home




Cloudy Nights Sponsor: Astronomics