Is this prism safe to use with a TeleVue NP127is refractor, which is a Nagler-Petzval design. In addition to the first objective doublet lenses, this has a second doublet at the focuser end of the OTA. Thank you.
Question by: Terry on Aug 23, 2019 6:55:00 AM | 1 Answer(s)
We do not sell TeleVue-telescopes and are not sure about the design of the lenses.
So we'd have to ask you to check the manual or consult your TeleVue-dealer. If the telescope can be used for projecting the sun, it can also be used with a Herschel wedge.
Answer by: Baader Web Team (Admin) on Aug 26, 2019 10:20:00 AM
I have never used a Herschel Wedge before on my refractor--always mylar film, or glass filters on the forward end of the scope.
Will the unfiltered solar energy entering my(very expensive) air spaced triplet objective possibly damage the lens due to over heating? Could I use the wedge/and refractor continuously for 2 or 3 hours with out worry of damage to either? Thank you. Jon Mayer
Question by: Jon Mayer on Jul 11, 2019 5:59:00 PM | 1 Answer(s)
When you have a good refractor, all the light and also the the heat passes through the lenses and end up in the Herschel wedge. There the heat will be dissipated and the lens will be only a few degrees warmer but not really hot. So there is no danger for damage of the lens. We checked the Herschel wedge in summertime on an 8" Zeiss Refractor -.a whole day - and it survived very well.
Answer by: Baader Web Team (Admin) on Jul 12, 2019 8:44:00 AM
Greetings. I am having focusing issues with this product on a Televue NP 101 (non is) telescope. Are there adapters than can help with this?
Thank you.
Question by: Giuseppe Barbieri on Jun 11, 2017 3:47:00 AM | 1 Answer(s)
If your problem only occurs with a camera, you can replace the 2" Clicklock clamp with the T-2-adapter #1508035 to attach the camera directly to the Herschel wedge.
If you have problems with eyepieces, you can try to use the adapter #1508035 to attach another eyepiece clamp with T-2-thread - e.g. #2458100 - or an eyepiece, where the field stop is moved into the 2"-barrel, closer to the telescope.
The Herschel Wedge requires a backfocus of 114mm, of this 47mm are used by the 2" Clicklock clamp. To measure the backfocus of your telescope, point the telescope at the full moon, hold a piece of paper behind it and measure the distance between the drawn-in focuser tube and the sharp image of the moon.
Answer by: Baader Web Team (Admin) on Jun 12, 2017 10:15:00 AM
I wanted to know if the Herschel prism is recommended to use it with a D-ERF filter in front of the lens to prevent heat from entering and protect the tube? or the D-ERF is only recommended for use in H & alpha ??
Question by: Rafael Segura on Apr 21, 2020 9:37:00 AM | 1 Answer(s)
Generally you can use the Herschel Wedge on normal refractors without DERF. The DERF is mainly designed as a prefilter for Halpha telescopes. But in case you want or need to keep the heat out of the OTA you can also combine the Herschel Wedge with an DERF
Answer by: Baader Web Team (Admin) on Apr 21, 2020 9:57:00 AM
Is the Herschel wedge compatible with 1.25-inch eyepieces?
Question by: Michael Graham on Jan 7, 2021 12:13:00 AM | 1 Answer(s)
Yes, you just need a standard reducer from 2" to 1.25" like Baader 2" to 1¼" ClickLock Reducer (T-2 part #15B) # 2956214, Baader Reducer 2"/ 1 ¼" (T-2 part #15) # 2408190 or 2" / 1¼" Economy-Reducer with 2" filter holder # 2408153
Answer by: Baader Web Team (Admin) on Jan 7, 2021 11:04:00 AM
The documentation states that the Solar Continuum filter can be removed when using a fully apochromatic APO refractor*. What is implied is that a 1.8 ND filter should be substituted when doing visual observing – with of course the 3.0 ND filter still being in place. Please confirm.
If this is the case, please also clarify if the 1.8 ND filter should be placed where the Continuum filter was with the 3.0 ND behind it closest to the eye piece, the other way around with the 3.0 ND closest to the prism with the 1.8 ND closest to the eye piece, or whether it makes no difference.
*The documentation specifically mentions Astro Physics, TEC, and Zeiss. I am using a Tele Vue-85 which claims APO performance.
Question by: Herb H. on Jun 11, 2020 3:49:00 PM | 1 Answer(s)
We do not comment on the APO-status of the TV-85, but we confirm that visual and imaging results will show solar surface details in better sharpness when keeping the continuum filter in the light path.
To be straight! The Herschel wedge warrants for a safe solar viewing experience, with only the ND 3.0 filter in place! However, the photopic reception of brightness is very different for different eyes (and related to age as well!).
When adding a solar continuum filter, the user has the same amount of transmission reaching the eye as without such a filter - but only within a 10 nm wide part of the spectrum at 540 nm. For this reason the "overall brighness" is perceived as being less. But if the Herschel wedge (w. ND 3.0 filter in place) were transmitting a dangerous amount of energy - even the small 10 nm "window" would constitute a "danger".
So for a 99.9 % majority of people it is not "necessary" from the aspect of safety, to add another ND -filter on top of the necessary ND 3.0 filter. But - a small number of people do inherit raised sensitivity for brightness, leading to eventual phototoxic reactions in the eye during prolonged and repeated exposure to light levels that would be perceived as normal by others.
Effects of phototoxic overreaction have been exhaustively investigated for the new generation of LED and CREE light sources which can compete in their radiation intensity with solar brightness in the meantime - when stared into at close distance. So the same precautions as valid for direct intensive LED illumination must be observed for Herschel-wedge operation just as well.
Fortunately most people have a "built in" aversive-reaction, to avoid excessive amounts of light falling onto the retina. So everyone observing the sun should be attentive to constantly observe his own "comfort feeling". If the visual brightness is experienced as causing strain on the eye, or an "afterglow-experience" will remain for some time when lifting the eye from the eyepiece, - in these cases a further added 0.9 ND filter will largely help to have a comfortable seeing experience. Adding a 1.8 ND filter though onto the 3.0 ND-filter will dim the solar image to a degree that fine solar details become invisible (unnecessarily).
Do test the Herschel brightness experience in good faith for a few seconds with only the ND 3.0 filter in place (always!). Depending on your age then maybe add a 0.9 ND- or even 0.6 ND-filter, until the image brightness is perceived as comfortable even at viewing sessions of up to 3 minutes. After each 3 minutes a short pause is mandatory, to check for any "afterglow"- effects, for dizzyness or for impaired vision. This is because brightness strain on the eye can bring out hidden retina damages or very early retina dislocation that went unnoticed before.
Only for imaging purposes, the ND 3.0 filter may be taken off the light path and replaced with one of the photographic ND-filters (0.6/0.9 or 1.8 ND) - so as to arrange brightness in a way that the shortest available camera exposure time can be made use of.
Answer by: Baader Web Team (Admin) on Jun 15, 2020 2:42:00 PM
Could you please let me know how to use this prism in conjuntion with 1.25" double stack cotinuum + polarizing filter + Maxbright II binos?. Thanks in advance.
Question by: Jose Carvajal on Apr 26, 2020 12:23:00 AM | 1 Answer(s)
The basic adaption of our bino-viewers is by replacing the 2" ClickLock of the Herschel with
Baader Adapter 2" (male) / T-2 (male) # 1508035
Then you have a T-2-thread, onto which you can mount the binoviewer or the T-2 QuickChanger as described in the manual (page 18 in the manual of the MaxBright II); the 2"-filters of the Herschel wedge fit into the 2"/T-2 adapter. We recommend a T-2 quickhanger, so that you can insert the glasspath correctors for T-2 into the binoviewer; be careful with the 2.6x gpc as it may hit the filters in the Herschel.
By using the T-2-connection, you can also use
Baader T-2 Conversion Ring # 2958110 plus
Baader Double T-Filterholder 1¼" # 1508030
to mount a 1.25" filter in front of the binoviewer. Again, this may be problematic with the 2.5x gpc as it faces towards the telescope and not into the binoviewer, so make sure that you have enough backfocus.
Installing a single polarizing filter is tricky, as you can't rotate the binoviewer as easily as an eyepiece. There should be enough place to mount the filter in front of the double stack and use the T-2 quickchanger to access it for adjusting the brightness.
Answer by: Baader Web Team (Admin) on Apr 28, 2020 12:18:00 PM
Can I use the BDSF sunscreen at the same time, to protect my lens from televue 85, and then put the herschell baader prism?
Would it work well?
Question by: Francisco on Jun 4, 2020 6:35:00 PM | 1 Answer(s)
When using the Safety Herschel Wedge, no additional front aperture filter is needed.
Please also read the instructions for the Herschel Wedge thoroughly and only use this product if you feel well informed about the consequenzes of wrong handling.
Answer by: Baader Web Team (Admin) on Jun 5, 2020 8:36:00 AM