Special Solar Filters

Nachdem ich eine Mail mit der Bitte um ein Feedback erhalten hatte, habe den Baader K-Line Filter im Zusammenspiel mit dem Baader Cool Ceramic Herschelkeil 4 Tage später (nach meiner ersten Bewertung hier) noch einmal ausprobiert und ein weiteres Mal hat er mich überzeugt. Obgleich aktuell auf der Sonne minimales Minimum zu beobachten ist, machte es Spaß die zarten, vorhandenen Fackelgebiete in der CaK und CaH Linie herauszuarbeiten und entsprechend den Wellenlängen von 393 + 396nm habe ich dann auch das Bild der Sonne passend eingefärbt. ;-)

Habe in der vergangenen Woche den Filter erhalten und heute ergab sich kurz die Gelegenheit, eine halbstündige Wolkenlücke, den Filter im Zusammenspiel mit dem Baader Cool Ceramic Herschelprisma zu testen. Es ergab sich ein Problem in der Zusammenarbeit mit meinem 4 Zoll APO Triplett mit 550mm nativer Brennweite, ich kam nicht in den Fokus, der volleingefahrene OAZ war noch immer eine Kleinigkeit zuviel an Abstand. Blieb nur die Linse von der 2.69x Düring-Barlow zu holen und an die 1.25 Zoll Nase der ZWO Asi Kamera zu befestigen, dann war fokussieren möglich, aber leider eben nicht mehr die Sonne voll im Bild zu haben. Als Alternative blieb nur eine andere Kamera mit größerem Sensor zu nehmen, da Panos/Mosaikaufnahmen, insbesonders jetzt in der Minimum-Zeit der Sonne, nicht funktionieren, zuwenig Oberflächendetails anhand derer sich die Stitchprogramme orientieren könnten. Damit klappte es nun einwandfrei, ein 1.8ND-Filter und das Herschelprisma sorgten für ausreichende Lichtdämpfung, aber erlaubten noch immer sehr kurze Belichtungszeiten mit dem montierten K-Line Filter.

Full sized (160mm) Baader D-ERF filter provides several choices for my visual/imaging solar Ha system with a Daystar Quark Combo unit. With scope's full aperture (150mm) this D-ERF mask can be used with 4x barlow (=150/4800mm setup, F/32). In more limited seeing conditions I can use aperture mask of 100mm together with a 2.5x barlow (=100/3000mm setup, F/30). And by limiting scope's aperture even further (=75/2400mm, F/32 system) a 2x barlow can be used. Baader D-ERF seems to be worth every euro spent there, because I could get a contrasty and detailed Ha-view with above described 3000mm focal length setup tested today (despite of some high altitude clouds moving around!). Minor minus for this quality filter comes from the missing commercial frame options available from Baader for this filter type. Anyway, my ATM DIY frame solution for this D-ERF filter placement can be seen in the attached images. I'm looking forward to get more excellent results with this Ha system.

Habe mir diesen hochwertigen D-ERF Filter für den Umbau zugelegt. Bringt ein zuverlässiges solides Bild. Keine Geisterbilder etc. . Visuell auch ein Genuss mit DER Sicherheit für die Augen!!!

Sehr gute Qualität. Preislich optimal. Meine Empfehlung.

Purchased this from a US dealer in the US and made a filter for the front of my C8 using the enclosed filter material. The filter and film are designed for PHOTOGRAPHIC USE ONLY, no visual use. I have only done one test using the filter(s), the one you make that is a blocking filter on the front of the telescope and the Calcium K band filter which is attached in a 1.25 thread in front of a camera T-Mounted and placed in the eyepiece holder. I used a Point Grey Grasshopper 3 Five megapixel camera which is monochrome. The sun had some sunspot activity the first day I was able to test the filter and the filter brought out details in the image that were stunning. The image is likely better than any white light images I've taken but the front filter I created using the enclosed photographic film is a larger opening than my white light filters and photos have used. It's great to have a calcium K filter option that is affordable compared to older Calcium K telescopes. Baader also includes a warning in this, to NOT USE it visually. I figured it might be safe with Baader visual film and tried it with that film on a small scope but I think the Baader visual film blocks out the wavelengths that Calcium K could show. Most people cannot see Calcium K anyway and as Baader points out the Calcium K telescopes are dangerously close and radiation in that band is ikely dangerous to eyes anyway, So ALL CALCIUM K scopes should be used for photographic use ONLY, not just this filter.

I use the Solar Continuum (SC) almost exclusively. Here is the "Theory" behind the SC filter. The photosphere of the sun is obscured by the gases above it (the chromosphere). The Chromosphere is only about 10,000 miles deep, but it is red and it obscures the yellower light coming from the surface. The SC filter is tuned to cut this red so that it does not obscure the photosphere to the same degree as it would without it. That is the theory. Here is my own experience but it gets technical. Filters block energy and because of this, to get something you loose something. The SC is amazing for seeing four different classes of features. the first is the structure of the fingers in the penumbra of sunspots. I can easily see more fine detail using the SC than without it, but only when seeing steadies and power is high (I use zooms exclusively for this reason... So I can amp up when I see that seeing has steadied). The second area is pores. I see them with much more authority when using the SC. The third is granularity. Great in white light using wedge of film, but better when using SC. Last is faclula near the limb of the sun. . With the SC, they really jump out!!! Downside. Because it is tuned more to the photosphere, when you look into the center of a sunspot (bridges) you won't see some of the detail inside the sunspot with the same authority. Bridges and light islands are sometimes ejections into the chromosphere (bridges are often arches but we see them looking down so we can't tell that at the eyepiece.) You can still see bridges and arches, but they won't stand out out as well with the SC in place. I have observed bridges as being wider and softer without the SC (the parts that are closer to us no doubt) and light islands inside the umbra will seem to be less well defined. I can sometimes see light islands with no SC that are invisible with the SC, and again, this is because these are actually I think more of where the "Steam" is sitting just above the surface. (At least I think this is what is happening but admit to the possibility of being mistaken). Here is an image that shows the kind of detail I can see inside the sunspot that without the SC that is dulled by the SC, but the fingers around the sunspot are greatly enhanced. https://apod.nasa.go...pot_vtt_big.jpg And if using an Achromat, SC turns it into a solar Apo. I highly recommend SC. I have used a lot of "Magic" filters over the decades that did not really seem to do nearly as much as I had read they would do, but the SC is in a class by itself. Outstanding for studying anything but the detail in the Umbra of sunspots. If you are looking and see light islands, you can yank the SC to study them and see fainter ones sometimes that you can't see with the filter in place.

I want to congratulate you for having such a good filter at a very good price. Even if the sun was completely "clean" in white light, your CaK filter revealed some very nice detail. Please find in attachment an image of Monday's Eclipse (03.10.05) here in Portugal. You may use it at your discretion. Image Details: Camera: Atik ATK-16HR Exposure: 0.002s Telescope: TeleVue 85 Filters: Baader Photosolar film and Baader CaK filter.