Baader K-Line Filter 1¼" (double stacked)

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Baader K-Line Filter 1¼" (double stacked)

# 2458355

€ 295.00 Price excl. German VAT tax (19%): € 247.90

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  • Warning: for photographic imaging only
  • for solar work use only with 3.8 AstroSolar 200x290mm Photo Film (included)
  • never use any eyepiece filter for solar observation without objective front filter
  • non-ageing sealed coating edges
  • Never look into the sun with the K-Line filter without an additional OD-reduction filter. For more information read the PDF Notes about the stacked 1¼" K-Line Filter

Product Questions

Sort by ASC
What's the actual size of your 2" filters in "mm" with and without frame/ring? What step down adapter is suggested from a 52 mm to "-- mm"?
Question by: Waqas Ahmad on Oct 10, 2016 7:54:00 PM | 1 Answer(s)
What are the threads and pitch of your 1.25" and 2" filters?
Question by: Anders G. on Sep 20, 2017 12:55:00 PM | 1 Answer(s)
Hi, will this filter work with an unmodified Sony a6300 camera or do I need a modified sensor to register this wavelength?
Question by: Franco Meconi on Mar 20, 2019 4:12:00 AM | 1 Answer(s)
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Additional Information

Manufacturer Baader Planetarium
SKU (#) 2458355
EAN Code 4047825009531
Weight (kg) 0.027
Transmission Range CaK-II
Filter Thickness (without cell) 2 mm
HBW (Halfbandwidth) 8nm
CWL (Central Wavelength) 394 nm
AR-Coating dielectrically coated, planeoptically polished
Special Features doube stacked
Filter size 1 25 inch
Filter Usage Solar
Filter mounted Mounted (classic 8mm)
Type of Filter Narrowband
Single or Set? Single Filter
Filter shape round

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2 Item(s)

Greg K 228/08/2017 17/08/201706:04
  • Rating:
Finally I can do Calcium K imaging
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.

  • Price and ease of use
  • Nothing, the product is great
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R. Tripa 297/10/2005 25/10/200508:49
  • Rating:
A good filter at a very good price
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.
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