Lumicon Solar Prominence Filter (8" scope)

[Matt Wastell]

Hi all.

I have had this for a while - but ever since I have had the Lunt Ha scopes I have not used it.

Lumicon Solar Prominence Filter (LF4050?)

Includes –
1. Narrow Band Pass Filter (1.5 Angstrom bandpass)
• Fits 2” diagonal / accepts 1.25” eyepieces
2. 58mm Energy Rejection Pre-filter
• Fits 8” SCT telescopes

This is an older style two-part 1.5 Å bandwidth solar prominence filter. It includes an energy rejection filter (ERF) and H-Alpha filter unit.

The ERF is a 58mm filter and is mounted within an aluminum cell to fit an 8” telescope tube.

The H-Alpha filter unit (1.5 Å Bandwidth) fits to a 2” diagonal and accepts 1.25” eyepieces. The filter has a tuning mechanism that allows you to optimize transmission and contrast for the prominences you are examining.

From memory it is purely a prominence filter, no disc detail is visible.

If you have an 8" scope and you want to play with the Sun.....

..........make an offer!

Matt

[h0ughy]

matt how long have you had this filter? did you get it new?

[Matt Wastell]

Hi David
I purchased it new from Bintel - I think in 2005 (after Venus transit 2004 - this is when my Sun interest really kicked in).
It has been kept in great condition and I believe the filter(s) have a life expectancy of 20 years.

http://www.lumicon.com/store/pg/10-Lumicon-International-FAQs.aspx

Solar Prominence Filter
Q:What is the purpose of the required Energy Rejection Prefilter component of the Lumicon Solar Prominence Filter system?
A:To protect the human eye from dangerous solar radiation.
Q:Why is an off-axis location required for the 58mm or 77mm Energy Rejection Prefilter?
A:Simply to avoid obstruction by the telescope's centrally located secondary mirror. Unobstructed telescopes would not require an off-axis location for the Prefilter.
Q:Is the Lumicon Solar Prominence Filter system safe to use on Schmidt-Is the Lumicon Solar Prominence Filter system safe to use on Schmidt-Cassegrain telescopes?
A:Yes. The Lumicon Solar Prominence Filter system was designed to function normally on all commercial SCTs. Its 58mm or 77mm diameter Energy Rejection Prefilter stops down the SCT's aperture, effectively producing a focal ratio that lies within the optimum range to prevent overheating.
Q:Can the Lumicon Solar Prominence Filter be used on telescopes having focal lengths shorter than 1200mm?
A: Only if a Barlow lens is used to produce an effective focal length of at least 1200mm, and only if Lumicon's 58mm Energy Rejection Prefilter is used. The Barlow lens must be located before the delicate narrow-bandpass (1.5) filter.

Thus, the components would occur in the following order:
1. Energy Rejection Prefilter
2. Telescope Objective
3. Barlow Lens
4. Narrow-Bandpass (1.5) Filter
5. Eyepiece
Q: Can the 1.5 Angstrom bandpass component of the Lumicon Solar Prominence Filter be used safely with other brand-name prefilters?
A: No, the reason being that the two filters of any brand-name Solar Prominence Filter system comprise a matching set and must be used together exclusively. Lumicon does not know the specifications of other brand-name Solar prominence filter systems and therefore cannot recommend the indiscriminate use of its 1.5 Angstrom bandpass filter component with other brand-name energy rejection prefilters.
Q: Can I look at the sun directly by holding the prefilter in-front of the 1.5 Angstrom filter?
A: No! The two filters, in combination, require a substantial image magnification in order to reduce the light intensity to a safe level.
Q: What is the lifetime of the 1.5 Angstrom bandpass component of Lumicon's Solar Prominence Filter system?
A:15 - 20 years. The lifetime is shortest near the ocean or in regions of high humidity.
Q: Is the Energy Rejection Prefilter included with the purchase of a Lumicon Solar Prominence Filter System?
A:Yes. The customer specifies his telescope type when ordering, and Lumicon then selects the appropriate Energy Rejection Prefilter