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Solar filter identification

Started by dumenko, 01/10/2012 02:30PM
Posted 01/10/2012 02:30PM | Edited 01/10/2012 02:46PM Opening Post
I have a "Astro-Physics 152mm Starfire" that purchased a few years ago. It came to me with a few extras, one of the extra was a solar filter that I have not been able to find any in formation about to date. I am hoping that someone on this forum may know of the suppler of the filter or have info on the unit. I will attach a few photos of the unit if I can. There are no identification or manufacturer markings on the filter itself, only a couple of tags on the inside cover. This filter is an exact fit on the out side of the lens cell, it fits the cell perfectly with dew shield removed seams to have been made for this 152mm Starfire. I have had a talk with the folks at Astro-Physics about the filter and they could not identify the unit. The glass filter is high quality with reflective coatings on both sides and set in a metal cell. Any help on identifying the unit would be greatly appreciated.

Attached Image:

dumenko's attachment for post 54745
Posted 01/10/2012 02:34PM | Edited 01/10/2012 02:46PM #1
Second photo of the filter

Attached Image:

dumenko's attachment for post 142879
Posted 01/10/2012 04:22PM #2
It is too bad that your pictures are so tiny. 19kb image is really not necessary - you can post as big as 450kb.

In any case, do not assume that because it is glass with nice shiny reflective coatings that it willproduce a high quality image. Most of not all of these inexpensive glass filters used cheap and cheerful window glass - have you ever looked thru your window with your scope? If so, you get the point.

Good glass filters are super expensive, because they basically have to be polished to the level of accuracy of a test plate. On both sides, no less! And the glass has to be first rate optical glass with no striations.

The nearest thing to that is a Baader Astro filter made from a very thin plastic foil material that has been carefully annealed and coated on both sides. Yes, believe it or not, it will outperform a typical inexpensive glass filter.