Beginner Solar filter recommendation

I couldn't find much on this so thought I would ask.
Does anyone have a recommendation on what would be the best beginner inexpensive solar filter - say below $250 or- for a Celestron 8 inch CPC telescope. I know virtually little about this aspect of the hobby but I am interested in doing this. It seems that these filters can be very expense. Any help or recommendations will be great. Thanks.
Jay

Glass Solar filter type 2 from Thousand Oaks Optical. Around 100 dollars or so.

John

Jay Martin said:

I couldn't find much on this so thought I would ask.
Does anyone have a recommendation on what would be the best beginner inexpensive solar filter - say below $250 or- for a Celestron 8 inch CPC telescope. I know virtually little about this aspect of the hobby but I am interested in doing this. It seems that these filters can be very expense. Any help or recommendations will be great. Thanks.
Jay

Depends on you. If you just want a great, inexpensive filter, go with one that uses the Baader Astro-Solar Film. You will not beat that for image quality. If you want something a bit more durable, a glass filter, that is, my favorite is the JMB Identiview. Its image quality is comparable to Baader, it's more likely to stand up to my abuse, and it provides a very pleaing orange-yellow Sun.

8)

Jay,

If you do things carefully, I do not believe you have anything to fear. We make a big deal about solar filter safety because it is important---but not because it is difficult.

I would strongly suggest you go with the Bader Solar filter and mount it yourself on a cardboard especially cut to fit your mount. On a C-8, I would consider making an off-axis arrangement. That is, you cut a piece of opaque cardboard (and I think it is called pasteboard, not corrugated cardboard) so that it fits snugly just inside your tube in front of the corrector plate. Then put velcro in the right places so that it cannot move from that position. Tilt your scope upside down and shake a couple of times. Give the cardboard a tug. If it stays on, and it is truly covering the whole inside of the tube and not any light can go down its sides to get to the corrector plate, it is safe. The only critical things here is to make sure the cardboard covers the whole aperture plus the surrounding ring, snug up to the inside diameter of the tube.

Then cut a three or four inch hole (the distance from the center of your secondary assembly and the edge of the corrector--or maybe half an inch shorter-- is the diameter of this hole) off center through the cardboard. That is, there is now a hole in your cardboard three or so inches round off center so that the hole clears both the secondary assembly and the corrector plate.

Now, cover this hole (the whole hole--past the edges of the hole) with Baader solar filter material. Tape the edges of the material in place.

Put the whole assembly on the front of the scope. And view.

The points to watch for is that the cardboard in fact stays right in place even if you happen to turn the scope funny, or some child wants to poke his or her finger at it.

Second, make sure you inspect before each use to be sure there are no holes in the solar film.

If you do this, you will be as safe as can be.....

Alex

Several things to think about, here, Jay.

If you want to spend big bucks, you want hydrogen alpha as in Coronado or soon to be Lunt or Daystar, etc. I shall leave these alone.

If you want "white light" remember that there is not much to see in white light right now. It has been boring!

But, back to white light choices. It is reputed (and I agree) that the Baader Solar Filter material is a little sharper than glass filters. It is also generally less expensive. It's kinda weird to look at, being just a piece of shiny saran-wrap like plastic---but it works great.

But it is a bluish white color. I happen to like my sun yellow. So, for solar star parties with the kids and such, I prefer my THousand Oaks glass filter. The only article I have ever read comparing the different solar filters says it is the best choice for those wanting a yellow sun. (Actually orangish) Or at least that is the way I remembered it.

Then you have to ask the question, full aperture or not? Eight inches is a good size scope, and you do not really need that much aperture.

At any rate, If I were you, I would build myself a solar filter from Baader solar film. It is by far the least expensive alternative for a beginner.

Alex