Solar Filters

[Les R]

One thing that I was hopeful of being able to do was take some images of the sun.

But would only be looking at using one telescope to do this. Which would be better to use? The SE6 or the WO 66? (I've seen the large silver coloured ones - just unsure if that is the best / only method other than a solar scope.....And I've seen reference to Ha filters to capture prominence - but just the disc and sunspots is sufficient for now.

I assume with the filter, I would be able to use my nexstar 5 imager CCD too?

If the SE6 would be better, I would look to try to get now. I know the inside measurement is 175mm and the external is 180mm - I know these aren't cheap! (Which is why I asked if the WO66 would be a better option as I presume the filter would be cheaper?)

PS .... I am acutely aware not to look at the sun with just the telescope..... Which is another reason why I'm quite concerned about the fitting of these filters as if it is at the end, theee obviously need to be completely secure and no chance of falling off........... And Im just hoping someone isn't going to say you need a special telescope and neither are any good.

[The Thing]

Hi Les,

The best way to get started solar imaging without breaking the bank is to get some Baader Solar Film and make your own, there are many stockists. I have an 8" SCT and made a solar filter out of a pizza base with three holes in it (look up Hartman Mask) each covered by the film. I use an elastic strap to hold the disc in place. And you don't need any guiding

Hope that helps

Duncan

[The Thing]

And make one for the finder as well! Don't want scorched eyeballs!

[Mike]

The 66mm will be ideal for viewing the sun with. You want a small aperture as it is so bright. Of course if you are going to image the sun seriously in Ha or calcium then a larger aperture will allow greater resolution. But for white light filtering the 66mm is ideal.

[Les R]

Hi Les,

The best way to get started solar imaging without breaking the bank is to get some Baader Solar Film and make your own, there are many stockists. I have an 8" SCT and made a solar filter out of a pizza base with three holes in it (look up Hartman Mask) each covered by the film. I use an elastic strap to hold the disc in place. And you don't need any guiding

Hope that helps

Duncan

Ah, thats brilliant. Thanks for that. I had seen references to these filter sheets, but wasn't sure if they were any good. I haven't watched th YouTube clip all the way through, but looks interesting.

And make one for the finder as well! Don't want scorched eyeballs!

On my SE6 it'll be a Telrad.... I assume that wouldn't make any difference as its. It magnified?

The 66mm will be ideal for viewing the sun with. You want a small aperture as it is so bright. Of course if you are going to image the sun seriously in Ha or calcium then a larger aperture will allow greater resolution. But for white light filtering the 66mm is ideal.

Cheers Mike. Well the good news is the sheet actually has enough on an A4 sheet to be able to do both! But the bad news at the moment, is I still don't know where I stand with the WO66. He said he would have accepted my offer but that I wouldn't be able to get it by Friday. And despite asking, he still hasn't confirmed if its a deal or not and despite suggesting we can conclude this easy in a phone call, has now said wait until HE gets back from a week away. I just can't help thinking I'm being strung along in the hope a better offer comes along. Silly really as removing the postage which he included in his price, I only really offered £10 less than what he would have received once he's paid postal costs. So I think it's highly probable I will be looking elsewhere unless he gives a firm yes or no.

[The Thing]

I wouldn't try and use a Telrad with the sun - it's a bit bright! Instead get a small cardboard box, make a pinhole in one end and fit a piece of paper in the other as a screen, mark the centre of the paper and bluetak to the top of the Telrad box (pinhole forwards). You can then align this with the scope and bobs ya uncle. Another way is to make a shadow finder. These things should be made on Blue Peter!

[Les R]

I wouldn't try and use a Telrad with the sun - it's a bit bright! Instead get a small cardboard box, make a pinhole in one end and fit a piece of paper in the other as a screen, mark the centre of the paper and bluetak to the top of the Telrad box (pinhole forwards). You can then align this with the scope and bobs ya uncle. Another way is to make a shadow finder. These things should be made on Blue Peter!

lol... I didn't mean use the telrad as a finder.... But that it's not a magnified bit of kit.

Not sure how you mean with your description though! The telrad is almost as long as the SE6!

[The Thing]

I was thinking the telrad was on the scope to be used for solar viewing. It would a good base for a solar sight as the body is pretty much in line with the scope the base is stuck to due to the shape of the baseplate. Also a Telrad has a nice flat top surface (until you get to the glass bit that is!) So a card box of roughly the same width can be attached to the top of the Telrad box and be aligned-ish.

BTW you can get more bases for your telrad so you can use it on all the scopes you acquire. I love my telrad.

[Les R]

I was thinking the telrad was on the scope to be used for solar viewing. It would a good base for a solar sight as the body is pretty much in line with the scope the base is stuck to due to the shape of the baseplate. Also a Telrad has a nice flat top surface (until you get to the glass bit that is!) So a card box of roughly the same width can be attached to the top of the Telrad box and be aligned-ish.

BTW you can get more bases for your telrad so you can use it on all the scopes you acquire. I love my telrad.

Ive just had a look online to see if I can see any drawings of what you mean and how its afixed but cant see anything. (Its easy to know what it looks like when youve see it - but Ive no idea - and I would even be picking the telrad up until Friday - so dont even know what that looks like in the flesh either!) What I'm hoping to be able to do, is get the solar filter sorted (ie made up and ready for the film to be inserted - which will also be picked up on Friday at Edenbridge)

Dont suppose you have already earned a blue peter badge - or know of a source on how to do this easily with pretty pictures?

[The Thing]

The Telrad is essentially a black plastic box with batterries, lamp and reticle at the far end and a mirror (inside), lens and glass window at 45deg at the near end (as you look through it).

A basic solar finder is really a pinhole camera with a screen for the sun image. This my favourite but you probably don't have any film canisters (a bit of an anachronism). Also look here for more.

[Les R]

The Telrad is essentially a black plastic box with batterries, lamp and reticle at the far end and a mirror (inside), lens and glass window at 45deg at the near end (as you look through it).

A basic solar finder is really a pinhole camera with a screen for the sun image. This my favourite but you probably don't have any film canisters (a bit of an anachronism). Also look here for more.

What's a film canister?  I get the principles, I just can't work out how the finder alignment actually works!

I've just brought a load of card home to have a go at making the tube from the link you posted on YouTube. It's definitely harder than it looks.... And the guy glanced over the biggie about how to get round the dovetail. I'm guessing I'd have to remove it to be able to do it. One end looks easy enough with allen keys, but the other is covered in thick metal that doesn't want to move!

And it looked so easy!

[mickw]

Basically it's a tube with a lid on one end and an opaque bottom or cover.
A small hole in the centre of the lid (facing forwards/upwards)
When the scope/tube is pointing towards the sun, a spot of light will be projected onto the opaque end of the tube.
The spot of light will will appear on the centre of the opaque surface when the tube is pointing directly at the sun

[Les R]

Basically it's a tube with a lid on one end and an opaque bottom or cover.
A small hole in the centre of the lid (facing forwards/upwards)
When the scope/tube is pointing towards the sun, a spot of light will be projected onto the opaque end of the tube.
The spot of light will will appear on the centre of the opaque surface when the tube is pointing directly at the sun

Yeh, I understand that mick.....but it needs to be completely aligned with the telescope..... Though I guess it's not precision alignment, just a rough find!

The solar filter tube is more annoying at the mo 'cos unless I get that sorted, the rest doesn't matter!

[Mac]

use the telescope itself as a finder scope.

By that i mean look at the shadow produced by the telescope.
as you move the telescope towards the sun, the shadow will get smaller in size on the floor,
until its at its smallest, at which point the sun should be visible in the eyepiece.

telescope sideways to the sun will produce a large shadow.

   O (the sun)


-------

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half way there the shadow is smaller

\
\
  \
   \
    \
----

pointing at the sun, the shadow is the smallest

¦
¦
¦
¦
¦

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Simples.

Mac