Solar finder

[Stub Mandrel]

I can't believe how difficult it is to 'find' the sun when a bit of haze gives it 'soft edges' and the scope is unfocused.

I have ideas for a quick and dirty 'solar finder':

• A pinhole camera with a translucent screen inside a tube, with a target dot.
• A pin or pointer casting a shadow on a card.
• A long thin tube casting a shadow on a card.

Does anyone have any suggestions about what might work best or any other ideas?

 

[brantuk]

For a mere thirty squids you can't beat one of these:

http://www.firstlightoptics.com/lunt-solar-accessories/tele-vue-sol-searcher-for-lunt-solar-telescopes.html

[ngwillym]

or there's this:-

 

[baggywrinkle]

I have the TV one and it works well. I also have another design I bought off eBay. I will post the details later.

[Floater]

I'm a great fan of finders and give +1 for the TV Sol Searcher.

Here are links to others.

http://www.dynapod.com/dyna-hp1.html

I have one of these (imported two to save on postage and gave one away). They work well and Alan Rifkin is a fellow astronomer and a nice guy to deal with.

Or,

http://www.astro-engineering.com/prod/astro-engineering/solar%20finder/AC618.html

These occasionally come up on Astroboot but are often 'out of stock'. Again, I have one and it works well.

Finally (from me), you could have a look at the attached pdf.

Hope some of this helps.

 

a collection of solar finder designs 0v6.pdf

[Stub Mandrel]

2 hours ago, brantuk said:

For a mere thirty squids you can't beat one of these:

http://www.firstlightoptics.com/lunt-solar-accessories/tele-vue-sol-searcher-for-lunt-solar-telescopes.html

Ah! That's more or less what I was thinking of making.

[Stub Mandrel]

Thanks for the idea, looks like a pinhole is the simple approach

[brantuk]

I did think of making one at the time too. But opted for the easy way out - as I more often do in these advancing days of mine lol

[michael.h.f.wilkinson]

I have a TV Sol-Searcher and the Coronado "Sol-Ranger" that came with the SM-II 60mm scope. The former has the latter beaten by a mile, because you can use the TV by looking either from the front or the back at the shadow of the hole on the transparent disk on the rear, unlike the Sol-Ranger which only can be viewed from the rear. This means you are looking more-or-less into the sun, causing you to be dazzled and not seeing a thing through the EP anymore, especially in DS mode where the sun's image is pretty dim.

[Peter Drew]

I just bend a piece of 1" x 1/8" aluminium stock up at each end then drill a 1/8" hole in one end and a 3/8" hole in the other. I then  glue a piece of milk bottle plastic over the 3/8" hole as a screen for the pinhole image to form on. You don't have to look towards the Sun at all to line up the telescope. £30 quid would make about 50!  

[Gina]

I'd probably 3D print one.  Might do if I get back to white solar imaging.

[Stub Mandrel]

Well I'm so impressed by all these suggestions!

A few days ago I found a sheet of translucent film, I just dug it out again, found some 35mm tube with a handy 'viewing notch' in the end from an old display unit, and cut a square out of a notebook that's nearly full. Ends held on by insulation tape, (when I find a bit of 1 1/2" ali bar I can turn some smart end caps to hold the two plastic discs in place).

A genuine pinhole was too small, but a number 60 drill was fine (about 1mm).

Unfortunately it's just a tidge to big to fit in the finder holder for a waste of time R/A finder that doesn't work with my brain.

How's this for a ten minute job :-)

Dot applied with a sharpie the sun is targeted on the spot but it doesn't really show in the pic.

 

 

And looking through the carefully dimensioned and machined viewing port ;-)

Allows bi-directional viewing as someone suggested.

Thanks all for your great suggestions. Obviously a bit of a tidy needed and a mount, but once finished I'll post a new pic!

[Stub Mandrel]

Right... If a thing's worth doing it's worth oiverdoing ;-)

I used up a bit of my poor old Halson Inversion fork tubes, smaller diameter so I could use a bit of 1 1/8" OD by 7/8" ID end caps. I had planned to use superglue, but as the heated up during boring, I ended up with both caps being a force fit. This should fit in my finder bracket too.

Wee window for viewing from the sunny end:

A little extension to shade the far end for 'normal viewing':

 

 

[Gina]

Neat

[Floater]

Better and better. Power to you.

[brantuk]

Nice one! Ingenious and thrifty.

[SteveInNZ]

If you take the two bits off the end so you just have a tube, you can look at the shadow on the ground. When it's pointing at the Sun, the shadow is a circle. If it's not pointing at the Sun, it's pretty easy to see how to move the scope to get it pointed at the Sun.

 

Steve.

 

[Joe12345]

I always get it pointed roughly at the sun, then look for the projection of the finder. I then move the scope until the projection is on the shadow of the finder. Works well, but apparently the crosshairs can burn? Mine are still going strong!

[Stub Mandrel]

The abject failire of 'shadow' methods is why I wanted a proper finder.

Good news is it didn't take me too long to find the sun with the DSLR and align the finder (now in a cheap Seben holder).

That spot is ENORMOUS!!!!

Filled my memory card :-)

Proof of pudding: