Finding The Sun With A Telescope.

[Suzy]

Seriously... how hard can it be to find the Sun :mad2: .
Please help save my sanity. :sadeyes:

I have a Dobsonian telescope and I get so frustrated at the length of time it takes me to find the Sun.
Is there an easier way than the shadow method which I currently use?

I will appreciate and be grateful for any help, thank you. :)

[astroron]

What I have done is made a small sun filter to fit over my finder scope,
Works simple. ;)
Cheers

[glend]

You can glue a wooden match stick vertically standing on end to a circle of cardboard (cut to fit the finder scope aperture.). Punch a small hole in the disk to provide a hole for the match shaft in the cardboard disc before you glue it with something like superglue, it only takes a few minutes to make. With the cardboad sundial in place just move the scope until there is no shadow - ie it points directly at the sun. At that point you scope should find the sun in its field of view. I hope you have a Baader safety film filter or something similiar and are aware of the dangers to your vision - standard warning for a question like yours.

[Suzy]

Ron, not so simple I'm afraid :sadeyes: .

I don't have a finderscope on my 4" dob which is the one I mainly use for solar observing. I only have a red dot finder.

I tried popping my eclipse glasses behind the Red Dot Finder window (without light on of course) while wearing my sunglasses under my hat.
I feel uncomfortable using this method ? so I was very quick. I got it within view of the RDF easily & quickly but then when I panned around I got nothing each time. So I resorted back to the shadow method and eventually got it.

[astroron]

IC thought you were using the big dob. :)
Cheers:thumbsup:

[Suzy]

Hi Glen, thank you for your concerns and they're definitely worth noting for others reading this thread. I regularly observe the Sun so yes I do have Baader solar film :D.

I don't have a finderscope on it to do the cardboard cut out. Just an RDF.

But I really do like your sundial method so I will definitely give it a go when using my 10" dob.
But I tend to use my 4" for this job a lot more as it's easier to take it outside for the short time I spend observing the Sun and it already has the filter permanently attached to it (re designed the cap to accommodate one). When I do night observing, I just simply take the cap off, as one does :D.

I guess if I can't find a quick method for my 4", I will only be observing through the 10". Just so much more mucking around getting it set up and taking it out for a quick session.

[Rob P]

This works nicely on my 120mm refractor, and it may be possible to transfer to your dob; but I just move the scope around until I have the smallest, sharpest shadow behind the scope. A variation on the sundial method described by Glen.

Good luck :thumbsup:

[OzEclipse]

Hi Suzy,

I use the shadow method then look for the image with solar filter in place in the optical tube but leave the eyepiece out while I do this. However I also use a refractor so it's easier to shadow hunt than with a small dob.

If you want to make a solar finder, a very cheap and easy way is to make a pinhole finder. There are many ways to do this. One way is to get a short piece of tube 20-30mm diameter and 50-80mm long. Square tube is better than round. Cover one end with cardboard and punch or drill a 1mm hole. Cover the other end in something translucent. A piece cut out of the side of a plastic milk container works well.

You don't need any adjusting screws, just fix the tube to the side of your scope. Magic Mount double sided art tape will suffice and is completely removable. Double sided tape will be a more secure fix if the tube is square.

Find the sun once by other means and stick a small piece of black electrical tape cut in the shape of an arrow to the translucent screen to indicate the suns position. Some people mark it with a black pen but the tape is moveable if the scope collimation changes dramatically or the double sided tape moves, just reposition the black tape.

Another way is to go to an electronics store like jaycar. Buy a small light coloured plastic electronics box. Drill a 1mm hole in one end. Fix it to the tube leave the to open and project the image onto the opposite wall of the box. use the black electrical tape arrow to indicate the correct position.
cheers

Joe

[cometcatcher]

I just use the shadow method, but the ideas above sound good too. Sometimes the shadow method can be tricky to line up.

[AndrewJ]

I second the pinhole finder method
I just use a bit of 30mmPVC pipe with masking tape at the front and a pinhole in the middle.
On the back, i taped some std white paper.
Fit to scope and line up sun once the hard way.
When lined up, you can see the projected white dot easily on the paper, and just use a pencil or fine texta to draw a crosshair at that location.

Andrew

[N1]

Here's my aiming method. Works to within less than a degree. The GSO dob I use has a collar at the front. I make sure the entire OTA is in the shadow of that collar. Same method on the frac with the baader film tube attached. Works a charm. No need to build anything :D

[mithrandir]

Suzy, I've got a couple of these: http://www.dynapod.com/dyna-hp1.html

The HP-2 fits all my scopes and telephoto lenses.

You could make something similar. The angled piece forces it to line up with the tube.

[Suzy]

Mirko that's not fair and too easy and I'm very jealous! :tasdevil:
I wish mine had that :sadeyes:.
Thank you so much for those photos, especially if you made big effort today to do them especially to show me, it's much appreciated.

Joe, I really like your suggestion and you've explained the step by step process extremely well. You would make a great teacher :D.
Thank you so much, I'm very grateful for the time it took for you to type all that. This sounds like the answer & worth having a go at.


Andrew, many thanks for the link. Nice & cheap at only around $12. But I think it looks too big for my little 4" with my ep & RDF already on the front of the tube. This looks like it's more for a refractor by the looks ? .

Andrew J, I appreciate your tips as well, thank you :).

Kev, it sure is. And time consuming grrr.

Rob P, That's what I do now. I can get the shadow really skinny but then I struggle to move the scope in alti. to get the shadow right there too.

[brian nordstrom]

:thumbsup:Suzy , look at my LP triplet thread , a few behind this one as I type , I had the same problem and grabbed a TelVue Sol searcher , $39 and typical TV quality that works really well , mine is stuck on with double sided tape and works a treat , grab one , these are small and very well made .
Brian.

[h0ughy]

out of all the toys i have the one thing that never really fails me is the shadow method - that and a large screen PC with a camera in the scope

[Larryp]

Suzy, Bintel sell a Kendrick Sun Finder which uses adhesive tape to attach to a solar filter-works the same as the Sol Finder that Brian mentioned, and only $25.00
I have used this and the Sol Finder, and both work very well.

[Suzy]

Larry, wow!

:prey2::prey2::prey2:

This looks fabulous! And so cheap!
I'm going to go for this. :D

Except I might mount it with electrical tape so I can swap it between scopes.

Do I need to align it :question: . Or do I just slap it on the front-middle of the tube :shrug: .

Thank you Larry. :party:

A thank you to you as well Brian for suggesting the same kind of thing also :D.

What's really annoying me now after reading all these suggestions, is that I've struggled for the past 5 years thinking the shadow method was the only way & finally, I broke & couldn't take it anymore. I wish I'd pursued this years ago. :mad2:

Houghy- you sound like you've got the shadow technique down to a fine art :thumbsup:

[SteveInNZ]

If you take the finder out of the bracket, you can sit a tube from tin-foil or Gladwrap in the bracket and hold it there with your finger. It's lined up with the OTA axis casts a shadow that's easy to line up. Cut it in half to make it shorter. I don't think Bintel sell them though.

Steve.

[jjjnettie]

If you had one of those 50mm finders on your scope, I was going to suggest making a filter for it.
The lids from cans of spray paint fit over them perfectly, or use a spare dust cover to make one.

[julianh72]

Suzy,

I also use a Red Dot Finder on my solar-viewing scope (90 mm Mak, 1,200 mm FL).

I use the shadow method, but rather than using the shadow of the telescope on the ground, I cast the shadow of the RDF onto the palm of my hand. (Shadows which are close to the object casting them are much sharper-edged and clearly defined than more distant shadows, such as that of the OTA onto the ground. The RDF for example barely casts a recognizable shadow onto the ground when the OTA is close to soar-aligned, but it is crystal-clear when cast onto my hand just behind the RDF.)

My RDF casts a shadow with two "illuminated" features that help me get a good solar alignment:

First, there is a slightly shaded circle through the main RDF "window", which sits in a short tube. This is my "coarse" alignment - I just move the scope until this is as circular as possible. The tube in which the RDF window is mounted is then parallel to eh Sun's rays.

Then there is a narrow slit under the body of the RDF, where it attaches to the top of the mounting bracket. No light passes through the slit until I am very close to solar-aligned in one direction, and then I just need to slew the telescope very slightly in the perpendicular direction until the image of the slit onto my hand is nice and sharp-edged. I then find the sun is close to central in my lowest-power eyepiece, so I can fine-tune the alignment through the eyepiece, and swap out for a higher-power eyepiece.

Depending on the make and model of your RDF, you may have slightly different shadows and light paths to mine, but you might find a similar light path to help you out. (E.g. even if there are no handy "slits" in your RDF mount, just aligning the shadow of the body of the RDF to make the smallest, sharpest-edged rectangle possible might be good enough.)

Hope this helps!

[ZeroID]

Suzy, a short length of straight rigid plastic tube ( I use a 150mm length of electrical conduit pipe, 20mm ID ) attached and aligned on the side of the dob. You could put a white translucent surface at the back, paper will do. Just aim at the sun till the sun shines through the tube or lights up the whole 'screen' surface.
On the refractor it just slides into the small 30mm finder mount.
Cheap, easy.

[mithrandir]

Suzy, I use mine on a 500mm telephoto, a 5" refractor and a C8. I gave one to a friend to use on his 12" Newt. I like the way the elastic forces it to align against the tube and there's no adhesive involved so it's easy to move between devices.

I had made my own but that only fitted the 5" and when I replaced the grab handle with a Losmandy D plate I lost the attachment point.

[charsiubau]

After reading ZeroId's post I tried the idea out on my small refractor. I simply taped a small piece of grease proof paper (baking paper) over the rear end of my red dot finder (it's a qwikpoint) and moved the telescope until the piece of paper was fully illuminated. It worked a treat and so quick and easy. Thanks ZeroId. Once the sun is found I'd cover up the front end of the red dot finder so it doesn't overheat.

[ZeroID]

:thumbsup: Sweet !!

[julianh72]

I wouldn't have thought there is any need - most RDFs are "zero magnification" devices, so it's just a piece of glass or plastic, with no magnifying (concentrating) effects to do any damage.