Safely viewing the Sun

[astrollie]

I am interested in observing the sun, before I do so I want to make sure I've got the correct equipment.

I have ordered this solar safety film.. http://www.firstlightoptics.com/solar-filters/baader-astrosolar-safety-film-nd-50.html  to cover the end of the smaller cap on my 200p, 

I am also going to construct a cap for the end of my finderscope with the safety film.

What else should I be using? Also any tips, I'm pretty new to all this

Thanks

Oliie

[Peter Drew]

Hello Ollie, welcome to SGL.

You are on the right track and what you propose, if done correctly, will be safe. My only extra comment is that the aperture at the end cap is going to be around 2", if you make an off axis version without the end cap then you could achieve at least 3" clear aperture offering better resolution. 

[Mr Spock]

A good tip is to keep the caps on your normal finder and use a proper solar finder. Normal finders will produces dangerous levels of light and heat.

[astrollie]

Thank you for the replies, ill see what I can achieve with the A4 sheet I have bought.

By proper solar finder do you mean something like this? http://www.amazon.co.uk/Orion-9x50-Solar-Finder-Scope/dp/B00CPY7H8C

[Mr Spock]

I was thinking of something like this http://www.telescopehouse.com/solar-observing/solar-accessories/televue-sol-finder.html

[astrollie]

That looks much more affordable   thanks Michael

[Gazabone]

Personally I'd forget the finder completely, leave the dust caps on. You can get a good alignment from the scope's shadow on the ground. I did make quite a nice solar finder for one of my scopes from an old finder scope. I took out all the glass, removed the rear section (so I'm left with a single cylinder) and replaced the front element with a suitably cut up old credit card (which I covered with silver foil but that was just for looks) and pierced a pinhole in the centre. At the rear I cut up an old translucent yogurt pot and marked an X in the centre. The pinhole transmits a nice dot onto the rear "element" which, once the finder is aligned (sits in the normal finder mount) makes alignment beautifully straightforward without casting your eyes anywhere near the direction of the sun.

[Knighty2112]

When I view the sun through my scope, I tend to use the telescopes shadow to know when I am close to the sun through the EP by putting my camping chair behind the scope that I sit on, then observe the shadow of the scope on the back of the chair. When I can see the circular outline of the scope I know I am close to the sun, and normally start off with my 32mm EP to centre the sun in the scope before I use a higher powered EP on it.

[astrollie]

Sounds like there's a few options then, i think il try using my telescopes shadow to measure first and see how I get on. How often would you say the filter should be replaced? Or does this depend on amount of use and how safe its stored?

[Spikey]

Make sure you have some way of taping the cap on the end of your scope securely. They have been known to blow off or fall off on occasion. Not what you need when solar viewing !  

[nameunknown]

I would just leave the cap on the finder and use the "shadow" method, and tape to ensure the filter stays on the scope. Using a finder for the sun means a lot of tempting chances of looking in the solar direction - just not good for the eyes - they are difficult to replace!

P

[LukeSkywatcher]

Its amazing how difficult it can be to locate that big yellow thing in the sky. The shadow methos is about the easiest,cheapest and safest.

[Floater]

Its amazing how difficult it can be to locate that big yellow thing in the sky. The shadow methos is about the easiest,cheapest and safest.

Indeed, it is surprising to find that you have to 'find' the sun. But you do. So why not use a finder?

The shadow method is certainly the cheapest, but no safer than a custom-made solar finder. And it's certainly not the 'easiest' - a finder is the easiest way to get your telescope pointing at the sun.

[LukeSkywatcher]

Indeed, it is surprising to find that you have to 'find' the sun. But you do. So why not use a finder?

The shadow method is certainly the cheapest, but no safer than a custom-made solar finder. And it's certainly not the 'easiest' - a finder is the easiest way to get your telescope pointing at the sun.

True enough i guess. Maybe for a Christmas gift to myself i'll add a Sol finder for my solar observing.

http://www.telescopehouse.com/solar-observing/solar-accessories/televue-sol-finder.html

I'll probably have to use sticky pads to attach it to my Celestron 70mm Travelscope.

[Drop Of Sun]

 We solar fans seem a bit split on shadow method versus solar finder! I prefer a solar finder myself. I guess try shadow and if you find that brill you don't need a finder?

[astrollie]

Yeah my plan exactly... just going to try the shadow method first then if that fails il get one of the solar finders for around £20.

Once the clouds have moved and I've tried out the solar filters on my telescope I'm going to start looking for equipment/filters for photographing it.

[Knighty2112]

Make sure you have your longest focul length EP in first when you do the shadow method. I use my 32mm EP and get the sun in view in less than 30 seconds using the shadow method. If you use a lower one first it will be very difficult to get it located easily.

[Floater]

As can be seen in my sig, I have four solar finders, each on different scopes. And the TV Sol Searcher is excellent (as with most TV kit, although there is at least one exception) but it's very expensive for what it is.

Apart from some great offers on Astroboot now and again, the most economical is possibly the HelioPod - even including import fees. And the guy who runs the business is a fellow star-gazer and a nice man to deal with. I bought two for economy of shipping and gave one to another solar enthusiast who had faffed around shadow-boxing ... No more faffing now.

[BVietje]

The TeleVue Sol Searchers work great, but you can make one by using a hole in a thin piece of plywood and a target painted white.  Once you find the Sun by the shadow method, and have it centered in a low-power eyepiece, just trace it's bright image on the white screen, and you're off to the races.  Only advantage of the Sol Searcher is that the "screen" is a translucent piece of ground glass, so you can use it from the tailstock end of a longer instrument.

Let us know how you make out, astrollie.

[BVietje]

For beginners, teachers, or travelers, another good option is a Sun Funnel.  Here's a PDF of instructions on how to make one from the Astronomical Society of the Pacific:

http://www.astrosociety.org/tov/Build_a_Sun_Funnel2.pdf

The lead author is Rick Fienberg, former editor-in-chief at Sky & Telescope, and it discusses many details.  The only thing I would add is about choice of eyepiece:  1) don't use an eyepiece you care much about, 2) avoid a cemented eyepiece, as the optical cement can melt & boil, and 3) definitely don't use an eyepiece with any plastic parts!  I've done this for years, and its a great way for a small group to all view at the same time.  You can also center the image and photograph it daily, and even do real science with students (or for your own enjoyment), who can calculate the differential rotation of the Sun.  I'll try to attach a NASA PDF file with instructions for making sunspot measurements using basic spherical geometry....

OOOPS!  The file was too big.  For those interested, search for "Tracking Sunspots" from NASA -- the file is called "spotexerweb.pdf"

Another great reference for solar observing is found here:    https://books.google.com/books?id=7pCKCgAAQBAJ&pg=PA129&lpg=PA129&dq=sun+funnel+template+for+sunspots&source=bl&ots=ZDo_t-HPVJ&sig=K0H1jdS-UlyA-eIMtp9qsUei9OM&hl=en&sa=X&ved=0ahUKEwjYmuO9ytLJAhWD1CYKHT1UArgQ6AEIKDAC#v=onepage&q=sun%20funnel%20template%20for%20sunspots&f=false