Is it even worth it?

[LukeSkywatcher]

I am thinking that i would like to do some solar observing with my Celestron 70 Travel scope.

Of all my 3 scopes, it is the most portable.

With just 70mm apeture would i see any sunspots? (with the correct filter.................Badder solar film).

Or is 70mm just a waste of time and effort.

[yeti monster]

In ye olde days, when I first got my 84mm Prinz Newt, using the dreaded and now (quite rightly) frounded upon, glass EP solar filter, I saw sunspots whilst I had the aperture mask on the objective end of the OTA (about 30mm diameter).

So I'm sure that you'll easily see sunspots with 70mm.

How much magnification you'll be able to achieve, I cannot say...

At the time, I did wonder how the filter managed to become cracked one day, I noticed that I was getting bright flashes to one side of the FOV. Thankfully I then inspected the filter by dismantling it, whereby the glass fell out in 2 pieces. It was replaced and the new one gave good service, but I am really glad to have been warned off them by SGL members since returning to (far more serious) astonomology.

Remember folks: Only use the correct filter media, set over the objective of your equipment for solar viewing.

[Talitha]

Your scope will be just fine, Paul. I've used 11x70s and the sunspots looked great.. they'd benefit with the magnification your scope can get.

[Brendan of Borg]

Agreed!

[Merlin66]

99% of my solar observing/ imaging is done with an 80mm aperture.

It will work very well.

Use the Baader Solar Film securely mounted.

[John]

I was thinking of getting a similar scope and a Baader filter to mount alongside my PST so that white light and H-alpha views could be compared easily.

I used to see some nice details when projecting the sun with my old Tasco 60mm refractor so the 70mm should produce some nice views with the correct filter in place.

[Ags]

As a teenager I did solar projection with my refractor. It had a 70mm nominal aperture, but if you looked down the tube you could see it was stopped down to 50mm or less. I could see numerous sunspots by projection.

[67champ]

Paul, sounds like you are in business!

d

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[brianb]

70mm should do just fine .... I've even managed to get an impression of the surface granulation (true "rice grain" granulation, not the coarser mottling) with only 60mm.

If your scope is a short focus achromat i.e. has significant chromatic aberration, use a green filter (Wratten #58 is good, Baader solar continuum is excellent but expensive) to enhance the contrast.

[LukeSkywatcher]

Thanks all for the advice. My days of making a solar film myself are over so i will buy one ready made. I thought 70mm would be pushing it a bit.

[yeti monster]

What's wrong with the Blue Peter approach? I made a lovely one for my TAL-1 last time home and I'm even considering a HUGE one for the 10" SNT...

[LukeSkywatcher]

I was never any good at making stuff i saw on Blue Peter.

[Talitha]

I hope you're clear when the filter is delivered, and that Sol has a lot of freckles to see. Let us know how things turn out, ok?

[yeti monster]

Get some web-camming done, I'm even starting to make out granulation in some of my post processing.

[LukeSkywatcher]

With the weather the way it is over the last couple of weeks, i am in no rush to get the filter. I think i'll put it on my Christmas wish list.

[yeti monster]

You never know what tomorrow will bring, the sun may pop out for 1/2 an hour or so and you'll wish that you'd got them scissors out!

[LukeSkywatcher]

I suppose even i could make one using the "stop down" cap on my scope. Mind you i think the cap on my 70mm scope stops down to about 35mm.

I guess thats more then enough when you take into consideration the magnification. It would mean i only have to stick a disc of solar film inside the cap.

Easier said then done.