How do I observe the Sun?

[BWBlackett]

I have a 10" Skyliner Dob and was thinking about looking for a few sunspots. I've looked at FLO's website and they sell Baader AstroSolar Safety Film ND 5.0. Would I have to cover the whole of the end of the telescope or would it work using the supplied dustcap and just using the film to cover the small 2" hole in the dustcap?

Any suggestions appreciated.

Brian.

[ianporter13]

Brian,

just use the small cap and you'll be fine, if you look at most of the solar filters for bigger scope you'll see that they are mostly sub aperture in just the same way as you'd get with your setup.

Ian

[lunator]

Brian

I agree with Ian.

You only need to use the smaller hole. Light grasp isn't an issue

Make sure you cover your finder as well.

Cheers

Ian

[BWBlackett]

Thanks for your help. I use a Red Dot Finder so no worries there.

Is the dust cap a good enough fit or do I need some other protection ?

Brian.

[radioactive]

Thanks for your help. I use a Red Dot Finder so no worries there.

Is the dust cap a good enough fit or do I need some other protection ?

Brian.

I don't understand that comment Brian sounds very dangerous to me !!

[Astroman]

While light grasp isn't a problem, resolution is. The more aperture you have, the better resolution you'll get.

That said, a 10" scope is almost too much for observing the Sun. Stopping her down to 8" or less won't hurt much for your application. And, the added effective focal length may work to your advantage. I'd suggest a 6" or 5" aperture mask with film attached.

[BWBlackett]

Sorry, what I am trying to ask is am I alright putting some of the Baader film over the 2" hole in the 10" dust cap which fits in the end of my Dob - I think the answer say yes - but it might be to small?

Am I safe with this arrangement or is there a risk that light can get in around the edge of the 10" dust cap - is it a good enough fit, has anyone else tried a similar setup ?

Brian.

[Astroman]

You should be fine covering the 2" hole in the dust cap, as long as you secure it well. I have tried this arrangement and it works great. I'm just saying, you'll see more detail, (as soon as there is some detail to see), with a larger covered hole.

[Macavity]

The idea is to mimic something like this (Sorry my friends at RVO). You might get the approx. dimensions from the picture. An off-centre filtered hole, basically to avoid the secondasy mirror - With the rest obscured!

http://www.rothervalleyoptics.co.uk/detail.php?id=544

Solar filters are usually a "good fit" to the OTA. They might supply Velcro, to act as "belt and braces" just in case etc. They still (slightly) horrify me, but I'm getting more used to the safety aspect... Double/Triple checking etc.