Which OTA/filter(s) to use for solar

[inapottingshed]

I'm interested to have a go at solar observing, without running to the expense of yet another scope. I have a W.O. 72mm, and a Genesis 4" refractor I can use. Which would be the better candidate? And what filter(s) do you recommened? I can spend a couple of hundred, at most.

[Merlin66]

I've got an ED80 and the Genesis, both of which I use for solar observing and imaging.

I find the ED focal length of 740mm a bit easier to use. As far as apertue is concerned, it doesn't matter for the Sun - plenty of light there!!!

For your budget, you're limited to white light observing. (Even the cheapest Cak etc set-up would be close to 400 plus due to the energy rejection filters. The easiest way to get into Ha is with the small Lunt or PST telescopes, but again we're in a similar ball park.)

A Baader solar film white light filter can either be home made ( for about 20GBP, or purchased for around 60GBP, add a green filter for 9GBP ( or a Baader Continuum for 40GBP) and you have a starting point for white light observing. Other alternatives include a Herschel wedge and ND3 filters but I think that works out more expensive..

The size of the sun's image is approx 1/10 the focal length ie 7.5mm with the ED80, so 4 shots with a webcam will cover the surface.

Hope this helps....welcome to the Bright side!!

[brianb]

Merlin has this pretty much sewn up except to point out that there is plenty of material in an A4 sheet of solar film to make filters for both of your scopes, leaving enough left over to do a normal pair of binoculars (useful for a quick look) as well.

Narrowband viewing, or imaging, is not realistic for £200, you won't even get a second hand PST for that.

[Swamp Gas ?]

Buy some solar film for about 15 pounds - make your own filter - it takes under an hour.

Get it done asap - there are three major spots to be seen as of yesterday - very impressive.

I've been waiting to use mine for a while and the recent activity is guite visible.

Nice picture here of sunspot 1024:

http://bongo69.files.wordpress.com/2009/07/sunspot-10241.jpg

Soho images etc here http://sohowww.nascom.nasa.gov/sunspots/

[A McEwan]

Slightly off-topic, but does anyone know where has the best price on a Lunt 60? I missed out on a superb 2nd hand one, and have been looking around various places but they seem to be around the £1200 mark - a bit steep for me. Unless anyone knows of somewhere cheaper...?

PMs welcome if necessary! Cheers,

Ant