Large sunspot visible for 3-4 days in mid-April 2016

[sophiecentaur]

Now that is a good example of perspective!

If I go the the expense of buying a solar filter for my 200mm Dobs, is that the sort of picture I should be expecting? That would mean an extra potential half days gazing every day.

 

[1oldman2]

If I go the the expense of buying a solar filter for my 200mm Dobs, is that the sort of picture I should be expecting? That would mean an extra potential half days gazing every day.

I have to claim total ignorance when it comes to this question. I'm pretty sure the image Dotini posted is from NASA's SDO so that would be tough to compete with from earth. I would think Dave, Russ, Dotini or Andy would be able to recommend the best case answer for choosing a filter.

 

[Dotini]

If I go the the expense of buying a solar filter for my 200mm Dobs, is that the sort of picture I should be expecting? That would mean an extra potential half days gazing every day.

Got that pic off Yahoo - was probably a pro level shot. Here's the site: https://www.yahoo.com/news/transit-mercury-producing-awe-inspiring-171007799.html

Solar gazing is probably best for a short time in the early morning after sunrise.

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[sophiecentaur]

And talking of Solar Filters. There are filters available on eBay that fit onto the small hole in the cover of my 200p. They also fit on the finder scope. Are they worth the bother? The resolution can only be around a tenth of the full mirror. (Or rather, ten times the angular resolution)

 

[1oldman2]

Got that pic off Yahoo

Cool, that's an interesting shot.

 

[Dotini]

Cool, that's an interesting shot.

Heh heh! Almost as if the sun were opening like a magnetic flower in greeting to its little relative, Mercury.

 

[1oldman2]

Heh heh! Almost as if the sun were opening like a magnetic flower in greeting to its little relative, Mercury.

True, I know its only a matter of perspective but it looks like that flare could engulf mercury.

 

[Andy Resnick]

And talking of Solar Filters. There are filters available on eBay that fit onto the small hole in the cover of my 200p. They also fit on the finder scope. Are they worth the bother? The resolution can only be around a tenth of the full mirror. (Or rather, ten times the angular resolution)

I would not mess around with kludging a solar filter. Since you are just starting out, at the so-cheap-it's-practically-free end of the spectrum, try a mylar blanket- the sort that comes in first aid kits- secure it to the barrel with an elastic band (or some Kapton tape). I tried a mylar balloon, but there was a very visible 'weave' type pattern so I was out $2.50 US. After that, I scrounged up a reflective ND 4 filter that I insert where the lens filters go, attaching it with some Kapton tape. The reflective filter comes first, before any polarizer/UV blocker/etc. Important- make sure it's a *reflective* filter, not an absorbing filter.

If you want to try spectral solar filters, they are incredibly expensive sub-angstrom width temperature-controlled etalons. I don't have those. I tried using a rescued 'narrowband' filter (+/-10nm) from an old microscope in conjunction with the ND 4, but the spectral width is still too broad.

As for the finder scope, I wouldn't bother if you are not using the finder- in fact, you may want to remove the finder for solar viewing just in case you happen to glance through it. It's not like you will have trouble finding the sun...

 

[davenn]

I would not mess around with kludging a solar filter. Since you are just starting out, at the so-cheap-it's-practically-free end of the spectrum, try a mylar blanket- the sort that comes in first aid kits- secure it to the barrel with an elastic band (or some Kapton tape).

yup, read my post #23

Dave