Some white Light shots enhanced with an OIII filter...

[Cschur]

Hi all,

Here are a few shots from yesterday with my 90mm f/12 Maksutov fitted with a front filter of 5.0 Baader astro solar film, and the camera which was a DMK3U was fitted with a green narrow band OIII filter from Lumicon. I had read that for white light imaging, Jenkins new book says that a G filter, near 500nm is perfect for improving the view of sunpots, granulation and faculae because the contrast of these features is greatest here. (sunspots are essentially dark red, and faculae is essentially bluish)

Here first is a full disk image with a 60mm refractor for a key to the close ups with the 90mm Mak. Images taken with out the filter were so bad from poor seeing that Registax simply would not register them at all. Here, with this filter which approximates the G band filter I can start to see granulation around the sunspots. Not bad for a 90mm, ay? the last shot is with a coronado 2x barlow for fun. probably too much magnification, but I was experimenting right?

[Merlin66]

Very nice capture!

[Dave]

Very nice.

[Montana]

Great pictures! a definite improvement. Always try a higher magnification, you never know what the processing will reveal

Alexandra

[Cschur]

Alexandra, your right - more magnification to the seeing limit is worth a try. I see your shots with inter granular lanes, and my novice attempts with hardly any granules visible and I know I have a long way to go. Give me a few weeks, Ill try to have it down...

[DrNeb]

Ok, this might be a dumb question. But as the sun is pretty large... how big would you say those sunspots are relative to our pale blue dot?

cracking capture though! nice work.

[Cschur]

I think I remember reading the sun is 108x the size of the earth. so these umbra in the sunspots have to be approaching earth sized.

[Tron]

NASA say 100 Earth's can fit into the diameter of the Sun, people on here say 108.

I am more inclined to not believe NASA

[markt]

NASA say 100 Earth's can fit into the diameter of the Sun, people on here say 108.

I am more inclined to not believe NASA

It's actually 109.

Diameter of sun = 1392000km

Diameter of earth = 12756km

Divide the top one by the bottom and you get 109.

NASA is rounding down...

[Tron]

It's actually 109.

Diameter of sun = 1392000km

Diameter of earth = 12756km

Divide the top one by the bottom and you get 109.

NASA is rounding down...

Rounding down and leaving off "9" is quite a large error (On an Earthly scale )

[PeterW]

Depends how round they are in comparison, are you comparing diameter or volume and also it hard to define exactly where the surface of the sun is. 10% uncertainty seems pretty good for an astro measurement!

Peterw

[markt]

are you comparing diameter or volume

If it's volume, this is proportional to the cube of the radius, so 109 cubed (to the power of 3) is approximately 1.3 million - so you could fit 1.3 million Earths inside the sun.

The surface of the sun is defined as the photosphere - although this a relatively meaningless definition of surface as it's obviouslly not solid...

[smerral]

Nice shots - and that filter seems to be working a treat! I am looking at ways at improving my white light images and this filter is certainly worth considering:)

[Merlin66]

The Baader Continuum will give similar results....even a light green gives improvements...

[Tron]

Which filters gives the best white light improvement? Continuum, K-Line, Green, OIII, UHC-S (L booster)?

[Merlin66]

based on past experience, the Continuum followed by the Green.....now the OIII results are in, I'd add that alongside the Continuum.

[Tron]

I'm getting bored of the same old white solar disc's now just want to get new types of images lol.

I even took shots of the daytime moon before I do the Sun since both are in the sky easy to capture.

Is it possible to block the solar disc on the baader white light filter and capture the corona or would I need an unfiltered coronagraph for that?

[Merlin66]

You'd need some specialised optics to image the corona....completely different ball game from "standard" white light imaging....

[Cschur]

Thanks everyone! I also found in my experimentation that my meade G filter for CCD imaging gave very good results by significantly darkening sunspots and bringing up the faculae considerably. the seeing was not improved nearly as much as the OIII filter, which made the seething sun rock solid.

[sheri_barri]

Very well done! The filter makes an amazing improvement from standard 'white light'. Cheers for sharing your experiment's results!