Sunspot 798 (10 Sept 2005) Prime Focus and Barlowed

[Dennis]

Hi

Set up this morning and noticed a giant sunspot - wow it was Huuuuge!

Grabbed the following images using the Vixen 4” refractor and Meade LPI:

• Prime focus (20 images auto-stacked)
• TeleVue x2.5 PowerMate (12 images auto-stacked)
• TeleVue x5 PowerMate (single image due to turbulence)

Meade LPI set to 90% quality to minimize the effects of variable seeing.
Baader full aperture solar filter.
Vixen 4” f9 refractor.
Vixen GPDX mount.

Cheers

Dennis

[fringe_dweller]

Hot hot hot!! (pardon the pun) very very nice Dennis! :eyepop: :thumbsup: :thumbsup: keep em coming please
kearn

[RB]

Amazing Images Dennis,

Great detail on the sunspot.
Well Done !! :thumbsup:


Andrew

[davidpretorius]

aurora hunting i will go....

[atalas]

Up close and personal ! great shot Dennis ,amazing to think that those dark spots are brighter than the moon .

Louie :thumbsup:

[iceman]

Wow absolutely stunning, Dennis! Incredibly sharp shots, even at the longest FL.

I don't think the seeing was that good when I tried mine, I couldn't come to focus properly with the barlow, the seeing just couldn't support it. So I stuck with prime @ 1250mm.

[acropolite]

DaveP said :rain:Not unless you've got an aeroplane, a pilots licence and a night and instrument rating to go with it.....:poke: BTW nice shots Dennis, must get some of that film; does it come in that pretty orange colour as well???

[davidpretorius]

doesn't everyone have one of those, well not true, i do not have a pilot's license, but my pilot does!!!

[Dennis]

Hi Phil

I have made filters using the Baader visual film and astrophotography only film. Both are white light you see in the images. I did once have a 1000 Oaks glass filter which did produce an orange Sun but unfortunately it also produced a lot of ghosting in the refractor.

I have been really impressed with the Baader film as it allows for short exposures with the LPI to freeze the often poor seeing.

Cheers

Dennis

[Dennis]

Hi Mike

The seeing was reasonable at prime focus and using the TeleVue x2.5 allowing the Meade LPI software stack several images to improve the result. At x5 I managed to grab over 250 individual images before the seeing really turned bad and less that 10 were any good. These would not stack as each one was quite "different" due the image shearing from frame to frame with the seeing.

The Vixen 4" is a very forgiving 'scope to image with due to its short focal length (918mm). I acquired the images between 8:30 and 9:30am.

Cheers

Dennis

[xrekcor]

Dennis,

Nice images!! have been thinking of trying the LPI out through the
baadar film myself. Whats the difference between the visual and
photography films? can you get away with using just the visual stuff?

regards,CS

[Dennis]

Hi Rob

I’ll try to answer your question by explaining my set up and how I use these filters, so here we go:

• I use the standard Baader Solar Film (visual and astrophotography) when I am imaging with the LPI at prime focus and with the PowerMate x2.5 Barlow.
• I use the Baader Solar Film 3.8 (astrophotography only) when I plug in the PowerMate x5 Barlow.

With my 4” f9 refractor, here are some examples of the LPI exposure settings:

Baader Solar Film (visual)
• Prime Focus: exposure 0.002 secs
• PowerMate x2.5 Barlow: exposure 0.008 secs
• PowerMate x5 Barlow: exposure 0.032 secs

Baader Solar Film 3.8 (astrophotography)
• PowerMate x5 Barlow: exposure 0.001 secs

Basically, the standard Baader Solar Film is fine for prime focus, the x2.5 Barlow and when the seeing is good, sometimes even the x5 Barlow.

To use the x5 Barlow I need to fit the Baader Solar Film 3.8 although I first focus through the visual film as the Baader Solar Film 3.8 (astrophotography) comes with a warning to not use it visually.

Notes on LPI and image stacking:
1. At prime focus I can usually always use the LPI “in-camera” track and stack function to stack around 10 to 20 images to improve the final result.
2. Using the x2.5 Barlow I can only use the LPI “in-camera” track and stack function when the seeing is above average, otherwise the final result is smeared due to combining individual images that do not quite register due to the shearing between each frame.
3. I have never been able to use the LPI “in-camera” track and stack function with the x5 Barlow, even with exposures as short as 0.001 secs, as the sun spot image shears and ripples so much on the display. In fact, parts of the image are in focus whilst other parts are blurred due to the variations in seeing at such high magnification, even across such a small field of view.
4. I purchased the Baader Solar Film 3.8 (astrophotography) from Claude Voarino at Astronomy and Electronics Centre at http://www.astronomy-electronics-centre.com.au/ and from memory it cost me around $50 for an A4 size sheet.


Hope that helps.

Dennis

[RB]

Dennis,

Thanks for sharing those details with us, very informative.
Once again awesome images mate.

:thumbsup:


RB