Deep sky interloper says Hi!

[ollypenrice]

A first light for our new Lunt 60 and DMK21...

The haze got me and extinguished the prominences before I could grab a video file but at least I got to run through the system and can't wait for more. The haze turned out to have snow in it! No wonder it was thick.

Lots to learn since this is all new but very exciting. Tips, links to tutorials, anything at all received with glee.

Olly

[PAC]

Very nice first image.

[mattifor]

Lovely first shot Olly.

I am a waiting arrival of a Canon 400D that has been modefied for astonomy work, I hope it can also be used for solar imaging.

Only tried with web cam so far but not very sucessful.

what are you using as a mount for the Lunt 60?

Did you get the double stack unit also?

I have the double stack only used it for visual sofar, but find the image a little dark with it fitted, however it does show the prominences clearer, have not tried imaging with the double stack on yet.

I thought you were too far south for snow.

Ivor

[ollypenrice]

Hi Ivor,

We are a bit far south for snow but we are also at 3000 feet so we qualify that way! Good prediction for tomorrow though.

I only have a single stack at this stage but Helen, one of our current guests, has the double stack filter so we may get to compare. I have used a double stack setup here courtesy of a previous guest and was mighty impressed. We get strong sunlight here though so the image was bright. Before the cloud this morning the proms were the brightest I have ever seen in a solar scope but the still morning air was a huge help.

It was night time rather than daytime seeing, if you like.

I have a few mounts available; for visual, alt az TeleVues (Pod and Gibraltar) and for imaging a couple of EQ sixes plus a Tak EM200. I think all the driven mounts will be much of a muchness for fast frame rate cameras, really. However, the Tak is impeded by the roll off for early morning sun, something I had not thought about till this morning! Curses, more concrete.

I want to give the sun a go in the Atik 4000 too, but I don't want to disturb it because we are in mid project on the deep sky and flats are all done. That will have to wait.

It will be interesting to see how a modded DSLR does. Keep posting!

Olly

[Merlin66]

Olly,

IMHO the DMK is probably the best solution....grab 1000frames or so and use RegistaxV5.1 to stack and wavelets....the results should be impressive.

Ken

[ollypenrice]

I agree Ken, though it would be nice to get the whole disc in one from time to time.

Olly

[mattifor]

Hi Olly,

Well you spured me into using the double stack again.

after 15 minutes of getting the two units tuned to optimum, showing the prominences across the whole disk and the flare plumes along the outer rim at the same time, I can say that this mornings view of the sun is the best that I have ever achieved before.

Can't wait for the camera to arrive, bet we have three weeks of cloud when it does arrive.

Ivor

[Merlin66]

The diameter of the Sun's disk is approx 1/100 the focal length.

ie a fl of 1000mm would produce a solar image 10mm in diameter.

So to get a full disk image this size would have to match the CCD chip.

A DMK41 has a chip 4.8mm x 6.3mm, so the maximum focal length to get a whole disk image would be around 480mm.

I've seen observers use the AtiK x0.5 nosepiece reducer to get a suitable focal length. ie the ED80 is 600mm fl; with the reducer this would be 600/2 = 300mm.

The resolution due to the pixel size would be obviously reduced.

(The DMK21 is 2.8mm x 3.7mm so would need a fl of 280mm for full disk)

[ollypenrice]

Cheers Ken,

I think I do have one of those Atik reducers so it might be worth a go but it is a shame to lose the resolution. Since my FL is 500mm I need a slightly larger chip than the DMK 41. Does such a camera exist, I wonder?

Ivor, great to hear that you are all fired up. Me too and this aff the weather should be clear. Wheeee....

Olly

[brianb]

Since my FL is 500mm I need a slightly larger chip than the DMK 41. Does such a camera exist, I wonder?

Oh yeah .... Skynyx 2.2 .... lovely camera, shame abou the price tag ....

For my full disk images I use the Solarscope 60 (480mm fl) and DMK41, the image doesn't quite fit so I use one of the screw in Atik 0.5x reducers. As I have a modified nosepiece (shortened to get to focus with the PST) I'm actually getting about 0.65x with the reducer, not 0.4x as the geometry would indicate. Results are not too bad from the resolution point of view, here's yesterday's Ha composite (disc & proms exposed seperately & combined in Photoshop)

The prominences do vary a lot in brightness ... the ones in the north west (top right of my images, which are always oriented as a "naked eye view" with celestial north at the top) were moderately bright; the interesting ones in the south east were pretty faint & I only just managed to register them through the low altitude murk & thin uniform high cloud I had to work with yesterday.

2010 Nov 25, 1057 UT. Transparency & seeing both on the poor side of moderate.

Gain 280; exposure 1/625 sec gamma 60 (surface), 1/120 sec gamma 100 (proms). 250 exposure AVI (surface), 500 exposure AVI (proms) processed in Avistack v1.81 - seems to work far better for solar / lunar work than Registax, for me; stacking best 40% of frames captured.

Ideally a +5 dioptre spectacle lens (but made to better surface tolerance than spec lenses are) in a screw-in filter mount would be ideal, achromatism is not an issue when working in monochromatic light!

[jgs001]

Very nice result Olly

[ollypenrice]

Well Brian, if I got a result half as good as that I would be over the ... sun!

I will try the Atik reducer if I can find it.

Thanks,

Olly

[sheri_barri]

Great first shot Olly. I think you might be hooked

The double stack enhances the surface features with amazing detail and worth investing in.

I have to second Brian's recommendation on the Skynyx to capture the full disk although the cost is steep.

The DMK produces fine results as well so I look forward to your next solar posting!

Cheers,

Sheri