FD 07-08

[MAURITS]

Is there something to see today or is it a calm sun, or is my capture bad?

I used the IMX174MM camera instead of the 120MM camera.
I don't know if the 174MM camera is more sensitive?
The scope is a hybride 60mm with the Lunt LS35 frontfilter and the BF600.

Gray FD.jpg (56.87 KiB) Viewed 1128 times

[marktownley]

Nice capture Maurits! There is nothing to see today, the sun is about as blank as it gets!

[MAURITS]

Thanks Mark, I began to doubt.

[LTHB]

Nice disk!

This afternoon I was also looking for the two small active regions that GONG showed on pictures taken in the morning, but couldn't find anything in h alpha.

[Carbon60]

Nice disk, Maurits. You might need to tweak the tuning to get more even illumination, but other than that it’s looking good.

Stu.

[Montana]

I would say your tuning is a little off band, see Stephane's image for the 7th August viewtopic.php?f=4&t=26425
Nicely processed though

Alexandra

[MAURITS]

Thanks LTHB, Stu.

Yes Alexandra, I see the difference now. Is it a matter of focussing, are something else?

The previous image 24 juli (first resonable FD) was taken with my ASI 120MM, the last image was taken with the ASI 174MM.
Is this a possible indication (camera wise?)

[Montana]

There is nothing wrong with camera or focus, you need to adjust the etalon tuning ring till you get maximum surface contrast and more even illumination.

Alexandra

[ffellah]

A nice disk, Maurits. Too bad the sun is so quiet.

Franco

[marktownley]

There is nothing wrong with camera or focus, you need to adjust the etalon tuning ring till you get maximum surface contrast and more even illumination.

Alexandra

Sorry to say Maurits, but I don't think you will get on band with this etalon across the whole of the disk. The bottom of the disk is closest on band and then as you go to the top of the disk it drifts off band to become relatively featureless, hence the brightness gradient too. By adjusting the tilt of the etalon to get a more even field in terms of brightness and detail across the disk I think you will find it is tuned off 656.28nm (the Ha centreline) and you will be lacking in detail. By adjusting the tilt of etalon to get onband to 656.28nm you will find the sweetspot becomes a tight band / stripe maybe about 10 arc minutes across. Depending on the orientation of the etalon will depend what angle this runs through the field of view.

There's nothing you can do to fix this, that particular etalon is just not suited for your environmental conditions.

I've got through many external etalons before finding one that is flat and onband for my environment.

[MAURITS]

Thanks Mark for this explanation.