FDs & G-Band images (New G-Band Animation added)

[yltansg]

Hi everyone,

Greetings from Singapore. It has been raining and cloudy for quite a while. I am glad to have 30 minutes this morning with thin layer of clouds over the Sun to get this 3 full disks. Generally a blank disk on WL and some filaments and prominences on HA and interesting areas of magnetic field concentration in the CAK image.



Alfred

[ffellah]

A beautiful set, Alfred. I am glad you had some sun after a long time.

Franco

[eroel]

Alfred:
Beautiful 3 flavor session.
Best regards,
Eric.

[MapleRidge]

Those are very sharp Alfred...well done

Brian

[Carbon60]

A very fine tryptic, Alfred.

Stu.

[marktownley]

Three very nice disks Alfred!

[yltansg]

Thanks Mark, Stu, Brian, Eric and Franco. Seeing condition continue to be poor today. I took 2 more scopes out of cold storage. These were the images from today's session.

For H-Alpha imaging, a150mm refractor with ARIES D-ERF and Lunt 50.


This was the best of 3 H-Alpha images taken this morning (17 Dec 17)


For G-Band imaging, I used an ARIES C8 ERF with a 430nm filter


It was a struggle to get a decent G-Band image this morning.


This was taken on 1 Nov 17 with the same setup when the seeing was better.

[marktownley]

Good additions! Seeing makes all the difference!

[Derek Klepp]

Thanks Alfred and good to see the comparison in seeing conditions.

[Montana]

A lovely traffic light! and the close ups are fab but the 1st Nov is the business
Alexandra

[ffellah]

That granulation is amazing, Alfred. Well done !

Franco

[yltansg]

Thanks Mark, Derek, Alexandra and Franco for your kind comments. Here is a time-lapse gif made from 12 stills taken on 6 Oct 17 from 7:58am to 8:06 am local time.



Enjoy it.

Alfred

[pedro]

Great HR (granulation) images there Alfred, well done

[yltansg]

Great HR (granulation) images there Alfred, well done

Thanks Pedro. I am able to get reasonable G-Band images with the Edmund Optics 25mm 430/10nm filter when the seeing is average and better. However I have not been able to get a decent image with the Baader Calcium K-Line Filter. I have been trying for some months now Most of the time I used the 430/10nm first and the seeing became poor by the timing I changed over to the K-line filter. Will share findings.

Alfred

[christian viladrich]

Hello,

The G-band image taken on Nov 1st is pretty good. Well done !

There is no wonder that you get unsatisfactory K line images with the C8. The spherical aberration is so large in near UV that the instrument is no longer diffraction limited.

In the whole, and for diameters larger than around 150 mm, a G-band filter gives images more satisfactory images than a K-line filter:
- the contrast is about the same,
- the sensitivity to turbulence is lower,
- most optics are much better at 430 nm than at 396 nm.
BTW, what is you exposure time with your 430nm FWHM 10 nm filter and the C8 ?
Best regards
Christian

[yltansg]

In the whole, and for diameters larger than around 150 mm, a G-band filter gives images more satisfactory images than a K-line filter:
- the contrast is about the same,
- the sensitivity to turbulence is lower,
- most optics are much better at 430 nm than at 396 nm.
BTW, what is you exposure time with your 430nm FWHM 10 nm filter and the C8 ?
Best regards
Christian

Hi Christian,

Thanks for the valuable information. I am still hoping to catch a nice K-Line image when there is very good seeing

The following are the setting for the 1 Nov G-Band image:
FPS (avg.)=151 Shutter=0.082ms Gain=92 (23%)
Histogramm(min)=84 Histogramm(max)=148 Histogramm=58%

Alfred