2nd Foray into Hi-Res Imaging! (Ca K added.)

[p_zetner]

Greetings Everyone.

I now have my feet wet and understand a little more about approaching high magnifications / resolution.

Here is an image of AR12665 with good seeing and a focal length of ~5600mm. System speed is f/28 which is a little fast for the Daystar giving about 0.7A fwhm bandwidth, according to Christian Vladrich's calculations
http://www.astrosurf.com/viladrich/astr ... lar/FP.htm
and there is, of course, the usual continuum leakage associated with a single stacked filter. I'll address these issues in future imaging but am pretty satisfied with the performance of the system. Camera control used Firecapture and Image stacking used AS2 and a stack of ~400 out of 9000. (Probably a little over the top but no significant degradation in sharpness of the final image and an overall improvment in noise.)

Cheers.
Peter.

083216-083516_pp_siz_ARL5x5shrp_16b_flat-corr_proc_lbl.png (551.67 KiB) Viewed 1998 times

[ffellah]

A very nice close-up, Peter !

Franco

[p_zetner]

Thanks very much, Franco!

Here is a view of the active regions 2666 and 2665 in Ca K.

Cheers.
Peter.

Crop_085721_0000_pp_siz_ARL5x5_lins_shrp_flat-corr_proc_lbls.png (628.17 KiB) Viewed 1974 times

[marktownley]

Looking nice Peter!

I've certainly found with my 8" HaT and double stacked Quark get better results with a longer focal ratio telecentric. With the native HaT telecentric (f27.9) I find the image quite washed out detail wise compared to when I use the Quark with its native telecentric (f43) and then a telecompressor after this to bring things back to a more seeing and pixel sampling friendly f30(ish). That way you keep the tighter bandpass of the filter and I find easier to post process the more contrasty images. I'm sure you've got something tucked away in your comprehensive box of lenses that could rig up

Out of curiousity what is the transmission curve like for the 0.2nm CaK filter from Omega? You're getting nice images from that CaK rig.

Mark

[Carbon60]

Nice close ups, there, Peter.

Stu.

[Derek Klepp]

Looking good Peter.

[Montana]

Superb! the CaK is particularly nice work

Alexandra

[oreoluna]

Hi Peter.
Wonderful CaK image.
Jozef

[p_zetner]

Thanks for the feedback, everyone.

Mark: Definitely have to aim for a telecentric with higher f number. I will try to configure f50 with a reducer following. The Omega CaK filter is this one http://www.ebay.ca/itm/Optical-Filter-A ... 2388c6fd30. The claim is 2 Angstrom fwhm with 60% transmission. The filter I bought seems to have pretty uniform throughput .... not always the case with Omega filters. I think I may have posted the optics before. Here's the configuration I use (lenses are Edmund Optics achromats, 40 mm dia.) except the positions of Lunt etalon and Omega filter are interchanged. Image plane is 73 mm from last lens surface.

All the best.
Peter.

IMG_0779.PNG (392.98 KiB) Viewed 1921 times

[eroel]

Peter:
Very good H alpha result, the CaK is stunning.
Best regards,
Eric.

[MapleRidge]

Superb resolution in CaK Peter

Brian

[p_zetner]

Thanks Eric and Brian.

Still need to work on improving contrast in H alpha.

Best regards.
Peter.

[marktownley]

Thanks for the detail Peter. I've been mulling myself for sometime whether to mount my CaK filters in a telecentric beam as a means to gain some contrast. I was looking at the Omega CaK filter very recently, but my experience with them in the past has always been 'variable'

More shots more often please!