'Ex' AR12655 With The Airylab HaT - 10th May

[marktownley]

Hi All,

A cool and frosty start to the day with plumose ice patterns on the cars, however not a cloud in the sky, so got up early and got the HaT out for a peek as to what was happening; not much! Those the big scope revealed the small remains of this active region that was about a few days ago. Used the double stacked Quark with the PGR Chameleon 3 with 2x2 binning to give me nice large 6.9um pixels and and nice and fast 4ms exposure time.

ar12655-bw by Mark Townley, on Flickr

ar12655-colour by Mark Townley, on Flickr

Seeing not perfect but better than cloud! Hope you like and I hope its clear again tomorrow morning!

Mark

[Valery]

Hi Mark

Glad to see you in imaging with your main caliber!

Please, take a look at your photo after my attempt to make it looks more detailed.
May be you will like it? A bit smaller image scale and a bit more sharpening may be
add better visibility of details?

Valery

[marktownley]

Yes, I like it Valery, thanks!

[ffellah]

Great image, Mark !

Franco

[Valery]

Yes, I like it Valery, thanks!

Mark,

Your scale, IMHO, is a little too big when no extra details can be extracted. With a 0,8x scale, as I did with your photo,
you will have the possibility to shorten the exposure in about 2x, will have better s/n. Both are very important factors
in the fighting for sharper images. And FOV will also be almost 2x bigger in area!
I always prefer to use a bit smaller scale than a bit larger scale vs optimal. The best compromise, according to my findings,
is F/17-18 for a 5,8micron pixel size. If the seeing is very good, then F/20-22 for the same chip.

I believe that the more experiments will be done, the better the results will be at the end. All in all you told, when decided the
203mm HaT, that you will have a plenty of space for different experiments!

[Carbon60]

Great images, Mark. You just need a nice juicy sunspot and great seeing to really show off the HaT.

Stu.

[Derek Klepp]

Cheers Mark and Valery thanks for the info.

[robert]

Especially like the first image. Valery's version looks like a double image to me, a bit too over processed for my taste. Glad the HaT is working well
Robert

[marktownley]

Thanks all. The following day activity had diminished somewhat, as had the seeing, so I shot again same setup but this time using the Baader solar telecompressor to give a 0.7x reducing factor.

ar12655-bw by Mark Townley, on Flickr

ar12655-colour by Mark Townley, on Flickr

Hey Valery, I don't know if there is any science in this, but my observation, if I am using a collimated etalon system then I would totally agree with your f17-f22 numbers, but, with a telecentric system for some reason the f number can be pushed quite a bit more before things turn to mush. The HaT native f is f28, and, i've effective used this with a 1.4x barlow in the past. Also using the HaT and the Quark with (f42) with it's native 4.2x telecentric works too. I don't know why, just what i've found!

Mark

[Valery]

Mark,

These F/30-43 do work. Bu no additional details and just decrease illumination on the chip and this leads to unwanted:

1. Exposure increasing ----> poorer atmosphere freezing
2. Slow down of the fps, expecially for prominences ---> smaller number of frames within a given cadence duration
3. Lower S/N
4. narrower FOV

In general telescope efficiency decreasing.

[Montana]

Mark where do you live, the arctic? no frosts here thank goodness these are great images and glad to see the HaT out

Alexandra