From: Alan Friedman <alan@greatarrow.com>
Date: July 13, 2012 9:47:30 AM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] Sun Spot Images
HI Ray,
Certainly good seeing is the stuff dreams are made of… but there are two caveats that keep us afloat regardless.
1. The sun tells an interesting story at many focal lengths. From provocative sunsets, to full disk shots, to quarter suns focused on dramatic prominences, to the high resolution photos that we get once in a blue moon. You have to choose the focal length to match the seeing and the events of the day. Many of my full disk shots are taken on days when the seeing is lousy.
2. Daytime seeing is almost always awful… but it also changes constantly and rapidly. If the sun is not very actively I wouldn't bother but if there is something exciting going on, I will get out and under a blanket and try to wait out a few steady moments in which to record. I usually wind up with something. The recently posted close-up at 7500mm focal length was made from 70 frames gleaned from one video. I waited an hour and shot a lot of data to come up with these 70 frames. The seeing was pretty good at this moment. Sometimes the frames show good detail, but morph and bloat and stretch terribly. It is very hard to stack frames of this type. Fortunately there is a lot of light coming from the sun. You can usually use a setting with 0 gain (brightness amplification) which should make it possible to prepare an image from single frames, or portions of single frames.
keep at it, my friend.
all the best,
Alan
On Jul 13, 2012, at 5:36 AM, Ray Byrne wrote:
Hi Milton and Alan,
One of my astro passions is the Sun. Since I was at high school and the school astronomical society I used to use the science labs observatory at lunchtimes and project the Sun on to the dome wall and do daily tracings of sunspot positions. Now I have my own observatory and great equipment but it seems I can never seem to achieve results like you have both got here. Well done Milton especially with such a small aperture to get such detail your scope must be performing to it's limits. I think that (correct me if I'm wrong) that the main reason that you guys can get these results is that you have had good seeing when these images were captured. I can imagine that doggedness and persistence must play its part as does good equipment that is well adjusted and clean. Also that skill and technique and knowledge of software is important too. But would you say that these images are primarily the result in the good seeing you had?
In case I do get good seeing sometime (BTW is the jet stream south of you guys at the moment or in a favourable position relative to your locations) can you share with me the process you use to achieve these results? I've got an old book called "High Resolution Astrophotography" by Jean Dragesco and I wonder from reading about seeing in that whether I'm unlucky enough to have permanent poor seeing due to some local circumstance. I have a very small backyard and my fibreglass observatory dome takes up most of it (well half of it). My house is only about 5 yards from the obbo and is tall as it's a 3 story town house and is part of a terrace of such houses. I only have a view of the South East and South then my house and the adjacent ones are blocking my view. The prevailing wind in the UK comes from the West so I wonder whether there are vortices caused by that wind hitting my house and flowing over it and causing local poor seeing for me. I'm surrounded by houses with concrete tiled roofs, tarmac paths and roads. It just that I never get good results no matter how hard I try when my friend Mick Hyde who live about a mile away with virtually the same gear gets great results (been published in magazines, LPOD, and even in Celestron literature). What do you guys think?
Sorry to bore you with all this but if you could perhaps give me the benefit of your wisdom I'd appreciate it greatly.
My set-up is as follows:
For Solar work
C9.25, NEQ6, DMK21AF04 or PGR Chameleon, Baader film full aperture filter, Baader Solar Continuum Filter. I also use an 80mm PST for Ha and a Skywatcher 102mm f9 Equinox ED Apo with an Intes Herschel Wedge for white light too
BTW what is Alan's sun color schema?
TIA
Ray
On 13 Jul 2012, at 02:23, Alan Friedman wrote:
Hi Milton,
Considering you were working with 1/2 the aperture (at the same focal length), I think than turned out damn good. It's been a great week for solar activity and I'm glad you found some good seeing.
I had a steady morning yesterday and pushed the 10" mak to 7500mm. I found 70 decent frames in an hour of looking and shooting. Here is the result:
http://www.avertedimagination.com/img_pages/maelstrom.html
best wishes,
Alan
On Jul 12, 2012, at 7:37 PM, milton_aupperle wrote:
Hi Folks;
While I was re formatting, zero erasing, unbacking up all my partitions on the MBP17", I decide I would reprocess my July 9th Sun spot movies (45 gigs of video data):
Here is the best of them - using Alan Friedman's sun color schema:
http://groups.yahoo.com/group/Astro_IIDC/files/Solar/SunSpot_20120709_120210L_MJA.jpg
This was taken 3,850 mm focal length (2.5x Televue) with the MAK 127 mm Orion scope white light filter, a red Astrodon filter and the Grasshopper 2 camera cooled to 25°C (it's 43°C in the sun today - 33°C in the shade). Best 200 frames out of 6,200 captured - stacked and aligned with Astro IIDC - 16 MAP points.
Not as good as Alan's :
http://spaceweather.com/images2012/11jul12/archipelago.jpg?PHPSESSID=5njjknjnulprffm9omuengtac7
, but getting there :)
TTYL..
Milton Aupperle
