The sun in Ha - 6-2-13

[DrRobin]

A bright, but cold morning and quite a wind so I took a quick capture before going to work. There was some cloud going across the disc and there was a lot of turbulence as it was taken at 08:30, just 35 minutes after sunrise.

The close ups are to follow

[DrRobin]

And the first of the 2x.. this time with my screw in barlow. All pics Lunt 60 with a DMK 41 and stacked in Reg 6.

I am having to re-process the other 2x, something went wrong and there was very little detail.

[Montana]

Super! I love the filaments and what a great spike prom, must have been a fabulous view

Alexandra

[DrRobin]

Thanks Alexandra,

Unfortunately, I am too busy at work to bring my scope in, so I decided to get a quick capture before leaving home. The whole session from start to finish was only 20 minutes, a bit rushed, but it was just as well as it has been windy and wet here this morning.

I noticed that spike prom and when I get chance I am going to try to re-process the proms to see if I can bring out any more detail.

Robin

[DrRobin]

Hi,

I reprocessed the first 2x and brought out the detail much better, copy below.

[DrRobin]

Hi,

Following others on here, I tried processing the proms again, this time shifting them from white to a slight blue tint and then process and colour the disk separately. It has certainly made the proms stand out, even if the background is no longer black.

[jezhughes]

you get to bring your telescope to work

[DrRobin]

Hi,

My Lunt packs away in to an aluminum case (like your Solarmax) and the Merlin mount fits in an old laptop bag. I keep a spare tripod (and EQ3 head) plus battery in the corner of my office and if it is any good have a half hour coffee break outside, or if the weather is really bad, shoot through the window in another office.

After imaging, I set my laptop to stack the results, transferring the results to my desktop for post processing. I would be better off stacking on my desktop, but then I rreally would get no work done.

I work quite long hours, we are a small company and no one minds too much as long as the work gets done.

Robin

[Steve Ward]

Nice start to the day sir ,

Good to see you caught some action , nothing doing here still . . .

[markt]

Looks good! What settings are you using on the DMk41?

[DrRobin]

Thanks Steve,

It was sunny most of the morning up north, but it was windy and very cold, so it was good to get my capture from the garage before going to work. I have been out tonight to try and get an image of Jupiter, started by checking the collimation and would you believe it it started snowing! It did stop pretty quickly, but I never got any good views and now I have packed up it is just starting to snow again.

Mark, I use a 0.5x focal reducer set very close to the DMK41 so it gives about 0.8x, that way I can image the whole of the disc in one go. I set the gain for around 500 and then adjust the exposure to get about 75% on the histogram. In good clear skies that gives me an exposure of around 1/1000th, plus or minus a bit. If there is mist or high cloud that can come down to around 1/100th. I often settle on an exposure and then get fine control by tweaking the gain and when it is cold I find the touch pad on my laptop is too coarse for the exposure and adjust the gain more often to get the histogram to 75%.

I then either use a Cemax 2x Barlow or a screw in Barlow lens. The Cemax gives a little over 2x and the screw in Barlow less gives a little under 2x. Exposure times vary greatly but are usually arund 1/125th plus or minus a fair bit depending on seeing.

In both cases for the proms I push the exposure and or gain up a bit, perhaps nearly doubling the exposure.

[David Smith]

Cracking images for such a short session Robin.

[markt]

Mark, I use a 0.5x focal reducer set very close to the DMK41 so it gives about 0.8x, that way I can image the whole of the disc in one go. I set the gain for around 500 and then adjust the exposure to get about 75% on the histogram. In good clear skies that gives me an exposure of around 1/1000th, plus or minus a bit. If there is mist or high cloud that can come down to around 1/100th. I often settle on an exposure and then get fine control by tweaking the gain and when it is cold I find the touch pad on my laptop is too coarse for the exposure and adjust the gain more often to get the histogram to 75%.

Hi Robin. I would try imaging on absolute minimum gain - 260 is the minimum setting for it with my DMK31 - I find inreasing it above the minimum setting introduces noise into the image very rapidly. Also try going for ~95% on the histogram. We only have 256 shades of grey to start with in 8 bit imaging so exposing to 75% is only using 190ish of these - any image stretching you do after this is post processing is only going to degrade the signal to noise ratio. Mark

[DrRobin]

Hi Mark,

I will give that a try next time, thanks for the tip. I did however, think the idea of going for 75% was to avoid saturation after stacking, but I take your point about not using the entire scale. I have however, noticed that when imaging using a 2x where the surface covers the entire frame, there are no low values on the histogram, so it starts at say 25% and finishes at 75%. I guess In these situations there isn't much you can do about it.

Robin

[michael.h.f.wilkinson]

Very nice shots!