Arzachel, Alphonsus & Ptolemaeus mosaic

[Dennis]

Hello,

Had another busy Lunar morning, enjoying some great seeing in the absence of the jetstream over Brissie.

Grabbed 3 avi’s of:

Arzachel (734 from 1800)
Alphonsus (538 from 1800)
Ptolemaeus (449 from 1800)

Equipment details
Celestron C9.25
TeleVue x2.5 PowerMate
Philips ToUcam
Takahashi EM200 mount
JMI NGFS motofocus

Imaging details
Acquired with K3CCDTools
Stacked withRegistax3
Stitched by hand in Corel PhotoPaint

Cheers

Dennis

[iceman]

Wow Dennis, that's incredible! Did you try stitching them in autostitch? You should give it a go.

There are some bright areas that are a bit overexposed.. were the capture settings too bright, or is it a result of the processing (sharpening)?

Another excellent image. It's great to see some more lunar stuff, there's been a lack of it lately.

[Dennis]

Hi Mike

Thanks for the tip. I downloaded Autostitch and ran it on the 3 originals and wow! What a fantastic application! I am humbled by the talent of the authors of these apps, like Registax, Autostitch, etc.

Cheers

Dennis

[iceman]

That's a much better mosaic, Dennis! Seemless, now.

Well done.

And you're right, they do the hard work so it's easy for us!

[bird]

One of my favourite regions of the moon - thanks!

Bird

[h0ughy]

beautiful! Simply wonderful! Huge amount of detail and extremely pleasing to the eye!

[[1ponders]]

Great mosaic Dennis. Like bird, one of my favourite regions and you did a fine job on it. Plenty of detail. Thanks

[beren]

:) Superb image ......great detail on a interesting area. The deterotion of the crater walls from Arzachel to Alphonsus to Ptolemaeus is striking with no central impact ejecta evident in Ptolemaeus {check the one in the nearby crater Alpetragius} .And the spinelike extension of ridges leading into Alphonsus centre from its edge and Arzachel .Top stuff :)

[fringe_dweller]

"*crackle* Houston, Houston! this is apollo 30, we are currently x miles from lunar orbit, there appears to be some people already in orbit around the moon!! they appear to have the acronym IIS and ozzie/NZ flags as markings on their crafts - please respond - over
just magic Dennis! :)

[Striker]

Thats a great image Dennis....well done mate.

[Dennis]

"err, Roger Houston...<crackle>...this is IIS here, orbiting the Moon with our 60mm Tasco refractor poking out of the docking bay. Should be home before tea tonight, please put the kettle on...over and out..."

Cheers

Dennis

[Robert_T]

Dennis this one is truly poster quality :prey2:

Your "mooning" is the best! :lol:

any tips for getting the right exposure - I always seem to be under or over exposing - and processing in registax to get sharpness over the whole field?

cheers,

[Dennis]

Hi Robert

For most of the images, I used my default settings of:

Brightness slider: approx midway.
Gamma slider: hard to the left.
Exposure: 1/25 sec.
Gain slider: hard to the left.
Frame rate: 10 fps.
Grab time: 180 seconds.

However, after some feedback from the IIS crew, I discovered that K3CCDTools has a “live” histogram bar which reads from 0 to 255.

On Lunarscapes with a large brightness range, the default settings used to produce pure white highlights on the rims of strongly sunlit craters. By sliding the Brightness left (decrease) and Gamma right (increase) I noticed that often I could prevent the numbers from maxing out at 255 in the histogram bar, yet still keep the image looking satisfactory.

Previously, I believed that Gamma had to be hard left and never touched, just like the Gain slider which appears to give me lots of grain and a “thin” image when I am forced to use it.

Assuming good collimation and tracking, the greatest contribution to these hi-res images is, in my opinion:
Sharp focus
Excellent seeing

Even though we have enjoyed 3 to 4 days of excellent seeing in Brissie, I notice that the portion of the image where I place the Registax “Align Square” often comes up sharpest with other parts of the image slightly softer. This ties in with the observation that as I acquire the avi, the on-screen image on the Notebook computer is “swimming” as areas slowly drift into and out of best focus, as the waves of seeing pass over the image.

Hope that makes sense.

Dennis

[Robert_T]

Thanks Dennis, some handy exposure tips (esp reducing brightness while upping gamma to reduce sunlit crater edge over-exposure) that I'm now itching to try out!


cheers,