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Last Night's Astro Image

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Neil Wyatt26/06/2018 08:43:16
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Posted by Michael Gilligan on 26/06/2018 08:06:40:

The lack of need for autoguiding is fundamental to their approach ... The stability and accuracy are engineered-in, obviating the need for "sophisticated" feedback loops [*]. Skip lightly down to the HPS Technology section on this page : **LINK**

Of course the irony is that guiding out errors in lesser mounts is just as effective in practice. As I recall unguided mounts need you to spend ages building a 'sky model' before you start imaging because it needs to be able to compensate for diffraction effects in the lower sky which can vary considerably from day to day. Nothing is that simple.

Michael Gilligan26/06/2018 08:50:57
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Posted by Neil Wyatt on 26/06/2018 08:43:16:

Of course the irony is that guiding out errors in lesser mounts is just as effective in practice.

.

So ... are you saying that R.O.G. wasted a lot of money ?

devil MichaelG.

Neil Wyatt26/06/2018 08:56:02
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From someone who knows people who work at Greenwich:

"Main instrument is a C14, there is a Skywatcher 120mm f/7.5, the Takahashi FSQ-106 (which was donated), a 100mm Lunt H-Alpha scope, all riding on a Software Bisque Paramount ME II. "

Neil

Michael Gilligan26/06/2018 09:08:34
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Posted by Neil Wyatt on 26/06/2018 08:56:02:

... all riding on a Software Bisque Paramount ME II.

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Thanks, Neil ... I stand corrected. blush

From the video, the mount looked like a 10-Micron from a couple of years ago.

MichaelG.

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For my penance: http://www.bisque.com/sc/pages/ParamountMEII.aspx

Edited By Michael Gilligan on 26/06/2018 09:12:58

Neil Wyatt11/07/2018 22:16:58
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Last night's Saturn:

Edited By Neil Wyatt on 12/07/2018 23:25:19

Mark Rand12/07/2018 02:07:15
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No astronomical equipment involved, but went to lock up the shed in the early hours of this morning and Mars was incredibly bright. Thought it was an aeroplane until I realised that it wasn't moving!

Edited By Mark Rand on 12/07/2018 02:07:45

Neil Wyatt17/07/2018 11:21:52
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And here's a Jupiter from 10 July:

Neil Wyatt29/07/2018 19:46:55
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And Mars from 25 July:

Ed Duffner29/07/2018 20:49:35
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I was out the other night photographing Jupiter, Saturn and the moon also on the 25th (my Birthday). I don't know how you manage these images Neil, they are incredible results - well done!

I have some MP4's that I need to convert to AVI so I can process them in Registax.

Ed.

Neil Wyatt30/07/2018 09:28:32
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Thanks Ed. I've found 'Handbrake' useful for converting video, but if you use PIPP to prepare your video before stacking think it handles MP4.

For the record, this is how I do planetary images:

1. Long focal length, 150mm x 1200mm scope with a >3x barlow for about 4m focal length.

2. Good polar alignment for accurate tracking.

3. ZWO ASI 120MC - main advantages you can capture RAW video using a cropped field of view. I go for 480 x 480 pixels (I use Sharpcap to capture the video). This lets me run at 80 to 120 frames per second.

4. An 'atmospheric dispersion corrector' - difficult to get the hang of initially, this reverses the smearing of the image caused by diffraction at lower elevations.

5. I also have a filter wheel for RGB imaging with a mono camera, but when using the colour one I just have it set at the IR/UV cut filter.

6. I focus by maximising the contrast score in Sharpcap, this is very sensitive.

7. I set gain to max, USB speed to maximum and use the shortest exposure that gives reasonable images.

8. I capture runs of 5,000 frames. By keeping to 1 to 2 minutes of capture, smearing caused by rotation of the planet is minimised.

9. I pre-process in PIPP but set it NOT to debayer the raw frames

10. This allows me to debayer in Autostakkert!3 and use 1.5x drizzle (if you debayer in PIPP the bayer pattern become visible when drizzled). If data isn't as sharp as I'd like not using drizzle give better results.

11. I usually sharpen with wavelets in Registax than finish off in Astra Image, but some images really benefit from more work in Photoshop - for example that Mars image was impossible to colour balance properly without using something like photoshop.

Final note, Saturn has very little surface detail so the image above is several runs of 5,000 frames combined and just the best 10% or so stacked. This has given a hint of the position of the Encke ring as a change in tone, although my scope isn't big enough to resolve it as a discrete line.

There is no right or wrong for processing, but I'm tending to go for more 'gentle' processing these days as I dislike planetary images with too much contrast unless the details are there to justify it.

Ed Duffner30/07/2018 21:05:54
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Thanks for the info Neil,

I use a CPC1100 SCT on its Go-To fork mount in Alt-Az arrangement, used to have the EQ wedge to go with that but had to sell it along with my Neodymium filter. I also use a DSLR now, a step up from Neximage by Celestron.

Although I have a couple of Barlow lens' I haven't tried them with a DSLR yet. To be honest it never crossed my mind to use that sort of setup- with a Barlow and no eyepiece.

Kind Regards,
Ed.

Neil Wyatt30/07/2018 22:29:26
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Posted by Ed Duffner on 30/07/2018 21:05:54:

Thanks for the info Neil,

I use a CPC1100 SCT on its Go-To fork mount in Alt-Az arrangement, used to have the EQ wedge to go with that but had to sell it along with my Neodymium filter. I also use a DSLR now, a step up from Neximage by Celestron.

Although I have a couple of Barlow lens' I haven't tried them with a DSLR yet. To be honest it never crossed my mind to use that sort of setup- with a Barlow and no eyepiece.

Kind Regards,
Ed.

You might find that using a plain webcam is better than using the DSLR. the combination of smaller pixels an ability to capture a lot of data quickly makes a big difference.

Neil

XD 35131/07/2018 08:42:45
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So are you all going to be looking at Mars in the next week or so ? , I read today that it is the closest to earth that it has been in 15 years .

Neil Wyatt31/07/2018 11:08:46
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Posted by XD 351 on 31/07/2018 08:42:45:

So are you all going to be looking at Mars in the next week or so ? , I read today that it is the closest to earth that it has been in 15 years .

And for the rest of the century!

It will be reasonably large until late September, so I hope the dust storm will quieten down before it's too small to be worth the bother. These are my four best images over this years 'planet season':

XD 35131/07/2018 14:37:27
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Excellent ! I would have no hope of doing anything like that here in Sydney ! Too many lights and too much smog .

The article,mentioned the dust storm , Nasa is also waiting for it to end so hopefully the rover they have up there will boot up out of hibernation .

I was watching a documentary about one of the earlier rovers - that little buggy just wouldn't die ! It got to the stage it had lost drive on troo of its six wheels and they hit soft ground and bogged it for the sixth time , unfortunately that was the end of that little machine . Amazing engineering and incredible problem solving abillities in the team that built and drove it .

Neil Wyatt31/07/2018 16:58:08
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Posted by XD 351 on 31/07/2018 14:37:27:

Excellent ! I would have no hope of doing anything like that here in Sydney ! Too many lights and too much smog

My mars is at 10.5 degrees above the horizon, in Aus it's nearly overhead this year. Planets are bright enough that light pollution doesn't matter - my Venus was taken at about 5;30 in the afternoon sunset being about 10p. I could have done it at noon, but I had to wait for the scope to be in shade. Jupiter is doable while the sky is still blue.

SillyOldDuffer31/07/2018 17:42:07
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Posted by Neil Wyatt on 17/07/2018 11:21:52:

And here's a Jupiter from 10 July:

Jupiter's moons make an accurate clock. The moon apparently on the horizon top-right is Io, and the black dot is its shadow. For Io and the shadow to be in that position, I reckon the photo was taken at 21:07UTC. Is that right?

Dave

Neil Wyatt31/07/2018 19:38:07
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Posted by SillyOldDuffer on 31/07/2018 17:42:07:

Jupiter's moons make an accurate clock. The moon apparently on the horizon top-right is Io, and the black dot is its shadow. For Io and the shadow to be in that position, I reckon the photo was taken at 21:07UTC. Is that right?

Dave

So you have Stellarium and have simulate light speed ticked?

Neil

SillyOldDuffer31/07/2018 19:56:14
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Posted by Neil Wyatt on 31/07/2018 19:38:07:
Posted by SillyOldDuffer on 31/07/2018 17:42:07:

Jupiter's moons make an accurate clock. The moon apparently on the horizon top-right is Io, and the black dot is its shadow. For Io and the shadow to be in that position, I reckon the photo was taken at 21:07UTC. Is that right?

Dave

So you have Stellarium and have simulate light speed ticked?

Neil

Certainly not. That would be cheating and a disgrace.

I used Sky and Telescope's on-line predictor. It's not a crime unless you get caught.

face 1

Dave

Neil Wyatt05/08/2018 17:13:26
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Some guiding problems last night, but in between the problems, excellent guiding so this stack of the best 90 minutes of five minute exposures has nice tight stars:

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