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Posts posted by Peakedge
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David
What size is your observatory? I need to downsize mine and now seems a good time as the roof needs replacing. Yours seems perfect, especially how the roof opens!!
Thanks to Gary for reinvigorating this thread and highlighting your set-up!
Kind regards
David
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I was recently allowed to purchase the excellently reviewed RVO Horizon 72 ED and field flattener but am struggling with the spacing/backfocus between flattener and sensor (1600mm). Its meant to be 55mm but test shots showed the sensor to be too close. I've increased the spacing to 60mm with the same results. Seems odd that I've increased it so much so doubting what I've done.
Has anyone else here had experience with this particular combination or can offer advice?
Attached is a shot from the other night showing my problem in the corners; trails all pointing to the centre. Please forgive the focussing.........
David
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2 minutes ago, carastro said:
Is this still open, I thought the closing date was on 11th?
Carole
You are quite right. My bad. I hadn't noticed the closing date so judges please ignore my entry.
David
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Excellent data, yet again. Thank you.
Here is my attempt in SHO palette and processed completely in PS CS5.
- Initial stretch of each channel with levels and slight curves.
- Removed stars from each using Starnet++.
- More stretching of each channel using levels and curves.
- Removal of some of the larger artifacts in each cannel using Spot Heal Brush.
- Brightness & contrast.
- Local contrast enhancement (Astronomy Tools plug-in).
- Tweak of levels.
- Combined each channel in PS.
- Selective colour, hue, saturation and vibrance adjustments.
- More brightness and contrast followed by levels tweak.
- Blurred colour image with small gaussian blur to remove noise.
- Created master luminance layer using all three earlier channels to avoid data loss.
- Levels, curves, brightness and contrast adjustments.
- Small noise reduction.
- High pass filter to sharpen.
- Stars reintroduced by layering original Ha image.
- Luminance combined with earlier colour image and opacity adjusted.
- Et voila!!
- Or something like that!
Hope you like.
David
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Welcome, from another Cambridgeshire resident!
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Both Starnet and Annies Actions are very good; Starnet to remove stars so the you can stretch an image without blowing them out, and Annies actions to reduce them. Starnet is free and standalone, and Annies Actions for PS. Both are an integral part of my processing.
Davis
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11 hours ago, tooth_dr said:
I don’t understand how noise in the light frame moves relative to the dark frame? The sensor is exactly the same for both.
Dirhering moves around the light signal on the sensor between exposures but the noise signal stays in the same place. Software recognises this and removes these outliers.
My understanding - use darks to remove noise from subs prior to stacking and then the dithering, via sigma stacking, removes other/remaining noise.
Agreed. Pretty sure that darks are applied to each individual frame in APP rather than on the final stacked image meaning that both are valuable in the overall image. Going through the APP work flow, Calibration is the step before any stacking is carried out allowing you to check effectiveness of the calibration frames; darks, flats etc, before Normalisation and Integration. You can select this at the top of the graphic display for each individual frame in APP.
Hope this helps.
David
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10 hours ago, sloz1664 said:
Really good SHO image David. Nice teals & golds
Steve
Thank you. Its the first time I'd done NB and whilst its quite straight forward to get the basic colours following all the advice on here and other places, the time consuming part is fine tuning them to taste, and a calibrated monitor helps too plus clean glasses! 😎
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10 hours ago, sloz1664 said:
Another fine image David. The cloud Gods have been favourable.
Steve
Thanks Steve. They were generous in providing a few hours here or there, if I'd been good which cant have been that often. 🤣
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I had this problem and went around the gap between the mirror and tube with black insulation tape. Latest solution was that I made a foam cap to slot over the end. I also tried a good quality black bin bag. Never thought of a..........
11 minutes ago, bottletopburly said:Black Shower cap ?
Was only a problem if I was taking darks or flats during the day.
Easy to solve but guess its more annoying than anything.
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Thank you all!!
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Thanks guys. Nice to know that I'm on the right track so far.
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Following on from my previous post, another hard fought battle to get enough subs to make an effort producing something this year. Anyway, my attempt at the Tadpole Nebula. Found this one a challenge to process and kept starting again. Couldn't decide on the best way to process the stars; processed starless stacks and tried reintroducing then through a Ha Luminance layer or adding a star layer but wasn't happy with either so settled upon leaving them in and masking them whilst doing the stretch. Forgot to say on the last post, stacked and pre-processed in APP and processed in PS CS5.
Details:
Ha - 82 x 3 min
Sii - 62 x 3 min
Oiii - 38 x 3 min
Total - 9 hrs 6 mins
Gain 300 Offset 20
Thanks for looking.
David
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My first posted picture for quite a while. Been battling gremlins that resulted in stripping down my mount and regreasing etc, all to reduce the amount of lost subs due to being overweight - the scope that is, not me though I could do with shifting a little. Unfortunately do not have the luxury with reducing the scope weight - almost 13kg on the HEQ5 Pro but got the rejections down to about 10% rather than 50. Like the rest of us UK based fools, battling the clouds for some time too.
Anyway, woes aside, here's my attempt at the Monkey Head Nebula. Equipment below.
Details:
Ha - 90 x 3 min
Sii - 68 x 3 min
Oiii - 75 x 3 min
Total - 11 hrs 39 mins
Gain 300 Offset 20
Constructive criticism more than welcome. Thanks for looking.
David
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There are a few simple gotchas with the polar scope and I'm ashamed to say, both have caught me out!!!!!!!
1. Have you removed the black cap from the opposite side of the mount?
2. Is the Dec axis in the correct position. There is a hole in the Dec axis spindle/axle that is aligned with the polar scope.
A symptom of either of the above, as well as not seeing any stars, is that the the polar scope illumination will appear too bright.
Hope this helps but both can easily catch you out.
David
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I wonder if it is the same as in DSS. Select it as the reference frame but leave the checkbox in the file list unchecked?
David
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Yes there is. I'm at work at the mo so not too sure but either on the Register tab or Integrate tab there is a large button labelled 'Set Reference Frame'. If you are stacking frames that are binned with those not binned, ie when processing LRGB for example, you need to ensure that an unbinned frame is selected so that APP knows to resize the frames that are binned.
Hope this helps but sure someone can supply the facts shortly.
David
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On 28/09/2019 at 12:25, andrew s said:
Is it a closed tube? The only things I can think of are stray light or reflections.
Regards Andrew
I had a similar problem and found light was entering from around the primary. Quickly cured by covering the mirror end with a few thick bin bags. Didn't notice at night because no ambient light!!!
David
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Had my 100d modified by Juan and the turn round time was amazing. He kept me informed at all times as to the progress of the mod and it was back with me within days! I would wholeheartedly recommend and wish all customer service was this good! Can't wait to for him to perfect debayering!!
David
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Have now completed my focuser now and installed. Thanks very much, tekkydave.
I have no problem using the focuser manually in APT and am delighted but am struggling setting it up for autofocus.
Has anyone managed this and got any advice?
David
Flip top lid!!!
in DIY Observatories
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David
All this detail is amazing and guess I know how I'm doing my roof now. I particularly like the Benny Hill music on the second video. That show is a fond memory from my youth, probably never to be repeated!
I was going to ask how the roof stays on but guess that is the pivoting arms that do that! What is the roofing material?
David