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Everything posted by ollypenrice
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Not to my not-very-good eyes but some observers reported that. Olly
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M33 - 130dps - odd light artifact
ollypenrice replied to Aramcheck's topic in Getting Started With Imaging
I won't say it's impossible but out-of-shot bright star flare has never produced anything like that for me. What I get is a widening, streaky beam like a light house beam in fog and it starts at the edge of the frame and widens and fades as it enters the image. The fix I've found effective is to aim the mount closer to the star causing the issue. If possible, I get it just in the frame while leaving the problem beam area also in the frame. I shoot a quick set of 'patch-repair' subs in which the flare has disappeared and I use the part overlapping the original image to effect a repair. Olly -
M33 - 130dps - odd light artifact
ollypenrice replied to Aramcheck's topic in Getting Started With Imaging
I use that, too, if I'm struggling and sometimes it works but sometimes it's right up a gum tree. Maybe my fault. Did you try SCNR green on this? I suspect it would work a treat. Olly -
That worked! 👋 As a general rule, push an image too far then back off to just what the data will support. 'Always leave a bit in reserve,' is my motto. It helps make an image look relaxed even when it isn't! Olly
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AstroArt. The price is reasonable and the recent gradient removal tools also work. I do all my stacking and calibrating in AA. It is fast, logical, well laid out and has lots of extras if you need them. APP also seems good. I have never got on with DSS but it would be mean to complain, given the price! Olly
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Yes, excellent. If this were mine I'd be looking to enhance local contrasts in order to reveal more structure. How to go about it depends on what post processing software you use. Olly
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Astronomy sales during the pandemic. Update.
ollypenrice replied to FLO's topic in Sponsor Announcements and Offers
There's a coincidence. I used to live on Johnson Rd myself at one time. 🤣lly -
That's not particularly unusual and is, essentially, vignetting. Did you shoot flats? If you did, what is slightly odd is that the vignetting is inconsistent across the colours. Blue seems worse affected than red. Blue has dropped off severely towards the corners as compared with red. A gradient removal tool in software would greatly reduce the problem but first I'd want to be thinking about the flats. Olly
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M33 - 130dps - odd light artifact
ollypenrice replied to Aramcheck's topic in Getting Started With Imaging
Nice M33 but I'd adjust the colour balance, myself. It looks very green as it is. Olly -
Barbell shaped stars - is this Periodic Error or Backlash ?
ollypenrice replied to jm_rim's topic in Imaging - Discussion
I'd have thought that backlash on that scale would be easy to feel by wobbling the C/W bar. Since it's in RA the first test would be to run the system east heavy. Olly -
Yes, still here. I did once try both a 35mm Panoptic and a 31 Nagler in a 10 inch Meade with the 6.3 reducer. I don't remember whether they actually increased the FOV, though I think they didn't. What I do remember was that the view was not very nice and I didn't use that combination. Sorry but I can't remember what I found stressful about the view. I certainly didn't like it, though. I only used those EPs at native FL. Olly
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That really is very odd. The subs you've shown us here look OK. We do need to be sure that no rogue subs from the run have crept into the stacking. This has to be the best guess but it may not be the case. Next, what software did you use for stacking and which algorithm did you select? And is there any chance that you asked the software to do anything else during the stacking? Some additional processing step? Olly
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Stacking filtered and unfiltered frames
ollypenrice replied to Nerf_Caching's topic in Imaging - Tips, Tricks and Techniques
This is the kind of question you can only answer by trying various ways of combining the data, and how you combine them depends on what software you're using. Any experimentation you do will teach you a lot about processing so it will be good experience. Olly -
An hour on M33 really isn't anywhere near what you need, especially with so little aperture. If you've been looking at M33 images you like on the net, check their exposure times. Plenty of images out there have over 20 hours. I agree with Alacant's advice on calibration. Stars: yes, check focus regularly and keep an eye on the sky. However, there are lots of post-processing techniques to control star size. First, get much more data. Olly
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From reading a lot of posts my conclusion is that the Quattro is supplied as a ready-made work in progress. What it isn't is 'plug and play.' If you are up for a serious bit of tinkering then it might be for you because it will, when sorted, deliver good, fast imaging. Just have an eye on your chip size when it comes to the flat field it will cover. 'Fast' and 'Cheap' are not natural bedfellows but there are images out there which show that, wth careful marriage counselling, they can become so! lly
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Barbell shaped stars - is this Periodic Error or Backlash ?
ollypenrice replied to jm_rim's topic in Imaging - Discussion
I'm surprised you say this. I'd have suspected backlash. Clearly the mount spends most of its time in one of two positions - at either end of the 'barbell' - and so must move quickly between these two positions. To me that says backlash, but I don't claim I'm right. Olly -
My Andromeda Is So Brown
ollypenrice replied to AstroRuz's topic in Imaging - Image Processing, Help and Techniques
You're getting there. The spiral arms are now very magenta, meaning the greens are too low. The sky top left is pretty good but the lower right has a magenta bias as well. It's a long time since I used Grad X but, from memory, the trick is to exclude objects and stars from the sample you give it. In Ps I'd probably use the colour sample tool to select background sky. Olly -
My Andromeda Is So Brown
ollypenrice replied to AstroRuz's topic in Imaging - Image Processing, Help and Techniques
The ultimate weapon against gradients is Dynamic Background Exraction in Pixinsight but there are other gradient tools. Gradient Xterminator for Ps, AstroArt, has one, as does Astro Pixel Processor. I'm sure there are others, too. There was a long discussion about galaxy colour on here during which Vlaiv convinced me that the 'red core-blue arms' thing is usually over-done by amateurs. It was only latent in my own data so I adjusted for less colour differentiation and less saturation as well. This colouration was influenced the Hubble image to which Vlaiv linked in the conversation. https://www.astrobin.com/full/dx6n5x/0/ Olly -
I'm a great fan of the mosaic and have just done an Astronomy Now article, I think for the next edition, on one approach to constructing them from individual panels. The project in question began with APP but wandered off into Registar and Photoshop as well. (My fault!) So, having done a few big ones of my own, and having participated in two absolute giants, I thought I knew how to do it. Then, last week, I was given a 12 panel M31 dataset to try and construct. Hmmm... So far I am not succeeding. What's difficult is that only a small number of panels have any background sky to use as a calibration reference. I suspect that software aiming to do it all in one click has exactly the same problem, which is why it fails. So, I'm sorry to say that I don't have the answer on how to build a seamless and even M31 galaxy mosaic. I think I would be able to do it if I had a smaller number of panels, most of them containing at least a bit of background sky. Difficult! But that's why we like it. Olly
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My Andromeda Is So Brown
ollypenrice replied to AstroRuz's topic in Imaging - Image Processing, Help and Techniques
I'm sorry but I don't see anything natural about the colour. The image, as it stands, strikes me as pretty monochromatic. (Not greyscale as in black and white but a kind of monochrome brown, monochrome meaning 'single colour.') As it stands, the colours are not being distinguished or separated. Look at the star colour. To my surprise, when I measured the sky, I found it was low in blue, not red. I was expecting the opposite. Vlaiv is getting there with the galaxy but the background needs to be neutralized. In my view a background sky should be at parity between red, green and blue. Olly -
I'm a great fan of the Baader LRGB set. I take Vlaiv's earlier point about achieving the teal blue of OIII in the RGB set but, in reality, aren't you going to combine dedicated narrowband OIII with your LRGB image, just as you are likely to want to combine Ha? In this case the OIII will completely overwhelm the teal blues of the RGB layer and the colour they end up contributing will be decided by the way you include the OIII. There is a simple way to add OIII to (L)RGB while retaining full control of its green-blue balance. (Using Ps or another layers program.) - Take a copy of (L)RGB and apply the OIII to green in blend mode lighten, at full strength, and save as OIII to green. Now apply OIII to blue in a second copy of (L)RGB and save as OIII to blue. - Stack the three images you now have as below in Layers: OIII to blue OIII to green (L)RGB Now you can use the opacity sliders to decide how weight the top two layers relative to each other and then how fully to apply them to the original. This will make the teal blues available to you and, if you have the original open as a guide, you can replicate its colour fairly closely in the OIII-enhanced version. In reality I'd not be using the (L)RGB for this but the HaLRGB but I'm sticking to the teal blue issue here. An example of HaOIIILRGB done this way: Olly
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The problem with the HOS, for me, is that it replicates to some extent a broadband colour image but without the blue reflection nebulosity. By getting right away from that, the SHO lets the image become its real self and show what it has to give. We see wonderful rhythmic sweeps in the gas and dust. Superb. If it were mine I'd want to soften those hard edged stars, which have a slightly spikey, intrusive look. A dead easy fix in a program with levels. Just blur a bottom layer and erase the right radius from the top layer. Olly
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Second for me, too. Super. Olly
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Both are excellent but I feel the first one has more dimensions of colour, something I instantly liked about it. (Browns varying in hue from yellow to red, blues from cyan to green, then the golds.) That's a very wide palette. It allows for more spacial dimensions to be presented, too, in terms of foreground-background. Olly