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Showing results for tags 'dslr'.
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I've caught the astrophotography bug and after several months of trying 1" exposures on a fixed tripod, I bought a HEQ5 Pro mount, on which to fix my Nikon D90 DSLR. Presently I'm using my 105-300mm Nikon zoom lens, which seems to do an 'alright' job and have captured a couple of 'not bad' images of M42 (the usual). My biggest issue at the moment is that, even with best focus using live-view and a bahtinov mask and a well aligned mount, the stars in my images all have a wierd conical shape. I'm wondering whether anyone might be able to diagnose the cause please? Could it be that the 300mm dslr zoom lens just isn't up to the job? Could it be spherical aberration? I don't want to have to buy another lens or astrograph *just* yet, if I can avoid it. I don't think it's a focus issue. I don't think it's a tracking issue either, because the conical shapes are the same at 5 second and 300 seconds. I have attached images of both scenarios, just to show the star shapes - simple OSC single frame, no processing at all, so ignore the sky glow in the 300 sec exposure. These are screen shots from "Raw Therapy", as my images are raw DNG files and I wanted to zoom in on the star shapes. Thanks, Ian
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Hi All, I noticed a few times while imaging with my Canon 700D (KStars/Ekos) that one of a series of subs will have much less background noise than those immediately before and after. At first I just though it was the way the FITS viewer displayed the images but when I check later there was a huge difference. I attached a screenshot (to reduce size) with successive images side by side opened in AIJ. I captured the sequence automatically and did nothing between subs. The subs are 60s and maybe max 30sec between the subs while the image downloads over WiFi. Any ideas? Best
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Having searched for a while I managed to acquire the legendary Pentax Asahi SMC Takumar 6 element 135mm f2.5 m42 lens to use for wide-ish images, I've also got a 200mm f4 to try. I'm using it with a modded Canon 600D. I'm wondering if there is a way to improve the infinity focus, the below was shot at roughly f5.5 with the 135mm to reduce star bloat (around a 10 image stack of 30s each, no calibration frames), but the focus is still off despite the lens being at it's infinity focus stop with the focusing ring. It could be the m42 to ef adaptor I have maybe too thick/thin (though I don't really see how much thinner/thicker it can be to make a difference), the lens is fully home against the front face of the ring and the ring is fully connected to the DSLR body. Any suggestions or is this the best I can expect from such an old and wide-ish lens? The image has been level stretched around 3 times, and the red channel brought down in line with the green and blue.
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Hi, Sorry if i havent posted in the right place. I am a newbie. I have setup my scope, fixed the back focus so there is travel either way. I can get reasonable focus including using a bahtinov mask. The issue I have is when I zoom in on the camera screen - it does not appear to be in focus. Is this normal? Thanks in advance
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Been wondering whether it's worth getting an Askar fma180 for my dslr to use as a secondary setup for widefield, not too sure about the lens quality. It'll be on an Omegon LX tracker which I've found to be quite good for unguided tracking. Open to suggestions for other lenses other than the usual Samyang/Rokinon, even older prime lenses. Camera is an IR modded Canon 600d.
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MineralMoonLargeRstx6.jpg.facbad774b6041cd9727e9f3ae2b8baa.jpg)
From the album: Mark's Stuff
My attempt at a Mineral Moon© All copyrights reserved M Clarke July 2021
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From the album: Deep Sky Imaging
This is NGC3603 and NGC3576 (AKA The "Statue of Liberty" nebula), a massive H-Alpha region containing a very compact open cluster, located in the constellation "Carina" about 20,000LY away. I took this photo during two nights, 14th and 15th March 2021. Imaged using a active cooled and full spectrum modded Canon 40D DSLR attached to a 80mm f6.25 refractor on a CGEM equatorial mount. Total exposure time was 3 Hours and 31 minutes in natural color through UV/IR Cut filtered subs from a semi rural sky. RGB: 19x60s, 19x120s, 18x180s and 20x300s subs @ ISO1600.© Mariusz Goralski
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Statue of Liberty Nebula (NGC3603) - 19Feb-15Mar2021
MarsG76 posted a gallery image in Member's Album
From the album: Deep Sky Imaging
This is NGC3603 and NGC3576 (AKA The "Statue of Liberty" nebula), a massive H-Alpha region containing a very compact open cluster, located in the constellation "Carina" about 20,000LY away. I took this photo on multiple nights, between 19th February and 15th March 2021. Imaged using my cooled and full spectrum modded Canon 40D DSLR attached to a Bosma 80mm f6.25 refractor on a CGEM equatorial mount. Total exposure time was 22 Hours and 1 minute using 7nm HII, OIII and SII Narrowband filters and stars are from natural color (UV/IR Cut filter) subs... imaged from a semi rural sky. HII: 6x600s, 6x900s and 4x1200s subs, OIII: 10x900s, 8x1200s and 1x1800s subs SII: 18x1800s subs RGB: 19x60s, 19x120s, 18x180s and 20x300s subs @ ISO1600.© Mariusz Goralski
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From the album: Peggson's astrophotos
I shot this yesterday from a Bortle 6 backyard. Edited in Pixinsight and Photoshop If someone here knows how to remove purple stars, please help me . I tried defringing but it didn't really work. Also the date is wrong should be 9.10.2020. lol© Peggson's photo
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The Horsehead , The Flame and Alnitak - HaO3RGB JanFeb2020
MarsG76 posted a gallery image in Member's Album
From the album: Deep Sky Imaging
I managed to get some time to process another of my images exposed in January/February 2020. This was the last image when my USB port on my Astro40D failed. This happened while imaging this scene but it happened toward the end of the imaging plan so I got almost the subs that I wanted. The total exposure time was 16 hours and 16 minutes in ISO1600 for all of the subs, RGB, (OSC through the UV/IR Cut filter), HAlpha and OIII. Imaged through my 8" SCT at f6.3, 1280mm FL.© Mariusz Goralski
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From the album: Marci’s Astropix
7x20s@ISO1600 (EOS1000D FSM) with 18-55mm kit lens -
From the album: Marci’s Astropix
15x240s@ISO800 Colour (EOS650D) 15x240s@ISO800 HII (EOS1000D FSM + 12nm HII) -
From the album: Marci’s Astropix
10x360s@ISO400 Ha (EOS1000D FSM + 12nm HII) 15x240s@ISO800 Colour (EOS650D) -
From the album: Marci’s Astropix
2hrs with EOS650D at 18Mp shooting visual colour range (240s subs @ ISO800), 1.5hrs with EOS1000D Full-spectrum-modified (no narrowband filters) at 10Mp (120s subs @ ISO800 as core blows out VERY easily in full spectrum). 5x dark frames and 20x bias frames for the EOS1000D session. No flats. Stacked in DSS 64bit with 2x drizzle, processed in Photoshop CC 2018 (very little needed doing to it to be honest, just pull the saturation up a bit to bring the colour out). This is a heavy crop hence the apparent low resolution of the final image. This was the last outing for the EOS650D before I killed it, hence no darks / bias applied to the subs from that camera - it died in process of taking it off mount to shoot darks etc whilst I packed everything else away.© M Coyles
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From the album: wvb_dso
NGC1499 17 * 3 and 4 mins frames -
From the album: The next step.
Was really chuffed to catch this comet, especially with the two tails. This i believe is the 5th comet i've caught 'on film' as it were. Along with Panstarrs - ISON - Jacques, and Lovejoy (forgot the numerical names). Equipment: ED80 - / 350D -/ EQ6 -/ CLS clip -
From the album: DSO Imaging
M52 20 x 3 min guided subs 10 each flat, bias and darks -
From the album: 2015 Various
© Aenima
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Below is a comparison between single dark frames taken with the Nikon D7500 and D5300 with exposure durations varying from 1 sec to 240 sec ( my usual main light frame exposure ) all at ISO400. Firstly a graph of the standard deviation of the noise in the dark frames versus exposure time: The standard deviation of the noise is a fairly constant 2 ADU less for the D7500 compared to the D5300 ( pretty much the difference in the read noise between the two ) However, the difference is not just in absolute terms but also in the quality of the noise ... Below are the dark frames - ranging from 240 sec exposures at the top to 1 sec at the bottom: D7500 D5300 The D5300 dark frames clearly show the pattern in the read noise ( banding down the bottom ) and also have far more chrominance noise compared to the D7500. At 240 seconds ( the main exposure I have been using ) the difference is starkly different; the D7500 produces images with much lower noise that is significantly more even and random and hence more likely to be reduced during integration. -
From the album: The next step.
One of my first targets but still trying to get a decent image - clusters are harder than they look to capture due to them being all stars so tracking errors and uncorrected optical problems are very quick to show up in the end result.© Aenima
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From the album: The next step.
No introduction needed for this amazing nebula, very popular, and lovely to observe. -
From the album: Astro snaps
Canon 400D, 15s exposure, Gaussian blur in Gimpshop to remove light pollution -
From the album: Astro snaps
Canon 400D, 15s exposure, Gaussian blur in Gimpshop to subtract light pollution. You can just about see the Andromeda Galaxy on here. -
Hi all, I don’t really have a specific issue but was hoping someone might help with general advice for astrophotography. I’m using a 130pds with Canon 500D, shooting raw, on a belt driven guided Vixen-GP. Guiding is SVBony SV-106 50mm with qhy5l-ii-c. I did two test sessions - One on Monday night, one on Tuesday. Both nights were remarkably clear. (I know...hard to believe!) The first night I captured m81+m82 together, prime, with 1 minute 800 ISO images over about 90 minutes. I know that’s not a huge amount, but enough to gain some experience+confidence, I think. I learned that 1 minute at 800 probably isn’t enough but, regardless, the first subs looked usable. I noticed, after the session, that subs became darker as time went on. Shooting between around 22:00 and midnight that made some sense, as the sky was getting darker, but the subject (m81+m82) and stars got substantially darker too. I expected the backdrop would darken over time but the target+stars should remain around the same brightness. Am I wrong? The stack of these images really pleased me, though - Although the target galaxies weren’t particularly bright or well developed, the image was nice and clear and the backdrop smooth and dark. A success, from my perspective. For the second night I decided to improve by increasing the sub lengths and also decided to 2X Barlow and focus on just m82. I’m aware Barlow would make the subs much darker than at prime so I did some tests at 3 minute exposure. Not seeing a huge difference in target brightness I tried 4, 5, 6…and finally 8 minute. Surprised at how little difference there was I tested increasing ISO bit by bit too. I ended up taking 8 minute exposures at 3200 ISO, wondering why the target and stars still looked so faint. I only got around 10 subs but, this time, I noticed they became brighter as the night went on - The exact opposite of what happened the night before, shooting at the same time (22:00 to midnight) The stack this time was very disappointing - Very grainy/noisy, backdrop nowhere near as dark - Pretty much monochrome looking - It looked like something from the guide-cam but noisier! I’m stacking with DSS, took 5 or more dark frames for each session, and used the same flat frames for both sessions. I also tried stacking both sessions without flats, which didn’t account for the difference. Environment was the same both nights - Same setup position, same neighbourhoods lights (or unusual lack thereof!), no rising moon… I suppose my questions are Why would my lights get darker (background, stars, and target) as the night went on on night one? Why would my lights get lighter (background, stars, and target) as the night went on on night two? Why would night one stack perfectly but night two stack looks terrible? Safe to say 3200ISO was pushing it but the stack should still look better than any sub, no? Many thanks to anyone who read my wall o' text. First session first sub First session last sub First session stack Second session first sub Second session last sub First session stack
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Equipment: EQ6R-Pro; Explore Scientific 80ED Triplet; ZWO ASI120MC guide camera; Canon 250D imaging camera; OVL field flattener. Software: NINA; PHD2 (multistar). I cannot solve this issue with the stars in my images. It started some weeks ago, and basically I am not able to image at all. Image 1 shows a 10sec exposure on the star Sirius, with the teardrop shaped stars around. Image 2 shows 120sec exposure on NGC7522, same night, same setup, again teardrop stars. On both images you can see the tracking is lower than 1, and on a windy night. Both images here show the exact same type of distortion to the stars. I did try a 240sec exposure and that was the same. Image 3 shows PHD2 on Sirius, changing any of the settings doesn't work. This was after a new calibration was carried out, which was very good (see image 4). Any ideas please? Tony
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