Steve143

Hi, Can anyone help with the images below? They have been created using 120x 60 sec exposures and stacked using flats and biases together (see 1), biases only (2) and no calibrations frames at all (3). They were all taken with a Canon EOS 70D at ISO800 using a 80ED-R fitted with an Optolong-Pro filter (unguided and no dithering). The stacked images were then processed using the same simple workflow in Siril. Each image has a cross-hatch pattern, especially in red and green, which is less noticeable in the stack with both flats and biases but this stack then has horizontal bands of light and dark - how can I get rid of this? In DSS I used the Intersection mode to stack and selected the detect and clean both remaining hot and cold pixels under the post calibration cosmetic settings. Is this caused by my camera or is it a stacking issue - or do I just need more integration time to reduce the noise? This is 2 hours of integration time. Thanks for any suggestions or advice. 1. Flats and bias used. 2. Bias only. 3. No calibration files used.

Yes, according to the Altair web site it is 63mm. The rotator is on the telescope side and I've attached a couple of photos. Thanks.

Where can I find the correct length needed so I can get the right adaptor to increase the length? Thanks.

The other issue that I've noticed with this image are the elongated stars in the corners. I'm using an Altair Starwave 80 ED-R refractor with the Starwave 0.8 V3 Reducer & Rotator connected to my Canon EOS 70D with the T2 and M48 adaptors. Is this issue caused by an incorrect optical train length with my set up from the reducer to the camera sensor? Or could the grub screws holding the rotator and reducer together be unevenly screwed in so causing a distortion when I screw the unit in the rear of the telescope or when I screw the T2 adaptor on before attaching my camera? Thanks for any help or suggestions. Steve

I did take some flat frames which helped with the dust motes. I do need more frames but kept the exposures short so as not to blow out the core of M42. I will try the offset (my camera is a Canon 70D), but I did stack the original subframes, along with biases and flats, in DSS using the sigma clipping algorithm and then tried processing in Siril. The image below is what I managed to get which looks a little better but still not perfect (still very noisy but the core isn't as blown out as my original effort). I've still got a lot to learn from image acquisition all the way through to image processing, but really appreciate all the help and support from everyone. Thanks.

I'm using a Canon EOS 70D.

I currently use Backyard EOS to control the camera and I think I can dither with that. Haven't tried it yet but I've installed the ASCOM drivers so I can attach my SW EQM-35 mount to Backyard EOS.

I checked the first and last subexposures and there is a small difference where the FOV has moved slightly downwards - but not by very much.

Do I need to be guiding before I can dither? The image above was taken without any guiding.

No. Not sure how to do that with my EQM-35 mount.

Hi, I've just acquired an Optolong L-Pro filter for my DSLR and tried it out on M42 recently. The individual subs looked good with noticeable reduction in sky glow. I took 100x 15 sec exposures (25 minutes in total) at ISO800 and stacked them in DSS. I then processed the stacked file in Affinity Photo using a colour preserving tone stretch and then removed the background gradient as much as I possibly could. What do you think is causing the vertical streaking across the image? The only calibration frames used were biases (I didn't take flats and you can see some dust motes on the left hand side). Thanks in advance for any help. Steve

Is there a way to improve the resolution of the Live View feature in Backyard EOS? I've had a frustrating evening trying to find a couple of targets and the Live View is just all noise. Only the brightest stars show in the view (even those are quite faint) and I had to keep capturing an image just to get my bearings. I was trying to find M42 and my GOTO got me near but I couldn't get on target before it got too low in the sky to be worth imaging. I then tried to get on M51 with no luck either. I'm in a Bortle 7 location and wasn't expecting much but thought I could see something given that we have good clear skies tonight. I've just packed up and come inside without getting anything. It's been a frustrating session...

Thanks. Can you tell me what these packages are? I was looking at the QHY PoleMaster as a solution - if I can get sight of Polaris!

Thanks. Would this periodic error cause the apparent movement of my field of view between each exposure? The movement is very small but noticeable when you move from one frame to the next.

Thanks. I can try that in Affinity too.

Hi all, As a beginner to astrophotography, I have just bought an Altair Starwave 80 ED-R to go on my SW EQM-35 Pro GOTO mount. I also have the Starwave v3 0.8x reducer and attached my Canon EOS 70D. From my garden I can’t see Polaris, so I normally set up and polar align using PS Align Pro (and I can do this during daylight too). I didn’t run any star alignment routines with the mount and then tried to image both M42 and M45. When I used the GOTO to get on target, I was a little off both targets so used the handset to get on target (which wasn’t too far off). Once on target I took some practice shoots with varying exposures. In the end I was getting 15 second exposures with no obvious star trailing (I’m sure if I had run a 2- or 3-star alignment routine I would have got longer exposures). These were all unguided too (this is potentially the next upgrade to my set up). The images below were taken at ISO 800, and I managed to get a total of just over 50 mins exposure time for M45 and 61 mins for M42 with 15 sec exposures for both. I also took flats and biases (no darks as many here think darks aren’t useful for DSLRs). I stacked the images in DSS using the intersection mode – I noticed when capturing the images that the EQM-35 wasn’t tracking properly as the star field of view of the individual images seemed to be moving from right to left between each exposure when viewed on my image capture software (Backyard EOS). I then took the stacked images and processed them in Affinity Photo. The processing routine was very quick and simple as I only used a colour-preserving tone stretch macro developed by James Ritson and then used the ‘remove background’ tool to get rid of the gradient. That’s all I’ve done to them so far. I’m sure with more practice and ability I’ll be able to tease out a bit more detail and make them look reasonably acceptable, but I would welcome any thoughts, comments, or advice on what I’ve managed to achieve. I know the core of M42 is a bit overexposed so probably need to learn how to use mask layers in post-processing. Obviously, I want to improve the EQM-35 tracking and have seen a few YouTube videos on how it can be tweaked to get it to perform better. I’ve also just bought an Optolong L-Pro filter to see if that will help with light pollution from my Bortle 7/8 location. I still need to try this filter out with my set up – when we get some clear skies again! Thanks for any advice/comments. It’s still a steep learning curve for me 😊

Hi, I recently captured some images of M31 and M42 using a DSLR and Samyang 135mm lens. I took 15s subs of M31, 30s subs of M42 as well as 60s subs of M42, all at ISO 800 at f2.8. I stacked all the subs in Affinity Photo and did some simple tone stretching. The results from M31 weren't too bad, but the two stacks of M42 had a really strong beige cast across them, which I'm struggling to remove without losing any detail of the target. M31 was pretty close to the zenith when I captured it and obviously M42 was closer to the horizon, and in the west, which I'm assuming accounts for the increased light pollution in my stacked images. Do you think I would be better off taking shorter exposures (and increasing the number of exposures) to try and counteract some of the effects of light pollution in my location? Would it be helpful to invest in a filter, like the Optolong L-eXtreme, to protect against light pollution while increasing light captured from nebula? Could I just simply process out the strong light pollution in Affinity Photo while maintaining the target? If so, are there any tips on how to do that? I'm still relatively new to imaging but have just acquired an Altair Starwave 80ED-R refractor that I want to use as my imaging scope, initially with my DSLR and then with a dedicated astro camera. Any help dealing with light pollution would be great! Thanks, Steve

Tracking mount for sure. The longer exposures from a tracking mount will make a huge difference to your images.

Thanks James. I've got a steep learning curve ahead of me. I managed to capture about an hour's worth of data on the Pleiades last week so will see what I can get using your workflow. Really appreciate all the information.

Hi, As a beginner I've struggled with this too, but I've also got the added complication that I don't have a clear view of Polaris from my garden. I have a GOTO mount and found a video on YouTube that shows you how to polar align using the SynScan controller to do a 3 star alignment, but I was thinking of getting the PS Align Pro app as this will also allow me to polar align in the daytime too.

Hi James, Which of the macros did you use for the Pleiades? Any info on the work flow you used would be helpful.

Thanks! That's a great image.

Thanks Olly. Plenty to think about!

Thanks Stu. I'm currently using a DSLR with a Samyang 135mm and a Canon 50mm. I've also been looking at the Evostar 80 ED as it's within my budget. I assume the longer focal length of the 80 ED will be suitable for galaxies as well as wide-field objects. Steve

Hi, I've been looking at various refractors as a first scope for astrophotography and I'm leaning towards this https://www.firstlightoptics.com/telescopes-in-stock/sky-watcher-evostar-72ed-ds-pro-ota.html I've already got a SW EQM-35 GOTO mount, but is this a good scope for a beginner in astrophotography? Or would you recommend something else? My main targets will be DSOs rather than planetary. Thanks for any advice or suggestions. Steve