Lee_P

@osbourne one-nil There's more discussion that you might find useful in this thread:

This is a real head-scratcher, I'm not sure what could be going on. Hopefully some SGL clever-clogs can shed light on the situation, but if not then the only thing I can think of is to go through the arduous process of changing one thing at a time to try and work out if it's something in your image train causing this. Could the 3D printed masks be a suspect?

DPI is dots per inch. You can change an image's DPI in software like Photoshop. If you're not sure how, feel free to send me your image and I can do it for you. Your camera is certainly capable of producing 12x16" prints 👍

I agree that manufacturers should be tighter on quality control. As the situation currently stands however, and speaking as a customer, I'd be interested in FLO testing filters prior to selling them, like how they bench test some telescopes (example here). I don't know how expensive / time consuming it is to test filters, but it might make commercial sense. If you want to buy a filter that all the major suppliers have in stock for the same price, but one has tested the filter beforehand, no prizes for guessing who you'd buy from.

Not sure about consensus, but I’m happy to share my opinions about the Askar D1 D2 filters. I reviewed them here, and now have even more experience with them. Important caveat: as has been flagged earlier, it appears that not all of these filters are made equal, so there may be an element of “equipment lottery” to be aware of. I think it’s best to split my opinion about the filters separately. I think that the Askar D1 (Ha/OIII) is fine, but a bit expensive for a 6nm filter. It’s not that much more to buy an Optolong L-Ultimate, which is a decent step up but still, as I’ve discovered, plays nicely with the Askar D2. The Askar D2 (SII/OIII) works really well to add extra data to your dualband images, and I’ve been having a lot of fun using it. Here are the three images I’ve produced so far incorporating the Askar D2. More details here and here and here. They’ve got better colours, and I think are just more interesting and nicer to look at, than my attempts using Ha/OIII data alone. “But given the price, I do wonder if there's any advantage left over using a mono camera & FW.” I think this depends on whether you will do purely SHO imaging, or want RGB as well. If you’re only ever going to do SHO then my advice would likely sway toward going mono. But if you want RGB as well; either to image broadband targets, or to add RGB stars to narrowband data, then data acquisition is still much simpler with OSC plus Ha/OII and SII/OIII filters (considering that no filters gives you RGB). This is my approach and I’m just using a filter holder, rather than an electronic filter wheel. “The downside of OSC + dual band is that without processing wizardry, the images produced by the dual band filters are not as good as SHO images from a mono camera” You need good processing wizardry to produce decent images regardless of what your setup is, so I don’t personally consider this to be a downside. Processing with Ha/OIII plus SII/OIII filters is a bit trickier than just regular dualband, but it’s OK really. I plan on writing a processing guide when I’ve time. Finally, without wanting to rehash all the usual mono vs OSC arguments, my viewpoint is that which option is best is dependent on the individual astrophotographer and what they’d find most fun to use. I’ve used mono before, but currently have more fun with OSC. Maybe in the future I’ll switch back to mono. It’s often said that mono produces better quality images, but I honestly can’t tell the difference when looking at final, completed pictures. I rarely look at a completed picture of mine and think “drat, I wish I had a mono camera as that would have produced a better image”; but I regularly think “I’m glad it was straightforward to collect that data.”

Far from the best comet photo here, but I'm pretty happy considering it was taken in a gap between clouds from my city centre location. I had to learn a few tricks for the processing, too. More details on my website here. * 30 January 2023 * Bristol, UK (Bortle 8 ) * Telescope: Askar 130PHQ Flatfield Astrograph * Camera: ZWO ASI 2600MC-PRO * Mount: Sky-Watcher EQ6-R PRO * Guide: William Optics 50mm Guidescope with 1.25″ RotoLock; ZWO ASI 120MM Mini * Control: ASIAIR Plus * Software: PixInsight, Lightroom * Filters: none * 105 x 30 seconds Total integration time: 52.5 minutes By Lee Pullen

Yep, a-ok!

It's sensor temperature. You're using a cooled camera, so this is easy. Don't overthink it Just tell the ASIAIR to set your sensor to your desired temperature (I always use -10 deg C), then when it's cooled you're good to go.

Specific advice here for @jpoulette -- one of the things that makes the Askar FRA400 a neat little 'scope is that there are no backfocus requirements; so long as the image is in focus, the backfocus is automatically correct. However, if you use the reducer then be aware that you will need to get your backfocus just right (probably 55mm or thereabouts) otherwise you'll get streaky corner stars. I'm not saying don't use the reducer, but it's just something to be aware of. Speaking personally, I never used a reducer with my Askar FRA400. Regarding "fast" optics in general, I try to sidestep the whole issue by treating astrophotography as a marathon rather than a sprint. My previous 'scope (the FRA400) was f5.6, and my current 'scope (Askar 130PHQ) is even slower, at f7.7. But *shrugs* it's fine, I just keep plugging away until I collect enough data. Granted, I might change my mind on this topic if I ever use a speed demon like a RASA 😁

Wow, quite the improvement!

It's great to see you're having a good time already reproducing my Askar FRA400 setup I think you'll be making things hard for yourself by adding something like that Powermate into your system. The Askar FRA400 is a beast at widefield, so let it shine there As has been suggested, you can always crop in a fair amount if needed. Having said all that, if you want to try it for a fun experiment then sure, go for it -- but I expect that will be a brief dalliance. I recommend a ZWO 2″ Filter Drawer with M48 / M42 connections. (This one, but maybe you want to find a supplier local to you). I recommend getting a ZWO EAF. Much better than a Bhatinov mask, integrates really well with the ASIAIR, and will fit your Askar FRA400 no problem. EDIT: just seen in your photos that you've got an EAF installed already. Not sure why you're using a Bhatinov mask..? Yes, same temperature for everything. I always set my 2600MC-PRO to run at -10 deg C. Use the same temperature for your light frames too. If you do this then you can build a library of dark and bias frames that you re-use every time. You'll want equatorial mode, as Ian says. Tweak your polar alignment until the ASIAIR gives you a smiley face. Simple!

Ten out of ten!

Incredible, that's really something.

Astrophotography can be so frustrating sometimes, I really feel your pain. A few thoughts: * You wouldn't want / be able to sell the refractor in its current state, right? So at least getting it looked at by Es would let you know what's wrong, and allow you to inform any potential buyers of the issues. * Can any of the issues be fixed in software? I'm thinking specifically of BlurXTerminator. In some cases it seems to work wonders fixing a number of issues; other times less so. * I recently bought a telescope that it turned out I didn't get on with, and was spending a lot of time and money to get it working as I wanted. I realised that it was sucking the fun out of the hobby. So, I drew a line under it, bought a new 'scope from FLO that was expensive but no hassle, and eventually sold the other one. The joy returned! * Affordable wide-field refractors can be great for imaging, and are quite forgiving to use too. Maybe consider that as an option for a while? Best of luck with whatever you choose to do!

Agh I'm too late to see the image 😕

Great, thanks very much!

Hi all, posting this on behalf of a friend, as image analysis isn't my strong suit. It's a single 90-second sub using a newly acquired but second-hand WO ZS61, and a Canon EOS 700D. To my eyes most of the stars look good, but some along the left side in particular seem a bit stretched. Would someone more experienced be able to give their opinion? Thanks! CR2.CR2

Thanks for pointing me toward this thread. Just tagging @powerlord too as I know they're interested in D2 images. It's a shame to hear you had a bad experience with the L-Ultimate. Maybe you had a dodgy one? Mine is good. Regarding your Spaghetti Nebula image above, that was D2 only, yes? Is the red the SII? FYI I've written a review of the Askar D1 D2 filters here, and have so far made a Heart Nebula photo with the D1 and D2; and a Soul Nebula photo with an L-Ultimate and D2.

Great pic! I'm using an Askar D2 with Optolong L-Ultimate, and find they're a good combo. You might want to try your D2 with your Antila. I'll keep an eye out for anything else you post about these filters 👍

Bravo!

Just on the point that's been made that mono produces better quality images, I performed a quick experiment just for fun. I looked through the 2021 and 2022 SGL Competition winners, and noted which cameras were used (with DSLRs counting as OSC). I then split the data into a few different categories. Just to stress that I know this isn't scientifically rigorous in any way and it can't be used to draw any firm conclusions, but I think it's interesting. On the flipside, I haven't done the same experiment with Astronomy Photographer of the Year images, but I think mono really dominates there. To reiterate my opinion on OSC or mono, I think that total integration time and processing skills are far more important than what camera type you're using. In any case, I enjoyed seeing all the images in rapid succession. We've got some really cracking imagers here on SGL -- OSC and mono!

Long integration times definitely help, especially from my city centre location. I also use colour masks during processing to isolate and boost the blue. I'll write up some processing notes sometime, once I've refined the process.

@powerlord Yep OK, next time I'll try boosting the saturation even more. I'm enjoying the D2 filter. My current thoughts are to use L-Ultimate + D2 for targets that have a decent amount of SII, but just L-Ultimate if the SII is lacking.

If you're curious, I posted an Askar D1 / D2 image here, and an Optolong L-Ultimate / Asakr D2 image here.

This image was an experiment in mixing filters with my 2600MC OSC camera. I used an Optolong L-Ultimate (3nm) for Ha and OIII, and an Askar Colour Magic D2 (6nm) for SII and OIII. I think it turned out well! This is also my first attempt at including RGB stars in a narrowband image. Thanks to @powerlord for encouraging me to give it a go. I've got the gist, but any tips for improved star colour gratefully received. Anyway, more info about this image can be found on my website here, and imaging details are below. Thanks for looking * January 2023 * Bristol, UK (Bortle 8 ) * Telescope: Askar 130PHQ Flatfield Astrograph * Camera: ZWO ASI 2600MC-PRO * Mount: Sky-Watcher EQ6-R PRO * Guide: William Optics 50mm Guidescope with 1.25″ RotoLock; ZWO ASI 120MM Mini * Control: ASIAIR Plus * Software: PixInsight, Lightroom * Filters: – Optolong L-Ultimate (Ha / OIII): 300 x 120 seconds (10 hours) – Askar Colour Magic D2 (SII / OIII) : 420 x 120 seconds (14 hours) – No filter (for RGB stars): 90 x 120 seconds (3 hours) Total integration time: 27 hours By Lee Pullen