philhilo

I have been working on my astrophotography for about a year, probably 10 sessions in all, with very slow but positive progress. Many sessions produced nothing as I added more kit, fell into various traps, and got to grips with things. I think I have made progress but now can’t quite decide where to go next (i.e what to buy) to improve my images. I currently have: SW 200PDS with SW coma corrector HEQ5 Pro Canon 750D, unmodded (and I don’t want to mod this as it gets used for work) Guided with SW 9x50 and ASI120mm mini using PHD2 (and a Telrad as the 200mm Newt is a pig to direct by eye) Stacked in DSS and processed with Gimp. I live in a Bortle 8+ area, occasionally getting out to 4 skies and really enjoy imaging galaxies. Despite the somewhat overloaded mount I tuck it away in a corner of the garden next to the house where I can get a decent view of the E to the zenith and achieve reasonable guiding in general, at around the +/-1 arc second. What’s going to do the most for my images with a budget of £700 or so? · I could go with a 80mm doublet/triplet refractor but then I lose the reach but maybe improve the resolution (but I doubt it). · An EQ6 mount, but is that going to improve things much given my current guiding (I know I am absolutely on the limit for the HEQ5 Pro)? · A good LP filter, but which one? · A dedicated cooled astro camera – the ZWO 1600mm would be fab, but at a £1k is a more than I want to put in at the moment? · Dedicated processing software, was thinking Pixinsight (not paying £40 month for the 1% of PS I would use!)? Alas money isn’t going to buy me the dark skies for which there is no substitute – however I don’t think wanting dark skies is going to be sufficient justification for moving house! Also getting to darker skies may only take an hour but that oh so complicates matters where families and children are concerned, so home, between the airport, the car plant, the large town, and the huge urban conurbation it is going to be for the majority of the time for the next few years. Also figured out I could take the easy road and shoot nebulas through a narrow band filter avoiding the light pollution, but I like galaxies! As a guide to where I am at I have attached a part processed (Gimp has crashed 😞 ) image of M42 (yes a nebula having stated I like galaxies), produced from around 2 hours of 60sec subs at ISO800 with darks, flats and bias frames. Any help or suggestions greatly appreciated. Cheers.

Good shots on a very similar setup to mine, and just about to post a question......

QHY8L vs unmodded Canon, yep DSLR isn't going to come out of the cupboard often!

Great shot with similar kit to mine, 200PDS, Canon 750D, guided, so inspiring. However what bortle sky are you under? Pretty good I reckon doing 10 minute subs! I am 8+, between an airport, a major car plant, a large town and a massive city, 1 minute at iso 800 is pretty close to max before a white out.

Thanks for the further replies, sorry I hadn't picked these up. More great reading and more things for my checklist. I see some folks responded to my most recent image so can see the focus issue seems to have gone - however I am now better prepared if it shows up again. Cheers!

Dang, so could well be soggy optics. I think most of my recent sessions have been after rain - its autumn. I was just hoping there was an upside to Newts. I don't think I could possibly ask my overloaded HEQ5Pro to cope with any more load, fans, dew heaters etc. I say thank you when she is tracking well - thankfully at home I can put the rig in a sheltered spot however the 2 weights are already sitting on the stop on the bar to achieve balance, and although I have two more weights it just isn't designed to take the load so I am reluctant to add more. Hairdryer or bust! Thus I was thinking get a decent 80/90 refractor, then later upgrade to an EQ6 (if I don't get sucked into a dedicated cooled camera). Trouble is I really like imaging galaxies so I like the power of the 200PDS (and I couldn't swallow the cost of comparable refractor....yet).

Thank you everyone for the feedback, that is very useful in pointing me in the right direction. Seems like 2 possible explanations for the excessive coronas/diff spikes - moisture on the optics, or moisture in the air. As I remember the target was pretty low to middling so I doubt it was a dew issue (and am I correct in figuring Newts don't tend to get dew issues as much due to the optics being way down out of the way), so most likely problem was the seeing. That's good news, one to check for in a test image. On the processing side I will have more time over the winter (hopefully) to get deeper into that, I might get pixinsight. Collimation, I have yet to try the collimation tool on APT so that's got potential over my current vexing collimator issue (and I can't figure out what surface isn't flat that is causing the wobble between collimator and OTA). I know the 200PDS is the 'wrong' OTA to be starting with but its what a lot of folk get before they get sucked into imaging. However it is also great to see lots of you using them and the images are inspiring. I am looking at a TS Optics 90/600 triplet on ebay, which would I think be better for some of the bigger objects (like M31) and be a little kinder on my mount. Fingers crossed for the bidding on that one. So thanks again folks, I will be back.

Further thoughts, I guess more integration time and less aggressive editing would be good for the image, would it turn the halos into nebulosity or would that just get me brighter halos with a hint of nebulosity?

So I finally have a reasonable image after probably 10 sessions of adding kit and general learning, and I was hoping folks could help me understand what I can do (technique, session craft, adjustments etc) and can't do (due to kit limitations) to improve. The image is M45, taken through a SW 200PDS with the SW coma corrector and no additional filtering using a Canon D700 in a bortle 8+ area. The image is composed of 29 x 60 secs subs at ISO 800 controlled by APT and guided using PHD2 . These were stacked in DSS and edited (very quickly and badly) in Gimp. I would love to think I was seeing the reflection nebula around the stars, however I don't think I am. I guess the fact that it is a Newt is giving me the diffraction spikes around the brightest stars, these appear to be slightly off to the bottom left - is that a collimation issue (I use a laser collimator but it doesn't sit flush to the OTA aperture so making a bit of a nonsense of the process!)? Then there are the halo's - is this an unavoidable feature of the Newt or some other issue? On the good side the stars are reasonably round right out to the edge so the guiding appears to be OK, and the coma corrector is doing its job. Thanks in advance for any feedback.

Thanks folks for the responses to my rant last night. I finally have a chance to reply. Finally got a CR2 file converted into a JPEG using REA and it has done something horrible to the colour (its gone orange), brightness (bright) and even the sharpness (loss of definition), however I have attached it. What I did was put the SW coma corrector for f5 Newtonians into the system between the SW 200PDS and my Canon 700D. I focused with this in place using a Bahtinov mask and APT. The APT tool told me focus was close and looked as good as any other time I have used it and got sharp images. I took a test frame of 30 seconds and got donuts. I checked the focus again with the mask and APT and it was still good. I took another test image and got the same result, donuts (at that point after 4 hours of battle I surrendered, however there might be another chance tomorrow evening so keen to resolve this). So baffled as to why it was in focus but produced out of focus images when I changed nothing and nothing moved.

So why did I have to pursue something so dang hard? I have got some reasonable data in the past and slowly introduced new things, usually with a struggle. However for tonight I thought I would introduce simple things, a mains power lead into my Canon 700D and a coma corrector into the system. So after a huge struggle to get a 1 star align (I have a telrad waiting to be installed) the camera just messed about and I eventually put the battery back in. When I finally got aligned and got Capella dead centre I thought I am close to giving up, the clouds are rolling in, lets at least get some images with the coma corrector and …… everything is out of focus despite the bahtinov/APT/live view suggesting everything is sharp. Recheck with bahtinov, sharp, reimage and all out of focus (or so it looks)....gave up. Second night of frustration and these possible nights are few and far between. Single__0002_ISO800_30s__20C.CR2Single__0002_ISO800_30s__20C.CR2

I love SGL, most of those common problems have been solved, turn the OTA around. Yep I have a HEQ5 Pro and a 200PDS and was looking at extension bars - now this solution might just solve the problem. I do have an EQ5 as well but the weights don't fit the HEQ5 bar.

Great shots with short integration times - from someone with a busy life in an urban sky - makes me think that an astro cam is the way to go.

Thanks everyone for the replies, I went back through the light frames and found one image of M103 amongst the M31s. DSS seems to have latched onto that and used it as its primary image......possibly.....I think. I restacked everything pulling out a couple of satellite trailed images, then did some stretches and curves on GIMP and what I got is below. 2 purchases coming up, an 80mm APO before I go to NW Scotland in September ( for the larger stuff, the 200PDS will still go - family will expect to see stuff), and a narrow band filter for use at home in the autumn/winter. Then I just have to get the guiding working and get my head around more complex processing.....there may be more questions. M31 final.xcf

Hi Adrenaline, that sounds like a stack of work - I have just about figured the histogram stretches! Thanks for that, I am using GIMP, Photoshop seems like a lot of £££ for something which I wont be touching the vast majority of it, PixInsight at least seems Astro dedicated if still a fair few £ (also reading the info on the website I do agree that some of the actions I have seen being taken on Photoshop did seem closer to painting an image rather than processing).

So, been working on imaging for a year or so, had a good outcome with M51 1st off - as in I could see it, wrestled with DSS, got 20 minutes unguided together lovely. Have slowly learnt that from a Bortle class 8 location that was a lucky start. Through a long slow process have moved on in tiny increments. Various other attempts with galaxies have shown that the light pollution swamps the dimmer galaxies - I can see them but never manage to pull them out of the background when processing. I thought I would take a stab at M31 - its bright, big (actually too big for my 200PDS) and not too low (unguided I want stuff not rocketing around). I got 20 minutes of 30 second subs with the centre of the galaxy clearly visible - looking good I thought, stars were there, pretty round stars (no coma corrector so coma shaped round at the edges), even some nice colours - put them with darks and bias frames (crushed I forgot to do flats, added to my imaging process checklist) into DSS and waited for the output and …… out came a very dark image, and any trace of M31 had vanished. Was I using the wrong set of light frames? Have I changed a setting somewhere? Tried restacking many times, pulling out various frames that weren't so good but to no avail, not much light and no galaxy. Tried processing the image in GIMP. Pulled the data out from the far left corner of the histogram into the visible realm and no sign of M31.What is going on? Baffled of Solihull. One of the lights and the DSS output attached (yes they are labelled as M103 - not that organised yet with Backyard EOS to switch naming between targets). M103_LIGHT_30s_800iso_+18c_20190808-01h30m38s196ms.CR2 Autosave001.tif