gasdoc

So dewshield made no difference. I also posted on cloudy nights and they agreed with Louise & Olly that it’s due to diffraction issues probably as a result of the filters and/or camera. I will do some experimenting with removal/ repositioning of bits and report back paul

Thanks Louise, I’m going to try tonight with the dewshield on at the same target and check all my connections etc. If that doesn’t work, I’ll reconfigure my imaging setup although I haven’t had these issues with my refractor. Best wishes Paul

Sure thing - see attached. Fingers crossed for a simple-to-fix error! BW Paul

Thanks Olly for the reply! So does that mean I'm stuck with this issue? To be honest, if there isn't a way to fix it, I'm going to return the Edge and stick with my refractor as it doesn't seem to suffer this issue. BW Paul

Hi all, I suspect this is a fairly common issue, but I haven't found the right search criteria to look it up on the internet for myself yet. I started imaging last night and found these artifacts on my Ha images (brief stack of 8 x 300 sec subs). Darks and flats applied (no artefact on either of these that I can see). My setup for this was: 1) Celestron Edge 8 HD (no dewshield on) 2) ZWO OAG to ASI 120 mini 3) ZWO filter wheel 4) ASI 1600 I use the imaging rig with my WO Z61 without any artifacts so I don't think it is due to any issues with the filter wheel/ OAG for example. I wonder whether it is internal reflections in the SCT? -? secondary mirror reflection - if so, at least the collimation looks reasonable Second question: why do there seem to be regular artifacts (I can count about 16 in a 4 x 4 arrangement? Any help much appreciated, and I fully expect a "you dufus, it's...…" response Best wishes Paul

Hi John I bought an EQ6R a few weeks ago and bought this monster: https://www.firstlightoptics.com/batteries-powerpacks/nevada-ps-08-6a-8a-regulated-linear-power-supply.html primarily for the consistency of output and the ability to power few heaters etc via the terminals. not sure if a similar device is available in the US though? Best wishes Paul

Hi all, I'm hoping I can get some wise advice on what to purchase so I don't chuck money down the drain (been there, done that!). I started out with a Celestron Nexstar 6 - spent a year failing to image using the alt-az mount using my DSLR, tried the wedge (epic fail) and then decided to purchase an SW EQ6R after playing with their little staradventurer and a WO61 (which I'm impressed with). My interests are nebulae and galaxies which I am finding more and more fascinating at this time of year! I have recently added the ASI 1600 mono which is a superb bit of kit and have just starting imaging with the Nexstar 6 (see firstlight M51 from the weekend with limited data). Hopefully I can play with this and the WO61 when suitable targets are in view. I have been considering investing in a large-ish refractor (SW esprit 120) but was wondering whether my money would be better spent on a slightly smaller refractor (SW esprit 100) and a celestron edgeHD 8 instead? Clearly slightly more expensive but would possibly give me more versatility? So questions: 1) Will the EdgeHD 8 give me a significant jump up in optical performance compared to my Nexstar 6 (which I've struggled with vignetting and coma correction) or should I just persevere and purchase a flattener/ reducer for the Nexstar 6 (I tried this with the DSLRs but it had terrible vignetting so I returned it) 2) Will the optical performance of the esprit 120 be significantly better than the Nexstar 6/ edgeHD8 and sufficient to crop more aggressively and given me a pleasing image of galaxies, thereby negating the need to purchase the EdgeHD8 Apologies for the long post! Best wishes Paul

Yep I’ve been using that but as you correctly assumed in your previous post, I’m coming from a dslr photography background and trying to get to grips with the whole pixel scale thing - the ccd suitability calculator tool is useful however for a guide. Many thanks for taking the time to explain the concepts though! Paul

😂😂😂 Yes I am resigned to that fact. Your images are beautiful - I’ve seen your stuff before and it’s always impressive but I have to be more realistic with what I can hope to achieve with a budget of £2500 and bortle 5 skies. sounds like I need to consider the esprit 120 to get the FL and complement my WO 61 and sticking with my dslrs (crop and full frame) for now then going for a smaller pixel astrocam - any suggestions? Zwo 183? (2.4 um pixels) - slightly under sampled but gives a similar FOV to your tec 140 plus atik 460?

Yes I'm getting myself confused on what's going to give me the best imaging possible for the money: 103 WO + cooled astrocam eg WO Z103 + zwo ASI 183 (gives a CCD suitability of 0.9 which seems ok?) 120 FL esprit plus my Nikon D7000 (I also have a D750). My intended targets are nebulas and galaxies - I realise galaxies are at the edge of these sorts of refractors' focal lengths, but I was hoping a smaller sensor astrocam would make this feasible. Obviously I can get the Esprit 120 and stick with the Nikon for now, and save up for a dedicated camera at a later stage. Only thing I've realised lately is that skimping on decent bits of kit ultimately ends in frustration and after succumbing to purchase, results in a "why didn't I do this earlier!!"

@alacantSo in the setup for PHD, I was selecting my zwo camera and then using "on camera" for the mount. Am I supposed to select EQMOD ASCOM HEQ5/6 there then instead? I tried this before but couldn't get it to work. I have my zwo guide camera attached to the mount via the autoguider port and also to the laptop. Do I disconnect the autoguider cable, then find a specific EQ6R driver, and just run the zwo using the single lead from camera to laptop, which in turn is connected to the EQ6R via its usb connection? Paul

Thanks John, looks like a beautiful scope but for that money I think I'd get the Esprit 120......hmmm, now there's another option to consider! @Lockie I'm not sure I'm discerning enough to notice the CA - and surely I can edit this out with photoshop? Thanks for the opinions though! I'm sure I'll be very happy with either - just want to know whether the price gap is justified in real world images.

Hi all, I have a WO Z61 which I love but I want more reach. Have just got an EQ6R Mount which I’m learning to use and the next step is probably a 100mm refractor (strictly AP only). Obviously the Esprit has excellent reviews everywhere and is a triplet but am I likely to notice £500 difference compared to the WO z103 doublet + reducer/flattener? Alternative: buy a dedicated Cooled Astro cam for my z61 and get some reach that way whilst entering that rabbit hole - OSC vs mono etc etc (Currently using FF and cropped dslrs)? Cheers Paul

Lovely - will read when I get home from work. Thanks paul

Ah, ok - sounds simple enough, thanks!

@alacant thanks - I’m using EQMOD already but thought the pulse guiding was done from PHD? Why does EQMOD improve this? Sorry - any links to simple explanation would be good but I can google if not! @ollypenrice I prefer your edit of my initial shot! I’ll read up about the orthagonal orientation (it’s a bit klingon to me at the minute!)

Hi all, Had a quick chance to try again - see attached log file. Seems fine - didn't manually alter backlash as wanted to see whether other tweaks fixed the issue. Haven't had a chance to look at the files once processed but raw subs looked much better. I don't understand these graphs in any depth but my error was about 0.17 apparently - can't find that in the logfile though. BW Paul PHD2_GuideLog_2020-04-12_115059.txt

@alacant many thanks - I presume those were my log files? I’ll try all of this - seems Ppec algorithm is easy to activate In PHD and is backlash compensation a binary on/off or do I have to measure something and set accordingly? Will investigate tonight if skies are favourable 🤞 cheers paul

Thanks everyone, @smr I use the sigma a lot for my standard DSLR stuff (wildlife etc) so selling not an option This was an attempt to see if I could get away without the added expense of a bigger refractor ( I am obviously lusting after an Esprit 100 but v difficult to justify to wife 😬 even after playing the "I need the stress relief during COVID" card [I'm nhs]). So I guess I'll try with the SCT tonight, cross fingers, and see how that performs otherwise its penny saving time! BW paul

Hi all, Anyone know of a cost-effective way to insert a 2" filter into the imaging train between a Nexstar 6" SCT and a DSLR? Apologies for another newbie ask but I'm confused which bits to get in the UK after watching this on youtube Seen this: https://www.harrisontelescopes.co.uk/acatalog/celesctron-sct-adapter.html#SID=24 But not sure that's just a different version of what I already have (https://www.celestron.com/products/t-adapter-for-schmidt-cassegrain-telescopes) And then not sure what other but I need to attach the filter? Any guidance much appreciated BW Paul

Many thanks for the advice - much appreciated! It seems entirely plausible that its the differential flexure but that doesn't explain why it wasn't an issue the day before. I'm going to try using my finderscope attached to my 6" SCT on a vixen mount tonight. Obviously the FL is even longer but on an EQ6R I would hope that this shouldn't be an issue. One thought, could the lack of entering the FL of the guiderscope made the guiding inaccurate? Or was it just poor PA and I didn't realise this as I assumed the low error on PHD meant I was dialled in accurately? So jobs for tonight: 1) Run sharpcap PA alignment routine 2) re-calibrate PHD now that I've entered the correct FL for the finderscope 3) try M101 again (clouds permitting) using the above arrangement Best wishes Paul

Yes I had issues with conflicts between EQMOD and starting PHD afterwards (guidescope view was pure white whatever I did) but after re-installing and ensuring I started EQMOD after PHD fixed this. Somehow I must have omitted the focal length of the guidance (but I’m sure I entered this). Re: mounting camera - yes accepted this is not ideal but was really a test to see what an effective 1000mm FL would give me of galaxies without having to fork out for an enormous refractor. I couldn’t find a way of mounting the camera securely to the vixen plate with the guiderscope attached - any suggestions very welcome though!! paul

Doh! Sorry - wrong file Now attached. The lens & camera are attached via a decent camera ball socket to the vixen plate which also has the guidescope on it. I tested it two nights ago with 2 min subs and the stars were pinpoint - which obviously made me think I had it all sorted so there must be something that I've done since then that has screwed it up. The conditions were better last night (less wind) so I can't even blame that. Paul PHD2_GuideLog_2020-04-11_201428.txt

Ha ha thanks Alan, Yes I'm at the base of an all too familiar exponential curve - good fun learning but annoying when you have to wait all day to try again! Paul