BrendanC

Thanks all.

Good to know flexure can be avoided with guidescopes.

I was hoping just to use the finderscope shoe but I've also come across mentions that it's not the best solution. The cheapest one rarely is!

I won't be moving the scope at all, it's permanently positioned in the garden. 

I'm still torn! I could spend £60 on a guidescope and it'll more than likely work - but then I'd always wonder whether I could get better results with an OAG. Or I could spend £110 on an OAG, and it might not work (the spacing isn't totally guaranteed apparently), then I'd be back to square one (although I guess I could sell the OAG at a small loss).

I'd just rather avoid that heart-sinking feeling of things not working, trying everything, getting more and more frustrated, which I might be more likely to get with an OAG than a guidescope. Then again, I want to avoid the heart-sinking feeling of having got everything to work with a guidescope, but always in the back of my mind wondering whether an OAG could have been a better solution.

So, still a bit stuck. But thanks for the additional considerations - two-ring mount is definitely something I should think about, which would push up the cost of the guidescope anyway.

Any more for any more?

I was all ready to invest in a nice little guidescope, probably the Astro Essentials one for £59, to use with my T7C (ASI120MC clone). Then my eye was drawn to OAGs - specifically the Orion Thin OAG, because I'll be using it with my Skywatcher 130PDS and Canon EOS1000D DSLR with Skywatcher 0.9x coma corrector. It should work spacing-wise.

BUT... I cannot make my mind up, so I'm hoping someone here can make it up for me!

The way I see it:

• If the guidescope works, then I'll always be thinking 'Hmmm, maybe it would work better with an OAG?'
• If the guidescope doesn't work, then it's a cheaper mistake - but then I'd probably go ahead and get the OAG and try that instead
• If the OAG doesn't work then it's a more expensive mistake but I can fall back to try a guidescope instead
• If the OAG does work then, well, I'm a happy bunny. End of.

By 'works' or 'doesn't work', it seems to me that:

• Guidescopes are easier to set up but suffer flexure (weight isn't really an issue - I've got an NEQ6 mount)
• OAGs can be more fiddly but don't suffer flexure

I guess what it all boils down to is:

• How often is flexure a problem with guidescopes?
• How often are OAGs more effective than guidescopes?

Any takers?

Yep - thanks to the help on this fab forum.

Fab. Thanks again. I'm pleased with this - not going to win any awards but it's nice to know I can actually use the thing if I want to do more solar system stuff.

Hey, great that everyone agrees! Looks like I'm onto something here.

I've used PIPP before a while back to do some conversions but never thought I'd need it again, so uninstalled it. I'll reinstall and try debayering.

Thanks again, really appreciate the help.

(Oh, and PS, I love this: In my opinion the best way to solve planetary imaging problems is to image DSO's instead )

Last night I took advantage of the single hour's worth of clear sky I've had for the past month and tested my T7C, a clone of the ASI120MC which uses the same chip and in fact runs off the ZWO drivers. I managed to capture Mars and everything seemed to go well - until I saw what came out of Registax...

Appalling, I'm sure you'll agree.

There's no colour information in, and I've looked at the histograms and it seems that the R, G and B channels all tend to zero throughout the capture. No idea what's going on there, but I'm prepared to tinker with things - turn up the levels, use a different capture mode etc - to see if I can fix that.

However, my main problem is with the pixelation. I have a strong feeling my lowly Bresser Mikrokular could have done a better job. I can see detail in there, but it's so very, very grainy.

I did a test with the moon a few days previously (ok, I lied, I've had two hours' worth of clear sky in the past month), and that looked ok:

So, can anyone offer any suggestions as to what could be going on here? Has anyone seen a similar issue and knows a fix? Is this a problem with settings, drivers, Registax - or maybe even my setup, which I'll admit is not ideal for solar system imaging (I got the T7C because I'm a cheapskate, also I thought I could use it for guiding but have the option for solar system imaging too). 

Setup is Skywatcher 130PDS, on an NEQ6 mount, and this was with the T7C through a Meade 3x Barlow. For the Mars shot, I captured 10,000 frames in Sharpcap at 320x240 (I also took other test captures at different resolutions, all came out the same). I made sure it was all focused properly before capture.

Or perhaps Mars is just beyond my setup and I should stick with Jupiter, Saturn, the moon, and DSOs through my DSLR?

Or maybe I shouldn't have been such a cheapskate and got an actual ZWO model instead?

I've also included the settings and histogram CSV file if they help

21_31_25.CameraSettings.txt

21_31_25.Histogram.csv

Any/all ideas welcome!

Thanks, Brendan

I know this is a very old thread, but did the OAG work in the end? Because I have a similar setup and am weighing up guide scopes vs OAGs. 

Amazing. I came across that earlier today. Did you post it on Facebook? 

I know, same here - never used it with a moon shot but tried it, without really thinking it would work, and it did!

I even tried submitting it to Astrometry.net just to see what happened, and as expected, it failed.

Hi all,

I've taken shots of the moon before with my bargain-basement Bresser Mikrokular camera, but just invested in a T7C camera - a cheapo version of the ZWO ASI120MC. This is mainly for guiding when shooting DSOs, but I got the colour version so I had the added flexibility of taking lunar and planetary images if I fancied it.

I got it working last night, took a bit of wrestling but I finally managed to get a shot of the moon - 5000 frames captured in SharpCap Pro and stacked and processed in Registax. Nothing too fancy but a good start.

However, now I'm all over plate solving from my DSO work, it did occur to me: which bit of the moon did I actually capture? Can you plate solve the moon?

Turns out you can't. The most common advice is to download an atlas and look for it. But, given that I'm very lazy, I found a workaround: use Google's Image Search.

So, on uploading my image to https://www.google.com/imghp, I get absolutely loads of results back telling me it's the Sinus Iridum plain: https://www.google.com/search?tbs=sbi:AMhZZisatfdoUDCjbhsh01nAM7fUZp_1y9b6gJiNTpRmsCAVJJtVGCCQ732121AuSY0D8OAB3LLJlE48sZSDneQ9c4QzL-MR5At6S9Nd9jfKPUn8JdW1zTMWcX4CdA5f-gZtD9u6aP9HMqJx1waq9BrKEyXjKSpNFRzxxEJ88xCqPJs9hTKzUdA0du_1xZ4WLatZkt7toR2X_1tBeV38zrtKYI6NBIgT-ASQBJJv4ztTcVwRx030BYuaS46BLGDJvGp1fQmMj2Dqnqan5wTH1X8yBIW-sPML6-YFyYgpIUXTW22gKZOkbY6ed5RUPmMJTqQPnYkJ-bXDDAw6nMHG-WrEtak9JX8W-Gcpw&hl=en-GB

Sorted! Or, should I say, solved!

This may be old hat around these parts but I thought I'd pass it on as a neat trick. You can't solve the moon, but you can ask Google to do the next best thing.

Deep into observing, felt two hands on my back. It was the cat (I was sitting on the ground), reaching up for a nice scratch. 

Apart from that, my heart pretty much stops every time anything goes wrong, ever. 

Thanks all. Issue was resolved long time long time!

Phew. Thanks everyone. Onward and upward...! 

Hi all,

So, another oddity... sigh...

I've very carefully monitored the histogram when creating my flats, and it's pretty much bang in the middle for each sub.

However, when I look at the master created in DSS, it's dark! With the histogram all packed to the left.

Is this normal? There's a load of gumf in the description txt flat that I presume DSS reads to 'unpack' it all which I expect (or rather, hope) provides DSS with what it needs to apply the master correctly.

However, having stacked loads of what I assume (or, again, rather hope) are decent subs, the master would vaguely resemble what it had been stacked from.

This is what one sub looks like:

And this is what the master looks like:

I know it's not ideal posting jpgs of these files so if anyone fancies looking at the originals I can share them on OneDrive or some such thing.

Or, is this expected behaviour?

Thanks, Brendan

I've tried APP and really liked its stacking, noticeably better than DSS, but not as strong with post processing. I'm still using DSS though, because I think my next important step is guiding, not post processing. 

Great advice, thank you! 

I have zero idea why clicking the image produces a blank screen. I just chucked them into the post and assumed the forum code would make it all work automagically.

I totally get what you're saying about the star field. I like Newts too! Those funky diffraction spikes. The broadband colours really come out with the extra integration time and StarTools magic. However, I do just really like the narowband images I've seen, and that's what I was trying to get.

I was going to look at Images Plus but I got a security warning on the website a few days ago, but that seems to have gone now. I might give that a blast too, as it's free. My main problem with Photoshop packs however is that my old CS2 Photoshop version doesn't have the sub-pixel setting and the 'preserve roundness' option for the Minimum filter used, and I'm really not prepared to pay £250 a year for Photoshop. I'm trialling Pixinsight and experiencing the same giddy learning curve other people have, so that's another digital toy to play with this weekend.

@Xiga Interesting that you prefer the original! I thought the stars were far too prominent. The reduced-stars version is much closer to other examples I've seen. I really wanted to show the nice, twisty-turny nature of the nebula. The best shots I've seen really get across the idea of it being the outer edge of the nova, almost like large, semi-translucent bubbles.

@alacant Thanks, I'll give this another try following your workflow recommendations. I'm still unsure what to make of StarTools. Sometimes it works great, other times not so, and there doesn't seem much 'wriggle room' in between. It definitely brings out much more than I've ever managed in Photoshop however. I've currently got the Pixinsight demo and it's just mind-blowingly complicated.

Hey, the star shrink in StarTools worked really well! I found the 'tight' setting was best, bit of masking, fiddling around with the settings, really huge difference. Thanks everyone.

Before/after shots...

Needs more work on the background gradients but there is much more definition to the nebula now.

Thank you! Lots of approaches then. I'm going to try them all over the weekend. One of my favourite things - just spending ages getting images to look nice.

Excellent, I seem to have completely overlooked the shrink module. Will give it a go although there's no way my attempt will ever approach the examples above which are stunning. Thanks again! 

OK, so here we go, I remember all this now from when I started out...

Which is best: Annie's, Carboni or Starizona? They're all very similar in price. Any votes?

@happy-kat Yep, thanks, tried that too (the 'heal' module) but it's not really cutting it for me I'm afraid. At the end of the day my image might even just be too noisy (it's from a DSLR). I'm currently re-stacking it with some different calibration files to see if that helps, then I'm going to try everything I can think of (again!).

@Kinch - great image, and thanks for the advice. Looking at my original 'reference' image (https://astrobackyard.com/ngc-6992-eastern-veil-nebula/) I can see that he also has stars albeit reduced.

@Adreneline - interesting, I've come across these kind of packs before but being fairly used to Photoshop, I tend just to follow tutorials and use my own experience to try these techniques. I've tried following the steps at https://photographingspace.com/star-reduction/ without much success, and they also have an action set. But yes, I've also heard about Annie's pack, so perhaps I should invest in that. I just need to confirm it works with my VERY dated version of Photoshop (CS2). Ideally I'd do everything within StarTools, but I often just touch things up in Photoshop at the end.

Thanks all. Looks like I chose a 'toughie' this time!

@Kinch - interesting, I just assumed that certain narrowband filters would help during acquisition. So, if not, then presumably the beautiful shots I've seen, with the nebula standing proud of the stars, and intact, were all achieved in post processing? 

I'll give Starnet another blast and look for that other program you mention, but I am still intrigued as to how those images are achieved! 

Hi all,

So I've captured about 11 hours' worth of the Eastern Veil Nebula. The actual nebula looks lovely - but, to quote Dave Bowman, 'My God, it's full of stars!"

I have a strong feeling most of the 'starless' veil images I've seen are taken using filters that just capture the nebula, not the stars.

However, given that I don't have filters, I've tried several post-processing techniques - using the Photoshop colour picker/feathering/filter method, StarNet, StartTools's 'heal' feature - and none of them really work.

Should I just accept that it's a very difficult object to image without filters, or does anyone know of any other approaches that might work? Ideally using Photoshop, StarTools, or some free software ie not shelling out for PixInsight etc.

Thanks, Brendan