The "No EQ" DSO Challenge!

[Nigel G]

I agree a new thread to discuss this is a good idea.

So, last night I had a battle with my imaging PC, It shut down on its own 3 times while gathering subs, 3 hours spent getting 1 hour of 30s on Horsehead, flame & Orion with my 135mm lens. then the fog rolled in. DSS refused a few subs.

I took darks flats and added the stock bias. I had a very hard time removing gradients so i'm re stacking without the flats to see if that helps.

The info is there, removing the gradients has taken so much detail out though.

Canon 1300D 135mm lens, 94x30s light ISO 1600, 40 flat, 50 dark, 50 bias. Star Discovery Alt-Az mount, DSS & StarTools.

Cheers

Nige.

[SteveNickolls]

1 minute ago, Nigel G said:

I agree a new thread to discuss this is a good idea.

So, last night I had a battle with my imaging PC, It shut down on its own 3 times while gathering subs, 3 hours spent getting 1 hour of 30s on Horsehead, flame & Orion with my 135mm lens. then the fog rolled in. DSS refused a few subs.

I took darks flats and added the stock bias. I had a very hard time removing gradients so i'm re stacking without the flats to see if that helps.

The info is there, removing the gradients has taken so much detail out though.

Canon 1300D 135mm lens, 94x30s light ISO 1600, 40 flat, 50 dark, 50 bias. Star Discovery Alt-Az mount, DSS & StarTools.

Cheers

Nige.

The diagonal composition is lovely Nige but is this less=more in LIFE to give you the roundalls over the stars?

 

Cheers,
Steve

[Nigel G]

1 minute ago, SteveNickolls said:

The diagonal composition is lovely Nige but is this less=more in LIFE to give you the roundalls over the stars?

 

Cheers,
Steve

Steve, this image has been wiped gradient and vignetting, isolated with a mask, less-more with a mask and isolate again to remove a very bad top left gradient  

[Filroden]

Be careful with gradients in Orion as some of it could be dust/nebula! Nonetheless, it's a great composition. I woke up at midnight the other night and saw Orion just coming over the horizon. It was too late to set up (my mount is quite noisy so I prefer to set it up before the neighbours children go to bed) but it's a wonderful sight. 

And you can clearly see the horsehead, something that terrifies me trying to capture in short exposures. 

Is this with the new LP filter?

[Nigel G]

Just now, Filroden said:

 

Is this with the new LP filter?

Ken, No this it without the filter. I did take a batch of 60s on M31 with the LP filter which is in line for stacking after the re stack of the wide field image.

Result will be posted. This will tell me if I wasted over £100  Mind you it could be good with the modded camera soon to be back in action.

Cheers

Nige.

[The Admiral]

That's a lovely combination of nebulae Nige, and it shows just how bright they are. Did you try the HDR module - reveal?

As a matter of interest, did you try wiping without using a mask? I must admit that on the occasions when I've tried using a mask it's not been that successful.

Ian

[Nigel G]

1 minute ago, The Admiral said:

That's a lovely combination of nebulae Nige, and it shows just how bright they are. Did you try the HDR module - reveal?

As a matter of interest, did you try wiping without using a mask? I must admit that on the occasions when I've tried using a mask it's not been that successful.

Ian

Thanks Ian.

I tried for 2 hours everything I could try in wipe, with mask without, inverted mask Gradient, vignetting, amp glow. small mask big mask lots of small masks.

A combination of gradient and vignetting with no mask worked best.

Cheers

Nige.

[Nigel G]

Which thread should a discussion on a new topic be posted? There isn't a general discussion topic.

I guess its imaging discussion

Edited October 30, 2016 by Nigel G
add text

[Filroden]

1 minute ago, Nigel G said:

Which thread should a discussion on a new topic be posted? There isn't a general discussion topic.

I guess its imaging discussion

Yes, I'd have suggested imaging discussion too. 

[Nigel G]

2 minutes ago, Filroden said:

Yes, I'd have suggested imaging discussion too. 

I'm on to it now.

[jimbo747]

On 10/10/2016 at 20:40, parallaxerr said:

 

If I was in to conspiracy theories I'd say the reason why SGL doesn't want to promote alt az imaging is that the equipment used is generally cheap, and this site is sponsored by FLO. If users found that they could achieve quality images using a £80 SLT mount and a £90 DSLR then less people would be prepared to splash thousands on mounts, guide cameras, filter wheels etc.

 

But I'm not, so I won't say that

[Nigel G]

 

 

[Stub Mandrel]

I'm not trying to muscle out the Alt-Az bit.

Just searching for a formula that not only creates a home for discussing alt-az issues, but puts the technical issues relating to the mounts in a specific section within a wider topic that also covers the common ground with small scopes/DSLRs/EQ mounts that can get lost in the rest of the forum.

Unfortunately 'budget' is an emotionally charged word and some people may read it as doing things on the cheap. For me trying to do AP alongside one of the other traditionally expensive hobbies (model engineering) it matters to make my money go as far as possible. That doesn't mean the cheapest possible kit or making silk purses out of sows ears, but it does mean getting the best out of what I have rather than simply upgrading for the sake of it. For example I shelled out on a 130P-DS and coma corrector because the 'return on investment' was significant and also the scope was better suited to my mount. For me it's about spending wisely and not putting people off who don't want to spend a fortune on a hobby they aren't sure will suit them long term.

Building on Steve's excellent post above, I think that since the emergence of affordable 14-bit DSLRs (I started with a 210-but D10) followed by other new CMOS sensors it's increasingly possible to get good RGB data at shorter exposures of 30 - 120 seconds, say. These require some form of tracking, but both Alt-Az (fighting field rotation) and unguided light EQ mounts CAN achieve this an give you a good majority of usable subs.

A significant proportion of those who got into AP in earlier days haven't had direct experience of this and because they think you need at least 5-10 minute subs for decent results they naturally discount an ALT-AZ or an EQ3 (I note that 'Making Every Photo Count' DOES say you can start with an EQ3!)

[Stub Mandrel]

1 hour ago, jimbo747 said:

If I was in to conspiracy theories I'd say the reason why SGL doesn't want to promote alt az imaging is that the equipment used is generally cheap, and this site is sponsored by FLO. If users found that they could achieve quality images using a £80 SLT mount and a £90 DSLR then less people would be prepared to splash thousands on mounts, guide cameras, filter wheels etc.

 

But I'm not, so I won't say that

I doubt it, to be honest. I know plenty of traders in the model engineering world, and to them the best thing that has happened to the hobby is the emergence of affordable, modest-capacity Chinese machines of serviceable quality. These bring so many people into the hobby the benefit from increased volume of machinery sales and more sales of accessories. Most importantly, the increased flow of people who previously thought they couldn't afford it into the hobby actually generates more sales at the top end as a significant proportion of them do decide to upgrade and extend their skills/capacity.

Any retailer can figure out that this isn't competing with top-end imaging, it's opening up imaging to people who otherwise would have been restricted to visual astronomy. It also means they are much more likely to find success, and then go on to buy more advanced or capable kit.

Another outcome is that you reduce the number of complete beginners going out and buying top end complex kit and failing to get anywhere with it. I'd lay money that the margins are better on accessories than scopes and mounts. A retailer who gets someone off to a good start with an economic scope/mount deal will make most of their returns as that satisfied customer develops their hobby and comes back for more goodies. Sell someone a super-dooper-sky-grabber-deluxe that they can't get to work, and you may never hear from them again.

If getting lots more people into imaging is the end result it HAS to be good for the hobby and what's good for the hobby is good for the trade.

[SteveNickolls]

Taking up Neil's concerns over potentially divisive words like budget, Alt-Az, EQ etc. the common thread running through our imaging is the duration (or lack) of individual frames. Our imaging takes up the central ground between very short exposure EAA and established EQ imaging. EAA had to fight for their recognition just as we are doing. What we are pursuing is the inevitable opportunity presented by growing technology that allows the unthinkable of capturing decent images not thought possible only a few years ago.

I rather think the growth in shorter duration imaging is inevitable given the development of more sensitive CMOS camera chips not needing long exposures and improved mount designs. In the future the use of heavy EQ mounts, while still having a place to allow imaging to the zenith and more accurately track objects, will diminish as more and more people see the advantages of using lightweight portable mounts and greatly more sensitive CMOS cameras. 

However getting back on point the discussion thread can surely accommodate discussion including mount types which by their inherent design share the limitation of imaging duration. Joseph Ashley had to draw some boundaries to sensibly limit the content of his book but we can afford to be a little more generous with no publisher or deadline to meet. More importantly the challenge, drive and ideas that cross platforms should not be lost because the paper was too small. Anyway just my 2d.

Cheers,
Steve

 

[Nigel G]

Now the results of the LP test.

The 2 following images are M31. the first my original of 120x30 and 80x45s ( a good example of looking for a post in this thread, I didn't log the subs so needed to find my original M31 post, funnily enough its on page 31  but took me some time to find it )

Second image is 30x60s with dark and bias, no flat. EOS 1300D with LP filter, 150P on Alt-AZ mount. DSS & StarTools.

My conclusion-The detail is greater in the first but it is 2 hours against 30 minutes the second has more body if you know what I mean.. The second image, easier to process, less gradients, a bit easier to draw the colour, far less noise in the whole frame edge to edge. Positive I think.

Nige.

[Filroden]

I would say the second image has more detail. I suspect it is the combination of lower background noise and also being easier to remove what little gradient there might be without also removing the galactic disk with it. At first glance I'd say the LP filter is making a big difference! 

[Stub Mandrel]

Just for the record, someone posted recently asking 'the astrophotography question' with a budget of $500 or $1000 if they wait.

One  of the responses, by an experienced and capable imager and clearly intended to be encouraging, included the following:
 

Quote

 

"Galaxies and nebulae are faint and require longer exposures, which in turn demands a highly accurate mount that can track accurately. You need fast-ratio optics for preference (f/5-f/6) and a large enough aperture telescope to provide the necessary fast f-ratio at a usable focal length (say, 600-700mm for nebulae - preferably longer for galaxies). The camera needs a larger sensor because the targets are often extended over a much larger area. A DSLR works well under dark skies but they don't work so well in light polluted environments, being colour sensors they suffer from background colour bias if light pollution is present. A cooled mono camera offers more control and is to be preferred."

"There is no doubt that delving into astro-imaging is an expensive undertaking and it is difficult to 'dip your toe in the water' so to speak on a limited budget. To do so involves many compromises which may leave you frustrated with the results you can achieve."

 

 

Surely this is exactly the sort of advice that is no longer accurate and is just going to put off most beginners?

 

 

 

 

 

[Nigel G]

Reprocessed the 135mm image, with no flats much worse so in the recycle bin. managed to get a bit more but it does need the intended 2 hours of subs.

original                                                                                                              Reprocessed

Nige.

[The Admiral]

42 minutes ago, Stub Mandrel said:

Just for the record, someone posted recently asking 'the astrophotography question' with a budget of $500 or $1000 if they wait.

One  of the responses, by an experienced and capable imager and clearly intended to be encouraging, included the following:

Surely this is exactly the sort of advice that is no longer accurate and is just going to put off most beginners?

Indeed! Did you wade into the fray with a suggestion to check out this thread ? In the nicest possible way of course!

Ian

[alacant]

40 minutes ago, Stub Mandrel said:

this is exactly the sort of advice that is no longer accurate

+1. Exactly. It would put anyone off. The advice is (at least) 10 years out of date. I think we should aim the level of posts at the level of the forum. The jargon is at times insurmountable. Just my €0.02.

[The Admiral]

22 minutes ago, Nigel G said:

Reprocessed the 135mm image, with no flats much worse so in the recycle bin. managed to get a bit more but it does need the intended 2 hours of subs.

original                                                                                                              Reprocessed

Nige.

I don't understand why flats should worsen the detail. The stars are so much less distinct fewer clearly visible in M42.

Ian

Edited October 30, 2016 by The Admiral

[happy-kat]

One should have an eye on value for money spent and rate of success for energy/money expended and desired end result and any other influencing factors. Pick and choose when it feels right to offer alternative suggestions as it doesn't always feel appropriate on every enquiring post. Nor should we lose sight that shorter exposures ultimately does limit what can be captured and consequently should be mindful of not portraying the same can be achieved with less. I try to tread carefully so as not to miss guide how someone spends their money and prefer to encourage pushing the boundaries of the equipment already owned to explore their interest.

[Nigel G]

11 minutes ago, alacant said:

+1. Exactly. It would put anyone off. The advice is (at least) 10 years out of date. I think we should aim the level of posts at the level of the forum. The jargon is at times insurmountable. Just my €0.02.

This should be posted in the new discussion post, all the support would only improve the chance of a new topic 

 

[Nigel G]

19 minutes ago, The Admiral said:

I don't understand why flats should worsen the detail.

Ian

Ian, it's the other way round, without flats much worse 

I reprocessed the same stack and binned the one with no flats, couldn't process it .

Nige

Edited October 30, 2016 by Nigel G