The "No EQ" DSO Challenge!

[parallaxerr]

Looks good Ken. Why is it that the cloudier weather makes us spend more on the hobby...which we can't do because of the clouds!?!?

I'm afraid I have been naughty today and fraternised with the enemy......I just bought a wedge

I'll get my coat now.

[Filroden]

4 minutes ago, parallaxerr said:

I'm afraid I have been naughty today and fraternised with the enemy......I just bought a wedge

I'll get my coat now.

Is that the turn coat?

[parallaxerr]

I'll reserve comment until I have had chance to try it, which will be a long time if the weather doesn't change soon!

[Nigel G]

Another short session last night, I set up, got target in position, first sub blank reddish image, look outside and , clouds.

30 minutes later a gap. Quick to start getting subs, it lasted 14 minutes. so got 12.5 minutes on Rosette with my 150P, modified canon with CLS filter.

25x30s with flat and bias, ISO 1600. For only 12.5 minutes, I'm pleased but I need to get at least 30 minutes a night for 3 nights on each object.

I'm getting data on 3 targets over several sessions to try to reduce crop sizes, at this rate it will take me a decade, blooming British weather.

This is a quick stretch before going to work, no detail work has been done.

Nige.

Edited December 20, 2016 by Nigel G

[schmeah]

 Very impressive efforts with alt-az mounts. It has renewed my interes in alt-az imaging. But I've not been able to read this entire thread so I apologize if this has already been discussed. Has anyone seen the impressive imaging results with the TTS-160 Panther alt-az mount, both long exposure (I've seen up to twenty minute subs) using an OTA rotator, and very short subs using the low read noise CMOS ASI 1600? Not a cheap mount, but proof that high end imaging is possible with a commercially available alt-az mount.

 

Derek

[happy-kat]

I can't read your question on my tablet, please remove the text formatting

[parallaxerr]

21 minutes ago, schmeah said:

Has anyone seen the impressive imaging results with the TTS-160 Panther alt-az mount

Hi Derek, I just googled this. Very interesting indeed, there is mention of de-rotating alt/az setups earlier in the thread but I haven't seen mention of this mount before.

[Filroden]

31 minutes ago, schmeah said:

 Very impressive efforts with alt-az mounts. It has renewed my interes in alt-az imaging. But I've not been able to read this entire thread so I apologize if this has already been discussed. Has anyone seen the impressive imaging results with the TTS-160 Panther alt-az mount, both long exposure (I've seen up to twenty minute subs) using an OTA rotator, and very short subs using the low read noise CMOS ASI 1600? Not a cheap mount, but proof that high end imaging is possible with a commercially available alt-az mount.

 

Derek

It seems a very expensive way to remain alt/az. At that price point I'd be recommending going straight to an EQ mount that had a good polar alignment tool and easy/no meridian flip. After all, set up time and cost are probably the biggest differences between the two mount types. If you remove cost barriers, you can get easier set up EQ mounts.

Alt/az is great for observation where rotation is irrelevant. It can also be used for photography if you know its limitations and can accept them. And we're showing you can minimise most of these. But they still remain. I love my mount but if I could spend that amount I would find a way to make EQ work for me than work the remaining issues with alt/az.

 

[parallaxerr]

I've been looking at your setup recently Ken, you have a really nice scope and camera and you're already tied to a laptop. Do you see yourself going EQ in time, or do you feel the ease of Alt/Az setup outweighs the potential gains going EQ, regardless of funds becoming available?

[Filroden]

7 minutes ago, parallaxerr said:

I've been looking at your setup recently Ken, you have a really nice scope and camera and you're already tied to a laptop. Do you see yourself going EQ in time, or do you feel the ease of Alt/Az setup outweighs the potential gains going EQ, regardless of funds becoming available?

It's not money stopping me. I set up outside the backdoor with a limited view. I have limited time so I don't want to spend that time setting up and aligning. Much of what I spend makes it easier/quicker for me. At some stage, if I can find a portable easy to set up EQ I will give it a go. Until then, I'll keep improving the automation of my current set up. Once I've got auto-focus down, im looking at controlling the mount from the laptop rather than the handset. The way I justify it is that the kit I have can transfer to an EQ mount if I take that step.

Edited December 20, 2016 by Filroden

[parallaxerr]

Time seems to be a major factor for many, myself included and I do like how quick the alt/az setup is.

For me, the wedge was the cheapest option that may have the potential to improve my images. I started looking at cameras and OTAs, but the cost is prohibitive right now (side note - don't buy a Land Rover that is due a £1400 service!).

I'm hoping my wedge experiment doesn't add too much complexity, reading the manual suggests it "should" be a relatively easy affair with the All Star Polar Alignment. We'll see on the next clear night!

[The Admiral]

1 hour ago, parallaxerr said:

I've been looking at your setup recently Ken, you have a really nice scope and camera and you're already tied to a laptop. Do you see yourself going EQ in time, or do you feel the ease of Alt/Az setup outweighs the potential gains going EQ, regardless of funds becoming available?

I was going to ask that very question! Ken's set-up is ripe for a simple transfer to EQ as most of the main issues seem well sorted.

1 hour ago, Filroden said:

At some stage, if I can find a portable easy to set up EQ I will give it a go. Until then, I'll keep improving the automation of my current set up. ...... The way I justify it is that the kit I have can transfer to an EQ mount if I take that step.

I can see you taking that inevitable step Ken . And don't feel that you need any justification! You've taken a very sensible step-wise approach to your astrophotography, keeping your options open. If only others would adopt the same approach rather than throwing everything at astrophotography in one go (as so often advised!), and then being disatisfied that they can't get the results they are seeking.

Ian

[The Admiral]

8 hours ago, Nigel G said:

Another short session last night, I set up, got target in position, first sub blank reddish image, look outside and , clouds.

30 minutes later a gap. Quick to start getting subs, it lasted 14 minutes. so got 12.5 minutes on Rosette with my 150P, modified canon with CLS filter.

25x30s with flat and bias, ISO 1600. For only 12.5 minutes, I'm pleased but I need to get at least 30 minutes a night for 3 nights on each object.

I'm getting data on 3 targets over several sessions to try to reduce crop sizes, at this rate it will take me a decade, blooming British weather.

This is a quick stretch before going to work, no detail work has been done.

Nige.

Very nice that Nige, and I'm looking forward to you getting more frames.

Ian

[Nigel G]

1 hour ago, The Admiral said:

Very nice that Nige, and I'm looking forward to you getting more frames.

Ian

Thanks Ian, I'm looking forward to be able to gather more frames  Could be a slot tonight between the cloud.

Nige.

[Filroden]

2 hours ago, The Admiral said:

I can see you taking that inevitable step Ken . And don't feel that you need any justification! You've taken a very sensible step-wise approach to your astrophotography, keeping your options open. If only others would adopt the same approach rather than throwing everything at astrophotography in one go (as so often advised!), and then being disatisfied that they can't get the results they are seeking.

Ian

By justification, I just meant my current spending on my alt/az set up. Spending on the camera and auto-focus work equally well now as with any future mount. I've resisted looking at wedges or rotators as they become redundant if I upgrade to a decent EQ mount.

I see this as a journey with an EQ mount as probably one of the very last big stops. With an EQ mount comes the learning of alignment (I can just plonk my mount down now and run a couple of minutes routine with the StarSense and I'm away) and guiding (though the ZWO ASI 1600 could eliminate the need for guiding as it seems to prefer shorter subs anyway). I'd also have to consider a more permanent pier/observatory set up which probably isn't for this house.

But I still have more to do with the current set up. I want to improve my focusing, both initially and through the session. I can move my mount with both the handset and from my tablet over wifi when it's stable. I'd like to extend that to being able to drive the mount directly from within SGPro so I can realign to a previous session's image both in terms of centering the image and by rotating the camera to match the middle of the rotation of the previous session. That way I can minimise cropping over multiple nights. Eventually, I'll do this remotely from the main PC through wifi link to the laptop. And then there is narrowband.

So I've got lots still to do

And on the focusing note...I could see stars this evening so I set up in the hope of running the calibration and learning how to use it in SGPro. Calibration was a success and I reached focus using the accompanying handset and again using the controls in SGPro. Both times I got a lower focus score then doing it my old way. However, there was a very high wind and lots of cloud coming over so by the time I got to run the auto-focus routine, the clouds were changing the focus score too much to get a good V pattern (it measures focus at 9 points around my best manual focus position and calculates the position of the minimum - the bottom of what should be a clean V shape).

Tomorrow evening looks more promising (tonight was supposed to be cloudy so this was just a bonus run).

My only concern from tonight though was that the focus point seemed to move quite wildly and at times it seemed focus wasn't changing even through I was changing the focus position. I'm hoping that it was just atmospherics and nothing software or mechanical. I might roll back my version of SGPro from the latest beta to the last stable version just in case.

So, if tomorrow is good, I hope to do a test run on something - possibly M78 - though I still have to test my 85mm lens at some stage!

[Filroden]

1 hour ago, Nigel G said:

Thanks Ian, I'm looking forward to be able to gather more frames  Could be a slot tonight between the cloud.

Nige.

It's the start of a very nice image. Some really clear and nice graduations of colours across the rings. With more subs, the noise will come down and it will look much finer. My only concern is your stars are still hollow. I don't think it's focus so I still think something in DSS is eating the cores. I suspect the cores are saturated and some process is affecting them and inverting them so they create hollows. I wonder if it's worth taking the 45 day trial of PixInsight and using its ImageIntegration routine to see if it makes a difference. It's fairly easy to do a basic integration if you don't calibrate - i.e. just check the initial results to see if it's DSS.

[Filroden]

4 hours ago, parallaxerr said:

I'm hoping my wedge experiment doesn't add too much complexity, reading the manual suggests it "should" be a relatively easy affair with the All Star Polar Alignment. We'll see on the next clear night!

I don't think it will. The Celestron handsets are fairly good and intuitive, and you already know your mount, so you're just doing your alignments using not two controls (alt and az) but 4 (ra and dec on the handset for your star aligns and alt and az on the wedge to align the polar axis).

It will be interesting to see how much difference it makes, though probably not for this thread

[Nigel G]

1 hour ago, Filroden said:

It's the start of a very nice image. Some really clear and nice graduations of colours across the rings. With more subs, the noise will come down and it will look much finer. My only concern is your stars are still hollow. I don't think it's focus so I still think something in DSS is eating the cores. I suspect the cores are saturated and some process is affecting them and inverting them so they create hollows. I wonder if it's worth taking the 45 day trial of PixInsight and using its ImageIntegration routine to see if it makes a difference. It's fairly easy to do a basic integration if you don't calibrate - i.e. just check the initial results to see if it's DSS.

Thanks Ken,  I'm going to look at the hollow star issue and find the cause,  as you suggest, it's not focus, it has to be in the stacking settings, I  need to adjust the hot and cold pixel removal or disable it completely to see.

Hoping for a gap in the clouds shortly 

Nige.

[schmeah]

9 hours ago, Filroden said:

It seems a very expensive way to remain alt/az. At that price point I'd be recommending going straight to an EQ mount that had a good polar alignment tool and easy/no meridian flip. After all, set up time and cost are probably the biggest differences between the two mount types. If you remove cost barriers, you can get easier set up EQ mounts.

Alt/az is great for observation where rotation is irrelevant. It can also be used for photography if you know its limitations and can accept them. And we're showing you can minimise most of these. But they still remain. I love my mount but if I could spend that amount I would find a way to make EQ work for me than work the remaining issues with alt/az.

 

Agreed. But let's say for the sake of argument that such a mount could  track and guide as well as a premium GEM of the same price and had an accurate derotator that would allow perfect alignment of subs without sacrificing any of the chip/FOV. And being alt-az it would not require a meridian flip nor accurate polar alignment. Why would anyone not prefer such a mount over a similarly priced  GEM?

 

Derek

[SteveNickolls]

8 hours ago, schmeah said:

Agreed. But let's say for the sake of argument that such a mount could  track and guide as well as a premium GEM of the same price and had an accurate derotator that would allow perfect alignment of subs without sacrificing any of the chip/FOV. And being alt-az it would not require a meridian flip nor accurate polar alignment. Why would anyone not prefer such a mount over a similarly priced  GEM?

Thanks for this Derek. If I ever win large on the national lottery everyone here will receive one and the derotator unit. 

Happy Christmas All.

Steve

[The Admiral]

3 hours ago, SteveNickolls said:

Thanks for this Derek. If I ever win large on the national lottery everyone here will receive one and the derotator unit. 

Happy Christmas All.

Steve

You might live to regret making that offer 

Happy Christmas to all as well.

Ian

[Filroden]

11 hours ago, schmeah said:

Agreed. But let's say for the sake of argument that such a mount could  track and guide as well as a premium GEM of the same price and had an accurate derotator that would allow perfect alignment of subs without sacrificing any of the chip/FOV. And being alt-az it would not require a meridian flip nor accurate polar alignment. Why would anyone not prefer such a mount over a similarly priced  GEM?

 

Derek

It's all too hypothetical still. Professional observatories all utilise alt/az but they can afford the kit needed to make it work. There are amateur alt/az mounts that can match mid-range EQ mounts for tracking but rotation remains the issue. That TSS mount can only derotate for up to 2 hours so it isn't great for long sessions. You can easily image for up to 2 hours on any EQ mount without need for a meridian flip so I don't see the benefit.

What we need is either a derotator that can manage 10+ hours at high accuracy or for the prices of large CCD/CMOS sensors to drop to the point they can fully cover the image circle so derotation can be done in software.

Until then the current equipment will give some improvements but not as much as the step up to an EQ mount.

[Nigel G]

I hope you win the lottery Steve

Happy Christmas all.

Nige.

[Filroden]

Merry Christmaltaz too everyone. May your morning afters be as clear as your night's skies!

[The Admiral]

3 hours ago, Filroden said:

It's all too hypothetical still. Professional observatories all utilise alt/az but they can afford the kit needed to make it work. There are amateur alt/az mounts that can match mid-range EQ mounts for tracking but rotation remains the issue. That TSS mount can only derotate for up to 2 hours so it isn't great for long sessions. You can easily image for up to 2 hours on any EQ mount without need for a meridian flip so I don't see the benefit.

What we need is either a derotator that can manage 10+ hours at high accuracy or for the prices of large CCD/CMOS sensors to drop to the point they can fully cover the image circle so derotation can be done in software.

The other benefit of a derotator though would surely be to allow increasing the sub exposure length, and image at higher altitudes, even if the total imaging time isn't extended, assuming that the mount tracking was good enough (which I know isn't the case with my mount).

Ian

Edited December 21, 2016 by The Admiral