446 replies to this topic

[jfrech14]

Yesss! I love that feature. As I know many of you own a 1600... Do you have issues (when taking flats) that if you take exposures too quickly, the camera just saturates? When I was taking quick flats for a test, I noticed that half way through the set the images just started to saturate and I had to decrease the exposure time to 0 to let it flush out. I did not change anything about the camera or setup and it has me worried about future data. Also, I wouldn't recommend changing camera gain settings while connected. I did this and it caused some weird effects. Might be obvious, but I always cycle the connection to my camera for setting changes. 

[Jon Rista]

Is that with the ASI1600, or the ASI071? I haven't had much time with the ASI071 yet, and it's been cloudy. So I've just been fiddling indoors. I haven't done any flats yet. 

[jfrech14]

Mine is with the 1600 but interested in seeing it it happens in the 071 too

[Jon Rista]

I am acquiring 250ms frames off a white wall. I'll just leave it running.

[tolgagumus]

I am acquiring 250ms frames off a white wall. I'll just leave it running.

Jon,

 

Did you get one?

[james7ca]

Wouldn't one of the limitations of having a tilt adjuster in the camera be that you can only use it to adjust any tilt that existed in the camera itself? What I mean is that you can't use it to adjust for tilt that may exist in anything that is forward of the camera (tilt in the focuser or simple tilt in the optics). This would seem to be the case because in the latter cases as soon as you rotate the camera you'd invalidate the correction. In fact, it could make the problem worse because as you rotate the camera you could begin to add additional tilt into the system such that there could be camera positions where the tilt would appear to be twice as bad as before you made the adjustment.

 

However, if you had zero tilt anywhere in your current system then you could certainly use the adjustment on the camera to square up the camera to your system, so it has potential use.

 

If my assumptions are correct then you just need to make certain that you know where the tilt exists. Either that or never rotate the camera (at least no without re-adjusting the camera tilt).

 

Not in any way a criticism of the camera, options are always good, just that you need to make certain that you are using that adjustment correctly.

[Jon Rista]

It also appears as though the latest driver fixed the fan behavior. The fan starts out off by default, and it will always start if you enable the TEC. I think that is an important fix to avoid overheating and I'm quite glad to see it implemented.

[tolgagumus]

Here is 2.5 hours with ASI071. I was testing a mount last night so I just shot this. I would have done 2 minute exposures but I was also testing the mount. I know it's not as deep as I normally go but the FOV on this is really nice. If this was only a test for the camera, I would have dome 2 min exposure so I had many more subs and then drizzle.

 

 

 

 

10x30" -10C bin 1x1
34x300" -10C bin 1x1

Edited by tolgagumus, 02 December 2016 - 08:43 PM.

[ReiverSkies]

So, I have a FSQ106-ED and am looking to upgrade from a modded DSLR.. 

 

should I got for this ASI071MC or stick to something like the 8300 chip?

David

[tolgagumus]

So, I have a FSQ106-ED and am looking to upgrade from a modded DSLR..

should I got for this ASI071MC or stick to something like the 8300 chip?
David

It depends on your skies. I would get a mono camera if you are in light pollution. The test images were taken during new moon from 20.8 magnitude skies using a vixen vsd at F/3.8

Sent from my SAMSUNG-SM-G870A using Tapatalk

Edited by tolgagumus, 17 December 2016 - 04:09 PM.

[ReiverSkies]

To be honest, in the NE of England - we have more of a problem with time without cloud than LP - which means one shot becomes a priority.

 

David

[tolgagumus]

To be honest, in the NE of England - we have more of a problem with time without cloud than LP - which means one shot becomes a priority.

David

A mono camera will be faster to reach a given signal to noise ratio. OSC cameras can do well in very dark skies. But as F as how much time is required, a mono camera will require less integration time.

[ReiverSkies]

But a mono with 8300 will require an expensive and complicated filter wheel setup

[tolgagumus]

But a mono with 8300 will require an expensive and complicated filter wheel setup

That's a decision each person have to make. I was only replying to your comment about how much time is required. So the advantage of this camera is not the time. It's the size of the sensor and cost. 

[ReiverSkies]

look.. if you have 1 or 2 hours of imaging a month due to weather, then you need to get the data. A filter wheel makes this harder. I have a manual filter wheel.. everything takes four times as long... and with the cloud we get around here you can't leave stuff alone for long before the autoguider looses lock. SO.... we have good dark skies in Northumberland, but I have a budget of 1500 which means the ASI071MC looks very appealing right now.

 

The 8300 is also very appealing, but I also would look for one with a Bayer Matrix.. simply because we dont have the luxury of hours of cloudless skies.

Edited by ReiverSkies, 17 December 2016 - 04:50 PM.

[Jon Rista]

look.. if you have 1 or 2 hours of imaging a month due to weather, then you need to get the data. A filter wheel makes this harder. I have a manual filter wheel.. everything takes four times as long... and with the cloud we get around here you can't leave stuff alone for long before the autoguider looses lock. SO.... we have good dark skies in Northumberland, but I have a budget of 1500 which means the ASI071MC looks very appealing right now.

 

The 8300 is also very appealing, but I also would look for one with a Bayer Matrix.. simply because we dont have the luxury of hours of cloudless skies.

This is all very wrong. Mono is more efficient regardless. For color imaging, a mono camera would require the use of LRGB filters. The L filter acquires signal from the entire visible spectrum at once, and most L filters have over 97% transmission. You also have higher transmission with RGB filters from an LRGB set, than from an OSC camera, not to mention the 100% fill factor as well as the higher sensor Q.E. Doesn't matter how you slice it...if you want to acquire data as fast as possible, mono trounces OSC. Hands down, no contest, game over. 

 

The only real benefit of OSC is a lighter post-processing load. You calibrate once, you integrate once, and you process once. THAT is the benefit of OSC. In contrast, with LRGB, you have to spend more time processing...you gotta calibrate four times, integrate for times, process about 4.5 times (once for each channel, then combine them, then process some more). However, if your primary issue is clear sky time...then an OSC is NOT the best way to make the most of those rare clear skies. It's the worst way. By far. Also, if your primary issue is clear sky time...well, then you'll have more than enough time to process LRGB data, too...when it's cloudy!

Edited by Jon Rista, 17 December 2016 - 06:47 PM.

[hfjacinto]

I always read that Mono is faster and I disagree, and the main reason is that Mono requires refocusing, at least 4 times more flats and if not automated it's a lot of work.npw that I'm automated I want to go to mono for no other reason other than sensitivity but osc is much faster for a simple rgb picture.

[hfjacinto]

Sorry Jon but I can easily acquire 1-2 hours of data for a star cluster with 1 focus and the data is as good as 4 filter changes with refocus. Especially if not automated Mono is tough. But if doing narrowband it's no comparison Mono is so much better.

[Jon Rista]

Sorry Jon but I can easily acquire 1-2 hours of data for a star cluster with 1 focus and the data is as good as 4 filter changes with refocus. Especially if not automated Mono is tough. But if doing narrowband it's no comparison Mono is so much better.

Sorry, I don't buy this either. For one it is rather subjective. How often you have to focus is entirely dependent on environmental conditions. I know people who don't focus for an hour (and, I also know that for many of them, their focus in their integrations is obviously soft, and in many cases you can clearly see the focus drift, with very sharp/bright star cores, and large soft halos), and I know people who focus every 10-15 minutes. Depends on where you live man. I've done OSC, I used my 5D III for over two years. I had to focus with that almost as often as I focus with the ASI1600 (well, once things settled a bit)...and that is 99% due to my scopes and my environment, not the camera.

 

You can also pick up parfocal filters. I never refocus when I change filters with my AstroDon LRGBs. Baader and Astronomik filters are also parfocal. The only time I ever have to adjust focus due to a filter change is when I switch to my SII filter. It's only a single step change for that filter, though, so quite trivial. Additionally, OSC requires interpolation, which BLURS the data. If you are willing to suffer the resolution loss with OSC, then you could certainly suffer the minimal shift from perfect focus when switching to a mostly-but-not-perfectly parfocal filter as well. For that matter, you could set your focus a little OOF at the opposite side of drift, and let it drift for longer between focusing, and end up with subs no less sharp than interpolated OSC. 

 

For the record, I do totally manual mono imaging. It is not tough. Not at all. I manually focus, and I manually dither. I usually do other things while I am imaging, and I just check the progress of my sequence about every 10 minutes, verify focus is still good and adjust if not (even during exposure...one of the benefits of manual focusing with a motorozed focuser, you don't have to wait in-between frames to run a lengthy and wasteful automated focusing routine!), and run a quick dither between frame sets. It's manual...but it certainly isn't difficult. And it's mostly just because I'm cheap that I haven't purchased SGP yet.

Edited by Jon Rista, 17 December 2016 - 07:22 PM.

[tolgagumus]

To make statements like above, we have to first define what our goal is. Since the time is the most important factor in this particular case, let's say we have 2 hours and we are doing 2 minute exposures. In this case if we do 2 hours of OSC vs 2 hours of mono, you will get a far better image. If you want to match the quality of the 2 hours of OSC image with a mono camera with rgb filters, you would need far less time. Either way it will be a win for the mono camera. If you have 2 hours a month to image because of weather, I don't see how we can conclude that changing filters and refocusing to be too hard to do.

[BigBanger]

I've done both, OSC and Mono/ LRGB. I also live in NE USA so I get very few dark (moon-less), clear nights per month. I agree with all the pros and cons expressed by the posters. I have resolved the issue by using both an OSC and mono-only (no RGB filters) camera. When I want to image a bright showcase object (M42, M31, M13, etc.) I will use my OSC camera (ASI1600mc-c, soon ASI071mc-c). When I want to go deep (I like to image faint galaxy clusters and associations), where color is often not as vivid, but increased sensitivity is important, I use my mono camera (ASI178mm-c).

 

One benefit of OSC cameras has not been expressed - It's ideal for color imaging fast moving comets if you choose to focus on the background stars and not the comet's nucleus. When those objects come around I find a 2 minute exposure is often the longest single exposure you can take before you start "schmeering" the comet. And of course you'll only want to keep/ publish your single best image because stacking is not an option.

[Jon Rista]

I always read that Mono is faster and I disagree, and the main reason is that Mono requires refocusing, at least 4 times more flats and if not automated it's a lot of work.npw that I'm automated I want to go to mono for no other reason other than sensitivity but osc is much faster for a simple rgb picture.

Sorry, again not buying the flats argument. For LRGB, flats take about 25-50ms. At least, that's been my experience with the ASI1600. You can set up a sequence to rip through all four filters and acquire 36 flats per filter in less than 10 seconds. A 36-frame stack of flats calibrates in about 10 seconds in PI, and integrates in about 20 seconds. So, you might spend a couple of minutes calibrating and integrating four master flats. You then name them effectively (I always embed a creation date in my calibration frame filenames, along with the filter, gain, offset, exposure and temperature). I then reuse my flats until such time as they no longer properly calibrate my vignetting and/or dust motes...which is usually as long as I keep my imaging rig assembled, which is usually 4-6 months. 

Edited by Jon Rista, 17 December 2016 - 07:21 PM.

[Jon Rista]

I've done both, OSC and Mono/ LRGB. I also live in NE USA so I get very few dark (moon-less), clear nights per month. I agree with all the pros and cons expressed by the posters. I have resolved the issue by using both an OSC and mono-only (no RGB filters) camera. When I want to image a bright showcase object (M42, M31, M13, etc.) I will use my OSC camera (ASI1600mc-c, soon ASI071mc-c). When I want to go deep (I like to image faint galaxy clusters and associations), where color is often not as vivid, but increased sensitivity is important, I use my mono camera (ASI178mm-c).

 

One benefit of OSC cameras has not been expressed - It's ideal for color imaging fast moving comets if you choose to focus on the background stars and not the comet's nucleus. When those objects come around I find a 2 minute exposure is often the longest single exposure you can take before you start "schmeering" the comet. And of course you'll only want to keep/ publish your single best image because stacking is not an option.

This is a solid compromise. You are gaininig the benefit of L imaging with the mono camera, so you can acquire a lot of signal fast. Using the OSC for your color would certainly shortcut the pre-processing time down from a full LRGB load. Of course, it's twice the cost for the cameras, since you need two!

 

Good point about OSC for moving objects like comets. Can't argue with that one.

Edited by Jon Rista, 17 December 2016 - 07:19 PM.

[hfjacinto]

Tolga pick an object and let's do 2 hours total no automation, just 2 hours no auto focus and I'll bet it's comparable. That means for a osc I can just pick an object do a manual focus and acquire 1 hour 55 minutes of data.

You would have to focus on r, acquire data, focus on g,, etc and then take 4 flats one for each.

Jon

Beginner is not going to buy partfocal filters at what they cost, the zwo filters from reading on here are not totally parfocal.

[hfjacinto]

I do want to add one more thing,now that I use SGP I see no reason to buy an osc. My lady 16 hour image I did while sleeping. If I had mono it would have been so much better. I'm just talking from someone that has used osc for a while and that is that it works. Tolga's image show how good an osc camera can be.