#321  
Old 09-06-2016, 08:36 PM
codemonkey's Avatar
codemonkey (Lee)
Registered User

codemonkey is offline
 
Join Date: Jul 2013
Location: Kilcoy, QLD
Posts: 1,658
Quote:
Originally Posted by Atmos View Post
Some are not too critical, I believe that straight flatteners are more forgiving than a flattener & reducer. My last setup was maybe 1.5mm off and it was noticeable.
Cheers Colin. Was your last setup a flattener or flattener + reducer?
Reply With Quote
  #322  
Old 09-06-2016, 09:31 PM
Camelopardalis's Avatar
Camelopardalis (Dunk)
Drifting from the pole

Camelopardalis is offline
 
Join Date: Feb 2013
Location: Brisbane
Posts: 4,585
Ah OK, OAG, that makes sense. With my Esprit small deviations from the stated back focus are noticeable.
Reply With Quote
  #323  
Old 09-06-2016, 09:54 PM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is online now
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,082
Quote:
Originally Posted by codemonkey View Post
Cheers Colin. Was your last setup a flattener or flattener + reducer?
I had a 0.8x Flattener, it worked really well but was quite sensitive to back focus.
Reply With Quote
  #324  
Old 10-06-2016, 04:21 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Posts: 5,216
Guys, surely for testing you can live without a flattener?
Reply With Quote
  #325  
Old 10-06-2016, 04:23 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Posts: 5,216
Quote:
Originally Posted by codemonkey View Post
I realised I'm probably going to need to use the flattener for my Esprit now that I'll be imaging with such a big chip. Looks like I'll need a couple of adapters from precise parts to hook it all up... about $432 to land them here Didn't factor that in.
Lee one of the CN guys has probably been down that path, there has been alot of posts about Precise Parts, and the Esprit is popular over there. Might be worth some searching. Isn't there a local adaptor maker?
Reply With Quote
  #326  
Old 10-06-2016, 04:42 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Posts: 5,216
Got through an amazing amount of subs last night despite the gusty wind conditions. The short subs enabled by this camera really makes marginal imaging conditions ( like wind) possible (imaging in the lulls). I ran over 150 narrowband guided 60" subs on NGC 6188 before midnight, while the door on the observatory was rattling in the wind. Not surprisingly the guide graph was not the best but it was saying on the chart for the most part. I was prepared to drop back to 300 x 30 second subs if conditions demanded shorter subs. . I was watching the subs on the SGP display, expecting to have to go shorter or shutdown but while some appeared wind affected most were fine. Of course under the old model of plus 300 second subs they would all be rubbish. The obs walls are fairly high and that helps but the top of the scope and light shield sticks up into the wind. I suppose the large trees up wind help as well. I expect i will have to page through all of these subs tomorrow (today) and get rid of any outliers, but even if only half are useable i will be happy.

Last edited by glend; 10-06-2016 at 04:57 AM.
Reply With Quote
  #327  
Old 10-06-2016, 08:29 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Posts: 5,216
SGPro Update v2.5.1.15 is Released

Main Sequence has released the promised SGPro update v2.5.1.15 to resolve the memory allocation issue that has affected some people using SGP to control the ASI1600. Release note here:

  • Fixing issue with large memory allocation
  • Implemented per-filter AF filter override. (for instance focus with RGB filters but then use override for narrowband)
  • Smart copy/paste for RA and Dec in the Mosaic and Framing Wizard and also the image plate solve hint dialog.
Link is here:
http://www.mainsequencesoftware.com/Releases

I have installed it and it was seamless.
Reply With Quote
  #328  
Old 10-06-2016, 09:47 AM
Camelopardalis's Avatar
Camelopardalis (Dunk)
Drifting from the pole

Camelopardalis is offline
 
Join Date: Feb 2013
Location: Brisbane
Posts: 4,585
Quote:
Originally Posted by glend View Post
Guys, surely for testing you can live without a flattener?
Glen, fast refractors can have quite horrible field curvature, all the more obvious when testing a camera with fairly small pixels
Reply With Quote
  #329  
Old 10-06-2016, 10:26 AM
rustigsmed's Avatar
rustigsmed (Russell)
Registered User

rustigsmed is offline
 
Join Date: Mar 2012
Location: Mornington Peninsula, Australia
Posts: 3,144
Quote:
Originally Posted by glend View Post
Got through an amazing amount of subs last night despite the gusty wind conditions. The short subs enabled by this camera really makes marginal imaging conditions ( like wind) possible (imaging in the lulls). I ran over 150 narrowband guided 60" subs on NGC 6188 before midnight, while the door on the observatory was rattling in the wind. Not surprisingly the guide graph was not the best but it was saying on the chart for the most part. I was prepared to drop back to 300 x 30 second subs if conditions demanded shorter subs. . I was watching the subs on the SGP display, expecting to have to go shorter or shutdown but while some appeared wind affected most were fine. Of course under the old model of plus 300 second subs they would all be rubbish. The obs walls are fairly high and that helps but the top of the scope and light shield sticks up into the wind. I suppose the large trees up wind help as well. I expect i will have to page through all of these subs tomorrow (today) and get rid of any outliers, but even if only half are useable i will be happy.
glen do you think short narrowband (20-30 seconds) will be achievable with the camera?
if you've got some wind affected subs try out average combine in DSS.
Reply With Quote
  #330  
Old 10-06-2016, 10:55 AM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is online now
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,082
Quote:
Originally Posted by rustigsmed View Post
glen do you think short narrowband (20-30 seconds) will be achievable with the camera?
if you've got some wind affected subs try out average combine in DSS.
At Gain 300ish 30-60s exposures are theoretically workable.
Reply With Quote
  #331  
Old 10-06-2016, 10:57 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Posts: 5,216
Russell i think yes short narrowband is achievable with the 1600. I have started going through all the files, basically running DSS to get scores and then checking samples. I have deleted about 50%, and processed them for the three layers. Whether 30 seconds is ideal , i don't know where the floor is, as the shorter the sub the lower the data threshold. I need to stretch to get the data to show, and 60" seems workable so far. Thankfully i did not have to shoot 30" narrowband last night, but i may test it in the future.
One thing i am finding is that Dark Calibration in DSS seems to be costing me narrow band signal data in myb6p" subs. I have compared output files of Ha and Oiii stacks with and without darks and the resulting image is much better without darks. It maybe just DSS, i fon't know how other stackers would handle it. Unfortunately i can't find a way to control DSS dark calibration thresholds. I have played around with the available dark options but so far i can't solve the problem.
However, this camera iscso low noise and smooth, that i think that imaging without darks at thise low sub times is feasible. Just have a look at Ray's M83 image, which has no dark calibration.
I will post up my NGC 6188 with out dark calibration, later today.

I should add that 30-60" LRGB subs would deliver a higher signal level than narrowband obviously, and so those sub times are easily achievable imho.

Colin i am using Unity Gain settings ( Gain = 139, Offset = 21) on my 60" narrowband subs and they seem to be ok.
Reply With Quote
  #332  
Old 10-06-2016, 11:07 AM
rustigsmed's Avatar
rustigsmed (Russell)
Registered User

rustigsmed is offline
 
Join Date: Mar 2012
Location: Mornington Peninsula, Australia
Posts: 3,144
Quote:
Originally Posted by Atmos View Post
At Gain 300ish 30-60s exposures are theoretically workable.
thanks Colin

Quote:
Originally Posted by glend View Post
Russell i think yes short narrowband is achievable with the 1600. I have started going through all the files, basically running DSS to get scores and then checking samples. I have deleted about 50%, and processed them for the three layers. Whether 30 seconds is ideal , i don't know where the floor is, as the shorter the sub the lower the data threshold. I need to stretch to get the data to show, and 60" seems workable so far. Thankfully i did not have to shoot 30" narrowband last night, but i may test it in the future.
One thing i am finding is that Dark Calibration in DSS seems to be costing me narrow band signal data in myb6p" subs. I have compared output files of Ha and Oiii stacks with and without darks and the resulting image is much better without darks. It maybe just DSS, i fon't know how other stackers would handle it. Unfortunately i can't find a way to control DSS dark calibration thresholds. I have played around with the available dark options but so far i can't solve the problem.
However, this camera iscso low noise and smooth, that i think that imaging without darks at thise low sub times is feasible. Just have a look at Ray's M83 image, which has no dark calibration.
I will post up my NGC 6188 with out dark calibration, later today.

I should add that 30-60" LRGB subs would deliver a high signal level than narrowband obviously, and so those sub times are easily achievable imho.

Colin i am using Unity Gain settings ( Gain = 139, Offset = 21) on my 60" narrowband subs and they seem to be ok.
thanks Glen, I'm interest in shorter subs as I'm thinking of using on a goto dob. I guess even binning 2x2 is an option considering the megapixels.

I wouldn't worry too much about using darks. I haven't used them for ages and if they are causing grief for now give it a shot without them
Reply With Quote
  #333  
Old 10-06-2016, 11:52 AM
Shiraz's Avatar
Shiraz (Ray)
Registered User

Shiraz is offline
 
Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,787
Glen
I have no experience with DSS, but if it seems to be stuffing up things when you use darks, try without. You may need to use bias though for your flats. Also suggest about 5 minute subs for NB if possible - that will give you SNR limited by shot noise and not camera noise. Shorter subs will work, but will require longer overall integration to get to the same result. Isn't it nice to be able to get lots of usable subs in bad wind though?

As a general comment, the dark noise is low and dark calibration may not add much benefit for brighter targets. It is probably still worthwhile for maximum depth on dim NB targets, but that will depend on how variable the bias is - it is likely that bias is reset with each power-on and full calibration will be a bit more complicated for this camera (ie we could possibly need new bias data for each power on or change of gain). I guess that we will all get a feel for how best to use this camera after we have more experience with it, but for now, I think that no-cal is a perfectly viable option - particularly for broadband.

this is more fun that a barrel of monkeys - the new camera really is a very interesting beast .
Reply With Quote
  #334  
Old 10-06-2016, 12:15 PM
codemonkey's Avatar
codemonkey (Lee)
Registered User

codemonkey is offline
 
Join Date: Jul 2013
Location: Kilcoy, QLD
Posts: 1,658
Quote:
Originally Posted by Camelopardalis View Post
Ah OK, OAG, that makes sense. With my Esprit small deviations from the stated back focus are noticeable.
Cheers mate. The OAG has adapters for various threads and since the spacing between the reducer and the OAG isn't critical, I could use something off the shelf for that, but I've been unable to find anything.

Quote:
Originally Posted by Atmos View Post
I had a 0.8x Flattener, it worked really well but was quite sensitive to back focus.
Cheers Colin.

Quote:
Originally Posted by glend View Post
Guys, surely for testing you can live without a flattener?
Sure, to start getting a feel for the camera, I can use it without the flattener. It remains to be seen how bad the curvature is as well, but I assume I will need to use it. Still, to begin using it properly I'll need said adapters.

Quote:
Originally Posted by glend View Post
Lee one of the CN guys has probably been down that path, there has been alot of posts about Precise Parts, and the Esprit is popular over there. Might be worth some searching. Isn't there a local adaptor maker?
I'm not sure if there's a local adapter maker. I'd prefer to go local if anyone knows of someone.

Camera has now arrived, so I'll get to try and plug it all up tonight when I get home.
Reply With Quote
  #335  
Old 10-06-2016, 12:19 PM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Posts: 5,216
Thanks Ray. Now I have just completed the first pass processing on NGC 6188 from last night (in the wind). From the 150+ subs I culled down to the 90 best scores (30 Ha, 30 OIII, and 30 SII). So total integration time is 30 minutes for each filter, no way I could have run 5 minute subs last night. Pretty happy with the resulting star shape in those conditions. As usual my senior moment with this image was forgetting to register the layers against one another, and I will need to go back and redo it to sharpen up the final image. This is my first attempt at the Hubble Pallet. Note no darks or bias frames or flats were used.

If you'd like to have a look, it is up on Astrobin here:

http://www.astrobin.com/full/251802/0/

Small low quality thumbnail below here.
Attached Thumbnails
Click for full-size image (NGC-6188-Narrowband--ASI1600-Unity-small.jpg)
203.0 KB47 views
Reply With Quote
  #336  
Old 10-06-2016, 12:27 PM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is online now
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,082
Glen, while you're running at Unity gain I believe that gives you ~1.75e- read noise. At 60sbuourd getting to the depth (fainter) stuff that I would at 225s. As Ray suggests, you'd be better off close to 300s. At 3nm filters that'll push out close to 480s.

That shot is looking pretty good for a relatively short overall time. Just need more subs to reduce noise but that is to be expected at a total of 1.5 hours
Reply With Quote
  #337  
Old 10-06-2016, 12:45 PM
Shiraz's Avatar
Shiraz (Ray)
Registered User

Shiraz is offline
 
Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,787
yep, that is an excellent result for the time taken.

looks like we will need to use darks for NB - your image shows some marks that I take to be wafer polishing marks - upper right. I get similar marks in my darks and assume that the silicon characteristics vary slightly and the dark current is different where these marks appear. I don't think there is anything similar in my bias results (haven't checked at long exposure yet). On that basis, maybe try subtracting bias from your darks and then subtract the remaining dark signal from your lights - that will leave enough of bias pedestal to protect your data and the bias noise seems to be pretty low, so will stack out with dither. Ultimately a full bias/dark calibration will be best, but if DSS won't do it properly, this may be a viable approach for now.

broadband signal is high enough that none of these effects are visible.
Reply With Quote
  #338  
Old 11-06-2016, 09:16 AM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 15,149
Pretty good there Glen. 30 minutes each filter would look similar I think with other cameras?

Greg.
Reply With Quote
  #339  
Old 11-06-2016, 09:40 AM
codemonkey's Avatar
codemonkey (Lee)
Registered User

codemonkey is offline
 
Join Date: Jul 2013
Location: Kilcoy, QLD
Posts: 1,658
Looks like there's still more issues with SGP and this camera. Using the latest versions (ASCOM driver v1.0.2.7 and SGP 2.5.1.15) I can consistently get frame & focus to deliver a seemingly unlimited number of frames of whatever length, but the sequence will only capture one frame >= 1second. Subsequent downloads fail. I've been unable to get the sequencer to download any frames at all using sub-second exposure times, whilst again, frame and focus has no problems.

Camera is connected via a USB 3 port direct to the laptop (no hub in the mix) using the supplied cable. I've tried adjusting the USB limit (45 & 90 were used) to no effect.
Reply With Quote
  #340  
Old 11-06-2016, 10:26 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Posts: 5,216
Quote:
Originally Posted by codemonkey View Post
Looks like there's still more issues with SGP and this camera. Using the latest versions (ASCOM driver v1.0.2.7 and SGP 2.5.1.15) I can consistently get frame & focus to deliver a seemingly unlimited number of frames of whatever length, but the sequence will only capture one frame >= 1second. Subsequent downloads fail. I've been unable to get the sequencer to download any frames at all using sub-second exposure times, whilst again, frame and focus has no problems.

Camera is connected via a USB 3 port direct to the laptop (no hub in the mix) using the supplied cable. I've tried adjusting the USB limit (45 & 90 were used) to no effect.
Hm, i am still using Ascom driver V 1.0.2.5 , i did not realise ZWO had a new one. Do you know what prompted that Lee? 2.5 is only a couple of weeks old.

Anyway it probably does not impact SGP frame and focus. Here is what i have found and how i use frame and focus.
I only use 'Take One', and this works just fine, based on advice from CN beta testers, as i am usually moving the scope slightly between takes anyway, i also use it to focus with my mask. I stay away from the continuous take mode because thst's all it does, take continuiously and not download. I suspect, given the amount of time it takes for one take to download and be displayed, that the downloads are over-run by the next frame and the necessary handshake can not take place.
I like to be able to alter the frame duration as i find say a 20 sec frame is good for small framing changes on nebulas, take one is good for this sort of thing. Make sure you are not saving those frames, there is a box to tick to save, i don't think its a good idea, these files are big and the less disc space used the better.
Check your camera setting box, you maybe surprised to see that even if your running usb3 it defaults to usb2 operation. I see this all the time, it doesn't interfere with my imaging but it does lengthen downloads from the camera slightly. This may also be the reason for the Continuous frame and focus not working.
So in a nutshell: Use Take One, it works and what's the hurry anyway. I woukd still do it that way even if continuous worked. Your alternative might be to frame and focus using Sharpcap as it can be a video stream if you want, however it coukd be messy switching apps for that, especially if your checking focus on filter swaps. The beauty of parafocal filter sets, focus once - this has worked really well on my Baader filters which are parafocal.

Hope that is of some use. Ray is using SGP, lets see what he says.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 06:05 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
Celestron Australia
Advertisement
Meade Australia
Advertisement
Lunatico Astronomical
Advertisement
OzScopes Authorised Dealer
Advertisement
NexDome Observatories
Advertisement
Bintel
Advertisement
SkyWatcher Australia
Advertisement
Astronomy and Electronics Centre
Advertisement