ASI2600MC first light ... or not.

[xa-coupe (Jeff)]

I fired up the new camera tonight and thought it was going to be relatively straightforward... I couldn't have been more wrong.


Firstly, live view. I wouldn't waste my time other than for focus. So much for my fantasies about being better than a DSLR.



Secondly... I couldn't get an image even if I did a 3 minute exposure. I think this is due to a total lack of knowledge of how gain and binning and so on works. I was also using an L-Extreme filter which may have been a tactical error too.


I was using APT, -> Unity - 100, 180 second exposures, 1x1 binning ( tried 4x4 but it developed some serious cross hatches) and left everything else. WO GT81 with a .8 reducer. I have been using the L-Extreme due to the light pollution but I'm wondering if I have to ditch it temporarily to sort these things out.


I'd be interested in hearing anyone's experiences and advice.


thanks


Jeff

[h0ughy (David)]

OK to frame use gain 370, and focus if you're using a bahatnov mask then take it back to 100 or 110 after you frame Focus shots should be 5 sec

[Startrek (Martin)]

Jeff,
Here’s my APT procedure I put together last year when I received my 2600MC
It may help you
Just remember I use Newts and use my diffraction spikes to achieve good focus which works a treat. I suppose if your using a refractor you can still use my method but not as accurate ( I don’t use a software based focuser , I use a JMI autofocuser with a handcontroller and view each 20 sec sub in APT until I’m satisfied
I’m very rarely out of focus
Hope it helps in some way
Cheers
Martin

[Startrek (Martin)]

Originally Posted by Startrek

Jeff,
Here’s my APT procedure I put together last year when I received my 2600MC
It may help you
Just remember I use Newts and use my diffraction spikes to achieve good focus which works a treat. I suppose if your using a refractor you can still use my method but not as accurate ( I don’t use a software based focuser , I use a JMI autofocuser with a handcontroller and view each 20 sec sub in APT until I’m satisfied
I’m very rarely out of focus
Hope it helps in some way
Cheers
Martin

Sorry
Just set your 2600MC to Gain 0 or Highest Dynamic Range ( it’s worked for me in both Bortle 8 Sydney skies and Bortle 3 dark skies at my holiday retirement place
Good luck !!

[AdamJL]

To get a "live view" (you're right, astro cameras suck compared to DSLRs in this regard), I use 2 second exposures at gain 500 and loop them.
That's a rough focus. Then I drop the gain down and start dialing in fine focus with the Bahtinov mask.

3 mins should get you stars at least, even with the L-Extreme. But in terms of nebulosity (or whatever you're taking pictures), remember that some objects are FAINT and will require more exposure time. What were you trying to shoot?
And you might need your program to auto-stretch your subs to see the target. Not sure if APT does that, but NINA (amazing!) does.
If it helps, I was shooting Carina with 4 minute subs and the L-Extreme filter in Bortle 5/6 skies.

Also, as far as I know, "unity gain" doesn't exist for this camera.

The 2600MC is a fine camera, let's try and get your problems solved

[h0ughy (David)]

Yes sorry I left off the auto stretching

[The_bluester (Paul)]

Just be aware that if you are a long way out of focus you will generally see nothing.Depending on the scope, a couple of MM out of focus and the stars will have turned into diffuse blobs that you will be lucky to see.



If you want to use live view you would probably want to bin the camera as high as it will go to reduce image download times

[Startrek (Martin)]

Jeff,
I had the exact same opinion of live view on APT after using a DSLR for 4 years but I did find a work around in APT which works well
Just run through my attached procedure and I’m sure you will be able to frame ,focus and capture in no time
I don’t use APT live view to focus , only to frame up , even the Focus Aids are next to useless IMO
I never focus in the target field as the stars are usually too small ( with exception of a few like M42 and Horsehead) , I always focus on a 1.5 to 2.5 magnitude single Star somewhere near the intended target or as close as possible to the target.I use the diffraction spikes to achieve tight focus as I only image with newts, if you use a refractor just use a batinhov mask which will be similar
The Histogram tool works well in APT for framing up and checking subs , I set the crosshair feature and take shorter test exposures to centre the target and final framing.
When using the Duoband filter or L Extreme , if the target is really dim and even after stretching in the Histogram is still very faint , I just use the Star field of the intended target to frame my object ( bit like manual plate solving ) I take a photo of the object on my phone from Astrobin etc... and visually use its Star field to align the frame manually using EQMOD. EQMOD I can move my target to the it’s final position fairly quickly
This seems a very antiquated way of doing things but hey it’s works and works well . I can be focused , framed up and ready to capture in 15 mins
Good luck and hope you get up and running
Alternatively you can learn to plate solve but I can’t help you with that
Cheers
Martin
PS: I run APT independently , the only link between my other software is the the dithering function in APT which communicates with PHD2

[Zuts]

Originally Posted by The_bluester

Just be aware that if you are a long way out of focus you will generally see nothing.Depending on the scope, a couple of MM out of focus and the stars will have turned into diffuse blobs that you will be lucky to see.



If you want to use live view you would probably want to bin the camera as high as it will go to reduce image download times

With a new camera I usually give it a try during daytime so i can at least get a rough starting position, and see that the camera and software are playing nice and producing an image. As Paul says if you are to far out you wont see anything.

[xa-coupe (Jeff)]

Thanks guys. I did get a single star (Hadar) to show after I took the filter out ... so I focused on that. I was also having mount troubles as well as some weird stuff with APT, so at that stage I said '"dash it" or words to that effect and packed up and went inside.


I will have to get my head around gain and how it relates to ISO and the nuances of it all. I'm still at a loss as to how to focus with the L-Extreme but I will get there!!


I made a few changes... a new laptop, a new camera and a new guide scope. The new laptop is acting weird so I am reverting back to my old laptop which is quite old but stable. I'm also considering changing to NINA but I'll find out if the old laptop fixes my issues before changing yet another thing.

[Robert_T]

Originally Posted by xa-coupe

Thanks guys. I did get a single star (Hadar) to show after I took the filter out ... so I focused on that. I was also having mount troubles as well as some weird stuff with APT, so at that stage I said '"dash it" or words to that effect and packed up and went inside.


I will have to get my head around gain and how it relates to ISO and the nuances of it all. I'm still at a loss as to how to focus with the L-Extreme but I will get there!!


I made a few changes... a new laptop, a new camera and a new guide scope. The new laptop is acting weird so I am reverting back to my old laptop which is quite old but stable. I'm also considering changing to NINA but I'll find out if the old laptop fixes my issues before changing yet another thing.

dont overthink it... i dont think gain and binning are the main source of your troubles .. the defaults should work fine....it becomes more a case of changing these later or not to suit targets and conditions...not changing just to get it to work. Sounds more like focus and APT issues/stretching etc that may need to be tweaked so you can see stuff... I gave up on APT in the end and now use NINA which I find easier and less finicky. Mind you I dont bother with live view since going to astro cameras.

[xa-coupe (Jeff)]

Originally Posted by Robert_T

dont overthink it... i dont think gain and binning are the main source of your troubles .. the defaults should work fine....it becomes more a case of changing these later or not to suit targets and conditions...not changing just to get it to work. Sounds more like focus and APT issues/stretching etc that may need to be tweaked so you can see stuff... I gave up on APT in the end and now use NINA which I find easier and less finicky. Mind you I dont bother with live view since going to astro cameras.

I'm still not entirely sure how to focus with the filter but I'll persevere until I work it out. I do have a habit of over thinking simple things and under thinking complex things



The new laptop may well be the culprit. I swapped back to my old machine to take some darks and it worked perfectly that time. I had an error previously saying the APT was still waiting for the image from the camera, and that error did not occur last night at all when taking darks. Same USB cable and all. The hint was that the cursor wouldn't stop going nuts and opening and closing stuff with no input from me at all .....



Tonight is a good night (finally) for me to image ... here's hoping.

[AdamJL]

I don’t focus with the filter.... that L -Extreme cuts out a LOT of light which would mean super long subs to try and focus with.
I focus, tighten the lock once dialled in. Add the filter and then start shooting.

To quicken the process, you can focus on a distant object during day time (something far away... clouds, the moon, distant houses etc) and that will shorten the time to focus later at night

If your scope has markings for focus, use that. Otherwise do what I do and put a bit of tape on the focus barrel and mark the line for perfect focus. That means next time you can come back and be dialled right on. You might need a bit of tweaking but it will be very quick

As for gain, just stick to Gain 100 offset 50 for now. Gain 100 gives you lower full well but less noise (sounds counterintuitive but it’s true). Offset just means you won’t clip your blacks (it applies a gain value to your base so you always expose SOMETHING)
You can tweak it as you become more familiar with the camera

[xa-coupe (Jeff)]

Thanks Adam. Do you find the focus changes with the filter out and in? With a DSLR I have to focus with the filter in as it changes significantly.

[AdamJL]

Originally Posted by xa-coupe

Thanks Adam. Do you find the focus changes with the filter out and in? With a DSLR I have to focus with the filter in as it changes significantly.

No I haven't noticed it. But I'll be out shooting tonight so will check and confirm for you

[xa-coupe (Jeff)]

Originally Posted by AdamJL

No I haven't noticed it. But I'll be out shooting tonight so will check and confirm for you

Thanks

[Startrek (Martin)]

Originally Posted by xa-coupe

Thanks

Jeff
I’ve focused in APT using my 2600MC with my ZWO Duoband filter , L Extreme filter and no filter
I have no issue at all focusing
Select “Live View” set exposure to 2 secs , binning 4x4
Open the Histogram
I just slew to a 2.0 to 2.5 magnitude single Star near or in the vicinity of my intended target
Centre it using the APT reticle on the main screen
Set a Capture plan and name it “Focus” ( 15 sec, Bin 1x1 ) press ok and start
Select image Preview On 1:1 then press the ICT button to zoom in on the Focus Star in thumbnails
Use the Histogram tool to right stretch or left stretch the image and adjust up and down using the arrow buttons ( course or fine ) to achieve the best exposure on the focus Star to check focus in thumbnails
Adjust focus and repeat procedure to check Focus Star again by pressing Camera then “edit” then press “Update current” then OK then Start
Once exposure is completed check focus Star in thumbnails again against the original focus Star exposure just above
Repeat iterations until focus Star is focused
Usually takes me 4 to 8 exposures to achieve tight focus ( 2 or 3 minutes )
As I use newtonians I use the diffraction spikes to achieve tight focus but you could use a batinohv mask with a refractor to do the same thing
I’m imaging at 900mm and 1000mm so a 2.0 to 2.5 magnitude Star is adequate
If your focal length is short say 500mm you may have to choose a brighter 1.0 to 1.5 magnitude focus Star
Once focused I just slew to my target , frame up, set capture plan , run PHD2 take a test exposure and if happy with it , start capture plan

Cheers
Martin

[Startrek (Martin)]

Jeff,
I suppose the moral to the story about focusing is “Don’t focus in your target area as the stars are usually to small and dim” ( with some exceptions like M42 and the Horsehead with Alnitak )
Focus on a brighter single Star around mag 2.0 to 2.50 ( not double star or variable star or pulsating star ) in the vicinity of your intended imaging target , so you get a good visual on the 15sec exposures in APT thumbnails and adjust your focusing accordingly exposure after exposure until your focus is tight
It hasn’t failed me in 7 months using the 2600MC with all those filters or unfiltered
Remember to set your camera to Highest Dynamic Range (Gain 0 )

Cheers
Martin

[AdamJL]

So I tested it tonight. Bahtinov mask without a filter then mask with. There was a definite difference in focus which was interesting

However I don’t know that just by removing the filter drawer I accidentally bumped focus as I was aiming on Sirius which was high overhead. My camera is chunky and does actually pull a bit on the focus rack so that could have done it.

Something to keep an eye out for anyway. When I upgrade my scope it will be to one with a 3.7” focuser!

Oh but I was still able to see stars in my image with the filter. I used 2 second exposures again and gain 300 for unfiltered and filtered images and everything was fine

[xa-coupe (Jeff)]

I've managed to battle though and get some data too. What I can't seem to do is get APT to allow anything greater than gain 100, auto stretch has helped me heaps and allowed a kind of decent focus.


I've uploaded an image of Carina, 30 subs, no calibration frames and minimal processing. I have to say that I am pretty impressed in the camera. The extra detail is immediately obvious.