Crab and Whirlpool experiments

[Bagnaj97]

I bought myself a filter wheel and LRGB filter set in anticipation of being able to afford a dedicated cooled mono camera, but in the meantime I thought I'd try using my guide camera for imaging. This was my first attempt at mono imaging (and subsequent processing) and my first time using SGPro, so it was more of an experiment than a serious attempt! The visibility was also quite poor - 4 miles and red according to ClearOutside - and the sky was bright orange.

 

M1 Crab Nebula

20x30s each of RGB, 30x30s each of Ha and Lum. 50x each of bias, flats and darks.

Celestron C6n, AVX, Altair GPCAM Mono v1, Baader HaLRGB filters.

 

M51 Whirlpool Galaxy

40x30s each of RGB, 90x30s Lum. 50x each of bias, flats and darks.

Celestron C6n, AVX, Altair GPCAM Mono v1, Baader HaLRGB filters.

[Tommohawk]

Seems pretty good to me, given poor vis and quite short subs.

Which camera are you hoping to get?

[MartinB]

That's some result from a little guide camera!

[Bagnaj97]

10 minutes ago, Tommohawk said:

Which camera are you hoping to get?

Probably the ASI1600mm-cool. People seem to be getting good results with it and it's substantially cheaper than CCDs with a similar chip size. The QHY163 also looks good, but I haven't been able to find any info on whether it's ok with 1.25" filters - which I've already bought. Part of the reason for this experiment was to get used to what seems to be the ASI1600 way of imaging - lots of short, high gain, subs.

 

8 minutes ago, MartinB said:

That's some result from a little guide camera!

There's a lot more potential to be had - there was something iffy going on with my calibration frames. PI was complaining about no correlation between the darks and lights (or something to that effect) and the final "calibrated" images are still a mess, apart from the crab Ha, which was quite clean considering it was only 15 mins of data.

Edited January 27, 2017 by Bagnaj97

[Tommohawk]

1 hour ago, Bagnaj97 said:

Probably the ASI1600mm-cool. People seem to be getting good results with it and it's substantially cheaper than CCDs with a similar chip size. The QHY163 also looks good, but I haven't been able to find any info on whether it's ok with 1.25" filters - which I've already bought. Part of the reason for this experiment was to get used to what seems to be the ASI1600 way of imaging - lots of short, high gain, subs.

 

Yes I fancy the ASI1600 too. Shame the GBP isnt very clever at the moment!

[JohnC64]

Great result - especially using your guide cam.  Look forward to seeing your images when you get your new camera

John

[Magnus_e]

If that is your experiments with a guidecam first time processing mono, then I'm looking forward for things to come

[wimvb]

Great result for this little camera.

Since you are using PixInsight: the vertical bands are easy to remove with CanonBandingReduction (just rotate the images 90 degrees first).

As for the ASI1600 vs QHY163, they both use the same chip, so as long as the back focus is similar, they should both accept 1.25" filters.

There is a thread with images from the QHY163 somewhere in this forum.

Here, actually:

You might also want to check out the published dark frames from both cameras. It seems that both suffer from amp glow, but the QHY possibly a little more. The QHY also has some (in my opinion) ugly diffraction patterns from its microlenses, that shows up when imaging bright stars

I very much like the new CMOS cameras, but results like these would make me hesitate to buy one.

Cheers,

[Bagnaj97]

12 hours ago, wimvb said:

The QHY also has some (in my opinion) ugly diffraction patterns from its microlenses, that shows up when imaging bright stars

I'd seen that, but the ASI1600mm seems to suffer from the same thing. There are some examples in the ASI1600mm thread:

 

[wimvb]

You're right. I had seen one example of it withe the asi, but it seemed much weaker. It must be the sensor that is the culprit then. I wonder if all Sony exmor sensors suffer from this. Prior to the qhy image, I hadn't noticed it.

[Hicks]

On 27/01/2017 at 20:14, Bagnaj97 said:

There's a lot more potential to be had - there was something iffy going on with my calibration frames. PI was complaining about no correlation between the darks and lights (or something to that effect) and the final "calibrated" images are still a mess, apart from the crab Ha, which was quite clean considering it was only 15 mins of data.

 

If the flat frames are short enough in duration then I think the warning is normal. The scaled dark frame would be so short that it's possible it would add more noise than it removes. In this case I think PI just subtracts the bias from the flat and skips the dark.

That said, double check that you either already subtracted your master bias from your master dark or that when you do integration on the flats you have calibrate ticked for the master dark so that bias can be subtracted.

Edited January 29, 2017 by Hicks

[8324689]

Amazing images, can I understand were you using the GPCAM for imaging AND guiding simultaneously? Thanks

[Tommohawk]

1 hour ago, 8324689 said:

Amazing images, can I understand were you using the GPCAM for imaging AND guiding simultaneously? Thanks

this thread is a bit old now.... but I dont think its possible to image and guide withe the same camera.

[wimvb]

2 hours ago, 8324689 said:

Amazing images, can I understand were you using the GPCAM for imaging AND guiding simultaneously? Thanks

You can't image and guide simultaneously with one camera, unless you'd save the guide exposures. In this case a cmos guide camera was used for imaging. Because of the short exposures (30 s),  it wasn't necessary to guide.

[8324689]

Excellent - thanks for clearing that up. I thought so but wanted to make sure...