M42 SWED80 unguided

[rodrigol]

M42 from last night. PI integration and processing of 20 x 50 s lights; 10 Darks and 8 Bias. Taken with a Nikon D7200 at ISO 1600 on a SWED80 w/ Planostar 0.8 FFR. 

I really wanted to get longer exposures to reduce noise but PHD2 pulse guiding is not my forte yet. The CGEM DX mount can track decently up to a minute. I tried setting up PDH2 on al Altair 60mm starscope w/ QHY5L-II but the mount was going all over the place. I'm not sure what was going on and with the little time we have clear skies these day I gave up. 

 

 

Hope you can enjoy and perhaps comment on the image.

Thanks for watching.

 

[Demonperformer]

A nice result from such short subs. Bodes well for when you get PHD going.

[rodrigol]

Hopefully the weather will be forgiving and let me have another go soon. 

[alan potts]

That looks very nice, nice round stars from what I can see. My mount don't like PHD, I have tried now for 2 months to get it to work and have even bought a new Lodestar, and it still will not work. I am thinking of just giving up.

[wimvb]

Nice result for such short integration time. If you can't get PHD to agree with you, try increasing the number of exposures. In the end it's the total integration time that determines the result. As long as you stay "above" the read noise for each single exposure, you should be able to get the noise down by just increasing the number of exposures.

20 x 50 s = 17 minutes

200 x 50 s = (almost) 3 hours

[DougM43]

That’s a great image, I think M42 has to be one of the best objects to image as well as observe, it just always delivers.

i too am in the process of learning the ropes with guiding, I was out with the scope and camera last weekend (imaging M42) but with clouds due to roll in by 11pm I chose not waste time trying to guide and miss out on rare imaging time. I do wish I had though, I took 70 60s exposures but threw over 40 of them in the recycle folder due to elongated stars.

lesson learned

Doug.

 

[rodrigol]

Many thanks for the advice! Need to try st4 and USB vs. Pulse setup before I give up. I can't believe a cgem dx will not do better. Checking cables as well as the qhy for next time... And getting ready a zwo to test as well...Will try to keep you posted but on another post... You guys rock with good advice and ideas :-) 

[newbie alert]

I'm in buntingford next week..i see your not too far away if you want a hand with phd..let me know

I'm not an expert but I have my cgem guiding ok...

[rodrigol]

That is really a nice offer. Thank you! Maybe you can tell me if you are using St4 or pulse guiding, for  a start? 

 

I'm very grateful for your advice ?

[wimvb]

Couldn't help myself: I downloaded your jpeg, and did a little bit of noise reduction + background neutralisation.

There was a lot of noise in the red channel. Is your Nikon astromodded? Even if you did background neutralisation in PI, stretching the image will enhance the noise in the background. Easiest way to suppress this is color saturation with a luminance mask. Pin the saturation curve at about 25 % for the offending colours, creating a dip. With the mask in place, apply the process until the background seems neutral.

There is a dust bunny to the left of M 42. Taking flat frames would clean this up quite easily.

Btw, I rarely ever use ABE. DBE gives me much more control. I place a sample in each corner and along each edge. If needed, I move a few of these towards the middle. Rarely more than 10 samples. But I do make the samples as large as possible in order not to kill any faint dust in the background. (Dust has structure, a gradient doesn't.)

[newbie alert]

6 hours ago, rodrigol said:

That is really a nice offer. Thank you! Maybe you can tell me if you are using St4 or pulse guiding, for  a start? 

 

I'm very grateful for your advice ?

I'm not really totally sure ..the only way I can do it is to have the camera to the laptop and the laptop to the bottom of the handset as my camera hasn't got a separate guideport..not too sure if that's pulse guiding or not,but with my camera I have no other choice..works well thou..

[MarsG76]

Looks great, unguided and pin point stars is another level of achievement.

 

[rodrigol]

winbv: Many thanks for great advice! I do see a difference in your processing of the red channel and no, my d7200 is not modified. I still need to get to grips with taking whites/flats but know there is more than just keeping the camera sensor clean - all the OT needs to be taken care off - and that is where flats do us a great favour. I'm learning and ABE is a shortcut I've learned. I also need to invest more time learning to do DBE proper :-) and doing the best possible job of Range Selection to get the most out of using masks.

I love this community - Indeed many thanks for your advice!

 

R:)

[Allinthehead]

There's a lot to like about that image.

You just need to turn as Wim said 20 × 50 into 200 × 50 or get that guiding working if possible. It takes practice and time to get it right and you will waste some imaging time.

I know that anytime wasted trying to figure out guiding is usually down to mistakes i make when setting up.

A check list might be a good idea.

[rodrigol]

Tried to follow advice to get a better image from Wim and other here :-)

The result is below...with the dust bunny still there (to remind me to take flats!). I'm relearning using my D7200 for AP and find that ACDNR is essential at the begining of the workflow. I left as much of the original work as possible in order for you to see where I'm coming from..

Did I overdo it?

 

 

[iansmith]

Your second attempt has really cleaned up the noise I the fainter nebulosity and made it stand out much more than in your first image. Great result.

50s unguided seems to be working well for you so I wouldn't worry about guiding for this object. You just need more subs!

Cheers, Ian