Knmurphy1

Hi guys, Thanks for the comments. I didn't re-calibrate from whatever I did last (months ago when it was last clear). I'm still very much a novice. PA and focal lengths were correct Michael, calibration wasn't.  Guide cam was probably rotated also since it was removed. Comments have been very helpful, thanks.

Hi folks, I went out to image M101 tonight and I couldn't get my guiding working with the ASIAIR Plus and my ASI120MM guide camera (with 50mm/F4 guide scope). I have used it many times over the past two years with no issues. I restarted the whole setup several times with the same results. The odd thing is, I tried switching the guiding on the ASIAIR to the main telescope (Explore Scientific 102 ED) and ZWO183MC camera and it began guiding normally. I even took a 30 second image through the guide scope of M101 and everything was normal. Hope someone has some advice on this. Thanks for reading. See screenshot.

Thanks for the replies guys. It was actually a modified EOS1100 D Canon camera I used, not the ZWO - my mistake. I might try my CLS-CCD filter to see if that reduces the halos.

Hello all,

just wondering if anyone knows what might be causing the star halos on the big stars in my M45 image. Processing them out doesn't seem to be an option. 
Even before the image is stretched I can see faint circles around them. 
I used a ZWO183C and (an old) Televue 76.

thanks guys.

Kevin 
 

On 13/08/2023 at 09:48, M40 said:

The skymax is superb on planets but not the best on deep sky as you say. Couple of thoughts for you.

I stuck an eaf on the focuser and it works great, gone is the shakey hand syndrome. I use the hand controller for focus.

You have an excellent mount so weight is not a concern, I have recently installed a guide scope and camera to the skymax with the plan to use the guide camera as the main camera for plate solving and goto on an asiair. This will leave you free to use the skymax for visual or a second camera. Weather being what the weather is, it's setup and good to go but not tried it yet, but asking the question others use this method with no worries.

All the best.

Thanks for the tips. Using the guide scope to plate solve sounds like a great idea. I think it would need to be very accurately aligned with a scope of such a long focal length to get the object in the FOV.  Looking forward to viewing the moon and planets this Autumn. I have a 127 Mak for many years and I'm keen to see the comparison

On 13/08/2023 at 12:49, Cosmic Geoff said:

It might prove challenging, given the small field of view.  But why would you want to platesolve, other than for imaging (small) deep space objects? 

I found that when imaging planetary nebulae etc with an 8" SCT and f6.3 focal reducer,  the 'Precise GoTo' available on Celestron mounts was usually enough to get the object into the camera FOV.

Hi Geoff, thanks for the reply. Yes you are correct, I understand plate solving is not required on Solar System objects. I was curious about the plate solving in the event that I might try imaging a globular or the likes of the ring nebula at some point.

Hi everyone,

I bought a SkyWatcher SkyMax 180 which arrived today.  My intention is to view/image Jupiter, Saturn and the Moon this Autumn / Winter (and Mars later). Any thoughts on this scope? Pros, cons etc. Is it possible to plate solve with such a long focal length?  Is deep sky imaging difficult or worth bothering with? I understand that only small DS objects are feasible given the narrow FOV.

If you have experience with this telescope any comments or advice would be very welcome. Oh, I got a Crayford 2 speed focusser for the scope also. Thanks,

Kevin.

6 hours ago, Elp said:

Have you got another camera to test with the reducer? The reducer shouldn't introduce an unevenly lit imaging circle.

Yes, I'll try that with a DSLR, thanks

On 04/05/2023 at 10:03, tomato said:

Were you using active cooling on the camera?  It does look like moisture forming on the sensor to me although the symmetry of the light area is unusual. Do a I see a bright area on the LH edge of the image also?

Yes I was using cooling.  -10C. There is probably all sorts of noise and artifacts in the image as it wasn't processed. I was just testing the camera

On 04/05/2023 at 10:14, vlaiv said:

That is some amp glow, if I'm not mistaken.

Here it is additionally stretched

Yes its a ZWO 183 MC Pro. Lots of amp glow with this particular camera unfortunately.

By the way, I removed the 0.8x reducer and the "circle" issue seems to be resolved. Here's an image of M3 from 08.05.23. There are dark's added (or subtracted?) so there should be no amp glow. Not a perfect image by any means. Lots of cloud and bad seeing (in addition to my menial abilities).

10 hours ago, carastro said:

I haven't seen anything like this.  It doesn't look typical for lack of flat frames.  I hope you reolve the problem and would be interested to know what caused it.

Carole 

I will do, thanks Carole. I have never seen this before. I'm a relative novice, only recently switched from DSLR cameras.

9 hours ago, vlaiv said:

Was it exactly the same setup? Connectors / extension rings and all?

I did some calculations for faster 3" class scopes and 2" focusers - for field illumination. They are very short and have short FL and that causes vignetting on anything but focusers with very short draw tube.

If you add different extension - or even use different connection as QHY camera has fixed 2" part and it is removable with ZWO and that means different extension tubes to get the same thing with reducer, this can lead to different focuser position.

Different focuser position means that drawtube can be inserted further down into the OTA - and that will create vignetting with rather small central illuminated field - much like in image above.

If you want to rule out the dew and other things - just shoot some flats in daytime when it is warm and there is no chance of dew forming - but be careful to have focuser at the same position it was during the night. Examine flats - and if they have similar bright spot - then try to make your setup in such way that focuser is racked further out when you are in focus.

This can be achieved by pushing reducer / flattener in focuser tube instead of attaching it at the end of the tube (if it can be done).

In any case - above looks to be flats issue and should be solved with flats. I quickly ran synthetic flats on red channel and got this:

(so this is not background removal - not subtraction, but actually division with synthetic flat - as flats are supposed to work).

 

 

Thank you for that very detailed input. I think the only difference with the previous setup was that I used a 1.25" connection on the QHY 183 camera and a 2" for the above image. Not sure if this would make a difference?

I’ll check that out. Thanks for the input it’s very helpful 

The exposure time was 60 seconds - about 20 images stacked. The issue is on all the images. This was my first time using the set-up and I was just experimenting.  I have used a similar camera before (QHY 183C) with same scope / reducer without an issue.

No, there are no calibration files applied. I have never seen this before in a un-calibrated image

Hi Guys,

Any idea why I'm getting this circle in the middle of my image? I used a Televue 76 with an 0.8x reducer / flattener . Camera was a ZWO 183 MC Pro. The scope and camera are a good match apparently. Is it possible it was caused by dew. I was only testing the new camera and didn't use my dew heater.

Thanks for the input guys. I a total novice when it comes to CMOS and the relevant processing. Much appreciated

Good afternoon folks,

I recently bought a QHY183C camera and am somewhat confused with debayering. Any help with the following would be much appreciated:

1: If I take, say, 30 exposures, do I need to debayer them all separately before stacking?

2. ICan I do this in a batch?

3. Do I need to debayer the dark/flat/bias frames ?

4. What's the best software to use?

5. Is there a specific output file I should use (I'm using Sharpcap) (FITS, Tiff etc) ?

Any other advice would be very welcome as this is all new to me 😳.

I've been using a DSLR for a couple of years and new to this CMOS business. Any other advice or step by step procedure regarding this would be very welcome!

Have a great day,

Kevin.

Thanks a million for the input  guys. Will investigate all of the above. 

3 minutes ago, bomberbaz said:

Washing line, telephone line, tv arial or similar in the light path

The object was very high, probably 10 degrees from overhead so I don’t think there was anything in the light path. Thanks for the input 

Hi folks,

this is my first post and I’m hoping some of you might have some advice.

I recently bought a QHY 183C camera and finally got to use it after endless weeks of cloud. There are two issues, the first is the diffraction spikes on the stars to the right. Any ideas what is causing these? I’m using a Televue 76 refractor. with a 0.8 reducer. So there should be no diffraction spikes. Or am I missing something?

The second is the diagonal noise throughout the image. any ideas on this? 
It’s a live stack of 50 x 30 second frames. 
I expect some noise as I didn’t use any darks but I just find these streaks unusual. 
Any comments would be greatly appreciated.

Kevin.