Imaging with the 130pds

[Adam J]

Looks more like you need a little more spacing on the corrector to me. Maybe try 56mm back focus.

[JamesAstro2002]

Update: Luckily enough, the sky was clear tonight, although the seeing was horrible, I managed to test out the star field. All I can say is thank you to Matt, problem is resolved 🙂.

[matt_baker]

1 minute ago, JamesAstro2002 said:

Update: Luckily enough, the sky was clear tonight, although the seeing was horrible, I managed to test out the star field. All I can say is thank you to Matt, problem is resolved 🙂.

No problem, happy to help

[dyfiastro]

Hi everyone

First image from the new observatory and replacement telescope setup.

Still a little work needed in regards to equipment spacing etc... but was really good to get everything up and working.
looking at the image I think I need to reduce the spacing between the mpcc and ccd if anyone can help confirming this that would be great

M33 - Triangulum Galaxy

Total imaging time = 48 minutes

Skywatcher HEQ5, Skywatcher 130PDS, QHY8L, OVL OAG+QHY5II-M.

[matt_baker]

How much spacing have you got between the sensor and the mpcc? It should need about 34.8mm

[dyfiastro]

1 hour ago, matt_baker said:

How much spacing have you got between the sensor and the mpcc? It should need about 34.8mm

The OAG is around 15mm, the sensor flange distance is 20.2 which leaves around 22.3 to make up the 57.5mm spacing requirement for using the M48 threads from what I understand.
This I have set to a close as possible (within .5mm I would say) I am going to have to double check again however

[matt_baker]

Is it not supposed to be 55mm spacing for the MPCC?

[dyfiastro]

1 minute ago, matt_baker said:

Is it not supposed to be 55mm spacing for the MPCC?

I always thought it was however looking at other diagrams show it as 55mm using the T2 threads and 57.5mm using the M48 threads.
If it is indeed 55mm that will make life a lot easier trying to get the OAG par-focal as well, currently the guide camera is stripped down to the bare sensor to allow enough adjustment.

[Uranium235]

Its been a very long time.... perhaps too long..lol.

20x450 Ha on the Veil, starting off on something easy. No calibration either. I'll probably process it again later on when I remember what it is I used to do

[matt_baker]

Last Tuesday, I managed to go out and image M13 just fine, with only a couple of stars in one corner being elongated due to my focuser tilt.

Last night however, I was trying to image the Iris nebula and the stars looked awful.

I made sure to collimate and make sure the focuser screws were tightened nicely. Although I did push the mirror up slightly with the collimation screws to try and minimize the drawtube obstruction.

Collimation was done with a cheshire eyepiece and collimation cap.

My focus was also good from my bhatinov mask.

I think I know it's not caused by differential flexure, since the stars look awful even from a 5 second exposure which I've uploaded for all to see.

Could anyone help me out?

[Uranium235]

On 26/08/2019 at 20:11, matt_baker said:

Last Tuesday, I managed to go out and image M13 just fine, with only a couple of stars in one corner being elongated due to my focuser tilt.

Last night however, I was trying to image the Iris nebula and the stars looked awful.

I made sure to collimate and make sure the focuser screws were tightened nicely. Although I did push the mirror up slightly with the collimation screws to try and minimize the drawtube obstruction.

Collimation was done with a cheshire eyepiece and collimation cap.

My focus was also good from my bhatinov mask.

I think I know it's not caused by differential flexure, since the stars look awful even from a 5 second exposure which I've uploaded for all to see.

Could anyone help me out?

If you look closely at the corners, it will tell a story. The left side has normal coma (I assume youre using a corrector?), while the right  is a different type of distortion (radial).

That would indicate some tilt, either in the focuser, the way the corrector sits in the drawtube, or whether you have any loose connections. You might need to take time to square your focuser, simply tightening up all the screws doesnt quite mean that its pointing at the right spot on the tube wall.  You have to remove the secondary and put in a marker for where the focuser tube should be pointing. There is stuff on youtube how how to do this, but I wouldnt attempt it until you have the bits required (digital calipers etc..)

The stars in the middle are a bit so-so, but you didnt state whether you were guiding or not.

[matt_baker]

2 hours ago, Uranium235 said:

If you look closely at the corners, it will tell a story. The left side has normal coma (I assume youre using a corrector?), while the right  is a different type of distortion (radial).

That would indicate some tilt, either in the focuser, the way the corrector sits in the drawtube, or whether you have any loose connections. You might need to take time to square your focuser, simply tightening up all the screws doesnt quite mean that its pointing at the right spot on the tube wall.  You have to remove the secondary and put in a marker for where the focuser tube should be pointing. There is stuff on youtube how how to do this, but I wouldnt attempt it until you have the bits required (digital calipers etc..)

The stars in the middle are a bit so-so, but you didnt state whether you were guiding or not.

Yes, I'm using a Badder corrector and yes, I was guiding but this was a 5 second sub, and I doubt guiding would affect the stars at this time frame surely.

I'll go see how to amend this

I remember I did adjust my spider vanes my quite a bit the first time I collimated with a cheshire and never checked to see if they were centered properly or not. Maybe this could be a cause?

Edit: Also, what kind of tap would I need for a third thumbscrew and how would I go about doing it, if you don't mind me asking?

Edited August 29, 2019 by matt_baker

[Stub Mandrel]

On 26/08/2019 at 10:27, Uranium235 said:

Its been a very long time.... perhaps too long..lol.

20x450 Ha on the Veil, starting off on something easy. No calibration either. I'll probably process it again later on when I remember what it is I used to do

Rob... you really get all your amazing pictures with the ASI178MM cool?

[Adam J]

1 hour ago, Stub Mandrel said:

Rob... you really get all your amazing pictures with the ASI178MM cool?

FOV looks too big for it to be the ASI178mm cool but I may be proved wrong when Rob replies. 

[matt_baker]

Went back for another reprocess at M13.

Deconvoluted the stars this time, changed colours and cropped it down slightly

Some of the noise still bothers me but that's what you get when you image with a DSLR uncooled. Might aim for some more time on it when I can.

What does everyone think?

 

Matt

 

 

More upclose look at the core:

Edited August 31, 2019 by matt_baker

[alacant]

7 hours ago, matt_baker said:

what you get when you image with a DSLR uncooled

Hi

Great image.

I don't think it's a limitation. Maybe it just needs denoising? There's not a lot to work with on the .jpg but with the .tif, you should be able to flatten the background completely. I had a go...

Cheers and HTH. 

 

 

[Shaun_Astro]

Lovely globular cluster

My first stack with my 130pds on my heq5 of M27. 

A bit noisy because of iso 1600. Also bad shaped stars because of the sw coma corrector. Need to chomp the draw tube off a bit. 

[matt_baker]

6 hours ago, alacant said:

Hi

Great image.

I don't think it's a limitation. Maybe it just needs denoising? There's not a lot to work with on the .jpg but with the .tif, you should be able to flatten the background completely. I had a go...

Cheers and HTH. 

 

 

I think it also depends what kind of monitor you're viewing it from.

I have a crappy TN panel on one of my monitors that's bad at reproducing especially blacks, however on my IPS, it looks flawless so I'm not sure

What did you use to reduce the noise?

Edit: I think I've fixed it by lowering the background with curves

 

Edited August 31, 2019 by matt_baker

[alacant]

5 hours ago, matt_baker said:

I've fixed it

That's good. You could try wavelet denoise: GIMP.

Cheers

[Shaun_Astro]

Bit over stretched, but a hour and a bit on m31. Dew ruined half my subs! 

[Stub Mandrel]

37 minutes ago, Shaun_Astro said:

Bit over stretched, but a hour and a bit on m31. Dew ruined half my subs! 

Looks good, maybe a touch green on my monitor? Hope you don't object, I hit a grab of your image with HLVG (Hasta La Vista Green plugin) in Photoshop:

Edited September 1, 2019 by Stub Mandrel

[Shaun_Astro]

1 hour ago, Stub Mandrel said:

Looks good, maybe a touch green on my monitor? Hope you don't object, I hit a grab of your image with HLVG (Hasta La Vista Green plugin) in Photoshop:

Much better thank you! 

[alacant]

3 hours ago, Shaun_Astro said:

hour and a bit on m31

 

Excellent shot. I had a go at the stars...

[JamesAstro2002]

3 Hours of data on Andromeda with the 600D from last night.

I noticed that I seem to have them oddly shaped stars again. Last time, I fixed this by undoing the primary mirror retention clips a bit as they were tight up against the mirror. Now that i've been able to get back out for a night of imaging, they're back again! Any ideas as to why this could be ? I double checked the clips again and they're still loose, although they are still touching the mirror, are they supposed to touch it or not? I also made sure that the primary collimation locking screws aren't overly tightened. Also, through my cheshire, collimation looks to be spot on.

[Stub Mandrel]

M31  -the galaxy that just keeps giving.