M101

[Rodd]

6 minutes ago, gorann said:

Now you are falling into the deep hollow of the f-ratio myth. A 6" refractor collects 33% more photons than a 5" one, whatever reducer you throw at it (and you can throw one on the 6" also). It still has a bigger front lens!

That's true--or I can use my 11" at F7......but guess what....same problem.  I don't think the scope is the answer.   Actually, it has been so long since I used the Edge, I can't really remember what teh background was like.    Maybe its worth checking out.  But change eats up clear sky time.  When i get 1 night every 2 weeks or so, I just can't bring myself to make changes).

Edited March 2, 2020 by Rodd

[gorann]

4 minutes ago, Rodd said:

That's true--or I can use my 11" at F7......but guess what....same problem.  I don't think the scope is the answer.   Actually, it has been so long since I used the Edge, I can't really remember what teh background was like.    Maybe its worth checking out.  But change eats up clear sky time.  When i get 1 night every 2 weeks or so, I just can't bring myself to make changes).

I fully agree with that - when I get a clear sky all my ideas of testing things out goes away and I just want to collect data😉

[Laurin Dave]

What skies do you have Rodd/ Gorann?  Mine are Bortle4/5... I guess a question to answer (maybe you already know)  is whether your results are the same as someone with the same/similar kit in the same sky conditions ..  

[gorann]

6 minutes ago, Laurin Dave said:

What skies do you have Rodd/ Gorann?  Mine are Bortle4/5... I guess a question to answer (maybe you already know)  is whether your results are the same as someone with the same/similar kit in the same sky conditions ..  

Yes, changing the sky was my second suggestion to Robb, but it isn't a very fair one since I expect he cannot easily move. My SQM is often around 21.3 - 21.6, so bortle 2-3.

Edited March 2, 2020 by gorann

[Rodd]

2 minutes ago, Laurin Dave said:

What skies do you have Rodd/ Gorann?  Mine are Bortle4/5... I guess a question to answer (maybe you already know)  is whether your results are the same as someone with the same/similar kit in the same sky conditions ..  

Mine are given as Bortle 5 on Clearoutside website.  But They have to be more like 6.  My sky is so bad I have trouble finding constellations at times.  The milky way is not visible except on the darkest night at the meridian there is a hint of it

But....maybe its not my sky....maybe I am missing something that everyone else knows.  I have suspected that for a long time.  or maybe my nsensor is malfunctioning.  Maybe teh cables leak....I dont know. 

[Rodd]

Just now, gorann said:

Yes, changing the sky was my second suggestion to Robb, but it isn't a very fair one since I expect he cannot easily move. My SQM is often around 21.3 - 21.5, so bortle 2-3.

Yum!

[wimvb]

Light pollution is the most likely cause. For each magnitude you lose, you need 2.5 times as much integration time.

If Göran @mag 21.3 collects 1 hour of data, then at mag 19.3 (2 magnitudes), you will need more than 6 hours of data (2.5x2.5), to get the same noise level. Personally, I would put that time in luminance and not rgb. You can blur the colour before lrgb combination to get rid of the noise.

[gorann]

39 minutes ago, Rodd said:

Yum!

The reason I got into this hobby not that many years ago was that I had bought a weekend house, a small old farm on the Swedish countryside, and was amazed by the dark sky on clear nights. Then I realized I needed a telescope! Now I have many scopes and two obsys. I don't think I would ever had got that idea into my head when looking at the sky in Oslo (the capital of Norway) where I live and work in the weeks.

Edited March 2, 2020 by gorann

[Rodd]

33 minutes ago, wimvb said:

Light pollution is the most likely cause. For each magnitude you lose, you need 2.5 times as much integration time.

If Göran @mag 21.3 collects 1 hour of data, then at mag 19.3 (2 magnitudes), you will need more than 6 hours of data (2.5x2.5), to get the same noise level. Personally, I would put that time in luminance and not rgb. You can blur the colour before lrgb combination to get rid of the noise.

Yes but lum is much more susceptible to LP.  My lum subs look horrible while my RGB subs look dark--much better.  I would agree with you under one condition, and that is the FWHM of the lum is better than the RGB.  the other night I was collecting lum and the FWHM values were coming in at 3.5, while my RGB subs were down around 2.3-2.4.  I don't think, in that case, the lum was the way to go.

[Rodd]

23 minutes ago, gorann said:

The reason I got into this hobby not that many years ago was that I had bought a weekend house, a small old farm on the Swedish countryside, and was amazed by the dark sky on clear nights. Then I realized I needed a telescope! Now I have many scopes and two obsys. I don't think I would ever had got that idea into my head when looking at the sky in Oslo (the capital of Norway) where I live and work in the weeks.

Except narrow band. There are people who image NB from Manhattan (New York City--the whitish area on an LP map you can find).  Not for LRGB though, that's for sure. 

[wimvb]

3 minutes ago, Rodd said:

Yes but lum is much more susceptible to LP.  My lum subs look horrible while my RGB subs look dark--much better.  I would agree with you under one condition, and that is the FWHM of the lum is better than the RGB.  the other night I was collecting lum and the FWHM values were coming in at 3.5, while my RGB subs were down around 2.3-2.4.  I don't think, in that case, the lum was the way to go.

Two options:

Use a lp filter in stead of an L filter (this won't help with star fwhm). 

Collect lots of rgb and create a synthetic L. I believe you have already done this at times.

Unfortunately, there is probably no shortcut. From a light polluted site, you need to collect more data.

Btw, you may find this interesting:

https://skyandtelescope.org/astronomy-blogs/astrophotography-benefits-dark-skies/

[Rodd]

4 minutes ago, wimvb said:

Two options:

Use a lp filter in stead of an L filter (this won't help with star fwhm). 

Collect lots of rgb and create a synthetic L. I believe you have already done this at times.

Unfortunately, there is probably no shortcut. From a light polluted site, you need to collect more data.

Btw, you may find this interesting:

https://skyandtelescope.org/astronomy-blogs/astrophotography-benefits-dark-skies/

Oh my--my sky is 18.2!!!   I never new what that number meant and concentrated more on the Bortle number.  But I see that I need over 16 hours when someone else nees 1 in 21.8 skies--maybe well over 16 as the next step is 36.  So it could easily be 20-25.

"All who entereth here abandon all hope..."

[tooth_dr]

49 minutes ago, Rodd said:

But I see that I need over 16 hours when someone else nees 1 in 21.8 skies

If that’s true, that’s insane. 

[Rodd]

28 minutes ago, tooth_dr said:

If that’s true, that’s insane. 

Yep

[Tom OD]

That’s a very promising start Rodd. 
that spiral arm is close to the top of the frame but you might just get in all in. 
Tom. 

[wimvb]

7 hours ago, Rodd said:

Oh my--my sky is 18.2!!!   I never new what that number meant and concentrated more on the Bortle number.  But I see that I need over 16 hours when someone else nees 1 in 21.8 skies--maybe well over 16 as the next step is 36.  So it could easily be 20-25.

"All who entereth here abandon all hope..."

 

6 hours ago, tooth_dr said:

If that’s true, that’s insane. 

That's the math behind it. But ap isn't just numbers. Rely on what you see. @Rodd, you've produced excellent images in the past from your location. I'm sure that in the end, this one can be added to that collection.

But I must admit, since I moved to a mag 20.5 location, it has become easier to process the data I've collected. And I haven't had to rely on noise reduction as much as before. 

Edited March 3, 2020 by wimvb

[Rodd]

8 hours ago, Tom OD said:

That’s a very promising start Rodd. 
that spiral arm is close to the top of the frame but you might just get in all in. 
Tom. 

Thanks Tom.  Yeah, I botched the framing.  I probably won’t pick up   Really faint extensions if there are any at the boundary

Edited March 3, 2020 by Rodd

[Rodd]

7 hours ago, wimvb said:

'm sure that in the end, this one can be added to that collection.

Eventually.......its the eventuallies that are killing me.  I see the value of DSW or ITelescope--expensive though.  How many 20 hour images could  have made if I spent all my money on data instead of gear/

[wimvb]

I don't know about you, but for me, tinkering with the gear and getting everything working is a major part of the fun. Several astrophotographers that I know, and have gone remote, still have a setup at home just for that. 

[Rodd]

35 minutes ago, wimvb said:

I don't know about you, but for me, tinkering with the gear and getting everything working is a major part of the fun. Several astrophotographers that I know, and have gone remote, still have a setup at home just for that. 

Not me.....I loath it.  I even hate taking time away from imaging to focus.  part of that is the fact that clouds can appear very quickly.  Many were the nights where I would stop to focus, get it perfect, then look up, and swear at the almighty because clouds had rolled in in that short amount of time.  It has traumatized me.  So, when ever something does not work, or there is a glitch I experience a form of PTSD--my heart races, i start sweating, I feel trapped.  

[wimvb]

@Rodd do you have an observatory, or do you need to set up every time? This imaging season (since September) I've only completed two images, partly due to my observatory not being finished, but mostly due to the weather. But having an observatory means I can be up and running in a matter of minutes, and take advantage of even a few hours of clear skies. Without it, I'd probably have had no images at all this season.

[Rodd]

2 hours ago, wimvb said:

@Rodd do you have an observatory, or do you need to set up every time? This imaging season (since September) I've only completed two images, partly due to my observatory not being finished, but mostly due to the weather. But having an observatory means I can be up and running in a matter of minutes, and take advantage of even a few hours of clear skies. Without it, I'd probably have had no images at all this season.

I built myself a roll of box.  So I am permanently set up.  I do have to plug my focus controller in and plug the mount in and the computer.  It takes me 15 minutes or so. It’s a big help.   I wish everything was set to turn on with the flip of a switch and start imaging.  I’d say from unlocking the box, rolling it off, uncovering the rig, connecting the Focuser/mount and the computer, checking polar alignment, focusing then slewing to target is about 20 min