Andromeda is really getting on my nerves!

[Galactic Wanderer]

Hello everyone, 

This is my 7th try on Andromeda and I'm just not getting the results i was hoping for. After a previous topic (

) where @russp told me to up my ISO, I tried what he reccomended and still with an 1hr of data and ISO 1250, its getting really frustrating. 

Thanks, Seb

[spillage]

Hi Seb,

 

What setup are you using and what are the exposure times and numbers. Have you also saved as a raw image if so it might be worth including the file so we can have a proper look at the data.

 

cheers

Spill.

[Galactic Wanderer]

hey spill and thanks for your reply 

Unfortunately, I was doing some daylight imaging with JPGs and forgot to change the setting to RAWs before I started the astrophotography. I only noticed after when I was importing the images.  The exposure times were 30 seconds and I was pairing a Canon 60D with a Sky-Watcher 150PDS.

Is it because I am living in London and there is so much light pollution?

By the way, here is a single 30 second frame if that helps.

Thanks, Seb

[geordie85]

Being jpeg seriously hinders your images as they're compressed already so this will be a contributing factor to poor images. The light pollution won't be helping either 

[Galactic Wanderer]

I still find that hard to believe.2 weeks ago I was imaging in raw format and it turned into an again not brilliant result. I think it's just due to the awful light pollution in London

thanks Seb

[spillage]

There are people here who suffer bad lp and pull out great results. I am sure a clip in lp filter will help and someone here will be able to give you some good advice.

I quickly learnt that this ap game is a nightmare. You spend a fortune on kit then have to wait what feels like and age for clear skies. Even then you will find that you will forget to check do something or something that has worked for ever stops working for no apparent reason. Then when it finally all comes together you move onto processing but this is another story. But this is why I like doing it really is a challenge.

I would not worry too much about your last attempt just look towards your next effort and I am sure you will make sure you shoot in RAW.

I have just got hold of 150pds and so far I am really enjoying it. It might be worth going to your local Wilko's and buy yourself some flocking for it. It takes about an hour to do from start to finish.

[gnomus]

AP is hard.  I had been a terrestrial photographer for many years.  In some ways I think this held me back because I had numerous ways of thinking about photography that didn't help in AP.  My understanding of ISO was one such thing.  When you open your shutter for, say, 30 seconds a certain number of photons will hit the sensor.  This will not change with different ISO settings.  In a digital SLR a higher ISO does not mean a more sensitive sensor.  Rather, the different ISOs give different levels of amplification.  Both signal and noise are amplified and so the trick becomes finding the ISO setting that gives the optimal signal to noise ratio.

Most of what I read when I used a DSLR suggested that a setting of 800 or 1600 was best for my camera.  

The next battle becomes digging the faint signal out of the shadows which is, of course, where most of the noise resides..  With a JPEG the image has been reduced to 8 bit meaning that there are only 256 levels of gray available.  Furthermore, with JPEGs the camera has already done its own stretch on your data.  You need to shoot RAW.  You should also shoot flats and bias.  There is some debate about the benefits of darks in DSLR astrophotography.  If you dither you might not need darks.  

I don't know which part of London you are in and how bad your LP is.  Have you had a chat with local astrophotographers to ascertain what you could reasonably expect in your area?  The chaps at the Widescreen centre in London might be helpful.   Are you imaging at the right time?  There is little point trying to do DSLR imaging if there is any significant moon about, especially if you already have a LP problem.  You can get LP filters.  Astronomik and IDAS do them.  

The more data the better usually but you can get results with limited data.  This is less than 2 hours: https://stargazerslounge.com/topic/237475-m31-second-attempt/

[RayD]

3 minutes ago, gnomus said:

The chaps at the Widescreen centre in London might be helpful.

I may be wrong but I think they've moved up Cambridgeshire way somewhere.

[gnomus]

3 minutes ago, RayD said:

I may be wrong but I think they've moved up Cambridgeshire way somewhere.

Ah.  So who runs the Baker Street Irregulars now?

[RayD]

Just now, gnomus said:

Ah.  So who runs the Baker Street Irregulars now?

Sorry absolutely no idea.  I only found out by chance as I decided to pop in there one day and the shop was shut down, and when I checked their site it now shows them in Ely.  I wonder if they still do it from there?

[Galactic Wanderer]

8 hours ago, gnomus said:

Ah.  So who runs the Baker Street Irregulars now?

I do go to the baker street astronomers regularly. Last time I went in October, they were there so they must still come down.

Thanks, Seb

 

[Ouroboros]

It is sometimes said that Andromeda galaxy is a tricky target. My first attempts were very disappointing and I was discouraged.  But over time I learnt a lot by imaging and processing more modest targets. When I came back to M31, despite using exactly the same camera and processing software, my results were significantly better. OK not as good as some of the brilliant images you see from those using the best kit and hours and hours of data gathering and experienced processing, but pleasing enough to make an acceptable image.  So, you can do it because I did. 

A couple of comments about M31.  It is very large, appearing several times the size of the moon, and will fill the field of view of a DSLR connected to a telescope like yours (and my f/5 Newtonian) . It's easier I think to get a better image initially with less magnification.  Apart from often being aesthetically more pleasing, a wider field image gives you more sky around the galaxy, which provides a good sample of the background light pollution, and which you can work on to back off in the processing.  M31 has a very bright core relative to the nebulous regions around it. It helps having lots of data and to very careful stretch the image to lift the faint majority of the galaxy from the background LP and noise but without blowing out the core.

 

[Guest]

14 hours ago, Galactic Wanderer said:

Hello everyone, 

This is my 7th try on Andromeda and I'm just not getting the results i was hoping for. After a previous topic (

) where @russp told me to up my ISO, I tried what he reccomended and still with an 1hr of data and ISO 1250, its getting really frustrating. 

Thanks, Seb

re: the title of this post

"......said Cepheus to Cassiopeia....."

LOL!

[russp]

It's really difficult to tell what you're getting without RAW files and processing jpeg's is never going to be overly successful. London light pollution is always going to be challenging  shooting with a DSLR - are you at least able to get away from streetlights or are you stuck in the middle of the worst of it ? Have you tried assessing your Bortle scale to quantify the amount of light pollution? You're at the very least going to need to try and isolate the LP and remove the gradients it's causing without losing the detail in your shots then you can stretch the picture into something worth having. I'm not familiar with startools and DSS I'm afraid (I use PixInsight) so I can't help you with ideas on processing.

[PeterCPC]

I suggest that you need a good light pollution filter but also lots of subs with the ISO at no higher than 800. You basically need more data. It's a difficult target so don't give up.

Peter

[DaveS]

I've found the Astronomik CLS filter to be the best for my LP. Forget Bortle Scale, London is usually 9, dropping to 8 on a really good night, but any haze / dust at all in the air will wreck your visibillty. Keep an eye on the histogram, ISO 800 and subs to avoid the background getting too high.