M31 Revisited 13/10/12

Tzetze · 14-10-2012 11:10pm #1

Got back out targetting Andromeda over a couple of nights without the glare of a moon in the sky. Guiding was frustratingly bad and I'd to discard a lot of subs. The 26 that I used were far from ideal but it was either use them or don't process anything at all. Better guiding would have produced a much sharper image.

I've since re-tuned my mount, allowing both axes to run much more smoothly and removed some backlash in the gears. Of course clouds have ruined any hopes of giving it a test drive.

4h20m data
26x 600s subs
28x darks
25x flats
450D CG5-GT SWED80
Stacked in DSS, Tweaked in PS & Lightroom

M31 Revisited 13/10/12 by .Tzetze., on Flickr

14-10-2012 11:16pm

I have to say, and I've been following your sharing of photographs on this forum, that this is your best photograph yet. It's crystal clear, looks extremely sharp, and appears to be true to colour. A brilliant photo. Well done.

Tzetze · 14-10-2012 11:47pm

gvn wrote: »

I have to say, and I've been following your sharing of photographs on this forum, that this is your best photograph yet. It's crystal clear, looks extremely sharp, and appears to be true to colour. A brilliant photo. Well done.

Thankyou very much gvn. =]

Kersh · 15-10-2012 10:18am

That really is a brilliant picture. The detail is awesome.

Hopefully, someday I might manage something even nearly as good.

Tzetze · 15-10-2012 11:12am

How did you get on yourself Kersh, did you get a chance to get back out on Friday evening?

Kersh · 15-10-2012 11:35am

No, I never got out. It was hazy then on saturday, and cloudy last night. Hoping to get out at some stage this week if the weather plays ball.
When I do get out, I will be sticking to a strict system this time. All exposures the same length, but at iso800. As many as I can take, and loads of darks of same exposure.

Last time I was a bit excited, hopping around the place and trying too many settings and exposure times

the culture of deference · 15-10-2012 2:29pm

Stunning.

I had a look at some of your other pics on flicker. Would like some camera advice from you.

Bohrio · 15-10-2012 2:41pm

Cant help of thinking that one day... maybe, that picture could be my own one...

Tzetze · 15-10-2012 3:45pm

Kersh wrote: »

No, I never got out. It was hazy then on saturday, and cloudy last night. Hoping to get out at some stage this week if the weather plays ball.
When I do get out, I will be sticking to a strict system this time. All exposures the same length, but at iso800. As many as I can take, and loads of darks of same exposure.

Last time I was a bit excited, hopping around the place and trying too many settings and exposure times

Hehe, it's hard to stay focused alright. I take a pair of bins out with me to satisfy the need to gawp around.

The forecast doesn't look great for the next while, but hopefully it'll clear up soon.

Tzetze · 15-10-2012 3:46pm

the culture of deference wrote: »

Stunning.

I had a look at some of your other pics on flicker. Would like some camera advice from you.

Thanks, PM sent.

ZeRoY · 15-10-2012 3:53pm

Very nice shot TzeTze!

DubOnHoliday · 15-10-2012 4:20pm

You could look at that picture all day, well done.

ThatDrGuy · 18-10-2012 12:07pm

Beautiful Tzetze. What guiding method are you using ? Do you use another mouted scope ? Im trying to calculate how exactly Im
going to get a guided set up going. I think the 11 inch ota, plus camera, wedge, sub scope mounting rings, guidescope, ccd camera, dew shield, dew heater and counter weights are going to be so heavy as so be utterly unmanageable but I have nearly everything now so better give it a shot.

Tzetze · 19-10-2012 9:53pm

ThatDrGuy wrote: »

Beautiful Tzetze. What guiding method are you using ? Do you use another mouted scope ? Im trying to calculate how exactly Im going to get a guided set up going. I think the 11 inch ota, plus camera, wedge, sub scope mounting rings, guidescope, ccd camera, dew shield, dew heater and counter weights are going to be so heavy as so be utterly unmanageable but I have nearly everything now so better give it a shot.

Thanks TDG. I'm piggybacking a cheap LIDL 70mm refractor as guidescope with a mono DSI-II as a guidecam. Software is PHD Guiding. I'm tempted to upgrade guidescope to something like an ST80 but not sure how much improvement I'd see, if any.

Which guidescope/cam are you thinking of? I guess you've come across the DIY webcam/finderscope mods for guiding. You'll have long setup times to look forward to now! Any plans for an obsy yet?

ThatDrGuy · 20-10-2012 1:11pm

A finder scope mod is a very good idea indeed. My scope has a well mounted 9 x 50 finderscope which could work. Most mods will kill its finding abilities but it was never good at that anyway. A telrad would be much better. I was going to use a cheap refractor too. The only ccd I have at the moment is a neximage but even modded I don't think it's sensitive enough. I'll have to try and get something like a cheap mono dsi as well. I have a shoestring interface and phd guiding. I have never even tried a polar align yet so thats next mission. Then try and get a good long exposures going. I live in quite light polluted area too so don't know what a long exposure will look like. I'd love to get working on observatory, especially as my scope has a fantastic hibernate function but I live in rented accommodation alas so no joy there.

nanook5 · 20-10-2012 5:08pm

Amazing Photo!!!

robertxxx · 21-10-2012 8:30pm

That's a super photo, my mind wonders so much when I look at these great photos.

I'd say you have really top knowledge and gear for a photo like that.
What are all the numbers at the top of the photo?

Cheers.

Tzetze · 22-10-2012 3:38pm

robertxxx wrote: »

That's a super photo, my mind wonders so much when I look at these great photos.

I'd say you have really top knowledge and gear for a photo like that.
What are all the numbers at the top of the photo?

Cheers.

Thanks Robert. I have nowhere near top knowledge or gear. I still have a lot to learn yet - I'm just getting past the beginner stages tbh. The gear I use is pretty much at the low end of the spectrum for Astrophotography.

The numbers at the top of the photo are;
4h20m data - total exposure time is 4 hours 20 minutes.
26x 600s subs - 26 exposures each at 10 mins long (4h 20m)
28x darks - 28 dark exposures (used to remove thermal noise generated by the camera sensor)
25x flats - 25 calibration files (used to remove vignetting and dust caught in the light train)
450D - Camera
CG5-GT - Mount
SWED80 - Scope

Bohrio · 23-10-2012 10:46am

Tzetze wrote: »

Thanks Robert. I have nowhere near top knowledge or gear. I still have a lot to learn yet - I'm just getting past the beginner stages tbh. The gear I use is pretty much at the low end of the spectrum for Astrophotography.

The numbers at the top of the photo are;
4h20m data - total exposure time is 4 hours 20 minutes.
26x 600s subs - 26 exposures each at 10 mins long (4h 20m)
28x darks - 28 dark exposures (used to remove thermal noise generated by the camera sensor)
25x flats - 25 calibration files (used to remove vignetting and dust caught in the light train)
450D - Camera
CG5-GT - Mount
SWED80 - Scope

I am buying the motor for my cg4 mount this week, no need to postpone this anymore!

Hopefully we will get some clear skies soon.

I wanted to buy a barlow lens too but since I can't connect the camera directly to the 1.25 " adapter (on my XLT 150) I am thinking that the barlow might not work either (I can't focus to infinity when the 1.25" adaptor is connected). In all fairness I might be better of selling my telescope and buy another one if this going to be is the case before spending more money. What do you recon?

I could also just get a new scope (that shouldnt be too expensive) and use my current cg4 mount.

Tzetze · 23-10-2012 3:14pm

Bohrio wrote: »

I am buying the motor for my cg4 mount this week, no need to postpone this anymore!

Hopefully we will get some clear skies soon.

I wanted to buy a barlow lens too but since I can't connect the camera directly to the 1.25 " adapter (on my XLT 150) I am thinking that the barlow might not work either (I can't focus to infinity when the 1.25" adaptor is connected). In all fairness I might be better of selling my telescope and buy another one if this going to be is the case before spending more money. What do you recon?

I could also just get a new scope (that shouldnt be too expensive) and use my current cg4 mount.

There's a thread on that particular scope for AP here on Cloudy Nights. A quick read through and it looks like there are T-threads in the focuser. Have you attached your T-ring directly to your focuser or are you using a T-mount?

Looks like that scope performs well enough for AP though, however you'll probably struggle with the payload on a cg4. A 5 series mount would be better. If I were you, I'd be looking at something like a HEQ5 pro synscan as an upgrade although a CG5-GT would work well enough and comes in a couple hundred quid cheaper.

Bohrio · 23-10-2012 4:34pm

Tzetze wrote: »

There's a thread on that particular scope for AP here on Cloudy Nights. A quick read through and it looks like there are T-threads in the focuser. Have you attached your T-ring directly to your focuser or are you using a T-mount?

Looks like that scope performs well enough for AP though, however you'll probably struggle with the payload on a cg4. A 5 series mount would be better. If I were you, I'd be looking at something like a HEQ5 pro synscan as an upgrade although a CG5-GT would work well enough and comes in a couple hundred quid cheaper.

Hey Tzetze

I was actually looking at cg mounts now, CG5-6 (or HEQ if you have the money) seem to be the way to go and they are not "too" expensive. I will definetively look into it before buying the motor.

Yes, my T ring is mounted directly into the focuser (I think I got the idea from that forum) without the T-adapter so adding a barlow will force me to use the T-adaptor so I assume this is not an option. I think I will start looking at mounts and motors and see what's my best option and forget about upgrading my scope for the moment, once I get the hang of it I will go ahead and look into upgrading my telescope.

Thanks... I will keep you posted!

Rubecula · 23-10-2012 4:57pm

Long exposures usually have some sort of star trail due to the Earth's rotation, so you obviouslyy have good equipment to follow the sky that well. May I ask what you use?

Tzetze · 23-10-2012 5:28pm

Rubecula wrote: »

Long exposures usually have some sort of star trail due to the Earth's rotation, so you obviouslyy have good equipment to follow the sky that well. May I ask what you use?

Well the mount is motor-driven to rotate in a 24-hour period, but even the best mounts will have some degree of periodic error from the manufacturing process. There is also star drift to contend with which is due to not getting perfect polar alignment. A combination of PE and drift will limit exposures to a couple of minutes or less. To combat this and get longer exposures you can use a dedicated guiding system. There are a few different types of system, I use a cheap LIDL scope with a camera. Used along with guiding software, this will correct the mount for any movement of the guidestar.

Iancar29 · 23-10-2012 6:00pm

Tzetze wrote: »

Well the mount is motor-driven to rotate in a 24-hour period, but even the best mounts will have some degree of periodic error from the manufacturing process. There is also star drift to contend with which is due to not getting perfect polar alignment. A combination of PE and drift will limit exposures to a couple of minutes or less. To combat this and get longer exposures you can use a dedicated guiding system. There are a few different types of system, I use a cheap LIDL scope with a camera. Used along with guiding software, this will correct the mount for any movement of the guidestar.

Huh?.... so like you actually have 2 scopes then??? ... would it not be easier just doing a larger amount of shorter exposures to which DSS will then just align them up?

Tzetze · 23-10-2012 6:20pm

Iancar29 wrote: »

Huh?.... so like you actually have 2 scopes then??? ... would it not be easier just doing a larger amount of shorter exposures to which DSS will then just align them up?

Aye, 2 scopes. Yes, it would be a lot easier as you suggest because guiding is a whole nother headache to put up with, but it's worth working on it.
Here's the difference between 20x 120s unguided and 11x 600s guided...

M42 27/01/12 by .Tzetze., on Flickr

M42 21/10/12 by .Tzetze., on Flickr

M31 Revisited 13/10/12

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