The "No EQ" DSO Challenge!

[Herzy]

16 minutes ago, parallaxerr said:

I DO already have an Alt/Az - the Nexstar SE. That's the point, I'm just having a go with what I've got!

That's what I suspected. Sorry, misread your post. Good luck! I'll go ahead and delete my post.

BTW, how has that mount been going for you? Is it stable? My old mount would always shake for some reason. That's not something inherent to alt/az, just something my specific mount suffered from.

Edited October 4, 2016 by Herzy

[parallaxerr]

Rock solid. I only mount small fracs up to 120mm on it which are well below the design payload. I have no concerns over stability.

[The Admiral]

46 minutes ago, parallaxerr said:

M31 is nicely positioned for me at the moment but I want to learn to walk before I can run! The double cluster in Perseus is one of my favourite visual objects and nicely positioned too so should be a good target to start with. Being brighter I hope to get away with less/shorter subs and test my hand at DSS.

Welcome Jon, I'm glad that you've come over to the 'dark' side! It is true that clusters tend to be easier because you are not dealing with feint nebulosity and you can get away with a shorter total exposure, but there are many clusters and only one M31 . My advice would be to give it a go while you have the chance; it is big and fairly bright, so in that respect it is probably one of the easier galaxies. And of course, provided that you get your subs, then you can re-visit as your processing skills improve. After a while you may feel that you can do better, so the next time it comes around you can be fully prepared.

Cheers, Ian

[The Admiral]

32 minutes ago, Herzy said:

BTW, how has that mount been going for you? Is it stable? My old mount would always shake for some reason. That's not something inherent to alt/az, just something my specific mount suffered from.

I find my Nexstar to be nice and stable with very little shake, and I'm putting 6-7kg of refractor/camera on it. I think though it is important to use the spreader and tighten well, and I don't extend the legs more than about 30cm/1 ft.

Ian

[SteveNickolls]

1 hour ago, parallaxerr said:

Hi everyone,

Well, I've just finished reading the contents of this thread and I must say I'm thoroughly impressed with the quality of images here! I never thought it would be possible to creat images like these with the sort of equipment being used, I have obviously been brainwashed by the EQ only crowd

I was pointed in this direction when @happy-kat put me onto @The Admiral after disussing something about my Nexstar SE mount in another thread (I forget exactly what, now). Having spoken to Ian via PM I found myself being gently encouraged to have a go at Alt/Az imaging.

So...this is to say hello and I hope to join the party soon, as I've placed an order for all necessary bits to get my camera on the end of a scope (highlighted blue below)!

My setup will consist of:

• Celestron Nexstar SE 6/8 mount
• William Optics Zenith Star 66SD doublet Apo
• Baader SCT to 2" click-lock
• Baader Multi Purpose Coma Corrector (proven to work rather nicely with the 66SD here - http://www.stark-labs.com/craig/WO66SD/WO66SD.html)
• Nikon T-ring
• Nikon D3200 DSLR

Here's to hopefully contributing my first images before too long and quizzing you all on exactly where I'm going wrong! Looking forward to this little foray into imaging!

Jon

A very warm welcome to you Jon, these are exciting times for imaging using Alt-Az equipment. The different cameras, telescopes and mounts used adds to the melting pot along with the different processing software used.

If you haven't already had a look at the book by Joseph Ashley, "Astro-photography on the Go Using Short Exposures with Light Mounts" it's well worth getting as he explains the advantages and limitations of lightweight mounts very well. Many of us have been able to get 60 seconds or more light frames to produce the images you have seen. As an introduction to imaging I don't think Alt-Az work can be beat and for a number of people it is the difference between reading about imaging and actually getting outside with a portable set up. You will soon know if imaging is for you.

Best Regards,

Steve

[Nigel G]

9 hours ago, Filroden said:

Hi Nige

This is a strange one. I can clearly see the green in the first image but the same effect is missing from the second. Did you change some of your processing steps between the two images?

One thing that jumps out at me in the first image is that it is the cores of the stars which are green. Their halos all seem to carry the correct colours (reds, whites and yellows). It's as if the cores are over-exposed and some process you've done in StarTools is highlighting/masking the star cores and affecting just them?

I had a play with the jpeg in both PixInsight and Photoshop. I couldn't do much with the star colours - I could reduce the green but I couldn't re-tone the stars. However, it has a great little tool that reduces star sizes and when I ran that, the Veil lifted! A little brightening in Photoshop later and ...

That's a lot of Veil you've captured there. Nicely done. I think it's quite a tough target even with long exposures.

One more thing springs to mind (and it's been mentioned a few times in the thread), could the colour issue be something to do with debayering and therefore to do with that initial setting in StarTools? Alternatively, is it a setting in DSS?

Ken, you have made a better job than I

both images were stacked the same, same flats, darks & bias, processed pretty much the same, subs were taken exactly same settings and m45 straight after ngc 6992.

I have done a screen grab from both just after first develop , the difference is incredible , 2 images could not be further apart. I'm trying different settings in DSS.

There's no difference if I check 1st or 2nd option in StarTools.

Any ideas folks.

I still can't see how they can be so different. No wonder I'm having trouble processing with images like this to work with.

Cheers

Nige.

 

Edited October 4, 2016 by Nigel G
help

[SteveNickolls]

Here's the results of imaging NGC 1499 (California Nebula) over the last two nights. I manged to take 90 images on Monday and 90 last night but heavy dewing resulted in only adding 35 light frames to those of Monday. Still 125 minutes of imaging albeit at quite low altitude range (between 14 and 30 degrees) and local light pollution. The images were taken with my Canon 600D DSLR, piggybacked on the Startravel 102mm refractor and Synscan Alt-Az mount. The images were taken at a FL of 200mm (ISO 800) and together with x50 bias and x50 flat frames were stacked in DSS and subsequently processed with StarTools. No dark frames were used.

Cheers,
Steve

[parallaxerr]

39 minutes ago, The Admiral said:

Welcome Jon, I'm glad that you've come over to the 'dark' side! It is true that clusters tend to be easier because you are not dealing with feint nebulosity and you can get away with a shorter total exposure, but there are many clusters and only one M31 . My advice would be to give it a go while you have the chance; it is big and fairly bright, so in that respect it is probably one of the easier galaxies. And of course, provided that you get your subs, then you can re-visit as your processing skills improve. After a while you may feel that you can do better, so the next time it comes around you can be fully prepared.

Cheers, Ian

Well there's a challenge if I ever heard one! You are very persuasive Ian I'm sure I'll be on M31 sooner rather than later!

Edited October 4, 2016 by parallaxerr

[parallaxerr]

32 minutes ago, SteveNickolls said:

If you haven't already had a look at the book by Joseph Ashley, "Astro-photography on the Go Using Short Exposures with Light Mounts"

Thanks for the welcome Steve, I'll look into the book, see if I can download it for Kindle.

 

Edit: That didn't take long!...

Edited October 4, 2016 by parallaxerr

[Filroden]

45 minutes ago, Nigel G said:

Ken, you have made a better job than I

both images were stacked the same, same flats, darks & bias, processed pretty much the same, subs were taken exactly same settings and m45 straight after ngc 6992.

I have done a screen grab from both just after first develop , the difference is incredible , 2 images could not be further apart. I'm trying different settings in DSS.

There's no difference if I check 1st or 2nd option in StarTools.

Any ideas folks.

I still can't see how they can be so different. No wonder I'm having trouble processing with images like this to work with.

Cheers

Nige.

 

Very odd indeed though my backgrounds typically start green and I let BackgroundNeutralisation and ColourCalibration work their magic. I think it works in a similar way to auto-fixing white balance. You show it a known area of neutral background (akin to picking a known grey shade in daylight photography) and it then balances the colours. I therefore wouldn't be worried about green backgrounds if they can be corrected in software.

However, to have two such very different results! The big difference between the two images is their altitude. M45 would have been low and in light pollution maybe (making it very red heavy before correction) and the Veil is very high. Maybe that's all it is?

In DSS, do you select the option in the stacking settings that balances the colours (think it's at the bottom of the first tab)?

[Nigel G]

4 minutes ago, Filroden said:

 

In DSS, do you select the option in the stacking settings that balances the colours (think it's at the bottom of the first tab)?

The align RGB Channels in final image is checked, yes

[Filroden]

I wonder if unchecking that option might make a difference?

[Nigel G]

10 minutes ago, Filroden said:

I wonder if unchecking that option might make a difference?

I'll give it a try.

[SteveNickolls]

28 minutes ago, Filroden said:

I wonder if unchecking that option might make a difference?

I think it may well change this for the better.

Cheers,
Steve

[The Admiral]

Nige, StarTools expressly doesn't want any colour correction performed by DSS. See p18 of the ST Manual. I think aligning channels is akin to colour balancing, so should be OFF.

These 2 vastly different backgrounds reminds me of when I was trying to sort out the the channel balance parameters for my non-supported, by DSS, Fuji RAWs.

Ian

[Nigel G]

I tried un checking the box.

Not much difference in it, if anything a little harder to reduce the noise level.

Hmm

[SilverAstro]

7 hours ago, The Admiral said:

It is true that clusters tend to be easier because you are not dealing with feint nebulosity and you can get away with a shorter total exposure, but there are many clusters and only one M31 .

Interesting that you should say that, there are indeed many globular clusters to be had, many of them are in M31 as well ! And within the range of No-Eq as your image has shown !! Wow

By coincidence, - when you posted your superb image of M31 I went looking for Hubble's Variable, more of that in a minute, and along the way I found these M31 Globulars :-

The numbers should all be prefixed with " G " and are the references used in Paul Hodge's "Atlas of the Andromeda Galaxy" :-  http://ned.ipac.caltech.edu/level5/ANDROMEDA_Atlas/frames.html , aided by Robert Gendler's excellent interpretation of it. :- http://robgendlerastropics.com/M31NMmosaicglobs.html

The above is just a wee sampling of loadsa them

 

Edited October 4, 2016 by SilverAstro
to add the Gendler link

[SilverAstro]

The Hubble saga continues :

I did not know much about Hubble's Cepheid Variable apart from that he had found one (V1) in M31, thus was able to measure the distance  to M31  and demonstrate that the "nebulae" were in fact distant galaxies, leading eventually to the Hubble Constant.

Wouldnt it be fun if all that could be done with an AltAz I thort ? So off I went a'Googling ,  and many fuzzy drawings and pictures later I found this amateur (John Taylor)  site who has been after it as well :- http://cloudedout.squarespace.com/blog/2016/3/23/hubbles-cep

 I could not see any trace of it in Ian's pic and wondered if it was coincidentally not at max. however sadly it turns out that it is a measly mag18 at max a bit of a challenge !

Here is a blink of the location on Ian's pic with a snip from John Taylor's site :-

Edit : Oooops, I've removed the blink because (a) JT on his site says copyrighted and whilst I think it is ok to use snips like one would a quote I dont want to offend anyone ! and (b) Ian and I are both agreed that he has not (yet ) recorded V1 at the position JT has indicated.

 

Quite a remarkable agreement between the two views and you know, is it my fancy, or fortuitous pixel of noise, or maybe a suspicion of a V1 there ? ? Might need a few more efforts like that over the next few months Ian  

 

Edited October 5, 2016 by SilverAstro

[SilverAstro]

On 03/10/2016 at 07:40, Filroden said:

Yes, I lived in Somerset until August. I moved North so my skies are very different.

Ah ! That explains it !! I used to use you and Gina's contemporaneous (sp?!) imaging reports/4casts as fair warning of me needing to be outside - - recently unreliable !! I dont recollect you asking permission to emigrate

[The Admiral]

9 hours ago, SilverAstro said:

Interesting that you should say that, there are indeed many globular clusters to be had, many of them are in M31 as well ! And within the range of No-Eq as your image has shown !! Wow

By coincidence, - when you posted your superb image of M31 I went looking for Hubble's Variable, more of that in a minute, and along the way I found these M31 Globulars :-

The numbers should all be prefixed with " G " and are the references used in Paul Hodge's "Atlas of the Andromeda Galaxy" :-  http://ned.ipac.caltech.edu/level5/ANDROMEDA_Atlas/frames.html , aided by Robert Gendler's excellent interpretation of it. :- http://robgendlerastropics.com/M31NMmosaicglobs.html

The above is just a wee sampling of loadsa them

 

Thanks for that very interesting reply SA, though I confess to liking my globulars resolvable (that sounds rude, I don't know why!). And as to V1, I think your brain is deceiving you! It would indeed be remarkable to see it, though when I've more time later today I will just check out the tiff and see what gives. Pointless may be, but leave no stone unturned!

Ian

[parallaxerr]

Scope balance/weighting.

Guys, when seting up for Alt/Az imaging, are you biasing the weight of OTA and camera one way or another? I have read the EQ guys weight towards the East, I'm guessing to keep the mount geartrain loaded in the direction of tracking.

Thus, I assume biasing the weight toward the objective end is preferable as the Alt axis is driving up when pointing East? Would you bias toward the rear when pointing West?

[Filroden]

Well, you asked for something in red...

Here's my limited attempt at NGC281, Pacman Nebula. It rose above my mount's altitude limited very quickly (I'd not taken into account my cables so by 21:10 it was already too high at about 59deg). Still, I got 24 mins of L and between 11 and 12 mins each of RGB. To try and compensate I created a super luminous frame using data from L and RGB. It was a little better than L on its own, so I went with it.

Anyway, here's my attempt, including an annotated version.

It's a little noisier than I'd like but I can't complain for 24 mins of L data. Hopefully I can get another clear night before the moon comes up and it rises above my limit.

And just for Ian, a cropped version with some minor Photoshop tweaks.

[SilverAstro]

3 hours ago, The Admiral said:

but leave no stone unturned!

Absolutely ! We often comment about the gear that is now available to the umble amateur and remarkable comparisons with images by famous astronomers ( and their institutions) of yesteryear. But wouldnt it be great if we could detect the expansion of the universe from our back yards with an AltAz,  that is what set me off on my quest , , , well actually it was your amazing pic wot done it really !

May your thingies always remain resolvable

PS Thinks, didnt note what magnitude those globs were , , , > >

Edited October 5, 2016 by SilverAstro

[Nigel G]

2 hours ago, parallaxerr said:

Scope balance/weighting.

Guys, when seting up for Alt/Az imaging, are you biasing the weight of OTA and camera one way or another? I have read the EQ guys weight towards the East, I'm guessing to keep the mount geartrain loaded in the direction of tracking.

Thus, I assume biasing the weight toward the objective end is preferable as the Alt axis is driving up when pointing East? Would you bias toward the rear when pointing West?

Hi.

I balance my kit slightly top heavy, this seems to keep the mount nice and steady. The mount is then always driving the scope, I don't have a good view to my west due to London and surrounding areas being in that direction.  If my target was west I would balance slightly bottom heavy for the same reason.

I have a newtonian reflector. 

Hope this helps 

Nige.

[SteveNickolls]

3 hours ago, parallaxerr said:

Scope balance/weighting.

Guys, when seting up for Alt/Az imaging, are you biasing the weight of OTA and camera one way or another? I have read the EQ guys weight towards the East, I'm guessing to keep the mount geartrain loaded in the direction of tracking.

Thus, I assume biasing the weight toward the objective end is preferable as the Alt axis is driving up when pointing East? Would you bias toward the rear when pointing West?

Interesting point, my quick answer would be that it doesn't seem to matter much practically as Alt-Az mounts are quite rugged. I'd always previously tried to balance my equipment (an EQ mount) as told I should but when (ahem) I upgraded to the Synscan Alt-Az and Startravel refractor it was nigh on impossible to balance things as I thought was needed, instead with everything connected the equipment is back heavy. I think this may actually help in adding some inertia into the system resisting slight wobbles and indeed I have been able to get the mount to track very well for over 60 seconds for what is otherwise quite a light weight set up. I recall reading Joe Ashley having thought along a similar line. When I use the camera piggybacked on the OTA I alter the centre of balance yet again but have not noticed any fall off in performance. Perhaps the best thing is to experiment and let us know how you get on?

Cheers,
Steve

Edited October 5, 2016 by SteveNickolls