Gerry Casa Christiana

53 minutes ago, alacant said:

You have the mount, yes? This one has a rigid aluminium tube, a decent fat focuser and a secondary sized for AP. The SW doesn't;)

HTH

Yes the secondary on the SW is 65mm? Or 60 I forget. Better for planets. Yes I have eq6. Do you have this scope Alacant? 

Hello all

Just a quick question. I'm looking to upgrade my scope to a 10" but F5 Newtonian. Just wondered if I missed any online apart from Skywatcher GSO Orion. I've kind of been hoping for a carbon fibre but they tend to be expensive. I was also considering building one but that seems just as expensive. 

Any options I've missed? I would like to spend under 900 quid if possible. 

Cheers 

Gerry

1 hour ago, moise212 said:

https://www.cloudynights.com/topic/1429-rayleigh-limit-dawes-limit/

So 138 divided by diameter of telescope in mm  

1 hour ago, Uranium235 said:

Use the telescope capability calculator found here:

https://astronomy.tools/

All you need to do is punch in the aperture size and it will tell you the limits for your telescope.

Ah that. The pixel resolution of camera and scope. Just lost me with the Rayleigh didn't realise that was the tee for resolution of the telescope.  

11 hours ago, Uranium235 said:

Now properly calibrated:

Still a bit noisy, but what do you expect for just over 1 hr exposure! Its alright, but its not a miracle worker...lol

BTW: This was shot at just beyond the Rayleigh limit of the telescope (0.85" p/p)

Great shot. Can I ask how do you work out the Rayleigh limit for a given telescope. Go on tell me to get on my bike  Thanks Gerry

On 19/03/2018 at 15:08, alacant said:

Hi everyone. It was nice getting back to the sw130 having been working with a sw250p for the up and coming galaxies. It also shows how stable it is; wind -even gentle gusts- are enough to ruin frames in the 250 whereas the 130 is barely affected. Clusters in the wind:

m44

ngc2281

m46-m47

Thanks for looking and clear skies.

Blues looking good! 

49 minutes ago, vernmid said:

OK...I'm sold...Thank you

 

Will do. Many thanks.

So now I know what I'm doing this weekend! Will post hopefully successful results

Obviously longer exposures with guiding make a big difference too. Also I wasn't using flats in those days BUT I know for example the California nebula I could barely see it last year. Now it's easy. 

1 hour ago, vernmid said:

Hi John,

Do you have a before and after picture? I am about to pull the filter from my 350d and replace it with a Baader but keep loosing my nerve! Is the difference really noticeable? 

Thanks

Vern

 

Nice Horsehead BTW :-)

Same setup from last year except guiding and camera modded. I've noticed a very big difference personally especially in the h Alpha objects. 

4 hours ago, Stub Mandrel said:

Photoshop makes it very hard to work with split images, it's much easier in photoshop which has simple commands to split to various sets of channels and automatically recombine them.

 

You may need to change the mode to grayscale first.

Yes transparency is done with a slider when the layer is highlighted in the layer manager.

You need to:

Paste Ha on top of RGB

Select Ha layer

Set transparency

Zoom in

Choose transform tool

Align the same star on both images at (say) stop right.

Enable free transform (edit menu)

Reposition the rotation centre (little crosshair at centre of image) on top of the aligned star (can take a while to find them when zoomed in!)

Pan to opposite corner

Type in different rotation amounts until the images register (you can go down to 0.05 degree in PS2, which is about good enough)

Choose another tool and apply the transformation.

Remove the transparency and set the mode to luminance. Adjust transparency to get the effect you want.

 

To blend Ha only with the red layer you would split to RGB, do that on the red image, then recombine them.

 

Tried all of that but no success. I think I ruined the collimation on the night when doing a star test. So the stars won't actually line up at all! Lesson learnt!

1 hour ago, Stub Mandrel said:

Photoshop makes it very hard to work with split images, it's much easier in photoshop which has simple commands to split to various sets of channels and automatically recombine them.

 

You may need to change the mode to grayscale first.

Yes transparency is done with a slider when the layer is highlighted in the layer manager.

You need to:

Paste Ha on top of RGB

Select Ha layer

Set transparency

Zoom in

Choose transform tool

Align the same star on both images at (say) stop right.

Enable free transform (edit menu)

Reposition the rotation centre (little crosshair at centre of image) on top of the aligned star (can take a while to find them when zoomed in!)

Pan to opposite corner

Type in different rotation amounts until the images register (you can go down to 0.05 degree in PS2, which is about good enough)

Choose another tool and apply the transformation.

Remove the transparency and set the mode to luminance. Adjust transparency to get the effect you want.

 

To blend Ha only with the red layer you would split to RGB, do that on the red image, then recombine them.

 

I'm going to try it! Thanks! 

19 hours ago, Stub Mandrel said:

In recommended settings choose 'super pixels' this switches off debayering so red won't be affected by green and blue channels. This is so you can easily separate it later by splitting the final image into RGB layers and 'losing' G and B. It will be 1/4 the size of a normal DSLR image (1/2 as wide, 1/2 as tall).

Stack as normal. Open photo editor and split channels to RGB, be surprised how much detail is in the G & B channels, but delete them and save R as a mono TIFF.

If you later stack RGB data to provide colour to go with it you can use super pixel mode to get a colour image the same size to combine with it.

I'm having problems (maybe because I didn't use super pixel mode) to save in mono. When I delete the green and blue channels it won't let me save in anything except a PSD file. There is no option for tiff. I'm using CS2. 

I'm also having problems when I copy and paste the rgb onto h Alpha. They don't line up perfectly and I see rotate but it needs fine adjustments. Is there also a transparency option so I can see through one picture to another? Sorry for the questions. Maybe I should do it on a separate thread. Only if you have a quick answer  

Hello all. 

Did some frames in H Alpha on my dslr last night for the first time. Any way in particular to stack in DSS? I did flats and bias. 

Thanks

Gerry

Can I ask how you actually remove the tube. Is there a screw? 

Thanks!

Gerry

http://www.sensorgen.info/CanonEOS-1100D.html

in fact if you look at the read noise for your camera you can get away with bumping up the ISO. Try it you will be suprised by the results. Yes I know about losing dynamic range but in the beginning I got pictures like this with no guiding and no modification. 

On 01/01/2017 at 17:25, Peco4321 said:

Got my motors fitted now and had a brief go the other night and this is a 30 or 45 sec single exposure ISO 400. Next time I'm going to have a go at getting more and do some stacking. Apologies for the circle, I have this facebook thing going with all my friends were I dedicate a picture of something in the universe that reminds me of them, this is for my niece who is on an Equine course at university, so I needed to show where the HH is. 

Other objects I have dedicated so far for friends:

Kanes crater on the moon for a colleague called Kane

Carolines cluster near Caseopiea for a friend called Caroline!

The running man Nebula for a friend into cross country fell running 

The fishes Mouth of Orion Nebula for 2 friends into fishing 

The Alpine region of the moon for my brother who runs his own ski holiday business 

The Ring Nebula for a friend who forgot the wedding rings at his own wedding  

Capella for family who live near Rotterdam in a place called Capella a/d Ijssel  

I find this facebook thing of mine a good way of getting some info out to people who otherwise would never know what's up there.  Maybe it's a bit self indulgent of me, but friends seem to like it ?  

 

As your doing shorter exposures. I would bump up the ISO to at least 1600 you could even try 3200 a lot of my pictures in the beginning on a non modified camera were like that. Yes you get more noise but with processing you can sort it out. 

Can I ask what constitutes widefield. Thanks 

Gerry

Still good!  The next time check your focus a little more. You have double defraction spikes which is usually just being slightly off focus.  

All the best 

On 05/11/2017 at 00:20, Uranium235 said:

Just revisiting some old 130pds data with 2017 processing methods, hard to believe just 80min of Ha went into this

 

Hello 

Can I ask did you use oxygen for the blue as well? Great picture I want to revisit it because I tried without guiding and hope to get a better result. 

Does that mean I need to choose Kappa Sigma Clipping for lights or just Bias and Darks?

Thanks 

Gerry

Just to say to all that last night I auto guided for the first time. I do have to be honest though and say it took me 3 hours to work with PHD2 and then the line graph jumped over all the place. Not sure if it was right but I managed 4 subs of 420 seconds of the Markarian Chain and the stars seem perfect. Hopefully it's right. The only problem I have now is meteorites! Anyway I hope that guiding is not always going to be long winded. Thanks for all the help. If you know of the settings for PHD2  let me know. 

Gerry 

4 hours ago, carastro said:

I know nothing about statistics, I just do what works.  The skywatcher finderscope on your 150PDS will work OK as a guidescope, I had one and that's what i used.  No need to buy a guidescope and worry about how to mount it.  Just need a guide camera and the relevant  finderguider adapter.  

If FLO can't help I know a retailer who does them but as they are Sponsors of this site I should not post up another retailer.  

Image I did with it.  Bright stars are a bit squiffy as the focusser protruded into the  tube too much as it was the 150P version.  N.B.  These are 900sec subs, so you can see the guiding was OK. 

Carole 

Yes your absolutely right I just had trouble getting the adapter as mine is 30mm in diameter. 

Thats a great picture. What is it? I wouldn't mind trying that myself but it looks like you used h alpha and sii? I don't have any filters like that yet. 

Gerry 

On 05/05/2017 at 21:07, SonnyE said:

Thanks Olly.

The inherent curiosities with reflectors as a whole was what turned me away from them originally.

And in looking towards a telescope as an actual lens for imaging is how I landed in a Refractor as my choice.

Put simply, I suppose I'm Galilean. Less to go wrong = more to enjoy.

God willing I too would like a nice apochromatic refractor but as I'm new to it I want to get the most out of what I have.

Hello all

Well I have got my guide scope. I went with the qhy mini guide scope. In the end I got it from Modern Astronomy http://www.modernastronomy.com/shop/accessories/qhy-accessories/qhy-miniguidescope-kit/

Really good people I got mine delivered from the Uk to Italy in one day! I would have bought it from FLO if they had it. 

Well does it work do you ask? I've had it a week now at least but the moon! and now it's been raining! So I'm still waiting. I blame global warming and every person with a 4x4  just kidding. Yes just going to have to be patient. Not my greatest talent. 

I'll post my results when I get it going. 

Gerry

It's useful for those who want to do Astrophotography  and especially long exposures as usually the mounts themselves do track but depending on the mounts accuracy you might get 2 minute exposures like on mine. With the autoguider you add it so the accuracy of the mount can be kept perfectly centred on your star. So it makes small adjustments for you. 

The 1:3 focal length is no longer necessary as computers have come a long way and that is now out of date. 

So a small scope with a mono webcam is sufficient. Very basically speaking! 

Kind regards

Gerry

I just had delivered a QHY mini guide Scope. I intend to try it tonight if the sky is clear but thanks!