Adam J

Better with less red?

Wanted to put this in here as 6-months back this is the thread that inspired me to get a 130-PDS and start out in astro-imaging.

Its been a month long project...for only three nights of images. But last night got 7 x 20min frames with the OIII filter. So for the last time this year (baring the inevitable revision) here is the witches broom. 16 x 180s CLS filter (RGB), 8 x 1200s H-alpha 7nm Baader 2" filter (Red), 7 x 20min OIII 8.5nm Baader 2" (Blue). 130PDS, HEQ5 Pro, QHY5L-II and 50mm finder guider, Baader MPCC MKIII Coma corrector, Canon 1000D Cooled to -3c with my custom cool box. Lots of hard work and staying up till 4am but I am really happy with it and think it was worth the effort.

Thanks for the inspiration guys.

Compression makes it look blurred click on it lol

My very first picture, about 6 months back now.

2 minutes ago, al-alami said:

Thanks Adam for all that   will definitely give it a try  and yes I have a Canon  one of the big things about the filters is it would mean that I can shoot at home from the roof (at least as far as I understand).

Let me put a question out there, I'm trying to work out which would be better for guiding my 130PDS, would a finderscope with a camera on it do? or should I go down the St80 route? I'm on a HEQ5.  Am still trying to choose a guider as well, leaning towards the QHY5 at the moment (even they have many different type of it as well)

I use the Orion 50mm finder guider with my QHY5L-II (pictured) it gets the job done just fine at the 130P-DS focal length. I mounted it to the back of the tube to get it to balance, it wont balance if mounted to the front of the tube. I eventually added a 33cm dove tale to move the center of gravity backwards further. I did need a noise piece extension to get focus mind you, Orion designed it with the older guide camera in mind. I have no guiding issues with it, in my opinion the ST80 is just adding more weight for no real guide quality advantage. I can run my setup with a single weight using the finder guider, it would need two with the ST80.

3 hours ago, al-alami said:

Hi Adam,

Honestly I've read all about this stuff, but of course reading isn't the same as doing. Temperature wise, hmmmm I guess as a ball part figure in the summer its in the 20-24 centigrade range at night, while in winter it can get into the minuses (but that isn't the usual). So I guess as I get better (and solve my mount issues and start guiding) then the long exposures will become a major problem because of sensor heat.   When I said mono ccd I am sort of  leaning towards the Atik 383L+ (if I can find the money).  My biggest problem with ccd is that I hope at one point to make large prints from the pictures so I would need a might megapixel one.  Also one of the reasons I am leaning towards the ccd (apart from the better quality and all that) is that I am finding it a real pain to focus through narrowband filters.  I can't see anything through the viewfinder or on liveview, so for the time being I've just put them on the side till i can work out how to do it.

Yes, focusing. I cant say that I have had an issue with that myself, which is not to say that it is easy. I use Backyard EOS and it lets you mess about with the live view settings lots more / integrate multiple exposures, so that its easier to see a bright star while using narrow band filters. You can download a one month trial for free.

I start by finding a bright star, say Alpha Lyra or similar. I then focus on it with no filter to get it around about right. I then lock the focusing tube off nice and hard. I remove the camera and place my 2" narrow band filter (OIII/H-A) 7nm onto the nose-piece. I then turn up the gain / integration Backyard EOS frame and focus to say 4x video frames and ISO1600 on live view and with the star centered on the view adjust using the Full Width Half Maximum (FWHM) tool.  7nm wide filters are the narrowest that this will work with, 12nm is much easier, astrodon 3nm would not be possible in my opinion (while using live view). Someone jump on me is I am wrong here but as I understand it you dont focus a CCD with live view or an equivalent. You have to take multiple short exposures and use a FWHM tool or a bahtinov mask. In general as I understand it focusing is a little harder with a CCD than with a DSLR.

I would try the free Backyard EOS trial to help you focus easier than with EOS Utility...i think I remember reading you have a canon...if not Backyard Nikon for Nikon cameras. If that will not work you could try a bahtinov mask on a bright star.

You will notice significant noise reduction between summer and winter by the sounds of it. Noise halves every 6-7c so a 21c drop in temperature would give you a noise reduction to about 1/8th of the original value and would let you do longer exposures with the DSLR making the narrow band filters worth while. But in summer, unless your willing to mod the camera with cooling the value of narrow band is questionable in my opinion, though I would still have a go in BYEOS though as you have the filters why not?

On 18/08/2016 at 07:05, al-alami said:

I need to get myself a nice mono camera, I think my 130PDS would greatly enjoy it

 

You asked about narrow band filters earlier in the thread in the context of your DSRL. I have had some good results recently using both Ha and OIII with my canon 1000D. Problem is that to get that to work well I had to cool my camera down to negative temperatures using a cool box, allowing me to grab low noise 20 min exposures. I am guessing that Jordan is pretty hot, even at night? What ambient temps do you get? The most important thing for you may be that CCD cameras are cooled as opposed to mono per say, although mono is almost always the way to go in my opinion. Personally I would not rush into CCD as there is always allot to learn at first and CCD' being a little more fiddly than DSLR (harder to focus, needs filter wheels etc) can actually get in the way of the learning process when you are starting out. Allot can be achieved with a DSLR given a little patience and good technique.    

http://www.astrobin.com/260459/

I use a MPCC mkiii with my 1000D. It will not remove chromatic aberration its not designed to do that...you should not have chromatic aberration with a Newtonian anyway. So assuming that you mean Coma? It will remove coma very effectively and I would not be without it. If you are seeing coma on images still after using it then its most likely that the spacing between the MPCC and the Dslr sensor is not correct (usually caused by the thickness of the T-ring which should be standardised), I am not sure how well it would work with a full frame Dslr though. I would say its better than the sky-watcher one also. 

On 07/05/2016 at 15:45, StamosP said:

It was simple, at first i rubbed the edges with 120grit sand paper and removed most of the leaked coating, then using a small painting brush i painted it flat black. The result was shinier than i wanted so i used a small piece of green scotchbrite to make it matte by rubbing the paint job lightly.

I also used a piece of dc fix velour to the back of the mirror...

The problem is that i cannot center the 58mm secondary under the focuser using my sight tube, the holder should be approximately 5mm shorter (or the offset smaller). Even if i screw it all way in it is obviously closer to the primary than it should be...

Any thoughts?

Is it possible that the secondary from the 150pds would be a better compromise or is that the same one as the 130 or something?

I removed my secondary a few weeks back only to find that the person who had installed it had left me with a dirty great thumb print on it.

On ‎02‎/‎05‎/‎2016 at 08:49, The Admiral said:

On ‎02‎/‎05‎/‎2016 at 08:43, Nigel G said:

I was told that DSS will remove satellite meteors and airplane trails so I leave them in now and it does ☺

I tried stacking rotation of stars around Polaris with my roof in the shot as a reference,  3 hours of continuous 30 second shots, camera on fixed tripod, DSS result was a fine image of Polaris and my chimney, no other stars at all in the image  so DSS removed everything that was not bolted down ☺☺

I did get the image I was after using another photo stacking program. 

Nige.

Thanks for that. I usually weed out the worst ones, then separately register using DSS, and select the highest scoring ones for stacking. I'm going to see what happens if I throw it all into DSS and let it munch its way through to the end.

Ian

I can 100% confirm that it will do this....mostly because if your tracking is so bad that the stars are more lines than points I know from experience that it will remove the star-line things too lol. Something from my very early days.

5 minutes ago, Galatic Wanderer said:

I guess if the focal length is different by 100mm it wouldn't make that much difference.  Btw nice pics of M81 an M82. What camera and scope did u use?

SEB

I actually said above in short hand, its a Canon 1000D DSLR, with the IR filter removed (astro-modifed) with the a 130PDS and a coma corrector, the image is slightly cropped. I see that you are in London, what is the light pollution like near to you? I imagine that you may be forced down the road of narrow band imaging...

M81 and M82 form Saturday evening, my first attempt at Galaxies, I found the processing to be much more difficult to get a pleasing result than I have with with clusters or Nebula.  Needed more data but my DSLR battery failed me at about 3am lol. 1000D (modified): Astronomic CLS clip filter, MPCC Mk3, 14 x 400s @ 1600ISO, 30 x Flats but no dark frames (because of the battery), I had to spend an hour manually removing the hot pixels lol.

7 hours ago, Galatic Wanderer said:

I've got the sky watcher 150PDS. Would the results be better or worse. 

As the F-Ratio is the same (F5) in both scopes it will not make too much difference, the actual focal is 650mm for the 130PDS and 750mm for the 150PDS, it will be ever so slightly harder to guide as it weighs a little more but this is probably offset by the fact that you sometimes have to add weights to the 130PDS to balance the tube anyway. So in the end it just depends on what it is you are taking pictures of, it will be better for some smaller targets but you may struggle to fit larger targets into the frame.

Funny thing I was looking at M44 too, this is my attempt.  5x600s, 1000D, Flats and Bias, Astronomic CLS Clip.

Just now, belfieldi said:

Sorry Adam, I meant the images before I tweaked the vanes. Can't be certain that this is the cause of your extra spikes, but it's only a couple of minutes to check and prove it one way or the other. 

Yeah will give it a go  thanks for the help.

1 minute ago, belfieldi said:

Just had a look at some of my images, the extra spikes are only evident on the brightest stars, slightly fainter stars appear to have the classic 4 diffraction spikes.

Do you mean current images or old images from before you tweaked the spider vanes?

1 minute ago, Starlight 1 said:

   I do not think its your spider vanes the rest of the Stars only have 4   Alnitak is a big Star doing this to your image.

It has not done it with other peoples images with similarly over exposed stars.

1 minute ago, belfieldi said:

Hi Adam,

 

Check that your spider vanes are not twisted, the vanes on my 130P-DS were slightly twisted when mine scope arrived and that caused the two extra diffraction spikes in my images.

Clear skies

Ian

Ian where they offset in angle like mine or parallel ?

Hey all, I just started out in this hobby and have a 130P-DS, I have taken a few pics so far and its seems to be going quite well, however.....

I have a problem with my diffraction spikes. At first I thought that it was an issue with focus but I have now totally discounted that.

Basically I have 6 and not 4 like I am supposed to. See pictures.